The biennial TAUP series covers recent experimental and theoretical developments in astroparticle physics by invited plenary review talks and parallel workshop sessions of invited and contributed presentations. The purpose of TAUP is to bring together theorists and experimentalists working in Astroparticle Physics, to review and discuss the status and prospects of the field. TAUP consists of invited review talks, workshop sessions devoted to specific subjects and poster sessions.
Topics covered by the conference are:
The Conference is sponsored by IUPAP/ApPIC. Attendance is by invitation.
Overview, REcent Experimental Results, LIGO
Increasingly stringent limits on supersymmetry at the LHC and null results from direct and indirect detection are spurring wide-ranging discussions of theoretically well-motivated directions for novel dark matter searches. I will discuss recent developments in dark matter theory, covering a wide range of possible dark matter candidates and mass scales, and their interplay with cosmology and experimental probes of dark matter.
The talk summarizes general features of mechanisms that generate neutrino mass. The impact of current neutrino data on models for lepton mixing is discussed. Typical examples for new physics in neutrino experiments are given. A general prediction of almost all mechanisms for neutrino mass is the presence of neutrinoless double beta decay. The physics potential of this process is presented, both in the standard approach of light Majorana neutrino exchange, as well as in non-standard scenarios.
After the ground-breaking detection of gravitational waves from a couple of merging binary black holes in the first Advanced LIGO observing run, there is still a great deal to be learned about the population and astrophysics of gravitational-wave sources. I will share the latest news from the second observing run of the Advanced LIGO detectors, including the recently published event GW170104, and the picture we are starting to get of the masses and spins of merging binary systems.
I will also give a brief update on the status of the other ground-based gravitational-wave detectors which will join LIGO over the next few years, as well as pulsar timing campaigns and the LISA space mission.
"Underground" is getting more and more important for
researches with very low event rate. I will give a
overview the science that are carried out in underground.
XENON1T, the largest xenon TPC ever built, is performing the most sensitive direct search for WIMP dark matter on earth. As xenon TPCs become larger, long drift times and extreme fidelity requirements challenge the data acquisition, processing, and modeling. This talk explores how XENON1T dealt with these challenges for its first results, and what this implies for XENON1T's future physics prospects. (The results themselves are discussed in prof. Lindner's talk.)
PandaX experiment, located at China JinPing underground Laboratory (CJPL), is a 500kg scale liquid xenon dark matter direct detection experiment. With the first 98.7-day data, PandaX-II experiment obtained stringent upper limits on the spin-independent (SI) and spin-dependent (SD) WIMP-nucleon elastic scattering cross sections. Alternative models of dark matter are also explored using this data. Meanwhile, PandaX collaboration has launched an upgrade plan to build PandaX-4T detector with 4-ton liquid xenon in the active volume. The PandaX-4T experiment will be relocated to CJPL-II and is expected to run after 2020. Detailed simulation indicates that the sensitivity on SI WIMP-nucleon scattering cross section could reach 6x10^{-48} cm^2 after two-year's running.
A search for dark matter was conducted by looking for an annual modulation signal due to the Earth's rotation around the Sun using XMASS-I detector at Kamioka. It is a single phase Xe detector with 832 kg surrounded by low radioactive 642 PMTs with a water tank for cosmic muon veto. The detector has been performed satiable operation over 3 years with a very high light yield of 15 photoelectron/keVee. In this presentation, a new result with 1keVee energy threshold will be shown with 800 live days x 832 kg exposure in total by adding about 450 live days to previous result in 2016.
DEAP-3600 is a dark matter WIMP (Weakly Interacting Massive Particles) search experiment, which aims to detect nuclear recoils from WIMP scattering in an argon target located $2$ km underground at SNOLAB. At WIMP masses of $100$ GeV, DEAP-3600 has a projected sensitivity of $10^{-46}$ cm$^{2}$ for the spin-independent elastic scattering cross section of WIMPs. The beta emissions from the intrinsic $^{39}$Ar present in the natural Ar target, as well as external calibration sources, can be used to understand the detector energy response and position reconstruction in the energy region of interest for WIMP signals. This talk will present the techniques and results of the energy response and position reconstruction calibration in DEAP-3600.
The DEAP-3600 experiment is searching for dark matter with a single phase liquid argon (LAr) target, located at SNOLAB. For a background-free exposure of 3000 kg$\cdot$yr, the projected sensitivity to the spin-independent WIMP-nucleon cross section at 100 GeV/c$^2$ WIMP mass is 10$^{-46}$ cm$^{2}$.
The experimental signature of dark matter interactions is keV-scale argon recoils producing 128 nm LAr scintillation photons which are wavelength shifted and observed by 255 PMTs. To reach the large background-free exposure, a combination of careful material selection, passive shielding, active vetoes, fiducialization and pulse shape discrimination (PSD) is used. The main concept of the background rejection in DEAP is the powerful PSD, employing the large difference between fast and slow components of LAr scintillation light. Discrimination of electronic and nuclear recoils on the order of $10^{10}$ can be achieved, which is sufficient to successfully reject $^{39}$Ar beta-decays with a specific activity of 1 Bq/kg in argon with natural isotopic composition.
The designed background level of DEAP-3600 is less than 0.6 events in a 3000 kg$\cdot$yr exposure. The experiment was filled in November 2016 and is currently taking dark matter search data. This talk will report on the measured background levels in DEAP based on first data.
DarkSide uses dual-phase Liquid Argon Time Projection Chambers to search for WIMP dark matter. The current experiment, DarkSide-50, has a 50-kg-active-mass TPC surrounded by a borated-liquid-scintillator neutron detector and a water Cherenkov detector. DarkSide-50 has been running continuously since 2013, initially with atmospheric argon and then, starting in mid-2015, with argon from underground. The underground argon (UAr) is measured to contain lower Ar-39, the largest source of background, than atmospheric argon by a factor of >1000. After initial analyses of 50 live-days of atmospheric argon and 70 live-days of UAr, we have now collected 500 live-days of additional WIMP search data with UAr. This is being analyzed in a blind analysis. The proposed next stage of the DarkSide program is DarkSide-20k, a 20-tonne fiducial mass TPC designed to have background well below that from coherent scattering of solar and atmospheric neutrinos.
One technology being examined for future direct dark matter searches is a
single-phase noble liquid detector. The MiniCLEAN experiment is a test of
such an approach, using liquid argon to search for WIMPs via nuclear
recoils. The detector, located at SNOLAB, will have a 500 kg (150 kg)
target (fiducial) mass and is instrumented with cold photomultiplier
tubes. Pulse-shape discrimination will be used to reject the large Ar-39
radioactive background. The CLEAN design allows the argon target to be
exchanged with neon, meaning that a potential signal can be checked via
the dependence on nuclear mass. MiniCLEAN will also be run with an
enhanced Ar-39 "spike" to demonstrate the pulse shape discrimination
capability. An update on the commissioning status of the experiment will
be presented.
Parallel Neutrino Talks
A review of the theory and phenomenology of neutrino electromagnetic properties is presented. A massive neutrino even in the easiest generalization of the Standard Model inevitably has nonzero electromagnetic characteristics, at least nonzero magnetic moment. Although its value, determined by the neutrino mass, is very small, in other BSM theories much larger values of magnetic moments are predicted.
A discussion on a derivation of the general structure of the electromagnetic interactions of Dirac and Majorana neutrinos is given. Then we discuss experimental constraints on neutrino magnetic and electric dipole moments, electric millicharge, charge radius and anapole moments from the terrestrial laboratory experiments. A special credit is done to bounds on neutrino magnetic moments obtained by the reactor (MUNU, TEXONO and GEMMA) and solar (Super-Kamiokande and Borexino) experiments.
A thorough account of electromagnetic interactions of massive neutrinos in the theoretical formulation of low-energy elastic neutrino-electron scattering is discussed on the basis of our recently published paper [2]. The formalism of neutrino charge, magnetic, electric, and anapole form factors defined as matrices in the mass basis with account for three-neutrino mixing is presented.
The effects of neutrino electromagnetic interactions in astrophysical environments are also reviewed. The main manifestation of neutrino electromagnetic interactions, such as: 1) the radiative decay in vacuum, in matter and in a magnetic field, 2) the Cherenkov radiation, 3) the plasmon decay, 4) spin light in matter, 5) spin and spin-flavour precession, 6) neutrino pair production in a strong magnetic field, and the related processes along with their astrophysical phenomenology are also considered.
The best world experimental bounds on neutrino electromagnetic properties are confronted with the predictions of theories beyond the Standard Model. It is shown that studies of neutrino electromagnetic properties provide a powerful tool to probe physics beyond the Standard Model.
References
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[10] V.Cirigliano, G.Fuller, A.Vlasenko, “A new spin on neutrino quantum kinetics”, Phys. Lett. B 747, 27 (2015).
[11] C.Volpe, “Theoretical developments in supernova neutrino
physics : mass corrections and pairing correlators”, Int. J. Mod.Phys. E 24, 1,541,009 (2015).
[12] A.Kartavtsev, G.Raffelt and H.Vogel, “Neutrino propagation in media: Flavor, helicity, and pair correlations”, Phys. Rev. D 91, 125020 (2015).
[13] A.Dobrynina, A. Kartavtsev and G. Raffelt, “Helicity oscillations of Dirac and Majorana neutrinos”, Phys. Rev. D 93 (2016) no.12, 125030.
A minimal extension of the electroweak standard model with a massive neutrino allows a non zero magnetic moment, with the neutrino magnetic moment proportional to the neutrino mass. The experimental evidence from solar, reactor, atmospheric and accelerator neutrinos has demonstrated that neutrinos are massive, and may thus possess a non-null magnetic moment.
The limits of the effective magnetic moment of Solar neutrinos can be obtained studying the deviations from the standard shape of the electon recoils in neutrino-electron scattering. Recent improvements of the description of the Borexino energy scale allowed to include the low energy part of the neutrino spectrum in the analysis, namely the pp-neutrino contribution, improving significantly the sensitivity to the non-standard contributions in the weak nu-e scattering. Applying independent constrains on the neutrino fluxes from the radiochemical experiments, we obtain the best up-to-date limit of the effective magnetic moment of Solar neutrinos.
The studies on neutrinos and dark matters rely on the direct detection with detectors composed by pure atom or crystal. As current experimental searches for neutrinos and dark matters have lowered the detector threshold down to the sub-keV regime [1, 2], accurate many-body calculations for atomic ionization are warranted for giving reliable results of experimental comparisons. With the benchmark of comparisons with photoionization data [3] and analytic hydrogen calculations [4, 5], we perform ab initio many-body methods [6-9] to show how atomic effects modify the cross sections of neutrino or dark matter scattering with electrons in Ge, Xe and other targets within 5-10% accuracy [10-12]. In this presentation, we apply these methods to study low-energy electronic recoil caused by solar neutrinos in multi-ton xenon detectors [13], which is an important subject not only because it is a source of the irreducible background for direct searches of weakly-interacting massive particles (WIMPs), but also because it provides a viable way to measure the solar pp and 7Be neutrinos at the precision level of current standard solar model predictions.
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Since the discovery of neutrino oscillations in 1998 and the assessment of the Mikheev-Smirnov-Wolfenstein (MSW) effect, steady progress had been made in understanding neutrino flavor conversions in astrophysical environments. Neutrino self-interactions have proven to complicate the problem, making the evolution equations intrinsically nonlinear, and have triggered a decade of theoretical investigations. A variety of flavor instabilities has been uncovered, depending on the physical conditions and the geometry of the environment considered. In anisotropic media, the most general mean-field equations include corrections to the relativistic limit, due to the nonzero neutrino mass. This contribution creates a coupling between neutrino and antineutrino referred as helicity or spin coherence.
In this talk, we focus on the progress made in neutrino flavor evolution in astrophysical environments, and we discuss the effects of helicity coherence on propagation in binary neutron star mergers and core-collapse supernovae [1]. Such studies are crucial to assess the actual impact on the supernova dynamics and on the nucleosynthetic abundances.
[1] A. Chatelain and C. Volpe, "Helicity coherence in binary neutron star mergers and nonlinear feedback", Phys.Rev. D95 (2017) no.4, 043005, arXiv:1611.01862 [hep-ph].
Nonzero neutrino masses are required by the existence of flavor oscillations, with values at least of the order of 50 meV. We consider the gravitational clustering of relic neutrinos with minimal masses at the Earth neighborhood, where their number density is enhanced with respect to the average cosmic density. The local overdensity is found using N-one-body simulations, including an improved treatment of matter distribution in the Milky Way, both baryonic and dark matter. Our results could be interesting for future experiments aiming at detecting the relic neutrino background, such as the PTOLEMY project.
Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously. Recently, this process has been attracting attention both theoretically and experimentally. Natural xenon contains the double electron capture nuclei 124Xe with an abundance of 0.095%. Even two-neutrino mode has not been observed for the nuclei so far. The XMASS program is designed for multiple goals in particle and astroparticle physics using liquid xenon. We performed a search for two-neutrino double electron capture in a limited fiducial volume using 132 days of the commissioning data and set the most stringent limit on the half-life as 4.7E21 years. Owing to the detector refurbishment after the commissioning, we could increase the fiducial volume for this analysis by a significant amount, and hence more sensitive search is possible. In this talk, we will present a new result from 2 years of the XMASS data.
XENON1T, widely known as the next step in the challenging hunt for direct dark matter detection, provides the possibility for the study of interesting physics beside its main purpose. One promising example for this is the search for different beta decay modes of $^{124}$Xe. Here the process of Two Neutrino Double Electron Capture (2$\nu$DEC) is the first one to look for as it is predicted by the Standard Model and is favored compared to any process involing the creation of positrons (e.g 2$\nu$EC$\beta^+$, 2$\nu\beta^+\beta^+$). However, an observation of this decay would be the first direct evidence for this decay mode, since so far there is only an indication for $^{78}$Kr and an indirect observation for $^{130}$Ba. The detection for $^{124}$Xe would shed light on uncertainties coming from nuclear matrix element(NME) calculations and can help to distinguish the viability of different NME determination methods.
For $^{124}$Xe there is only a lower limit on the half-life set by the XMASS experiment at 4.7$\times$10$^{21}$ yrs. A previously conducted search using the XENON100 data showed the possiblity of the XENON detectors to search within this region due to the advantageous low background. For XENON1T the background around the signature of this decay at around
64 keV has been improved by more than one order of magnitude and combined with the large mass of the detector (>1 ton fiducial) it will be the most sensitive detector in the world and has a fair chance to find the 2$\nu$DEC. Since the data used for this search is the same as for the dark matter run, there has been data acquired since November 2016 and the results of this data set will be shown within this contribution. The work of the contributor is supported by BMBF under contract number 05A14PM1 and DFG (GRK 2149).
A new type of particle detector which combines the advantages of liquid noble TPCs and superheated bubble chambers has been for the first time demonstrated with a 30-gram prototype scintillating liquid xenon bubble chamber operated at Northwestern University. The new technology has the potential, which is the aim of current ongoing work, to be virtually only sensitive to nuclear recoils at thermal noise limited thresholds. We have observed simultaneous bubble nucleation and scintillation by nuclear recoils in liquid xenon with the prototype chamber. The observed single- and multiple-bubble rates when exposed to a ${}^{252}$Cf neutron source indicate that, for a thermodynamic `"Seit" threshold of 8.3 keV, the minimum nuclear recoil energy required to nucleate a bubble is between 11 and 25 keV. This is consistent with the observed scintillation spectrum for bubble-nucleating events. We see no evidence for bubble nucleation by gamma rays at the thresholds studied, setting a $90\%$ CL upper limit of $6.3\times10^{-7}$ bubbles per gamma interaction at a 4.2-keV thermodynamic threshold. This indicates stronger gamma discrimination than in $\mathrm{CF_3I}$ bubble chambers, supporting the hypothesis that scintillation production suppresses bubble nucleation by electron recoils, while nuclear recoils nucleate bubbles as usual. This chamber is instrumented with a CCD camera for near-IR bubble imaging, a solar-blind PMT to detect 175-nm xenon scintillation light, and a piezoelectric acoustic transducer to detect the ultrasonic emission from a growing bubble. The neutron and gamma measurements establish the noble-liquid bubble chamber as a promising new technology for WIMP and CE$\nu$NS detection.
Weakly Interactive Massive Particles (WIMPs) are among the most favored Dark Matter candidates.
As the Solar System moves through Dark Matter halo, the WIMPs may scatter on the nuclei in the
Sun/Earth, lose energy, and get trapped by their gravitational potentials. Their capture and subsequent
annihilations in the core of the Sun/Earth may subsequently give rise to neutrinos, through various annihilation channels.
We look at the possibility of detection of such neutrinos at INO (India-Based Neutrino Observatory),
which will house a 50-kt Iron Calorimeter (ICAL) detector. Detection of these neutrinos and studing their
properties would help us to reconstruct nature of light Dark Matter.
In the present analysis, we give an estimate of the muon events at the detector due to WIMP
annihilations in the Sun and the Earth; 10 years of ICAL running. For our work, WIMP masses upto 100 GeV have been considered.
The atmospheric neutrinos in GeV range will pose background to the signal neutrinos. However, exploiting
the excellent angular resolution of the ICAL detector, the background can be suppressed considerably. We
also perform a $\chi^{2}$ analysis to obtain 90\% upper limits on Spin-dependent and Spin-Independent WIMP-nucleon cross sections.
The Axion is a hypothetical low-mass boson predicted by the Peccei-Quinn mechanism solving the strong CP problem. It is naturally also a cold dark matter candidate, thus, simultaneously solving two major problems of nature. All existing experimental efforts to detect QCD axions focus on a range of axion masses below 20 ueV. The mass range above ~40ueV, preferred by models in which the Peccei-Quinn symmetry was restored after inflation, could not to be explored so far.
The MADMAX project is designed to be sensitive for axions with masses 40ueV – 400 ueV. The experimental design is based on the idea of enhanced axion photon conversion in a system with several layers with alternating dielectric constants.
The experimental idea and the proposed design of the MADMAX experiment will be discussed. First results from measurements with a prototype dielectric haloscope will be discussed. The prospects for reaching sensitivity enough to cover the parameter space predicted for QCD dark matter axions with mass in the range 40-400 ueV will be presented.
WISPy Dark Matter candidates have increasingly come under focus of scientific interest. In particular the QCD Axion might also be able to solve other fundamental problems such as strong CP-violation and could be responsible for inflation and structure formation in the early universe. Galactic Axions, Axion-Like-Particels and Hidden Photons can be converted to photons employing a surface boundary of different dielectric constants under a strong magnetic field. Combining many such surfaces, one can enhance this conversion significantly utilizing constructive interference. The proposed MADMAX setup containing 80 high dielectric discs in a 10T magnetic field might probe the well-motivated mass range of (40-400)µeV, a range which is inaccessible by existing cavity searches. We present the foundations of this approach, discussing implications on the accuracy of disc placement, dark matter velocity effects and expected sensitivity.
The COSINUS (Cryogenic Observatory for SIgnals seen in Next-generation Underground Searches) was brought to life to give new insight to the long-standing dark matter claim of the DAMA/LIBRA experiment. To be immune to potential target-material dependencies also COSINUS, as DAMA-LIBRA, uses NaI as target material. Our detectors are cryogenic calorimeters with phonon-light-readout - unique in the field of NaI-based dark matter searches. This experimental approach provides particle discrimination on an event-by-event basis and, therefore, even with a moderate exposure COSINUS will be able to reject or confirm a dark matter - nucleus interaction as the origin of the DAMA/LIBRA signal.
In this talk we present results of the first COSINUS prototypes which, to our knowledge, are the first measurements of NaI crystals as cryogenic calorimeter.
Florian Reindl on behalf of the COSINUS collaboration
Looking for low-mass WIMPs (<10 GeV) which could be pervading the galactic dark halo requires the use of light elements as target and detectors with very low energy threshold. The TREX-DM (TPC Rare Event eXperiment for Dark Matter) experiment is conceived to fulfil these requirements by means of a gas time projection chamber (TPC) equipped with novel micromesh gas structures (Micromegas) readout planes. The detector can hold, in the fiducial volume, ~20 litres of pressurized gas up to 10 bar, which corresponds to ~0.300 kg of Ar at 10 bar, or alternatively 0.160 kg of Ne. The Micromegas are highly segmented and will be read with a self-triggered acquisition, allowing for effective thresholds below 0.4 keV (electron equivalent). An exhaustive material screening campaign has allowed to design and construct the detector and shielding with the state-of-the art radiopurity specifications. The preliminary background model suggests that levels of the order of 1-10 counts keV-1 kg-1 d-1 are expected in the region of interest, making TREX-DM competitive in the search for low mass WIMPs. The experiment has been approved by the Canfranc Underground Laboratory (Laboratorio Subterráneo de Canfranc, LSC) and after completion of a series of measurements at ground level is expected to be installed at the LSC facilities by the end of the current year. A tentative schedule foresees a data-taking campaign of approximately 3 years starting with Ne, with the option to change to (depleted) Ar. Latest experimental results, status of the commissioning, description of background model and the corresponding WIMP sensitivity will be presented.
The PICO-60 experiment searches for dark matter using superheated liquid C$_3$F$_8$. The experiment is located at SNOLAB and is designed to be sensitive to spin-carrying dark matter particles. The PICO bubble chamber is a threshold detector that can be operated to be insensitive to minimally ionizing particles. Acoustic information is used to discriminate between nuclear recoil events and background alpha events.
It is very hard to directly measure the temperature and its variations inside a bubble chamber and understand the flow and heat distribution patterns in a superheated liquid. A new technique is being developed involving the growth and movement patterns of nucleation bubbles in the PICO-60 vessel to map the heat and flow distribution. The progress and results from this work will be presented in this talk. This measurement aims to verify the thermal and liquid simulations in this and future PICO detectors. Understanding the temperature profile inside the chamber allows to narrow the threshold uncertainty for dark matter searches in the future.
Over the last two decades, astrophysicists and astronomers have produced compelling evidence on galactic and cosmological scales indicates that ~80% of the matter density of the Universe consists of non-luminous, non-baryonic dark matter. Despite this fact, the composition of the dark matter remains unknown. One compelling candidate for particle dark matter is the Weakly Interacting Massive Particle (WIMP). Working in a low-background environment in the Soudan Underground Laboratory, located in northern Minnesota, the SuperCDMS experiment is designed to directly detect interactions between WIMPs and nuclei in its target Ge crystals. In this talk I will present the latest results from the SuperCDMS experiment including a high mass search with the SuperCDMS iZIP detectors, low mass searches with CDMSlite and results from a search for the signature of an annual modulation.
The EDELWEISS collaboration is performing a direct search for WIMP dark matter using an array of up to twenty-four 860g cryogenic germanium detectors equipped with a full charge and thermal signal readout. The experiment is located in the ultra-low radioactivity background of the Modane underground laboratory, in the French-Italian Frejus tunnel. We present the analysis of data obtained in extended data taking periods. WIMP limits, background rejection factors and measurements of cosmogenic activation are used to assess the performance of the third generation of EDELWEISS detectors in view of the search for WIMPs in the mass range from 1 to 20 GeV/c2. The developments in progress to pursue this goal in the coming years are also presented.
The CRESST experiment, located at Laboratori Nazionali del Gran Sasso in Italy, searches for dark matter particles via their elastic scattering off nuclei in a target material.
The CRESST target consists of scintillating CaWO$_4$ crystals, which are operated as cryogenic calorimeters at millikelvin temperatures. Each interaction in the CaWO$_4$ target crystal produces a phonon signal and a light signal that is measured by a second cryogenic calorimeter.
With the CRESST-II result in 2015, the experiment is leading the field of direct dark matter search for dark matter masses below 1.7GeV/c$^2$ , extending for the first time the reach of a direct search to the sub-GeV/c$^2$ mass region.
For CRESST-III, whose Phase 1 started data taking in August 2016, detectors have been optimized to reach the performance required to further probe the low-mass region with unprecedented sensitivity.
In this contribution the achievements of the CRESST-III detectors will be thoroughly discussed together with preliminary results and perspectives of Phase 1.
Liquid argon is known as an excellent target material for WIMP dark matter direct search experiment. Use of its ionization and scintillation signals, and scintillation pulse shape provides strong discrimination between the electron and nuclear events. Relatively small atomic mass (A=40) gives higher nuclear recoil energy for WIMP-Ar nuclear scattering, thus it potentially has higher sensitivity for low mass WIMP (~10 GeV/c2). On the other hand, the 128 nm VUV scintillation light of argon is relatively hard to detect with nominal photo sensors, and use of wavelength shifter lowers the light detection efficiency and likewise the spatial resolution of the reconstructed event. At present, there are no liquid argon detectors which prove their sensitivity for the low mass WIMP.
The ANKOK project is a dark matter search experiment in Japan using the double phase argon detector which is specialized for the low mass WIMP detection. Using a prototype detector, we are proceeding R&D efforts to establish its physics sensitivity. A detector with fiducial mass of about 30 kg is under construction.
We plan to operate the detector at surface within a year, following collection of the underground physics data in the next few years.
Despite several large-scale direct detection experiments worldwide, dark matter remains elusive. Not favored by theory, the low mass region of the weakly interacting particles parameter-space (<1GeV) has been largely ignored until now, and time has come to broaden the search.
The NEWS-G project builds on the experience gathered with the SEDINE detector, which has been operated for several years at the Laboratoire Souterrain de Modane (FRANCE). The goal is to build a 1.4m diameter low-background spherical gaseous TPC with a single central electrode. It is designed to work with a gas pressure up to 10 bars and to use light target materials such as Ne, He and H in order to look for WIMP mass down to 0.1 GeV. This will be possible by the use of low activity materials, and by the selection of SNOLAB (CANADA) as location for the detector.
In this presentation, I will present the concept of spherical gaseous TPC, validated by the data taken with SEDINE. I will then introduce the NEWS-G detector whose construction is ongoing for a deployment at SNOLAB planned at the end of 2017.
The PICO-60 bubble chamber has concluded its dark matter search runs using a superheated liquid C$_3$F$_8$ target. Its replacement currently under commissioning, PICO-40L, is a redesigned bubble chamber with an inverted vertical orientation. This design allows the replacement of the water buffer with a second fused silica jar acting as a piston. The removal of the buffer fluid is intended to eliminate backgrounds caused by water droplets, particulates, and surface tension effects. This redesign also lifts buffer compatibility constraints on potential target fluids, allows a wider range of operating temperatures, and enables full target recirculation and purification. A larger stainless steel pressure vessel will reduce the expected neutron backgrounds to a level permitting a background-free 40L one-year exposure. In addition to its extended physics reach beyond that of PICO-60, this detector will act as a prototype and proof-of-principle for the proposed tonne-scale bubble chamber PICO-500.
The China Dark Matter Experiment (CDEX) aims at direct searches of light Weakly Interacting Massive Particles (WIMPs) at the China Jinping Underground Laboratory (CJPL) with an overburden of about 2400m rock. Results from a prototype CDEX-1 994 g p-type Point Contact Germanium(pPCGe) detector are reported. Research programs are pursued to further reduce the physics threshold by improving hardware and data analysis. The CDEX-10 experiment with a pPCGe array of 10 kg target mass range is being tested. The evolution of CDEX program into "CDEX-1T Experiment" with ton-scale germanium detector arrays, aiming at both Dark Matter and Neutrinoless Double Beta Decay, will also be introduced in this study.
Millimeter-thick charge-coupled devices (CCDs) are outstanding particle detectors. Although initially developed for near-infrared astronomy, the low pixel noise also makes them the most sensitive detectors to signals from ionizing radiation. By virtue of their very low energy threshold (<100 eV of ionizing energy) and their unique capabilities for background characterization based on their high spatial resolution, CCDs are poised to become the leading technology in the search for a wide variety of dark matter candidates with masses in the range 1 eV/c/c – 10 GeV/c/c. I will present the status of the DAMIC100 experiment, an ongoing direct dark matter search consisting of an array of 16 Mpixel CCDs hosted in the SNOLAB underground laboratory. I will also discuss the recent progress toward DAMIC-1K, a lower-radioactivity 1-kg CCD dark matter detector with an ionization threshold of 2 electrons.
Parallel Neutrino Talks
The SNO+ experiment is located at SNOLAB in Sudbury, Ontario, Canada. It will employ 780 tons of liquid scintillator loaded, in its initial phase, with 1.3 tons of $^{130}$Te (0.5% by mass) for a low-background and high-isotope-mass search for neutrino-less double beta decay. SNO+ uses the acrylic vessel and PMT array of the SNO detector with several experimental upgrades and necessary adaptations to fill with liquid scintillator. The SNO+ technique can be scaled up with a future high loading Phase II, able to probe to the bottom of the inverted hierarchy parameter space for effective Majorana mass. Low backgrounds and a low energy threshold allow SNO+ to also have other physics topics in its program, including geo- and reactor neutrinos, Supernova and solar neutrinos. This talk will describe the SNO+ approach for the double-beta decay program, the current status of the experiment and its sensitivity prospects.
CUPID-0 (former LUCIFER experiment) represents the first demonstrator towards CUPID (Cuore Upgrade with Particle IDentification). CUPID-0 -consisting of an array of 24 enriched Zn82Se scintillating bolometers totalling 3.5 10^25 82Se emitters- has started its background measurement on March 2017. Thanks to the scintillation signal readout, the troublesome alpha-induced background is identified, allowing to reach an extremely low background above the environmental 2615 keV gamma-line. We will present the first results of the background in the RoI of 82Se as well as the future perspectives.
The MAJORANA Collaboration has assembled an array of high purity Ge detectors to search for neutrinoless double-beta decay in $^{76}$Ge with the goal of establishing the required background and scalability of a Ge-based next-generation tonne-scale experiment. The MAJORANA DEMONSTRATOR consists of 44 kg of high-purity Ge (HPGe) detectors (30 kg enriched in $^{76}$Ge) with a low-noise p-type point contact (PPC) geometry. The detectors are split between two modules which are contained in a single lead and high-purity copper shield at the Sanford Underground Research Facility in Lead, South Dakota. Following a commissioning run that started in June 2015, the full detector array has been acquiring data since August 2016. We will discuss the status of the MAJORANA DEMONSTRATOR and initial results from the first physics run; including current background estimates, exotic low-energy physics searches, projections on the physics reach of the DEMONSTRATOR, and implications for a tonne-scale Ge based neutrinoless double-beta decay search.
The goal of the NEXT collaboration is to observe neutrinoless double beta decay in gaseous 136-Xe using a time projection chamber (TPC) capable of doing both energy and tracking reconstruction from light produced via electroluminescence (EL).
The collaboration is now taking data with NEXT-White (NEW), phase-I of the NEXT-100 detector. With about half of the NEXT-100 linear dimensions (about 10 kg of xenon), NEW has the right size for demonstrating and fully understanding the different technological solutions to be implemented in NEXT-100. Furthermore, NEW is the first NEXT detector that is built with highly radio pure materials and operates underground in the Laboratorio Subterráneo de Canfranc (LSC), where NEXT-100 will be located. Its operation will permit a first in-situ measurement of the backgrounds to be expected in NEXT-100.
Overview of the NEXT experiment will be presented in this talk including a description of NEXT unique advantages over other detection techniques. Latest results of the NEW detector will be shown and discussed.
Experimental searches for neutrinoless double-beta decay (0$\nu\beta\beta$) are one of the most active research topics in neutrino physics. Its observation is in fact of major importance since it will prove the Majorana nature of neutrinos and may give access to their absolute mass scale.
Installed at Modane Underground Laboratory (LSM), the NEMO experiments provide a unique approach combining a calorimetric and a tracking measurement of $\beta\beta$ events emitted by a separated isotopic source. This approach allows to search for 0$\nu\beta\beta$ decays among several isotopes with good background discrimination. Furthermore, the NEMO experiments are able to measure all kinematical parameters of the event(s) which might allow to determine the process leading to 0$\nu\beta\beta$.
The talk will briefly review the latest results of the NEMO-3 experiment and will then focus on the status
of installation and commissioning phase of the SuperNEMO demonstrator.
The Bayesian discovery probability of future experiments searching for neutrinoless double-$\beta$ decay is evaluated under the popular assumption that neutrinos are their own antiparticles. A Bayesian global fit is performed to construct a probability distribution for the effective Majorana mass, the observable of interest for these experiments. This probability distribution is then combined with the sensitivity of each experiment derived from a heuristic counting analysis. The discovery probability strongly depends on whether the neutrino mass ordering is normal or inverted, and is found to be higher then previously considered for both mass orderings. For the inverted ordering, next-generation experiments are likely to observe a signal already during their first operational stages. Even for the normal ordering, the probability of discovering neutrinoless double-$\beta$ decay reaches $\sim$50% in the most promising experiments.
The nEXO Collaboration is designing a 5-tonne detector with initial neutrinoless double-beta decay sensitivity close to $10^{28}$years. The nEXO detector will be a homogeneous liquid xenon-136 time projection chamber inspired by the very successful EXO-200 detector. Energy resolution, event topology and event localization in the large homogeneous detector will work in concert to measure and eliminate backgrounds. In this talk we will describe the detector design choices and show the sensitivity that the detector can reach, using only materials whose radiopurity has been already demonstrated.
From the experimental point of view, very little is known about the gravitational interaction between matter and antimatter. In particular, the Weak Equivalence Principle, which is of paramount importance for the General Relativity, hasn't been directly probed with antimatter yet. The main goal of the AEgIS experiment at CERN is to perform a direct measurement of the gravitational force on antimatter. The idea is to measure the vertical displacement of a beam of cold antihydrogen atoms, traveling in the gravitational field of the Earth, by the means of a moiré deflectometer. An overview of the physics goals of the experiment, of its apparatus and of the first results is presented.
We have demonstrated a novel technique for measuring microscopic forces acting on optically levitated dielectric microspheres. The radiation field at the focus of a laser beam is used to levitate a microsphere in a harmonic trap where the displacement of the microsphere can be determined by the pattern of scattered light. Optical levitation isolates the microsphere from the surrounding environment at high vacuum, making exceptionally sensitive force measurements possible. We have demonstrated a preliminary sensitivity of $5 \times 10^{-17}$ $N/\sqrt{Hz}$ for forces acting on $5 \mu m$ microspheres and expect to be able to improve this by several orders of magnitude by eliminating non-fundamental sources of noise. The electric charge of a microsphere can be determined by applying an electric field and measuring the resulting force. We have demonstrated the ability to control the charge of the microspheres with single electron precision, which eliminates the main component of the electrostatic backgrounds from force measurements. As a demonstration of this technique we have searched for the presence of unknown charged particles with charge $>5 \times 10^{-5} e$ in bound in our microspheres, and for the presence of screened interactions associated with dark energy. Here we discuss the apparatus, our previous results, and outline our plans for future measurements that will include the investigation of gravity at short distance.
POLARBEAR is a ground-based CMB polarization experiment that is designed to characterize
the B-mode (curl component) signal at both degree and sub-degree angular-scales.
B-modes at degree scale can reveal the existence of primordial gravitational waves and will be
used for quantitative studies of inflation, such as the energy scale at which it occurred.
The sub-degree polarization data are an excellent tracer of the cosmological expansion rate
and large-scale structure in the universe through gravitational lensing, and can be used to constrain
the sum of the Neutrino masses.
POLARBEAR-1 started observing in early 2012 at 150 GHz with an array of 1,274
polarization-sensitive antenna-coupled transition-edge sensor (TES) bolometers,
and first detected the sub-degree B-mode signal using CMB data alone.
The POLARBEAR-2 is a project for receiver upgrade to cover two frequency bands
with 7,600 detectors per receiver
The Simons Array is a project to deploy three POLARBEAR-2 receivers on three telescopes.
Simons Array will survey of B-mode polarization at 95, 150, 220, and 270 GHz for
effective monitoring and removal of foreground contamination.
The first receiver is in final stage of integration.
It is scheduled to deploy during the 2017/2018 austral summer season in the Atacama desert in Chile.
The projected constraints on the tensor-to-scalar ratio (the amplitude of inflationary B-mode signal)
will improve over current constraints by almost an order
of magnitude to $\sigma(r=0.1) = 6.0\times10^{-3}$ ($4.0\times10^{-3}$ statistical), and the sensitivity to the sum of the neutrino masses
when combined with DESI spectroscopic galaxy survey data will be 40 meV at 1-sigma after foreground removal (19 meV(stat.)).
We will describe the current status and prospects of the POLARBEAR-2 receiver system
and the Simons Array project.
The present paper reports a study on variable generalized Chaplygin gas (VGCG) interacting with pressureless dark matter (DM) with interaction term Q chosen in the form Q=3HδρΛ, where ρΛ denotes the density of the VGCG. Detailed cosmology of the interacting VGCG has been studied and a quintom behaviour of the equation of state (EoS) parameter has been observed. A statefinder analysis has shown attainment of ΛCDM fixed point by the interacting VGCG. Subsequently, a reconstruction scheme for f(T ) gravity has been presented based on the interacting VGCG with power-law form of scale factor. The EoS parameter corresponding to the reconstructed f(T) has shown quintom behaviour. Finally we have studied the generalized second law (GSL) of thermodynamics in reconstructed f(T) cosmology considering the universe as a closed bounded system with future event horizon as the cosmological boundary. We have associated two different entropies with the cosmological horizons with a logarithmic correction term and a power-law correction term. We have studied the validity of the GSL for both of these corrections. Our result deviates from Bamba et al., Astrophys. Space Sci. 344, 259 (2013) (2013) in the sense that in the said reference, the GSL had a conditional validity for both of the corrections in the case of future even horizon. However, in the present case the GSL has failed to hold in power-law correction and has unconditional validity in logarithimic correction with future event horizon as the enveloping surface of the universe.
The damping of perturbations in the early universe produces a distortion in the energy spectrum of the CMB photons which depends intimately on the properties of the photon temperature transfer functions. Here we propose a new method for probing dark matter models on extremely small-scales (1 \, \textrm{Mpc}^{-1}\lesssim k \lesssim 10^{4} \, \textrm{Mpc}^{-1}) by looking at how these models affect the evolution of the photon transfer functions. We explore the dependance of the distortion on different dark matter models including warm dark matter and dark matter with elastic scattering off a relativistic species (we consider both photons and neutrinos). The photon temperature transfer functions are determined for each model and used to calculate the heating rate of the CMB photons and the distortion signatures in each case. We place constraints on the dark matter-radiation elastic scattering cross-sections and show the projected constraints for future experiments. We show that the distortion signal differs between all 3 dark matter models under consideration and can thus shed light on the small-scale problems associated with conventional Cold Dark Matter models.
With the recent discovery of high-energy neutrinos of extraterrestrial origin by the IceCube neutrino observatory, neutrino astronomy is entering a new era. The highest energy neutrinos observed to date exceed 1 PeV in energy, a regime of particular interest because the neutrinos should point back to the still elusive accelerators of the highest energy Galactic and extragalactic cosmic rays. This review will cover currently operating high-energy neutrino detectors in water and ice, the latest results from searches for a flux of extraterrestrial neutrinos, current efforts in the search for steady and transient neutrino point sources and the exciting physics program these detectors offer in studies of atmospheric neutrinos and indirect searches for dark matter. In addition, current and future detector upgrades such as KM3NeT in the Mediterranean Sea and "IceCube-Gen2"/PINGU will be discussed.
The direct dark matter detection field is entering an intriguing period where tonne-scale high-mass-WIMP-search detector systems are coming on-line, along with new systems focussed on low-mass-WIMP and spin-dependent-interaction searches. These detector systems open up new parameter space for detection of dark matter, with the projected sensitivities of subsequent generation detectors approaching those required to observe coherent neutrino scattering. This talk will overview the current status of the direct detection field, outlining current techniques and sensitivities, and survey the future potential of the field.
DEAP-3600 is a novel experiment searching for dark matter particle interactions on 3.6 tonnes of liquid argon at SNOLAB. The argon is contained in a large ultralow-background acrylic vessel viewed by 255 8-inch photomultiplier tubes. Very good pulse-shape discrimination has been demonstrated for scintillation in argon, and the detector has been designed to allow control of (alpha,n) and external neutron recoils, and surface contamination from 210Pb and radon daughters, allowing an ultimate sensitivity to spin-independent scattering of 10^{-46} cm^{2} per nucleon at 100 GeV mass. After several years of construction, data collection has begun late 2016. Details of the detector construction, commissioning and first analysis results from the experiment will be presented.
The PICO collaboration has operated several generations of dark matter detectors at SNOLAB. The most recent results of the PICO 60 experiment and the plans for future superheated liquid dark matter detectors will be presented.
Searches for dark matter (DM) have become a major focus of the LHC physics programmes. Run-2 DM results from the ATLAS and CMS experiments showcase the ability of collider searches to compliment the sensitivity of direct and indirect detection experiments. In this talk, we review the strategy and status of DM searches in ATLAS and CMS, and show how recent results strongly constrain models of WIMP DM. We explore the unique sensitivity of several DM search channels and highlight LHC constraints on low mass DM and spin-independent DM couplings. We consider the likely evolution of the ATLAS and CMS search programmes in Run-2 and conclude with a discussion of new ideas for extending the reach of future DM searches at the LHC.
Since the discovery of neutrino oscillation we know that neutrinos have non-zero masses, but we do not know the absolute neutrino mass scale, which is as important for cosmology as for particle physics. The direct search for a non-zero neutrino mass from endpoint spectra of weak decays is complementary to the search for neutrinoless double beta-decay and analyses of cosmological data.
The next generation experiment KATRIN, the Karlsruhe Tritium Neutrino experiment, is under commissioning. It will improve the best current limits from the tritium beta decay experiments by one order of magnitude down to 200 meV probing the region relevant for structure formation in the universe. KATRIN uses a strong windowless gaseous molecular tritium source combined with a large acceptance and high energy resolution MAC-E-Filter as electron spectrometer. In October 2016 KATRIN celebrated "first light": For the first time electrons from a photoelectron source were flying from the very rear over the full beamline of 70m length to the detector. In July 2017 KATRIN is performing an intensive calibration campaign with Kr-83m conversion electrons from the windowless gaseous source (still without tritium) and a condensed source.
To overcome the problem that KATRIN is using a close to opaque source already to obtain the required statistics, new technologies are developed to potentially improve the sensitivity on the neutrino mass: Project 8 is performing spectroscopy of the synchrotron radiation of gyrating electrons in a KATRIN-like source; ECHO, HOLMES and NuMECS are investigating the endpoint region of the electromagnetic deexcitation spectrum of Ho-163 electron capture with arrays of high energy resolution cryo-bolometers.
In this talk data from the commissioning of KATRIN and an outlook on the tritium data taking starting 2018 will be presented as well as a report on other up-coming direct neutrino mass approaches.
The nature of dark matter is one of the great mysteries of modern physics and may be the result of
new particles beyond the standard model. The Axion, originally conceived as a solution to the strong-
CP problem in nuclear physics, is one well-motivated candidate. In 1983 Pierre Sikivie proposed an
experimental search technique, known as an axion haloscope, that relies on a large microwave cavity
immersed in a strong static magnetic field to resonantly convert dark matter axions to detectable
photons. This became the foundation of the Axion Dark Matter eXperiment (ADMX), which has
recently began taking data at unprecedented sensitivity in the classical QCD-axion mass range of
several
micro-eV. In addition, several new detection techniques have been proposed to cover a large span
of potential axion masses beyond that of the classical window. There also exist a set of experiments that look for axions generated in the sun, from intense laser sources and from modifications to force of gravity at short range. In this talk I will describe the history
of axion searches and give a survey of the R&D efforts currently underway to explore
the entire potential axion mass window.
We directly measure exceptionally long ($\sim$ms) scintillation lifetimes of tetraphenyl-butadiene, a common wavelength shifter used on surfaces in liquid argon detectors. The magnitude of the scintillation tail relative to the prompt signal is found to differ under alpha, beta, and UV excitation, allowing for pulse-shape discrimination (PSD). Using PSD we show that surface backgrounds from Radon daughters in liquid argon detectors can be suppressed by a factor of $10^3$ with negligible loss of nuclear recoil acceptance.
Dark matter direct detection experiments rely heavily on calibrations to understand each detector’s response to predicted backgrounds. Certain backgrounds, such as neutrino-electron scatters, cannot be directly calibrated, and so beta- or gamma-decay sources are often used as a proxy. This treatment inherently assumes that interaction type and energy do not affect detector response to electron recoil scatters. The PICO bubble chambers have recently discovered that this assumption breaks down under certain conditions in a way that critically impacts detector performance. We have constructed a xenon time projection chamber at Fermilab to directly compare electron capture decays from Xe-127 against tritium beta decays, to determine if second-order differences will contribute to the profile likelihood analysis used by the LZ and XENON collaborations.
The SABRE (Sodium Iodide with Active Background Rejection) experiment will search for an annually modulating signal from Dark Matter (DM) using an array of ultra-pure NaI(Tl) detectors surrounded by an active scintillator veto to further reduce the intrinsic background. The expected rate of interactions between DM particles and the detector in fact modulates due to Earth’s changing velocity relative to the DM halo.
The first phase of the experiment is the SABRE Proof of Principle (PoP), a single 5kg crystal detector operated in a liquid scintillator filled vessel at the Laboratori Nazionali del Gran Sasso (LNGS). The PoP installation is underway with the goal of running in 2017 and performing the first in situ measurement of the crystal background, testing the veto efficiency, and validating the SABRE concept.
As part of this effort, GEANT4-based Monte Carlo simulations have been developed to estimate the background in the PoP based on radio-purity measurements of the detector components. The most recent simulations include detailed versions of the detector part geometries.
The second phase of SABRE will be twin arrays of NaI(Tl) detectors operating at LNGS and at the Stawell Underground Physics Laboratory (SUPL) in Australia. By locating detectors in both hemispheres, SABRE will minimize seasonal systematic effects.
In this talk, the status report of the SABRE PoP activities at LNGS will be presented as well as results from the most recent Monte Carlo simulation.
The ANAIS (Annual modulation with NaI(Tl) Scintillators) experiment aims at the confirmation of the DAMA/LIBRA signal using the same target and technique at the Canfranc Underground Laboratory (LSC). Several 12.5 kg NaI(Tl) modules produced by Alpha Spectra Inc. have been operated in Canfranc during the last years in various set-ups; an outstanding light collection at the level of 15 photoelectrons per keV, which allows triggering at 1 keV of visible energy, has been measured for all of them and a complete characterization of their background has been achieved. The crystal contamination is the main background source in the very low energy region of interest and the activity of the main contributors, like 40K and 210Pb, has been assessed; improvements implemented during the manufacture of the different detectors have resulted in a reduction of the activities in the last crystals produced. In the first months of 2017, the full ANAIS-112 set-up consisting of nine Alpha Spectra detectors in a 3x3 matrix configuration with a total mass of 112.5 kg has been commissioned at LSC. The latest results on the detectors performance and measured background will be presented and the excellent sensitivity prospects of the ANAIS 112 experiment for the confirmation of the DAMA/LIBRA signal will be discussed.
Astrophysical observations give overwhelming evidence for the existence of dark matter. While the DAMA collaboration has asserted for years that they observe a dark matter-induced annual modulation signal in their NaI(Tl)-based detectors, their signal has not been confirmed independently. Moreover, DAMA's observations are inconsistent with those from other direct detection dark matter experiments under most assumptions of dark matter. I will describe the COSINE-100 experiment, the current status and prospect for low-background NaI(Tl)-based dark matter experiments, and our strategy for resolving the current stalemate in the field.
The positive observation of dark matter by the DAMA experiment has to be re-examined by a NaI(Tl) detector since there are multiple negative results shown by Xe experiments. The PICOLON experiment is trying to observe dark matter with multiple highly radio-pure NaI(Tl) scintillator detectors.
In recent a couple years, 3”φx3” and 4”φx3” detectors were constructed for future target of 5”φx5” detectors. Different resins were applied for purification of NaI powder in order to remove Pb, Ra and K, also the housing material screening and purification was performed. Significant reduction on U and Th chain radio-impurities including $^{226}Ra$ and $^{210}Pb$, as well as on $^{40}K$. The background rate below 10keV is mainly suppressed to approximately 4 DRU.
The latest 4”φ detector background analysis, sensitivity of the detector to dark matter and next plans of the experiment will be reported in this talk.
Potassium-40 is a contaminant found in many rare-event searches. Its decay by electron capture to argon-40 emits X-rays and Auger electrons at energies of 3 keV and below, right in the region where direct searches for dark matter expect their signal. Most of the electron capture decays are to an excited state of 40Ar which emits a 1.461 MeV gamma ray allowing identification of the low-energy quanta. However, it has been pointed out by Pradler et al (PLB 720 399 2013), that an untaggable direct decay to the ground state is also expected, and that it has implications for the long-standing DAMA/LIBRA claim of dark matter detection. The KDK (potassium decay) experiment aims to make the first measurement of this decay to the ground state. The experiment involves a 40K source and a sensitive X-ray detector, surrounded by a unique, very efficient detector for the 1.461 MeV gamma rays, the Modular Total Absorption Spectrometer (MTAS), at Oak Ridge. We present the experimental setup, including calibrations of the X-ray detector, preparations of the 40K source, and an experimental determination of the better-than-98% tagging efficiency of MTAS, as well as the status of measurements.
The Jinping Neutrino Experiment will perform an in-depth research on solar neutrinos, geo-neutrinos and supernova relic neutrinos. Many efforts were devoted to the R&D of the experimental proposal. A new type of liquid scintillator, with high light-yield and Cherenkov and scintillation separation capability, is being developed. The assay and selection of low radioactive stainless-steel (SST) was carried out. The U and Th concentration is less than 1e-8 g/g for selected SST samples. A wide field-of-view and high-efficiency light concentrator is developed. Previous designs of light concentrators were optimized to attain a wide field view, 90 degree and a high efficiency, above 98%. At the same time a 1-ton prototype is constructed and placed underground at Jinping laboratory to 1) test the performance of several key detector components, like acrylic, pure water, using of ultra-high molecular weight polyethylene rope, 2) understand the neutrino detection technology with liquid scintillator and slow liquid scintillator and 3) measure the in-situ Jinping underground background, like fast neutron. The design, construction and initial operation of the 1-ton prototype will be discussed. A simulation framework is also developed to facilitate the experimental study of the 1-ton prototype and future detector design.
Parallel Neutrino Talks
Investigation of double beta decay (β+EC, EC/EC) of 58Ni was performed at the Modane underground laboratory (LSM, France, 4800 m w.e.) using the ultra-low background spectrometer Obelix and a sample of natural Ni. Spectrometer Obelix is based on P-type coaxial HPGe detector with a sensitive volume of 600 cm3 and relative efficiency of 160 %. The detector part of the cryostat is encircled by several layers of roman and low-active lead and flushed with radon-depleted air. The sample of natural nickel, containing ~68% of 58Ni with a total mass of ~21.7 kg was prepared in a shape of Marinelli beaker and placed on the Obelix detector. Three experimental runs were performed with the investigated sample in 2014 - 2017 years. New experimental limits (at 90% CL) on half-lives of β+EC and EC/EC decays of 58Ni to excited states of 58Fe were obtained in these investigations, improving the previous experimental limits by approximately two orders of magnitude.
Fifty years ago, Ettore Fiorini and collaborators published the first results of a $^{76}$Ge based search for neutrinoless double beta decay (0νββ). In the ensuing five decades, the sensitivity for 0νββ searches using $^{76}$Ge has increased by five orders of magnitude, from the 1967 limit of T$_{1/2}$ ≥ 3 × 10$^{20}$ years to GERDA’s recent result of T$_{1/2}$ ≥ 5.3 × 10$^{25}$ years. The current generation $^{76}$Ge experiments, GERDA and the MAJORANA DEMONSTRATOR, have now achieved the lowest backgrounds in the 0νββ region of interest of any 0νββ experiments. These results, coupled with the intrinsic superior energy resolution of Ge (0.1%) demonstrate that germanium is an ideal isotope for a large next generation experiment. The LEGEND collaboration, with 220 members from 47 institutions around the world, has been formed to pursue a ton scale $^{76}$Ge experiment. Building on the successes of GERDA and the MAJORANA DEMONSTRATOR, the LEGEND collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life significantly longer than 10$^{27}$ years, using existing resources as appropriate to expedite physics results. This talk will present an overview of LEGEND and discuss its envisioned first phase, a 200 kg measurement utilizing the existing GERDA cryostat at LNGS.
Neutrino-less double beta decay (0$\nu\beta\beta$) is acquiring great interest
after the confirmation of neutrino oscillation
which demonstrated nonzero neutrino mass.
Measurement of 0$\nu\beta\beta$ provides a test for the Majorana
nature of neutrinos
and gives an absolute scale of the effective neutrino mass.
In order to search for 0$\nu\beta\beta$ of $^{48}$Ca,
we proposed CANDLES detector by using CaF$_{2}$(pure).
The CANDLES detector aims at a high sensitive measurement
by an active shield and $^{48}$Ca enrichment.
The complete 4$\pi$ active shield is realised
by immersion of the CaF$_{2}$ scintillators in liquid scintillator.
The active shield leads to a low background condition for the measurement.
On the other hand,
$^{48}$Ca enrichment is also effective for the high sensitive measurement,
since natural abundance of $^{48}$Ca is very small (0.19\%).
Currently we have been developing the CANDLES III detector,
which contained 350 g of $^{48}$Ca without enrichment,
at the Kamioka underground laboratory.
In 2015, we installed a shielding system in the CANDLES III detector
to reduce background events by the high energy $\gamma$-rays,
which were emitted from neutron capture reaction in surrounding materials.
Using this shielding system, we reduced the background events from neutron capture
by two orders of magnitude.
After this upgrade, we started a double beta decay measurement in 2016.
In this paper,
we will report result of the double beta decay measurement
after the upgrade.
The MAJORANA DEMONSTRATOR is an experiment constructed to search for neutrinoless double-beta decays in germanium-76 and to demonstrate the feasibility to deploy a large-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and 76Ge-enriched germanium detectors totaling 44.1 kg, located at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA.
Data taken with this setup since summer 2015 at different construction stages of the experiment show a clear reduction of the observed background index around the ROI for $0\nu\beta\beta$-decay search due to improvements in shielding. In this talk we discuss the analysis approaches of the different datasets. Using models based on Monte Carlo simulations, the contribution of different background components -such as $2\nu\beta\beta$-decay, cosmogenic activation, and external radiation - can be quantified. In addition we discuss the statistical approaches to quantify the physics sensitivity of a possible $0\nu\beta\beta$-signal.
The KArlsruhe TRItium Neutrino (KATRIN) experiment is a large-scale experiment with the objective to determine the effective electron anti-neutrino mass with an unprecedented sensitivity of 0.2 eV/c² at 90% C.L. in a model-independent way. The measurement method is based on precision beta-decay spectroscopy of molecular tritium.
The experimental setup consists of a high luminosity windowless gaseous tritium source, a magnetic electron transport system with differential and cryogenic pumping for tritium retention, and an electro-static spectrometer section for energy analysis, followed by a segmented detector system for counting transmitted beta-electrons. First commissioning measurements of the complete beamline were performed in November 2016.
This talk will give an overview of the KATRIN experiment and its current status. Furthermore, results of the recent commissioning measurements of the complete KATRIN beamline will be presented.
The Electron Capture in $^{163}$Ho (ECHo) experiment is designed to investigate the electron neutrino mass $m_{\nu_e}$ with sub-$eV$ sensitivity by the analysis of the electron capture (EC) energy spectrum of $^{163}$Ho.
The sensitivity on the electron neutrino mass is crucially related to the energy available for the decay $Q_{EC}$ = $2833(30$stat$)(15$sys$)\,eV$, which has been precisely determined by the ECHo collaboration.
Accordingly, a sensitivity below $10\,eV$ is expected to be attained at the end of the present phase of the experiment, ECHo-1k.
In this phase, about $1\,kBq$ of high purity $^{163}$Ho is going to be implanted in multiplexed arrays of low temperature metallic magnetic calorimeters which are operated in a reduced background environment.
The goals of ECHo-1k are the precise characterization of the parameters describing the spectrum, optimizing the implantation process of $^{163}$Ho into the detector arrays, optimization of detector production and identification and reduction of the background in the experimental setup.
The results will pave the way to a future phase of the experiment, where activities of the order of $MBq$ $^{163}$Ho will be used.
This second phase aims to approach sub-$eV$ sensitivity on the electron neutrino mass.
Furthermore, the high statistics and high resolution measurement of the $^{163}$Ho electron capture spectrum will allow the investigation of the existence of $eV$ and keV-scale sterile neutrinos.
In this contribution, a general overview of the ECHo experiment is presented and the current status as well as the future perspectives are discussed.
Project 8 is a tritium endpoint neutrino mass experiment utilizing a phased program to achieve sensitivity to the range of neutrino masses allowed by the inverted mass hierarchy. The Cyclotron Radiation Emission Spectroscopy (CRES) technique is employed to measure the differential energy spectrum of decay electrons with high precision. We present an overview of the Project 8 experimental program, from first demonstration of the CRES technique to ultimate sensitivity with an atomic tritium source. We then highlight recent advances in preparation for the first measurement of the continuous tritium spectrum with CRES.
The MAJORANA DEMONSTRATOR is currently searching for neutrinoless double-beta decays in germanium-76 and will demonstrate the feasibility to deploy a tonne-scale experiment in a phased and modular fashion. It consists of two modular arrays of natural and 76Ge-enriched germanium detectors totaling 44.1 kg, of which 29.7 kg is enriched, located at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota, USA. The low-backgrounds and low thresholds (< 1keV) achieved by the DEMONSTRATOR allow for additional rare-event searches at low-energies, e.g. searches for bosonic dark matter, solar axions, pauli exclusion principle violation, and electron decay. In this work, we will present recent results on rare event searches and discuss the future reach of MAJORANA.
The ability to detect or "tag" the 136Ba daughter of 136Xe double beta decay in the nEXO liquid xenon TPC has the potential to eliminate essentially all background in the a second phase of nEXO operation. Several promising techniques for barium tagging are being developed within the nEXO collaboration. These include capturing the single 136Ba ion/atom in solid xenon on a cryogenic probe and detecting it by laser spectroscopy and capturing the single 136Ba on a conducting probe and detecting it by laser ablation and resonance ionization spectroscopy. The extraction of the 136Ba+ ion from the TPC and capture and detection in an ion trap is also being explored. Recent progress in barium tagging at the single ion/atom level will be presented.
The PandaX-III project at China Jinping Underground Laboratory (CJPL) will search for neutrinoless double beta decay of Xe-136 with high pressure xenon gas Time Projection Chambers (TPC). PandaX-III exploits the tracking capability of gaseous TPC to effectively identify possible signal and suppress background. The first TPC will contain 200 kg of enriched xenon at 10 bar and will be equipped with Micromegas charge amplification and readout modules. The projected energy resolution is 3% (FWHM at Q-value) and spatial resolution on millimeter level. We are commissioning a prototype TPC with up to 20 kg of xenon in the effective volume to validate our design of high voltage feedthrough, field cage, Micromegas readout plane, and to develop algorithms of track reconstruction. In this talk, I will give an overview of the PandaX-III design features, projected sensitivity, and the latest results of the prototype TPC.
The goal of the Advanced Mo-based Rare process Experiment (AMoRE) is to search for neutrinoless double beta decay of $^{100}$Mo using low-temperature detectors consisting of Mo-based scintillating crystals and sensors based on metallic magnetic calorimeters (MMCs). The detector system operates at millikelvin temperatures, which are reached using a dilution refrigerator, and performs simultaneous measurements of heat and light signals. The AMoRE-Pilot experiment, using five $^{100}$Mo-enriched, $^{48}$Ca-depleted calcium molybdate crystals with a total mass of about 1.5 kg, has been running in the 700-m-deep Yangyang underground Laboratory as the pilot phase of the AMoRE project. Several setup improvements through different runs allowed us to achieve high energy resolution and efficient particle discrimination. The current status of AMoRE-Pilot, as well as the plans for the next, higher-scale, experimental stages, will be presented.
High pressure gaseous Time Projection Chamber (TPC) provides a unique
combination of excellent energy resolution, event tracking for
background discrimination, and scalability, which are ideal for
neutrinoless double-beta decay searches. To harness the power of such
a TPC, a suitable charge readout scheme has to be realized. We are
developing a pixelated charge readout plane filled with an array of
CMOS sensors. Each CMOS sensor has an exposed metal patch for direct
charge collection, and integrates charge sensitive amplifiers as well
as signal processing and digitization/transmission circuitry. The
electronic noise is suppressed to a point that no additional
electron-gas avalanche gain is necessary. It provides competitive
energy resolution while improves on tracking capability, stability,
complexity and scalability compared to alternative readout schemes.
Moreover, ions drifting in the gas can be read directly since the
otherwise prohibitive avalanche gain is unnecessary. It enables the
use of alternative gases and double-beta decay candidate isotopes such
as $^{82}$SeF$_6$ gas, in which only ion drifting is possible.
With moderate modifications, such a readout plane could be used in
liquid noble gas and organic liquid TPCs for a broad range of applications.
The nEXO collaboration is developing a low-background detector to search for neutrinoless double beta decays in 5 tonnes of liquid xenon enriched in the isotope Xe-136. The detector concept is based on the success of the EXO-200 detector. However, the more than 20-fold increase in xenon mass would benefit greatly from the development of new technologies to record 175 nm scintillation light and charge signals of events within the detector. The nEXO collaboration identified Silicon photon multipliers (SiPMs) and charge readout tiles as the devices of choice for this application. Inside the detector, an area of about 4m2 has to be covered with SiPM devices to achieve an anticipated energy resolution of < 1% with nEXO. Recent measurements with small-scale prototypes of these devices demonstrated their suitability for the application in nEXO. Parallel to these developments, radioactivity studies of materials for the construction of nEXO are performed and HV tests are conducted to ensure that a drift field of at least 400 V/cm can be applied to nEXO without causing HV breakdowns. The development of the nEXO baseline concept is well advanced and results of the development will be presented.
A liquid scintillator containing a tetrakis (isopropyl acetoacetato) zirconium (Zr(iprac)4) has been developed for new project of neutrinoless double beta decay search using Zr-96 isotope, which is called ZICOS experiment. The liquid scintillator has 10 wt.% concentration of Zr(iprac)4, a light yield of 48.7+-7.1% for BC505, and an energy resolution of 4.1+-0.6% at 3.35 MeV assuming 40% photo coverage of the photomultiplier.
In order to investigate a half-life over 10 to the 26th years, which corresponds to neutrino mass below 0.1 eV, we have to use a ton scale of Zr-96 isotope, and have to remove background events such as Tl-208, which come from the surface of inner balloon as observed by KamLAND-Zen, over one order magnitude. For this purpose, we have developed new technique to use Cherenkov light in order to distinguish the signal and backgrounds using their charasteristic hit pattern of photomultipler, and then have got a method which has ability of 93% background reduction even though remaining 80% of double beta decay signal in study of the Monte Calro simulation. In this case, we need to separate Cherenkov light and Scintillation light even for a few MeV electron. Using difference of the ligh emission mechanism, we could also identify the shapes of time profile for Cherenkov light and Scintillation light with FADC data.
Here we will report recent results of our measurement and the conceptual design of ZICOS detector from the study.
Massive neutrinos demand to ask whether they are Dirac or Majorana particles.
Majorana neutrinos are an irrefutable proof of physics beyond the Standard Model.
Neutrinoless Double Electron Capture is not a process but a virtual $\Delta L = 2$ Mixing
between a parent $^AZ$ atom and a daughter $^A(Z-2)$ excited atom with two electron holes.
As a mixing between two neutral atoms and the observable signal in terms of emitted two-hole X-rays,
the strategy, experimental signature and background are different from neutrinoless double beta decay.
The mixing is resonantly enhanced for almost degeneracy and, under these conditions,
there is no irreducible background from the standard two-neutrino channel.
We reconstruct the natural time history of a nominally stable parent atom
since its production either by nature or in the laboratory.
After the time periods of Atom Oscillations and the decay of the short-lived daughter atom,
at observable times the relevant ``stationary" states are the mixed metastable long-lived state
and the short-lived excited state, as well as the ground state of the daughter atom.
Their natural population inversion is most appropriate for exploiting the bosonic nature
of the observed X-rays by means of stimulating X-ray beams.
Among different observables of the Atom Majorana Mixing,
we include the enhanced rate of Stimulated X-ray Emission from the long-lived
metastable state by a high-intensity X-ray beam.
A gain factor of 100 can be envisaged in a facility like European XFEL.
LUX-ZEPLIN (LZ) is a forthcoming experiment designed to directly detect WIMP dark matter. It aims to detect WIMP interactions with a liquid xenon time projection chamber containing 5.6 tonnes of xenon in the fiducial volume. LZ is projected to have a sensitivity to the spin-independent WIMP-nucleon cross section of 2.3x10^-48 cm^2 for a 40 GeV/c^2 mass WIMP after 1000 days of livetime. An overview of LZ's design and progress towards fabrication and installation in the Sanford Underground Research Facility, where data-taking is scheduled to commence in 2021, will be presented.
LZ will be a 10 ton dual-phase xenon Time Projection Chamber (TPC) searching for WIMP dark matter via direct detection. In order to achieve our desired sensitivity, we require an extremely radiopure environment. Gamma backgrounds originate outside of the bulk xenon and are mitigated by xenon’s self-shielding properties, as well as our position reconstruction and veto capabilities. More challenging are Kr-85 and Rn-222 because they are dissolved throughout the active region. This talk will comprehensively address our plans to reduce and mitigate backgrounds throughout construction, operation, and analysis.
The Super Cryogenic Dark Matter Search (SuperCDMS) and its predecessor CDMS have been at the forefront of the search for Weakly Interacting Massive dark matter Particles (WIMPs) for close to two decades. Significant improvements in detector technology have opened up the low-mass parameter space ( $^\lt\!\!\!\!_\sim$ 10 GeV/c$^2$) where the experiment broke new ground with the CDMS low ionization threshold (CDMSlite) experiment. Building on this success, SuperCDMS is preparing for the next phase of the experiment to be located at SNOLAB near Sudbury, Ontario. The new experimental setup will provide space for up to $\sim$200 kg of target mass in a considerably lower background environment. The initial payload of $\sim$30 kg will be a mix of germanium and silicon targets in the form of both background discriminating iZIP and low-threshold HV detectors, pushing the sensitivity towards WIMPs with even lower masses and improving the cross-section reach of SuperCDMS by more than an order of magnitude. The long-term goal is to reach the neutrino-floor below 10 GeV/c$^2$. In this talk I will present the status of and plans for SuperCDMS at SNOLAB.
The planned SuperCDMS SNOLAB dark matter experiment will seek direct detection of WIMP-like dark matter with masses in the 0.5-10 GeV/c$^2$ mass range. The experiment will employ four types of cryogenic radiation detectors sensitive to phonon and ionization signals. At the lowest recoil energies electron recoil backgrounds are expected to limit the cross section reach to ~10$^{-43}$ cm$^2$ near 1 GeV/c$^2$ dark matter mass. At higher recoil energies electron recoil and nuclear recoils are distinguishable on an event-by-event basis and it is expected for some recoil energy ranges solar neutrinos scattering coherently off detector nuclei will be the limiting background. This presentation will review the primary backgrounds expected in the SuperCDMS SNOLAB experiment, detailing their sources, and respective contributions. Discussion will include measures planned to mitigate and control the most significant background sources.
The PICO-500L detector will be a 500 litre bubble chamber designed to search for weakly interacting massive particles (WIMP). The experiment will cover a large range of mass and cross section parameter space, proving a variety of theoretical models. The PICO collaboration has built a well established technology, easily scalable and relatively inexpensive with flexibility to easily exchange targets following a discovery. PICO-500L will be located two kilometres underground at SNOLAB, with the goal to maintain all backgrounds below one event per year. A careful study has been made using GEANT4 to provide guidance on the material and components purity, as well as shielding requirements, with the goal to maintain the overall neutron budget to less than one per year. Results from a detailed Monte Carlo simulation to estimate the expected backgrounds in the detector using $C_3F_8$ as target material will be presented in this talk.
Liquid xenon is an ideal target material to probe Dark Matter and neutrino physics well beyond the sensitivity of ongoing projects. The DARWIN observatory is a proposed detector with a multitude of physics channels spanning particle, astroparticle, and nuclear physics. DARWIN will probe vanilla WIMPs down to the signal from atmospheric neutrinos, and search for light WIMPs, solar axions, axion-light particles and signatures of sterile neutrinos. The detector will be capable of accurately measuring solar pp neutrinos as well as the signal from coherent neutrino-nucleus scattering of solar boron-8 neutrinos. The detector will also be sensitive to neutrinoless double-beta decay of xenon-136 as well as rare nuclear physics processes such as double electron capture.
Neutron-induced backgrounds are among the dominant backgrounds in low-background experiments. One of the main processes that produce these neutrons is the ($\alpha$,n) reaction occurring in detector components. An accurate understanding of these backgrounds is important for any low-background experiment. In this talk, we will present NeuCBOT, a new tool for calculating ($\alpha$,n) yields and neutron energy spectra in arbitrary materials. By combining NeuCBOT calculations with ex situ measurements of the radioactive contamination of detector components, we will predict the neutron backgrounds in the DEAP-3600 Weakly Interacting Massive Particle detector.
DEAP-3600 is a single-phase detector located at SNOlab with over three tonnes of liquid argon. When neutrons scatter in the liquid argon, they produce a scintillation signal that can be differentiated from most backgrounds using pulse shape discrimination. After the neutron scatters in the argon, it will slow down and eventually capture in one of the detector components. By detecting coincidences between the nuclear recoils in the liquid argon and the signal produced by neutron capture products, we can place an in situ constraint on the neutron background rate in the experiment. By doing so, we will show that the neutron background rate in DEAP-3600 is consistent with the predictions made by NeuCBOT.
Germanium detectors with sub-keV sensitivities [1] offer a unique opportunity to study neutrino interactions and properties [2] as well as to search for light WIMP Dark Matter and axion-like particles [3]. The TEXONO Collaboration has been pursuing this research program at the Kuo-Sheng Neutrino Laboratory (KSNL) in Taiwan. We will highlight our results on neutrino electromagnetic properties, search of sterile neutrinos, as well as studies towards observation of neutrino-nucleus coherent scattering. The detector R&D programs which allow us to experimentally probe this new energy window will be discussed. The efforts set the stage and complement the CDEX dark matter experiment and beyond at the new China Jinping Underground Laboratory (CJPL) in China.
[1] H. T. Wong et al., J. Phys. Conf. Ser. 39, 266 (2006) ; H.B. Li et al., Astropart. Phys. 56, 1 (2014) ; A.K. Soma et al., Nucl. Instrum. Meth. A836, 67 (2016) ; L.T. Yang et al., arXiv:1610.07521 (2016).
[2] J.-W. Chen et al., Phys. Rev. D 90, 011301(R) (2014) ; J.-W. Chen et al., Phys.Rev. D 91,013005 (2015) ; J.-W. Chen et al., Phys. Rev. D93, 093012 (2016) ; S. Kerman et al., Phys. Rev. D93, 113006 (2016).
[3] H.B. Li et al, Phys. Rev. Lett. 110, 261301 (2013) ; Q. Yue et al., Phys. Rev. D 90, 091701(R) (2014) ; S.K. Liu et al., Phys. Rev. D 90, 032003 (2014) ; W. Zhao et al., Phys. Rev. D93, 092003 (2016) ; S.K. Liu et al., arXiv:1610.07521 (2016).
Parallel Neutrino Talks
In this talk, we will summarize the current status of global neutrino oscillation analyses in the three-neutrino framework. We will also discuss some scenarios where the measurement of the CP violation phase could be significantly affected by the presence of neutrino physics BSM.
The DeepCore infill array of the IceCube Neutrino Observatory enables observations of atmospheric neutrinos with energies as low as 5 GeV. Using a set of 40,000 neutrino events with energies ranging from 5.6 - 56 GeV recorded during three years of DeepCore operation, we measure the atmospheric oscillation parameters $\theta_{23}$ and $\Delta m^2_{32}$ with precision competitive with long-baseline neutrino experiments, by observing distortions in the neutrino energy-zenith angle distribution. Our measurements are consistent with those made at lower energies, and prefer a value of $\theta_{23}$ close to maximal.
The measurement of the Neutrino Mass Ordering (NMO), i.e. the ordering of the three neutrino mass eigenstates, is one of the major goals of many future neutrino experiments. One strategy is to measure matter effects in the oscillation pattern of atmospheric neutrinos as proposed for the PINGU extension of the IceCube Neutrino Observatory.
Already, the currently running IceCube/Deepcore detector can explore this type of measurement. Albeit with lower significance, such measurement can contribute to the current understanding. Furthermore, such an analysis exercises the measurement principle and evaluation of systematic uncertainties and thus prototypes future analyses with PINGU.
We present a three-dimensional likelihood analysis for multiple years of IceCube data searching for indications of the NMO with a data sample reaching to energies below 10GeV.
The IceCube-DeepCore detector has unambiguously observed muon-neutrino disappearance due to oscillations of atmospheric neutrinos. The associated tau-neutrino appearance may be measured as a statistical excess of cascade-like events in the detector. New high statistics event selections, optimized for the study of oscillations around 10 GeV, provide increased sensitivity for the measurement of muon neutrino disappearance as well as the potential for strong constraints on tau neutrino appearance. This talk will discuss the ongoing efforts to measure the tau neutrino appearance in the atmospheric neutrinos observed by the current
DeepCore array.
The IceCube Gen2/Phase1 detector has been proposed to in-fill IceCube's DeepCore region with seven new, densely-instrumented strings. These strings would provide the world's best sensitivity to tau neutrino appearance, with a precision of better than 10%, providing the most stringent test of unitarity in the tau sector to date. Gen2/Phase1 would also have improved sensitivity to muon neutrino disappearance and dark matter searches, and would provide a calibration platform that will improve our understanding of the optical properties of the ice, with positive impact on current and future IceCube analyses at all energy scales. The strings would be placed on a grid consistent with expansion to the future proposed PINGU array. In this presentation we describe the sensitivities of Phase 1 to neutrino oscillations and dark matter, the new calibration devices planned for co-deployment, and the impact those devices will have on future analyses.
The 760 ton liquid argon ICARUS T600 detector performed a successful three-year physics run at the underground LNGS laboratories, studying neutrino oscillations with the CNGS neutrino beam from CERN, and searching for atmospheric neutrino interactions in cosmic rays. A sensitive search for LSND like anomalous nu_e appearance was performed, contributing to constrain the allowed parameters to a narrow region around Δm$^2$~eV$^2$, where all the experimental results can be coherently accommodated at 90% C.L.
The T600 detector will be redeployed at Fermilab, after a significant overhauling, to be exposed to the Booster Neutrino Beam acting as the far station to search for sterile neutrino within the SBN program.
The proposed contribution will address ICARUS LNGS achievements and the ongoing analyses also finalized to the next physics run at Fermilab.
The OPERA experiment reached its main goal by proving the appearance of tau-neutrinos in the CNGS muon neutrino beam. A total sample of 5 candidates fulfilling the analysis defined in the proposal was detected with a S/B ratio of about ten allowing to reject the null hypothesis at 5.1 sigma. The search has been extended to nu_tau-like interactions failing the kinematical analysis defined in the experiment proposal to obtain a statistically enhanced, lower purity, signal sample. One such interesting neutrino interaction with a double vertex topology will be reported with a high probability of being a nu_tau interaction with charm production. Based on the enlarged data sample the estimation of delta-m^2_23 in appearance mode is presented. The search for nu_e interactions has been extended over the full data set with a more than twofold increase in statistics with respect to published data. The analysis of the nu_mu->nu_e channel is updated and the implications of the electron neutrino sample in the framework of the 3+1 sterile model is discussed. An analysis of nu_mu -> nu_tau interactions in the framework of the sterile neutrino model has also been performed.
T2K is a long-baseline neutrino oscillation experiment taking data since
2010. A neutrino beam is produced at the J-PARC accelerator in Japan and is
sampled at a Near Detector complex 280 m from the
neutrino production point and at the far detector, Super-Kamiokande.
Beams predominantly composed of muon neutrinos or muon anti-neutrinos have been
produced by changing the currents in the magnetic focusing horns.
The additional neutrino-mode data collected with T2K in 2017 have doubled the statistics relative to previous analysis releases.
This presentation will show the most recent T2K oscillation results
obtained from a combined analysis of the entire available data set in the
muon neutrino and muon anti-neutrino disappearance channels, and in the electron neutrino and electron anti-neutrino appearance channels. Using these data, we measure four
oscillations parameters: $\sin{\theta_{23}}$, $\sin{\theta_{13}}$, $|\Delta
m^2_{32}|$ and $\delta_{CP}$, as well as the mass ordering.
T2K also has new neutrino cross-section measurements. In addition to being interesting in their own right, measuring neutrino cross sections is vital as they correspond to a major systematic uncertainty for neutrino oscillation analyses. In particular, the new results focus on exploiting the water targets
in the T2K off-axis near detector, ND280, updating our charged-current measurements with a wider phase space, and addressing in more detail the neutrino interaction vertex. This talk will give an overview of the T2K neutrino cross-section measurements, focusing on the latest results.
VERITAS has been observing the northern sky at TeV energies with full sensitivity since 2007. Consisting of a ground based array of four 12m imaging atmospheric Cherenkov telescopes sited in southern Arizona it is one of the world’s most sensitive detectors of gamma-rays between 85GeV to 30TeV. VERITAS maintains a broad scientific programme in many areas of astroparticle physics, including, but not limited to: studies of the acceleration, propagation and indirect measurements of cosmic rays and their spectra; searching for indirect detection signatures of dark matter candidates; and tests of fundamental physics, such as setting constraints on Lorentz invariance violation. There is also an active multi-messenger programme with partners in the electromagnetic, neutrino, and gravitational wave sectors. We review here the current status and some recent results from VERITAS and examine the prospects for future studies.
The Pierre Auger Observatory has been designed to investigate the origin and the nature of Ultra High Energy Cosmic Rays.
The combination of information from a surface array, measuring the lateral distributions of secondary particles at the ground, and the fluorescence telescopes, observing the longitudinal profile, provides an enhanced reconstruction capability and opens the way for a multi-messenger approach.
A review of selected results is presented, covering the measurement of energy spectrum, arrival directions, and chemical composition and the search for primary photons and neutrinos. Finally, the motivation and the status for the ongoing major upgrade of the Observatory, AugerPrime, will be discussed with the emphasis given to its expected performance and future perspectives.
The High Altitude Water Cherenkov (HAWC) observatory is an air shower detector designed to study very-high-energy gamma rays (~100 GeV to ~100 TeV). It is located in the slopes of the volcano Sierra Negra in the state of Puebla, Mexico at an elevation of 4100 m. HAWC has a instantaneous field of view of 2 sr and a duty cycle of >95%, scanning 2/3 of the sky everyday. In this talk we will report the observations by HAWC that include the detection of ~40, point and extended, gamma-ray sources (already known and new) as well as their physical properties. Also HAWC monitors the flux from the Crab Nebula and two nearby active galactic nuclei, Mrk 421 and Mrk 501, every day as well as searching for transient on various timescales from other sources. HAWC also provides follow-up observations for alerts sent by other instruments like LIGO and IceCube.
The OPERA detector was used to measure the annual modulation of the atmospheric muon flux at the Gran Sasso underground laboratory (3800 m w.e.). We present preliminary results using 5 years of data (2008-2012) showing a flux modulation with a period of 1 year and a relative amplitude of 1.5%. The phase of the maximum intensity and the effective temperature coefficient $\alpha_T$, which correlates variations in the muon rate and seasonal temperature variations, are both in agreement with theoretical expectations and other experimental results at LNGS.
PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) is a satellite-borne experiment. It was launched on June 15th 2006 from the Baikonur space centre on board the Russian Resurs-DK1 satellite. For about 11 years PAMELA took data, giving a fundamental contribution to the cosmic ray physics. It made high-precision measurements of the charged component of the cosmic radiation challenging the standard model of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy and in the heliosphere.
PAMELA gave results on different topics on a very wide range of energy. Moreover, the long life of PAMELA gives the possibility to study the variation of the proton, electron and positron spectra during the last solar minimum. The time dependence of the cosmic-ray protons and helium nuclei from the solar minimum through the following period of solar maximum activity is currently being studied. Low energy particle spectra were accurately measured also for various solar events that occurred during the PAMELA mission.
In this talk a review of main PAMELA results, together with the latest analysis updates, will be shown.
The KM3NeT Collaboration aims at the discovery and subsequent observation of high neutrino sources in the Universe (ARCA) and at the determination of the neutrino mass hierarchy (ORCA).
This talk is focused on ARCA. The deployment of the firsts Detection Units at 3500 m depth offshore CapoPassero (Italy) started and two strings are in operation and data taking. ARCA will made of two buildings blocks made of 115 Detection Units corresponding to an instrumented volume of about 1 km3 and will provide a very large coverage of the neutrino sky (87% for up going muon neutrinos). The superior angular resolution (0.1° at energy higher of 10 TeV) will be very important for source search. In this talk the detector technology, status and perspectives for detection of high energy neutrinos signals from different candidate sources are discussed.
Horizon-T is a newly completed (Oct. 2016) innovative detector system constructed to study temporary structure of Extensive Air Showers (EAS) in the energy range above ~10^16 eV coming from a wide range of zenith angles (0 - 80 degress). The system is located at Tien Shan high-altitude Science Station of Lebedev Physical Institute of the Russian Academy of Sciences at approximately 3340 meters above the sea level. It consists of eight charged particle detection points separated by the distance up to one kilometer as well as optical detector subsystem to view the Vavilov-Cherenkov light from the EAS. The time resolution of charged particles passage of the detector system is a few ns. This level of resolution allows conducting research of atmospheric development of individual EAS.
The total of ~7200 Extensive Air Showers (EAS) with the energy above 10^16 eV have been detected during the ~3500 hours of Horizon-T detectors system operations since October 24, 2016. Among these EAS, a large amount had a spatial and temporary structure that showed the pulses with several maxima (modals or modes) from several detection points of the Horizon-T at the same time. These modes are separated in time from each other starting from tens to thousands of ns. These EAS are called multi-modal. Some are further classified as unusual.
Analysis shows that the multi-modal EAS that have been detected by Horizon-T have the following properties:
1) Multi-modal EAS have energy above ~10^17 eV;
2) Pulses with several modes are detectable at large distances from EAS axis.
The presentation will briefly overview a general performance of the detector
system, then the latest results from the collected data including the multi-modal and unusual EAS events will be presented.
IceCube-Gen2, the proposed extension of the IceCube Neutrino Observatory, will enhance both the surface and in-ice capabilities of the facility. Ideas for adding surface radio antennas are under discussion in addition to the upgrade and extension of the IceTop surface array using scintillator detectors. While the scintillators will primarily be used for improving the calibration and lowering the veto energy threshold for distinguishing cosmic ray from astrophysical neutrino events, they can also be used with radio antennas to search for photons of PeV energies from the Galactic Center.
The Galactic Center is visible from the South Pole throughout the year, at an inclination of around 61 degrees. Photons arriving at the South Pole from this direction, will produce inclined air showers in the atmosphere. Since radio emission of inclined showers leaves a large footprint on the ground, a measurement of the electromagnetic shower component using the radio technique is possible. It is already known that radio detection of air showers helps in the reconstruction of Xmax and the energy of the air showers with a very good accuracy. Using radio detectors along with particle detectors enhances the detection accuracy of the air shower events and helps in separating the photon induced events. Using such a setup at the South Pole can help in the identification of the Galactic Center as a PeVatron. In particular, the key for such a search is to use frequencies different from the standard frequencies used by air shower radio experiments. The first results will be presented in this talk.
Session of posters
Abstract: Observation of neutrinoless double beta decay would be a break through in particle physics, astroparticle physics and cosmology, as it would imply lepton number violation, establish the Majorana character of neutrinos and shed light on the evolution of the early Universe. Current experiments have half-live sensitivities up to several 1025 yr probing part of the parameter space predicted for degenerate neutrino masses. The next generation experiments aim to scrutinize half-lives up to 1027–1028 years range or effective Majorana mass of O(10 meV), as predicted by neutrino oscillation experiments in case of inverse mass ordering. I will review the latest experimental results and discuss the future projects with their projected experimental performances and sensitivities. Critical parameters as sensitive exposure, backgrounds will be compared amongst future projects and with the experimental state-of-the-art.
The GERmanium Detector Array (GERDA) experiment at the INFN Gran Sasso Laboratory, Italy, is searching for the neutrinoless double beta ($0\nu\beta\beta$) decay of the isotope $^{76}$Ge. High-purity germanium crystals enriched in $^{76}$Ge are the source and the detector simultaneously. The key design feature of GERDA is that detectors are deployed directly into an ultra-pure cryogenic liquid (liquid argon), acting both as cooling medium and radiation shield against the external radiation. The signature of the $0\nu\beta\beta$ decay would be a mono-energetic peak at the Q$_{\beta\beta}$-value of the process, namely 2039 keV for $^{76}$Ge.
Data from the first phase of GERDA (Phase I), collected between 2011 and 2013, gave no positive indication of the $0\nu\beta\beta$ decay of $^{76}$Ge with an exposure of about 20 kg yr. GERDA Phase I reached a background index at the Q$_{\beta\beta}$-value of 10$^{-2}$ counts/(keV kg yr) and set a lower limit on the half-life of the process of T$_{1/2}$ > 2.1·10$^{25}$ yr (90% C.L.).
The second Phase of the experiment is taking data since 2015 with a doubled mass of enriched Ge detectors. The goal of Phase II is to collect a “background-free” exposure of 100 kg yr, thus to reduce the background to 10$^{-3}$ counts/(keV kg yr). Newly developed custom-made BEGe-type Germanium detectors add 20 kg of mass and allow for a superior background rejection by pulse shape discrimination. The other key handle for the background suppression in Phase II is the instrumentation of the cryogenic liquid surrounding the detectors for light detection serving as additional active veto.
Initial results from Phase II with about 10 kg yr exposure (published in Nature vol. 544, April 6th 2017) allow to improve the limit on the half-life of $0\nu\beta\beta$ decay of $^{76}$Ge to T$_{1/2}$ > 5.3·10$^{25}$ yr (90% C.L.) and indicate that the target background is achieved, thus making GERDA the first experiment in the field which will be “background free” up to the design exposure. A total Phase II exposure of about 40 kg yr is expected to be available at the time of the Conference. All data collected after the initial data release are “blinded”, i.e. events in Q$_{\beta\beta}$±25 keV are not available for analysis, in order to prevent any selection bias. Preliminary analysis of the available data outside the blinded region confirms the background performance.
This presentation will summarize the basic concept of the GERDA design, the data taking and the physics results obtained in Phase II. A special focus will be given to the background achieved at Q$_{\beta\beta}$ and to the analysis of the residual background components. A new data unblinding is foreseen to take place shortly before the Conference; if confirmed, new physics results on $0\nu\beta\beta$ decay with about 40 kg yr exposure will be also presented and discussed.
Long-baseline neutrino experiments use neutrino beams produced at
accelerators to study the oscillation of neutrino flavours as they
traverse hundreds of kilometers between the primary beam target and a
far detector. Current long-baseline experiments have the world's best
sensitivity to the neutrino mixing angle theta_23 and the mass
splitting dm²_32. They additionally provide the only available data
about the complex phase of the PMNS matrix that is a source of CP
violation in the neutrino sector. In this review talk I will examine
the methodology and results from long-baseline experiments and discuss
future prospects.
Long-baseline neutrino experiments have been crucial in our understanding of neutrino oscillations. Future long-baseline oscillation experiments will seek to address the remaining questions in the standard 3-neutrino oscillation model, including CP violation, the mass hierarchy, and maximal mixing, in addition to searching for new physics. In this talk, I will give an overview of the status and prospects for future long-baseline neutrino oscillation experiments.
Indirect searches for dark matter are a cornerstone in the dark matter particle identification program. Searches for stable messenger particles produced as part of the self-annihilation or decay of dark matter have resulted in stringent bounds on dark matter properties. Searches with gamma-rays, neutrinos, and charged cosmic-rays will be summarized and constraints on the dark matter self-annihilation cross section, lifetime, and interaction with ordinary matter will be reviewed. The talk will conclude with an outlook in the discovery potential at current and next-generation dark matter search experiments.
Direct detection of dark matter is a promising approach to discovering the nature of dark matter particles. I describe the future of this field of research, focusing on new technologies proposed for reaching the irreducible neutrino background for low-mass dark matter, with particle mass less than 10 GeV/c^2. I also describe new technologies for axion dark matter detection, again focusing on new technologies that promise to expand the mass range available to experimental inquiry.
Direct dark matter searches are promising techniques to identify the nature of dark matter particles. A variety of experiments have been developed over the past decades, aiming at detecting Weakly Interactive Massive Particles (WIMPs) via their scattering in a detector medium. Exploiting directionality would give a proof of the galactic origin of dark matter making it possible to provide a clear and unambiguous signal to background separation. In particular, the directionality appears as the only way to overcome the neutrino background that is expected to finally prevent standard techniques to further lower cross-section limits. The directional detection of Dark Matter requires very sensitive experiment combined with highly performing technology. The NEWSdm experiment, based on nuclear emulsions, is proposed to measure the direction of WIMP-induced nuclear recoils and it is expected to produce a prototype in 2017. We discuss the discovery potential of a directional experiment based on the use of a solid target made by newly developed nuclear emulsions and read-out systems reaching sub-micrometric resolution.
NEWAGE is a direction-sensitive direct dark matter search experiment with a three-dimensional gaseous tracking detector (micro-TPC). Our goals are detection of dark matter - nucleus scattering signal in the micro-TPC and investigation of the characteristics of the kinematics of dark matter in the Galaxy. Our direction-sensitive dark matter search by NEWAGE-0.3b’ has been performed in Kamioka underground laboratory in Japan since Jul. 2013. A dark matter search experiment was performed from Jul. 2013 to Aug. 2016 (RUN14–17) with a total live time of 230.16 days which is about seven times larger than that of previous result (PTEP 2015, 043F01. DOI: 10.1093/ptep/ptv041). In the analysis, we improved the event selection and the background was reduced to 1/3 at 50 keV. In order to perform a direction-sensitive experiment with higher sensitivity, we also have studied a three-dimensional head-tail recognition of recoil nuclear tracks. This work is important to investigate the properties of dark matter in the Galaxy in the future dark matter research. We will present the latest results of NEWAGE with the three-dimensional head-tail recognition analysis, R&Ds and future prospects.
In order to perform Directional DM detection, low energy nuclear recoil tracks have to be detected. The MIMAC collaboration has recently reported the first detection of 3D nuclear tracks coming from the Radon progeny confirming the possibility to perform this kind of measurement with an ionization quenching measurement on these heavy nuclei. The nuclear recoils produced by monochromatic neutron fields have been detected by a MIMAC chamber, allowing the experimental determination of the electron-nuclear recoil discrimination at the same time that the angular distribution of the Fluorine recoils produced by the neutron elastic collision has been experimentally described.
A new facility called COMIMAC has been developed at the LPSC (Grenoble) to perform the 3D characterization of nuclear tracks of known kinetic energies. The first measurements performed by the Sino-French MIMAC collaboration will be reported showing clear differences with respect to the best simulation available.
We also report here the implementation of the measure of the signal induced on the cathode by the motion of the primary electrons toward the anode in a MIMAC chamber. As a validation, we performed an independent measurement of the drift velocity of the electrons in the considered gas mixture, correlating in time the cathode signal with the measure of the arrival times of the electrons on the anode.
We will also say few words about the status of the m3 detector based on MIMAC cells witch will be installed in Modan underground laboratory as well as about the ongoing effort to build the next generation directional Dark Matter detector : Cygnus.
The axion is a hypothetical particle invented for solving the CP problem in strong interactions.
The XMASS-I detector with 832 kg of natural xenon has the sensitivity for searching for axions produced in the Sun thanks to its low energy threshold and low background.
In the XMASS commissioning run, we obtain the model independent limit on the coupling for mass << 1 keV is g_aee < 5.4 x 10^-11 (90% C.L.) for solar axion analysis.
As expected event rate of solar axion signal has the seasonal variation depending on the distance from the Sun, such information can enhance the detection sensitivity and its evidence.
In this talk, we will present the result of a search for solar axion by annual modulation with about 1 year of XMASS-I data.
The LUX experiment has been searching for direct evidence of rare events including the interactions galactic dark matter. LUX is a 250 kg active liquid-xenon target situated 1.5 km underground at the Sanford Underground Research Facility in Lead, South Dakota (USA).
It is a liquid/gas time projection chamber capable of 3-D position reconstruction and nuclear recoil discrimination. We will present the latest results for analyses based on LUX data taken during the full operations period. These results will include world-leading results in WIMP direct detection based on spin independent and spin dependent couplings, and also using more generalized Effective Field Theory calculations. We will report results from searches for Axion and Axion-like particles. We will also report on searches for evidence of neutrinos with Majorana mass. We can also reported on significant and surprising findings concerning the response of the LUX to electron and nuclear recoil events spanning energies from 170 eV to MeV-scale.
International Axion Observatory (IAXO) is a new generation axion helioscope aiming to search for solar axions and axion-like particles (ALPs) with a signal to background ratio of about 5 orders of magnitude higher than the one achieved by currently the most sensitive axion helioscope, CAST. IAXO relies on large improvements in magnetic field volume and extensive use of x-ray focusing optics combined with low-background detectors. IAXO will probe a substantial unexplored region of the axion and ALP parameter space which is theoretically and cosmologically motivated, and thus will have significant discovery potential. IAXO could also be used to test models of other proposed particles at the low energy frontier of particle physics, like hidden photons or chameleons. In addition, the IAXO magnet could accommodate new equipment to search for relic axions or ALPs potentially composing the galactic halo of dark matter.
XMASS is multi-purpose experiment using a single phase liquid xenon technology located underground at Kamioka Observatory in Japan.
XMASS-I detector aims mainly for direct detection of dark matter particles with 832 kg of liquid xenon.
The key idea to reduce the background at low energies in XMASS is to use liquid xenon itself as a shield. The clean core of the 832 kg liquid xenon volume is used as sensitive fiducial volume by eliminating the volume near the wall which suffers from beta and gamma rays from the outside.
In this talk, we will present the physics results for our WIMP search using this fiducial volume of the XMASS-I detector with precise prediction of background events.
Radon is an important background consideration for rare-event searches such as dark matter direct detection and neutrinoless double-beta decay experiments. Materials of construction for these experiments often require screening of ultra-low radon levels, sometimes as few as tens of atoms in equilibrium. Radon emanation is one of the most sensitive and robust ways of making these measurements. A system for low-level measurements has been commissioned at the Pacific Northwest National Laboratory (PNNL) that achieves high sensitivity through use of custom high-efficiency ultra-low-background proportional counters. The system includes small and large radon emanation chambers coupled to a custom-built gas handling system with a cryogenic radon trap. The emanation system and detection method will be described, and characterization of backgrounds and efficiencies using a calibrated radon source will be discussed.
Activation of germanium crystals due to cosmic rays becomes a serious hazard for experiments searching for rare events with germanium detectors.
Cosmic ray induced activation of the detector components and, even more importantly, of the germanium itself during production, transportation and storage at the Earth's surface, might result in the production of radioactive isotopes with long half-lives, with a possible impact on the expected background. We present a measurement of the cosmogenic activation in the cryogenic germanium detectors of the EDELWEISS III direct dark matter search experiment. The decay rates measured in detectors with different exposures to cosmic rays above ground are converted into production rates of different isotopes. They are compared to model predictions present in literature and to estimates calculated with the ACTIVIA code.
As a few ultra-low background rare decay experiments at the Yangyang underground laboratory in Korea are being prepared and under operation, a number of ultra-low radioactivity measurement detectors have been developed. For a screening of raw materials or detector components, an ICP-MS, an argon gas ionization counter, a ZnS counter, and a number of HPGe detectors are operating. A silicon PIN photodiode based radon detector has been upgraded for a measurement of the air from a radon reduction system in a radon level of 10 mBq/m3. An array of 14 HPGe detectors was installed for an efficient measurement of background gamma rays from bigger samples than those could be tested in two single crystal HPGe detectors. As candidates of detector materials, various types of scintillation crystals such as CaMoO4, Li2MoO4, and NaI(Tl) have been grown with purified raw materials and tested for their radioactivity background levels with the above mentioned instruments. A summary of their developments and preliminary performances together with a future plan will be presented.
High-sensitivity, low-threshold material surface screening is necessary to meet the stringent radiopurity requirements for rare-event searches. The BetaCage is a proposed ultra-low-background time projection chamber (TPC) designed to screen alphas and low-energy betas emitted from material surfaces at trace levels, providing a transformative effect on isotopic assay efforts. I will describe the TPC design, the expected backgrounds and mitigation techniques, the estimated alpha and beta sensitivity, and the commissioning of a prototype TPC currently deployed at SDSM&T.
DUNE, the DEEP Underground Neutrino Experiment, will be a groundbreaking experiment for long-baseline neutrino oscillation studies, and for neutrino astrophysics and nucleon decay searches. Planning of DUNE continues to proceed rapidly. The DUNE Far Detector will consist of four 10-kiloton fiducial volume modular liquid argon time-projection chambers (LArTPC) placed deep underground at the Sanford Underground Research Facility in Lead, South Dakota, USA. The Far Detector will be coupled to the LBNF multi-megawatt wide-band neutrino beam planned for Fermilab. The LArTPC technology allows for detailed reconstruction of neutrino interaction and nucleon decay final states over an energy range from a few MeV to many GeV, providing high resolution vertex determination, precision charged particle tracking, particle identification, and calorimetry. Photon detector systems embedded within the LArTPC add precise timing capabilities for non-beam events. Designs for both single phase and dual phase LArTPC have reached advanced stages; and these designs will be tested through a full-scale prototyping program called ProtoDUNE, to be executed at CERN over the next few years.
The former Homestake gold mine in Lead, South Dakota, has been transformed into a dedicated facility to pursue underground research in rare-process physics, as well as offering unique research opportunities in other disciplines. The Sanford Underground Research Facility (SURF) includes two main campuses at the 4850-foot level (4300 m.w.e.) – the Davis Campus and the Ross Campus – that host a range of significant physics projects: the LUX dark matter experiment, the MAJORANA DEMONSTRATOR neutrinoless double-beta decay experiment and the CASPAR nuclear astrophysics accelerator. Furthermore, the BHUC Ross Campus laboratory dedicated to critical material assays for current and future experiments has been operating since Fall 2015. Research efforts in biology, geology and engineering have been underway at SURF for almost 10 years and continue to be a strong component of the SURF research program. Plans to accommodate future experiments at SURF are well advanced and include geothermal-related projects, the next generation direct-search dark matter experiment LUX-ZEPLIN (LZ) and the Fermilab-led international Deep Underground Neutrino Experiment (DUNE) at the Long Baseline Neutrino Facility (LBNF). SURF is a dedicated research facility with significant expansion capability, and applications from other experiments are welcome.
Dark matter constitutes over 80% of the matter in the Universe, but its composition remains one of the most profound mysteries in modern science. The Super Cryogenic Dark Matter Search at SNOLAB will use germanium and silicon ultra-high-resolution detectors to search for small energy depositions from galactic dark matter particles with masses below 10× the mass of the proton. Decay of radon daughters on or near the detector surfaces can lead to background events capable of masking the (small) anticipated dark matter interaction rate. To address this background concern, we have conducted a test measurement campaign to validate the cleanliness of critical detector fabrication processes for the surfaces of the detector crystals and their copper housings. I will describe these measurements and discuss the results, including implications for the expected dark matter sensitivity. I will also discuss the overall program for control of radon-related backgrounds in SuperCDMS SNOLAB.
Experiments currently searching for dark matter and studying properties of neutrinos require very low levels of radioactive backgrounds both in their own construction materials and in the surrounding environment. These low background levels are required so that the current and next generation experiments can achieve the required sensitivities for their searches. This presentation will describe the low background measurement facilities currently operating at SNOLAB and will discuss plans and options to expand these facilities to allow for the increased sensitivity required by the next generation of experiments.
Parallel Neutrino Talks
NOvA is a long-baseline neutrino oscillation experiment utilizing the NuMI beam from Fermilab and a 14 kton liquid scintillator far detector in northern Minnesota. Recent results for both the muon-neutrino disappearance and the electron-neutrino appearance channels will be discussed, as well as improvements and cross-checks for our next round of analyses.
All neutrino oscillation experiments face the problem of reconstructing the incoming neutrino energy using only the visible interaction products. Unfortunately, the initial neutrino interaction is not well understood, and some of the interaction products not are visible. In preparation for the analysis of neutrino oscillation data collected using liquid argon time projection chambers, the Cryogenic Apparatus for Precision Tests of Argon Interactions with Neutrinos (CAPTAIN) program makes crucial measurements addressing these problems in two distinct phases. The first uses Mini-CAPTAIN to measure the cross section of neutrons impinging on an argon target with a kinetic energy of more than 50 MeV. This measurement will help determine the signature of neutrino generated neutrons in a LArTPC. Mini-CAPTAIN, a LArTPC with 400 kg of instrumented mass, is currently deployed in a neutron beamline at the Los Alamos Neutron Science Center (LANSCE) at Los Alamos National Laboratory (LANL). The LANSCE beam provides a well-known flux of neutrons up to a kinetic energy of 800 MeV. The total cross section will be measured as a function of neutron kinetic energy, and partial cross sections for n + Ar → p + X and n + Ar → π± + X will be measured above the threshold for the produced protons and pions. I will report results from a February 2016 engineering run during which Mini-CAPTAIN collected neutron data with a photon-detection system, discuss the upcoming neutron data and their implications for the long-baseline oscillation analysis at DUNE. Finally, I will discuss a future deployment of CAPTAIN, a LArTPC with 5 tons of instrumented mass, at a stopped-pion neutrino source and the implications of the measurements for the future DUNE supernova physics program.
Hyper-Kamiokande is a next generation water Cherekov detector consisting of 2 tanks, each with 187 kton fiducial mass, to be built in a staged approach. Hyper-Kamiokande will detect neutrinos produced by the upgraded J-PARC accelerator complex, as well as atmospheric neutrinos. It will enable us to search for CP violation in the lepton sector with an order of magnitude more data than current long baseline experiments will collect. Hyper-Kamiokande will also make precision measurements of the phase delta_cp and the atmospheric mixing parameters by a combination of accelerator and atmospheric neutrinos. Hyper-Kamiokande also aims to discover the proton decay. This talk will discuss overview of the Hyper-Kamiokande project and its physics programs, focusing on neutrino oscillation physics and proton decay search.
Hyper-Kamiokande (Hyper-K) is a next generation water Chrenkov detector in Japan
consisting of two identical detectors (2x260 kton) with a staged construction.
Main goals of Hyper-K are a definitive measurement of CP violation
and neutrino mass ordering determination using beam neutrinos from J-PARC.
By relocating the 2nd detector in Korea with more than 3 times longer baseline
and more matter effect the sensitivities on the two measurements and non-standard neutrino interaction are improved.
Thanks to a larger overburden in Korean candidate sites, sensitivities on solar, supernova,
and supernova relic neutrinos are also improved.
In this talk I introduce this interesting option of having the 2nd tank in Korea
and present the physics potentials.
The proposed Hyper-Kamiokande experiment (Hyper-K) is a next generation large water Cherenkov (WD) detector with a broad physics program consisting of neutrino beam measurements in search of leptonic CP violation, astrophysical measurements and a search for proton decay. Hyper-K will act as the far detector to measure the oscillated neutrino flux from the long-baseline beam of 0.6 GeV neutrinos/anti-neutrinos produced by a 1.3 MW proton beam at J-PARC in Japan. To minimise systematic uncertainties, particularly due to flux and cross-section uncertainties, detailed measurements of the unoscillated flux are required with a suite of near detectors. This talk will review the challenges, and present the planned components of the near detector measurement suite, including a new intermediate Water Cherenkov Detector.
The Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino oscillation experiment with primary physics goals of determining the neutrino mass hierarchy and measuring delta_CP with sufficient sensitivity to discover CP violation in neutrino oscillation. CP violation sensitivity in DUNE requires careful understanding of systematic uncertainty, with contributions expected from uncertainties in the neutrino flux, neutrino interactions, and detector effects. In this presentation, we will describe the expected sensitivity of DUNE to long-baseline neutrino oscillation parameters, how various aspects of the experimental design contribute to that sensitivity, and the planned strategy for constraining systematic uncertainty in these measurements.
The reference design of the near detector for the LBNE/F experiment is a high-resolution Fine-Grained Tracker (FGT) capable of precisely measuring all four species of neutrinos. Other detector options under consideration are liquid-argon and gaseous-argon TPCs, as well as a hybrid between the detector concepts. The goal of the ND is to constrain the systematic errors below the corresponding statistical error in the far detector, for all oscillation studies; and to conduct a wide range of precision measurements and searches in neutrino physics. We present sensitivity studies of the measurements – critical to constraining the systematics in oscillation searches – of the absolute and relative neutrino flux using various techniques. The precision in the determination of the absolute and relative fluxes achieved in DUNE ND will allow to fully exploit the potential of the (anti)-neutrino probe.
Borexino is a 300 tons sub-MeV liquid scintillator solar neutrino detector
which has been running at the Laboratori Nazionali del Gran Sasso (Italy) since 2007.
Thanks to its unprecedented radiopurity, it was able to measure the
flux of 7Be, 8B, pp, and pep solar neutrinos and to detect geo-neutrinos. A reliable simulation of the detector is an invaluable tool for all the Borexino physics analyses.
The measurement of the solar neutrino interaction rates requires the highest level of accuracy from the simulation, which is used to generate the energy spectra of all the components used in the ?final fi?t of the recorded energy spectrum. The simulation accounts for the energy loss of particles in all the detector components, the generation of the scintillation photons, and their propagation within the liquid scintillator volume. Moreover, each
time a photomultiplier detects a photon, the algorithm proceeds with a detailed simulation of the electronics chain.
Finally, a novel efficient method for simulating the external background which survives the Borexino passive shield has been developed. This technique allows to reliably predict the effect of the contamination in the peripheral construction materials.
The techniques developed to simulate the Borexino detector and their level of re?finement are of possible interest to the neutrino community, especially for current and future large-volume liquid scintillator experiments, and for dark matter community, given the wide use of veto systems made of liquid scintillators. The contribution will show the level of accuracy of the simulation and will highlight the fundamental aspects to implement a high precision simulation of a liquid scintillator detector.
Large area and low background experiments such as nEXO (next Enriched Xenon Observatory, a proposed 5 tonne-scale detector) are looking for new and innovative ways to improve the sensitivity of their detectors. Installing the photodetectors and their electronic readout directly in the detector active medium is among promising approaches. In turn, this introduces new constraints on the radioactivity background and on the power consumption of the electronics. While the common baseline is to use silicon photomultipliers (SiPM), the Sherbrooke radiation instrumentation team is proposing a vertically integrated and digitally controlled SiPM (3D-dSiPM). The digital readout takes advantage of the inherently binary nature of the Geiger-mode avalanche photodiode, provides fast in-chip processing and overcomes the output capacitance challenge. Moreover, the 3D structure allows for an independent optimization of the photosensing layer and the electronic readout layer. This talk presents Sherbrooke’s 3D-dSiPM technology and its first prototype results. The work done shows no systematic degradation compared to its 2D equivalent architecture. Furthermore, the readout and trigger algorithm is presented as well as the current work underway to develop a 3D integration process with industrial partners. This last effort aims at providing high yield capability for large area tiles production.
Active background rejection can be achieved in next generation bolometric experiments for rare event searches by detecting the light (scintillation or Cherenkov) that follows an energy deposition.
The CALDER (Cryogenic wide-Area Light Detectors with Excellent Resolution) project is part of the R&D activities under development for the upgrade of the CUORE experiment, a ton-scale neutrinoless double beta decay experiment recently started at the Laboratory Nazionali del Gran Sasso (LNGS).
The CALDER goal is to develop large-area high-sensitivity light detectors with a resolution of 20 eV RMS, using phonon-mediated superconducting kinetic inductance detectors (KIDs).
Here we present the latest results obtained with aluminum KIDs and promising measurements done recently with multilayer titanium-aluminum chips
featuring a remarkable sensitivity. Once the target resolution is achieved, in the last phase of the project we plan to
demonstrate the performances of the new light detectors in a small prototype experiment with TeO$_2$ bolometers at LNGS.
Neutrino and astroparticle physics experiments involving detection of rare and weak interactions, like GERDA, MAJORANA, TEXONO, CDEX , CoGeNT have driven the development of large mass ultra low noise detectors.
With respect to other solid-state materials, germanium presents major advantages for high-sensitivity γ-ray detection. Its excellent electrical properties (lowest band gap and good carrier mobility) are coupled with the best energy resolution of any material. Large single crystals of HPGe (several kg), with impurity concentrations in the range can be grown on an industrial scale, which lead to high levels of detection efficiency.
Low-noise electronics have become key features in the design of high-purity germanium (HPGe) detectors, and has allowed the reach of record detector resolutions. At the same time, as relevant events sometimes have a detection rate as low as 1 event/year/kg of HPGe, an ultra-low radioactive background for all the detector parts, including the front end electronics, is also crucial to the success of these experiments.
This work focuses on the results obtained in the efforts of designing a large (>2 kg) HPGe detector having a modified “point contact” central electrode, combined with an ultra-low noise electronic front end. Measurements on manufactured detectors show record electronic noise performances (65eV FWHM pulser resolution on a 1.5kg HPGe crystal), which translate into a noise threshold below 200eV, making it the ideal instrument for Dark Matter and neutrino experiments. This paper will describe the progress towards reaching similar or better electronic noise performance in even larger HPGe detectors, with current focus to go towards 2.5kg crystals.
This presentation will provide a review of past and current techniques used to load metals in organic liquid scintillator. Both the techniques and their applications will be discussed.
SHIP is a new general purpose fixed target facility, whose Technical Proposal has been recently reviewed by the CERN SPS Committee and by the CERN Research Board. The two boards recommended that the experiment proceeds further to a Comprehensive Design phase in the context of the new CERN Working group "Physics Beyond Colliders", aiming at presenting a CERN strategy for the European Strategy meeting of 2019. In its initial phase, the 400GeV proton beam extracted from the SPS will be dumped on a heavy target with the aim of integrating 2×10^20 pot in 5 years. A dedicated detector, based on a long vacuum tank followed by a spectrometer and particle identification detectors, will allow probing a variety of models with light long-lived exotic particles and masses below O(10) GeV /c2. The main focus will be the physics of the so-called Hidden Portals, i.e. search for Dark Photons, Light scalars and pseudo-scalars, and Heavy Neutrinos. The sensitivity to Heavy Neutrinos will allow for the first time to probe, in the mass range between the kaon and the charm meson mass, a coupling range for which Baryogenesis and active neutrino masses could also be explained. Another dedicated detector will allow the study of neutrino cross-sections and angular distributions. ντ deep inelastic scattering cross sections will be measured with a statistics 1000 times larger than currently available, with the extraction of the F4 and F5 structure functions, never measured so far and allow for new tests of lepton non-universality with sensitivity to BSM physics.
After more than 20 years of data taking and analysis, Super-Kamiokande (SK) will undergo a major upgrade through the addition of 0.2% gadolinium sulfate by mass to its ultra-pure water. This will allow the efficient detection of neutrons, giving access to new physics signals while improving sensitivity to existing ones.
While this upgrade promises many improvements, there were several technical challenges to overcome before its implementation. To address these challenges a dedicated 200-ton gadolinium test facility, EGADS (Evaluating Gadolinium's Action on Detector Systems), was constructed in the Kamioka mine. EGADS has now been stably taking data at the target 0.2% loading for over two years. During this period it has maintained SK levels of water transparency with no detectable loss of gadolinium, successfully proving the concept of gadolinium-doped water Cherenkov technology. With this demonstration complete, EGADS itself is currently undergoing an upgrade and re-branding to EGADS (Employing Gadolinium to Autonomously Detect Supernovae). This upgrade will see new electronics and DAQ installed and real-time reconstruction implemented so that EGADS can autonomously detect and announce a galactic supernova should one occur.
This talk will discuss new technologies developed for EGADS and a gadolinium
loaded SK.
By reconstructing the arrival position and time of photons produced in
water or liquid scintillator on highly segmented fast photo-detectors one can
reconstruct tracks by using the `drift time' of photons, much as one does
with electrons in a Time Projection Chamber. I will present recent advances in event reconstruction techniques that are being developed in the context of a recently proposed THEIA detector with a broad physics program including
neutrinoless double beta decay, solar neutrinos, geo-neutrinos, supernova neutrinos, nucleon decay, and long baseline neutrino physics.
The Micro-X sounding rocket uses a Transition Edge Sensor (TES) array to make X-ray observations. The improved energy resolution of TESs compared to traditional space-based X-ray detectors brings new precision to both supernova remnant observations and the X-ray search for sterile neutrino dark matter. Current X-ray observations disagree over the potential presence of a 3.5 keV X-ray line consistent with a sterile neutrino interaction, and Micro-X is in a unique position to establish or refute the presence of this line. I will present the construction status of the instrument and expectations for flight observations, with special emphasis given to the prospects of sterile neutrino studies.
In this talk, we discuss the effects of a non-negligible threshold energy on our model-independent methods developed for reconstructing WIMP properties by using measured recoil energies in direct Dark Matter detection experiments directly. Our expressions for reconstructing the mass and the (ratios between the) spin-independent and the spin-dependent WIMP-nucleon couplings have been modified. We will focus on low-mass (m_chi <~ 50 GeV) WIMPs and present some (preliminary) numerical results obtained by Monte-Carlo simulations.
We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario "Impeded Dark Matter". We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden SU(2) sector, and a composite dark matter scenario based on a QCD-like dark sector.
Many theories of dark matter (DM) predict that DM particles can be captured by stars via scattering on ordinary matter. They subsequently condense into a DM core close to the center of the star and eventually annihilate. In this work, we trace DM capture and annihilation rates throughout the life of a massive star and show that this evolution culminates in an intense annihilation burst coincident with the death of the star in a core collapse supernova. The reason is that, along with the stellar interior, also its DM core heats up and contracts, so that the DM density increases rapidly during the final stages of stellar evolution. We argue that, counterintuitively, the annihilation burst is more intense if DM annihilation is a p-wave process than for s-wave annihilation because in the former case, more DM particles survive until the supernova. If among the DM annihilation products are particles like dark photons that can escape the exploding star and decay to Standard Model particles later, the annihilation burst results in a flash of gamma rays accompanying the supernova. For a galactic supernova, this "dark gamma ray burst" may be observable in CTA.
Dark matter particles interacting via the exchange of very light spin-0 mediators can have large self-interaction rates and obtain their relic abundance from thermal freeze-out. At the same time, these models face strong bounds from direct and indirect probes of dark matter as well as a number of constraints on the properties of the mediator. We investigate whether these constraints can be consistent with having observable effects from dark matter self-interactions in astrophysical systems. For the case of a mediator with purely scalar couplings we point out the highly relevant impact of low-threshold direct detection experiments like CRESST-II, which essentially rule out the simplest realization of this model. These constraints can be significantly relaxed if the mediator has CP-violating couplings, but then the model faces strong constraints from CMB measurements, which can only be avoided in special regions of parameter space.
There are a number of papers that calculate how the limits or positive results of current experiments would be if some specific twist is applied to the standard interpretation framework (e.g., SI interactions with f_p \neq f_n). These works are usually not performed by members of the experiments, and therefore make very simple assumptions on experimental details like efficiencies. Neveretheless, it is possible to retain this type of information without actually knowing it, by starting from the final exclusion plots and working backwards. This possibility is discussed and exemplified.
The galaxy rotation curve, gravitational lensing and the existence of large scale structure imply that the present Universe is filled with a mysterious form of invisible matter, called “dark matter (DM)”, which is about 27% ( roughly 5 times of visible matter) of the total energy budget. Hitherto the existence of DM has been consolidated via its gravitational interaction in a cosmological scale, starting from galaxy size. The main challenge at present is to probe the DM in a small scale, typically in an earth bound laboratory. The only information so far we know about DM is its relic density. However, the microscopic structure of DM is completely unknown. Unfortunately the standard model (SM) of particle physics, the best model that describes the fundamental interactions of visible matter, does not accommodate any such particle. In this talk we explore certain aspects of physics beyond the SM to include dark matter as well as non-zero neutrino mass confirmed by oscillation experiments. In particular, we extend the SM by including a light scalar triplet with hyper charge two and two vector-like fermions: one singlet and a doublet. A discrete symmetry is imposed on the additional vector-like fermions so that the dark matter arises as a mixture of the neutral component of the doublet and singlet. The scalar triplet acquires an induced vacuum expectation value after electroweak symmetry breaking and thereby inducing sub-eV masses to the neutrinos. We then obtain the parameter space satisfying relic density and to probe the model at collider.
As is well known, dark matter direct detection experiments will ultimately be limited by a "neutrino floor," due to the scattering of nuclei by MeV neutrinos from, e.g., nuclear fusion in the Sun. Here we point out the existence of a new "neutrino floor" that will similarly limit indirect detection with the Sun, due to high-energy neutrinos from cosmic-ray interactions with the solar atmosphere. We have two key findings. First, solar atmospheric neutrinos ≲1 TeV cause a sensitivity floor for standard WIMP scenarios, for which higher-energy neutrinos are absorbed in the Sun. This floor will be reached once the present sensitivity is improved by just one order of magnitude. Second, for neutrinos ≳1 TeV, which can be isolated by muon energy loss rate, solar atmospheric neutrinos should soon be detectable in IceCube. Discovery will help probe the complicated effects of solar magnetic fields on cosmic rays. These events will also be backgrounds to WIMP scenarios with long-lived mediators, for which higher-energy neutrinos can escape from the Sun.
Dark matter decays or annihilations that produce line-like spectra may be smoking-gun signals. However, even such distinctive signatures can be mimicked by astrophysical or instrumental causes. We show that velocity spectroscopy-the measurement of energy shifts induced by relative motion of source and observer-can separate these three causes with minimal theoretical uncertainties. The principal obstacle has been energy resolution, but upcoming experiments will reach the required 0.1% level. As an example, we show that experiments with the required energy resolution can cleanly separate the signal from background. We emphasize that this new smokingguninmotion signature of dark matter is general, and is applicable to any dark matter candidate which produces a sharp photon feature in annihilation or decay.
About 25 year ago LUNA (laboratory for Underground Nuclear Astrophysics) opened the era of underground nuclear astrophysics installing a home-made 50 kV ion accelerator under the Gran Sasso mountain. A second machine, with a terminal voltage of 400 kV, was then installed and it is still in operation. Most of the processes so far investigated were connected to the physics of solar neutrinos and hence to the hydrogen burning phase in stars. The interest to next and warmers stages of star evolution (i.e. helium and carbon burning) pushed a new project based on a ion accelerator in the MV range called LUNA-MV. Thanks to a special grant of the Italian Ministry of Research (MIUR), INFN is now building, inside one of the major hall at Gran Sasso, a new facility which will host a 3.5 MV single-ended accelerator able to deliver proton, helium and carbon beams with intensity in the mA range. Details on the new facility and on the foreseen experimental program will be given in the talk.
The DarkSide-50 two-phase liquid argon (LAr) detector has been searching for weakly interacting massive particle (WIMP) dark matter for the past three years, and during the last two years has been successfully operating the detector with argon that was extracted from underground CO$_2$ wells in Cortez, Colorado in the US. This source of argon has been long shielded from cosmic rays entering Earth’s atmosphere, and thus should have a lower concentration of the cosmogenically produced isotope of $^{39}$Ar that beta decays with an endpoint energy that causes the beta spectrum to entirely cover the LAr WIMP search region. A 70-day exposure of the underground argon (UAr) inside DS-50 demonstrated that the UAr extracted from Colorado contains $^{39}$Ar a factor >1000 less than atmospheric argon. This large reduction in $^{39}$Ar opens the door for the construction of much larger LAr detectors that can be used for the direct detection of WIMP dark matter, as well as other rare-event searches. This talk will focus on the details of two new projects called Urania and Aria, which aim to extract 100 kg/day of UAr from the same source of gas as that used to extract the UAr for DS-50 and then
further purify it, in an effort to procure 50 tonnes of detector grade UAr for use in a 20-tonne fiducial volume detector called DarkSide-20k and set to begin operations at the beginning of the next decade.
In the VIP2 (VIolation of the Pauli Exlusion Principle) experiment at the Gran Sasso underground laboratory (LNGS) we are searching for possible violations of standard quantum mechanics predictions. With high precision we investigate the Pauli Exclusion Principle and the collapse of the wave function (collapse models). We will present our experimental method of searching for possible small violations of the Pauli Exclusion Principle (PEP) for electrons, via the search for "anomalous" X-ray transitions in copper atoms, produced by "new" electrons (brought inside a copper bar by circulating current) which could have the probability to undergo Pauli-forbidden transition to the ground state (1 s level) already occupied by two electrons. We will describe the concept of the VIP2 experiment taking data at LNGS presently. The goal of VIP2 is to test the PEP for electrons with unprecedented accuracy, down to a limit in the probability that PEP is violated at the level of 10E-31. We will show preliminary experimental results obtained at LNGS and discuss implications of a possible violation.
GINGER (Gyroscopes IN General Relativity) is a proposal aiming at measuring the Lense-Thirring effect with an experiment based on Earth. It is an array of ring lasers, which are the most sensitive inertial sensors to measure the rotation rate of the Earth. GINGERino is a ring laser prototype installed inside the underground laboratory of Gran Sasso, it is aiming at understand whether the Gran Sasso laboratory would be a good location for GINGER. We describe the preliminary actions and measurements already under way and present the full road map to GINGER. The prototypes GP2 and GINGERino are described and the preliminary results reported.
DarkSide-20k is a proposed 20 tonne fiducial mass liquid argon TPC that will perform an instrumental background-free search for WIMP dark matter. The TPC will be outfitted with more than 125,000 silicon photomultipliers (SiPM) grouped into 5210 single-channel, $25\ {\rm cm}^2$ photosensors that are sensitive to single photoelectrons. We will present the performance of the photosensor and associated low-noise electronics at liquid argon temperature and discuss the strategy for scaling up production for DarkSide-20k.
JUNO (Jiangmen Underground Neutrino observatory) will use 20 ktons high light yield, high transparency and low background Liquid Scintillator (LS). The purification of LS is very important work of JUNO construction. This talk introduced the status of the JUNO LS purification. The pilot plant of four purification systems (Al2O3 absorption, distillation, water extraction and steam stripping) was constructed. The 20 tons purified LS is under the measurement. Several months later, we will get all the result of pilot plant purified LS.
Parallel Neutrino Talks
Super-Kamiokande (SK), a 50 kton water Cherenkov detector in Japan, is observing neutrinos and searching for proton decay and dark matter decays. The installation of new front-end electronics in 2008 marks the beginning of the 4th phase of SK (SK-IV). With the improvement of the water circulation system, calibration methods, reduction cuts, this phase achieved the lowest energy threshold thus far: 3.5 MeV kinetic energy.
SK studies the effects of both the solar and terrestrial matter density on neutrino oscillations: a distortion of the solar neutrino energy spectrum would be caused by the edge of the Mikheyev-Smirnov-Wolfenstein resonance in the solar core, and terrestrial matter effects would induce a day/night solar neutrino flux asymmetry. A global oscillation analysis using SK-I,II,III, and SK-IV data and combined with the results of other solar neutrino experiments as well as KamLAND reactor experiment has been carried out. The results of this global analysis will be presented as well. SK observed solar neutrino interactions for more than 20 years. This long operation covers about ~2 solar activity cycles. An analysis about a possible correlation between solar neutrino flux and 11 year activity cycle will be presented.
Supernova explosions in our galaxy may be rare, but supernovae themselves are not. On average, there is one ccSN somewhere in the universe each second. The neutrinos emitted from all of these ccSN since the onset of stellar formation have suffused the universe. We refer to this thus-far unobserved flux as the “relic” supernova neutrinos.
The flux of the supernova relic neutrinos is expected to be several tens per square centimeter per second. Theoretical models vary, but as many as five supernova relic neutrinos per year above 10 MeV are expected to interact in Super-Kamiokande. However, in order to separate these signals from the much more common solar and atmospheric neutrinos and other backgrounds, we need a new detection method.
Two years ago, the Super-Kamiokande Collaboration approved the SK-Gd project. It is the upgrade of the SK detector via the addition of water-soluble gadolinium (Gd) salt. Since then, we have been conducting many dedicated study and developments for deploying Gd to SK. This modification will enable it to identify low energy anti-neutrinos for the world's first observation of the relic supernova neutrinos via inverse beta decay.
We calculate the solar neutrino and antineutrino flux in the keV energy range. The dominant thermal source processes are photo production (γe → eνν ̄), bremsstrahlung (e + Ze → Ze + e + νν ̄), plasmon decay (γ → νν ̄), and pair emission in free-bound and bound-bound transitions of partially ionized elements heavier than hydrogen and helium. To calculate the latter we use libraries of monochromatic photon radiative opacities in analogy to a previous calculation of solar axion emission. Our overall flux and many details differ significantly from previous works. While this low-energy flux is not measurable with present- day technology, it could become a significant background for future direct searches for keV- mass sterile neutrino dark matter.
Astroparticle Physics in Hyper-Kamiokande
The Hyper-Kamiokande is a next generation water Cherekov detector consisting of two tanks, each with 187 kton fiducial mass, to be built in a staged approach. The total fiducial mass will be nearly 20 times larger than the highly successful Super-Kamiokande while significantly improved photodetectors will be used with the same 40 % photocoverage. The resulting sensitivity improvements will particularly benefit astroparticle physics at low energies.
This talk will present its projected physics reach in the areas of supernova neutrinos, solar neutrinos and indirect dark matter searches, based on the current design report.
The Deep Underground Neutrino Experiment (DUNE) experiment, a 40-kton underground liquid argon time-projection-chamber detector, will have unique sensitivity to the electron flavor component of a core-collapse supernova neutrino burst. We present expected capabilities of DUNE for measurements of neutrinos in the few-tens-of-MeV range relevant for supernova detection, and the corresponding sensitivities to neutrino physics and supernova astrophysics. Recent progress and some outstanding issues will be highlighted.
The ANTARES deep sea neutrino telescope, installed at the bottom of the Mediterranean Sea, has been continuously taking data for more than ten years. Thanks to its excellent angular resolution in both the muon channel and the cascade channel (included by all neutrino flavours), ANTARES offers unprecedented sensitivity for neutrino source searches in the Southern sky in the TeV-PeV energy range, so that already valuable constraints have been set on the origin of the cosmic neutrino flux discovered by the IceCube detector.
Assuming various spectral indexes for the energy spectrum of neutrino emitters, the Southern sky and in particular central regions of our Galaxy are studied searching for point-like objects and for several interesting extended regions of emission like the Galactic Plane or the Fermi Bubble. For the first time, cascade events are used for these searches with a median angular resolution of about 3 degrees.
ANTARES is also embedded in a manifold multi-messenger program with radio, optical, X-ray and gamma-ray follow-up observations of promising cosmic neutrino candidates. ANTARES is also looking for neutrino events in spatial and temporal correlation with astrophysical transient sources observed by other instruments, such as AGN flares, Gamma Ray Bursts, Fast Radio Bursts or with the newly discovered gravitational wave signals.
Strong constraints have also been set on the Dark Matter annihilation cross section and the spin dependent WIMP-nucleon cross section from the search of neutrinos potentially produced by annihilations of WIMPs trapped in massive objects such as the Sun and the Galactic Centre. Searches for signals of other exotic physics such as magnetic monopoles and nuclearites are also of interest for ANTARES.
A new estimate of the diffuse supernova neutrino background (DSNB) is presented, for scenarios with different core collapse rates and different distribution of black-hole forming collapses with the progenitor mass. The $\bar \nu_e$ component of the DSNB above 11 MeV of energy can be as large as $\phi \sim 3.7~{\rm cm^{-2} s^{-1}}$, and the contribution of black hole-forming collapses could dominate the flux above $\sim 25$ MeV.
We discuss the potential of detecting the DSNB at SuperK-Gd and JUNO, in about a decade-long period of operation, including realistic neutral-current background processes. The case when results from the two detectors are examined jointly is considered as well. We also examine an example of a future ${\mathcal O}(10)$ kt
slow liquid scintillator detector, and show that there the chances of detecting the DSNB could exceed 99\%. Our results motivate stronger experimental efforts in reducing the lower energy backgrounds at SuperK-Gd.
We explore oscillations of the solar 8B neutrinos in the Earth in detail. The relative excess of night νe events (the Night-Day asymmetry) is computed as function of the neutrino energy and the nadir angle η of its trajectory. The finite energy resolution of the detector causes an important attenuation effect, while the layer-like structure of the Earth density leads to an interesting parametric suppression of the oscillations. Different features of the η− dependence encode information about the structure (such as density jumps) of the Earth density profile; thus measuring the η distribution allows the scanning of the interior of the Earth. We estimate the sensitivity of the DUNE experiment to such measurements. About 75 neutrino events are expected per day in 40 kt. For high values of Δm221 and Eν>11 MeV, the corresponding D-N asymmetry is about 4\% and can be measured with 15% accuracy after 5 years of data taking. The difference of the D-N asymmetry between high and low values of Δm221 can be measured at the 4σ level. The relative excess of the νe signal varies with the nadir angle up to 50\%. DUNE may establish the existence of the dip in the η− distribution at the (2−3)σ level.
This paper studies the influence of the Earth’s magnetic field on the extensive air shower particles generated by CORSIKA code. The effect causes an azimuthal asymmetry especially on positive and negative muons in highly inclined showers. This asymmetry is quantified by introducing a new observable in terms of a transverse distance (TD) between the positive and negative muon barycenters across shower core in the shower front. It is found that the TD and its maximum value clearly show primary mass sensitivity. An experimental feasibility of the new method in a sea level experiment is also discussed.
Light component (H&He) energy spectrum of 125 TeV - 3 PeV is measured by the ARGO-YBJ detector with a wide field-of-view imaging Cherenkov telescope.
1.filling the gap between the direct observations of CREAM and the EAS xperiment, such as KASCADE;
2.The knee of (700±230_stat.±70_sys.) TeV is found with a significance of 4.2 sigma;
3.Spectra index: β_1=-2.56 ± 0.05 below the knee; β_2=-3.24 ± 0.36 above the knee;
4.Energy resolution: ~25% with offset <3%.
With the minimal assumption, the knee of the pure proton spectrum is derived to be at the same energy of 700 TeV. Taking into account the constraint of CREAM’s measurement at energies below 100 TeV, the proton and Helium spectra above the knee are discussed even if they are model dependent. The bending energy of Helium spectrum above 4X700 TeV, as the expectation of the model with E_b proportional to A, seems to be ruled out. A high precision measurement of the H&He and pure proton spectra in the energy range from 0.7 to 3 PeV is very crucial. LHAASO as the next generation high altitude EAS array with a combination of many detecting techniques will finish the measurement in few years.
Calorimeters are the key detectors for future space based experiments focused on high-energy cosmic rays spectra measurements.
Thus it is extremely important to optimize their geometrical design, granularity and absorption depth,with respect to the total mass of the apparatus, which is among the most important constraints for a space mission.
Calocube is a homogeneous calorimeter whose basic geometry is cubic and isotropic, so as to detect particles arriving from every direction in space,
thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic scintillating crystals.
A prototype, instrumented with CsI(Tl) cubic crystals, has been constructed and tested with particle beams. An overview of the obtained results will be presented and the perspectives for future space experiments will be discussed.
KAGRA is a 3-km interferometric gravitational wave telescope, which is being built at the underground site of Kamioka mine in Gifu prefecture, Japan. It is the first km-scale interferometer constructed at a quiet and stable underground site to reduce seismic and Newtonian noise. Also, it will be the first km-scale interferometer to utilize cryogenic mirrors to reduce thermal noise.
The project started in 2010, and the construction of the basic infrastructure including the tunnel and the vacuum system was completed in 2015. In March and April 2016, we performed the first test run with a simplified configuration, i.e., 3-km Michelson interferometer at room temperature. Here we present some of our recent results of the test run, and show the development status for the full configuration of KAGRA.
The detection of a gravitational wave signal in September 2015 by LIGO interferometers, announced jointly by LIGO collaboration and Virgo collaboration in February 2016, opened a new era in Astrophysics and brought to the whole community a new way to look at - or "listen" to - the Universe. In this regard, the next big step will be the joint observation with at least three detectors at the same time. This configuration will provide a twofold benefit: increase the signal-to-noise ratio of the events by means of triple coincidence and allow a narrower pinpointing of GW sources, and, in turn, the search for Electromagnetic counterparts to GW signals.
Advanced Virgo (AdV) is the second generation of the gravitational-wave detector run by the Virgo collaboration. After a shut-down lasted 5 years for the upgrade, AdV is being now commissioned to get back online and join the two aLIGO interferometers to realize the aforementioned scenario.
We will describe the challenges and the current status of the commissioning of AdV, and its current performances and perspectives.
Solar neutrinos are a unique probe of the neutrino oscillation physics and of solar models. An overview of the solar neutrino flux prediction and of the current available results will be presented. The new experimental data about the measurement of the flux of low energy solar neutrinos obtained with the Borexino detector (LNGS) will be shown and discussed.
Neutrinos are key particles in core-collapse supernovae. Intriguing recent developments on the role of neutrinos during the stellar collapse will be discussed, as well as our current understanding of the flavor conversions in the stellar envelope. Detection perspectives of the next galactic burst and of the diffuse supernova neutrino background will be also outlined.
The talk will cover the latest status and results for direct dark matter search with XENON1t and it will give an outlook on the planned improvements and upgrades.
Deep Underground Laboratories (DULs) with an overburden larger than 1000 m.w.e. provide unique and multidisciplinary infrastructures to carry out mainly research on extremely rare phenomena such as neutrino interactions, interactions of hypothetical dark matter particles and neutrinoless double beta decay. However, geophysics and biology in extreme environments are also studied in DULs. In this talk I will review the main characteristics of DULs worldwide. I will emphasize the multidisciplinary feature of DULs. I will report about the facilities in operation and about few new proposals.
The detection of rare solar neutrino signals in deep underground laboratories has confronted background challenges for more than 50 years beginning with the famous Chlorine experiment. In this talk I will review the successful background strategies employed for solar neutrino measurements, up to the present, and will summarize related strategies for background suppression for direct detection searches for dark matter particles and for neutrino-less double beta decay.
We consider the use of directionality in the search for monoenergetic sub-GeV
neutrinos arising from the decay of stopped kaons, which can be produced by dark matter annihilation in the core of the Sun. When these neutrinos undergo charged-current interactions with a nucleus at a neutrino detector, they often eject a proton which is highly peaked in the forward direction. The direction of this track can be measured at DUNE, allowing one to distinguish signal from background by comparing on-source and off-source event rates. We find that directional information can enhance the signal to background ratio by up to a factor of 5.
Axion like particles (ALPs) are fundamental pseudo particles with properties similar to Axions that have been involved to solve the strong CP problem in Quantum Chromodynamics. ALPs can oscillate into photons and vice versa in the presence of an external magnetic field. This oscillation of Photon and ALPs could have important implications for astronomical observations, i.e. a characteristic energy dependent attenuation in Gamma ray spectra for astrophysical sources. Here we have revisited the opportunity to search Photon-ALPs coupling in the disappearance channel. We use eight years of Fermi Pass 8 data of a selection of promising galactic Gamma-ray source candidates and study the modulation in the spectra in accordance with Photon-ALPs mixing and estimate best fit values of the parameters i.e. Photon-ALPs coupling constant ( g _ αγ ) and ALPs mass ( m_α ). For the magnetic field we use large scale galactic magnetic field models based on
Faraday rotation measurements and we have also studied the survival probability of photons in the Galactic plane.
The sub-GeV spectrum of cosmic ray antinuclei is a largely unexplored hunting ground for products of dark matter decay or annihilation. Because the conventional astrophysical background is extremely low, detection of even a few antideuterons in this regime would be a strong hint of a dark matter source. Meanwhile, measuring the low-energy antiproton spectrum will constrain both dark matter models and parameters of cosmic ray propagation. The General Antiparticle Spectrometer (GAPS) will perform the first measurements of this kind using the novel technique of exotic atom identification. Currently, the GAPS collaboration is developing the large, lithium-drifted silicon detectors that are key to this technique. GAPS is scheduled for deployment on long-duration balloon flight over Antarctica in late 2020.
The AMS-02 experiment has recently released a new measurement of the cosmic-ray antiproton spectrum. Assuming that cold dark matter (CDM) is made of self-annihilating particles, the AMS-02 data can be used to constrain the annihilation cross section. It is known however that CDM structures itself on scales much smaller than typical galaxies. This structuring translates into a very large population of subhalos which must impact predictions for indirect searches. I will present a dynamically constrained and consistent semi-analytic model of Galactic subhalos (based on arXiv:1610.02233) and discuss its impact on current constraints (or hot spots) inferred from the AMS-02 antiproton data.
I will discuss how future measurements of infrared emission from nearby neutron stars can be used as a largely model-independent probe of dark matter interactions with Standard Model particles. This relies on a recently discovered effect that even non-annihilating dark matter has on old neutron stars. The resulting sensitivity to dark matter interactions would exceed the reach of many terrestrial dark matter searches, extending well below the neutrino floor for both light and heavy dark matter, and would also uncover elusive ``pure higgsino" dark matter.
The Higgs can couple to SU(2)xU(1)xSU'(2)xU'(1) models in such a way that the diagonal vector-like SU(2)xU(1) corresponds to the electroweak gauge symmetry. This leads to a new class of Higgs portal dark matter models within reach of direct search experiments. I will introduce the corresponding dark matter models and their implications for direct search experiments. If time permits, I will also discuss renormalizable extensions of the dark sector in these models.
The wide range of probes of physics beyond the standard model (BSM) leads to the need for tools that combine experimental results to make the most robust possible statements about the validity of theories of new physics and the preferred regions of their parameter space. In this talk, I will introduce a new code for such analyses: GAMBIT, the Global and Modular BSM Inference Tool. GAMBIT is a flexible and extensible framework for global fits of essentially any BSM theory. DarkBit, the dark matter (DM) portion of the code, contains new tools for calculation of likelihoods from gamma-ray and direct DM searches, as well as routines for the calculation of the relic density of an arbitrary model and interfaces to existing DM codes. The rest of the code provides complimentary limits on production of new particles from the LHC and LEP, complete flavour constraints from LHCb, LHC Higgs production and decay measurements, and various electroweak precision observables. I will discuss the code’s capabilities, particularly focusing on the DM observable and likelihood calculators, and then present results of scans of the parameter space of the Minimal Supersymmetric Standard Model.
Parallel Neutrino Talks
Double Chooz (DC) is a reactor neutrino oscillation experiment based at the Chooz nuclear power plant in Northern France. In 2011 DC was the first reactor neutrino experiment to report indication of non-zero $\theta_{13}$, the last unmeasured neutrino mixing angle of the PMNS matrix. This result was confirmed in 2012 by independent experiments. Before the completion in December 2014 of the Near Detector (ND), situated ~400 m from the reactors, DC performed $\theta_{13}$ measurement using data from the Far Detector (FD), sitting at ~1 km from the reactors. Over the past years DC has vastly improved its analysis techniques and its sensitivity to $\theta_{13}$. The inclusion of ND data improves sensitivity even further, owing to the near iso-flux position of the two detectors, as well as identical detector design resulting in suppressed detection systematics. In its latest analysis, DC has boosted the event statistics by adopting a novel approach on the candidate selection, considering Inverse Beta Decay (IBD) events with neutrons captured on both Gadolinium (which is the preferred event sample in reactor neutrino experiments) and Hydrogen. This effectively increases the detection volume by more than three times and was made possible due to improved background rejection and reduced systematics.
Precision and accuracy of $\theta_{13}$ have a leading impact on the current explorations of neutrino CP violation and atmospheric mass ordering. Thus the redundancy of multiple $\theta_{13}$ measurements is critical.
In this talk the latest results of $\theta_{13}$ by DC will be showed. Some of the DC analyses beyond $\theta_{13}$ will also be addressed.
RENO (Reactor Experiment for Neutrino Oscillation) is the first reactor
neutrino experiment which began data-taking using both near and far detectors in 2011.
The last unknown neutrino mixing angle theta_13 in the PMNS matrix was successfully
measured in 2012 by RENO using 220 days of data from 6 reactors in Yonggwang, Korea.
In 2015 RENO made the first measurement of |dm^2_ee| and obtained a more precise
measurement of theta13 based on the energy dependent antineutrino disappearance
using 500 days of data. Roughly 2000 days of data have been accumulated.
In this talk we present new results with more statistics and reduced systematic
errors.
The Daya Bay Reactor Neutrino Experiment utilizes three pairs of powerful nuclear reactors as anti-neutrino sources, and employes eight functionally identical detectors with large target volume for near-far relative measurement. The detectors were placed underground with mountains to provide enough shielding for cosmic rays induced background reduction.
Now, the experiment has achieved unprecedented precision in measuring θ13 and the neutrino mass squared difference |Δm2ee|. The experiment can also perform a high-statistics determination of the absolute reactor antineutrino flux and spectrum, as well as a search for light sterile neutrino. An overview and the most recent results from Daya Bay will be presented.
The PROSPECT experiment is designed to make a reactor model-independent search for short-baseline neutrino oscillations and measure the antineutrino spectrum associated with
235U to high-precision. PROSPECT consists of a 4 ton highly-segmented
6Li-loaded liquid scintillator detector and will be operated at the High Flux Isotope Reactor (HFIR) at ORNL at baselines ranging from 7 to 12 m. Extensive prototyping has shown excellent light collection efficiency and background rejection capabilities. This talk will discuss the design, experimental program, and discovery potential of PROSPECT and present the status and performance results of the detector.
The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose underground experiment and the largest liquid scintillator (LS) detector going for neutrino mass hierarchy, precise neutrino oscillation parameter measurement and studies of other rare processes which include but not limited to solar neutrino, geo-neutrino, supernova neutrinos and the diffuse supernova neutrinos background. The R&D of the detector system is going, including central detector, LS, water Cherenkov veto, PMT system, top track etc. In this talk, we will try to overview the latest progress of the JUNO project in physics and hardware development.
The Earth is an anti-neutrino star, radiating more than 10$^{25}$ anti-neutrinos to space every second. This immense luminosity is fueled predominantly by the ß$^-$ decays of radiogenic isotopes in the Earth's crust and mantle. The anti-neutrinos produced by these decays, called geo-neutrinos due to their geophysical origin, give us important clues about the composition of the Earth's interior and the size and sources of the Earth's radiogenic heat flow, both in the current epoch and throughout its evolution. In this talk, we present a novel method for measuring previously unresolved components of Earth’s internal heating due to radioactivity, specifically those associated to potassium, the mantle and the core. The technique exploits the directional information of neutrino-electron elastic scattering and estimates the exposures needed to probe these contributions to the total geo-neutrino flux. These results chart the course for pioneering exploration of the veiled inner workings of the Earth. To conclude, we discuss the implications of ktonne-scale direction-sensitive detectors on nuclear non-proliferation by examining their prospects to remotely monitor nuclear reactors.
Thanks to an overburden of 6 km water equivalent and to a large mass of ultrapure liquid scintillator, the SNO+ detector is designed for performing low energy neutrino physics measurements and will address several fundamental physics goals, among which the study of geoneutrinos. The geoneutrino signal produced by U and Th distributed in the whole Earth’s mantle is comparable to that originated by the 50 km × 50 km Close Upper Crust surrounding SNO+. Regional characterization of the continental crust is generally performed through either geologic mapping, geochemical sampling, or geophysical surveys. Rarely are these techniques fully integrated, due to limits of data coverage, quality, and/or incompatible datasets. We combine geologic observations, geochemical sampling, and geophysical surveys to create a coherent 3D geologic model of the Close Upper Crust surrounding SNO+, which includes the Grenville Front Tectonic Zone, the Southern Province, the Superior Province, and the Sudbury Igneous Complex. Nine aggregate geological units are geologically characterized, geophysically constrained and geochemically probed with 112 rocks samples representative of the different lithologies, whose U and Th contents have been assessed via HPGe and ICPMS measurements. According to this coherent numerical 3D model, the predicted heat production at SNO+ is 1.5+1.4-0.7 µW/m3 and the expected geoneutrino signal from the Close Upper Crust is 7.8+8.4-3.2 TNU (a Terrestrial Neutrino Unit is one geoneutrino event per 1032 target protons per year) to be compared with a total bulk crust signal of 31.2+8.6-4.7 TNU. The 1σ variability of the geoneutrino signal given by the Close Upper Crust strongly limits the SNO+ potentials for discriminating among different BSE compositional models of the mantle on the base of geoneutrinos experimental measurements. Future works aimed at constraining the crustal heat production and the geoneutrino signal at SNO+ will be inefficient without a geophysical characterization of the 3D structure of the heterogeneous Huronian Supergroup, which provides the largest uncertainty on the expected signal.
In presence of non-standard neutrino interactions the neutrino flavor evolution equation is affected by a degeneracy which leads to the so-called LMA-Dark solution. It requires a solar mixing angle in the second octant and implies an ambiguity in the neutrino mass ordering. In this work, we explore the possibilities for resolving this degeneracy using a combination of oscillation results with past data from scattering experiments (CHARM and NuTeV). We also simulate future data from the COHERENT experiment and study the constraints that could be derived from its combination with current oscillation bounds.
The large datasets and often low signal-to-noise inherent to the raw data of modern astroparticle experiments calls out for increasingly sophisticated event classification techniques. Machine learning algorithms, such as neural networks, have the potential to outperform traditional analysis methods, but come with the major challenge of identifying reliably classified training samples from real data. Citizen science represents an effective approach to sort through the large datasets efficiently and meet this challenge. Muon Hunter is a project hosted on the Zooniverse platform, wherein volunteers sort through pictures of data from the VERITAS cameras to identify muon ring images. Each image is classified multiple times to produce a “clean” dataset used to train and validate a convolutional neural network model both able to reject background events and identify suitable calibration data to monitor the telescope performance as a function of time.
This presentation will outline the basic rhetorical principles for successful translation of scientific ideas into public knowledge. It will specifically focus on the definition of humans as a “Story Species” and demonstrate the art of science communication by turning the neutrinoless double beta decay equation into an intelligent story.
This talk will briefly outline the educational importance of play, and how and why to apply hands-on interactive learning to astrophysics outreach, following lessons learned at Science North, a third-generation science center in Sudbury, Ontario. Applying these lessons outside of the science center context will also be discussed.
This work presents indirect searches for dark matter (DM) as WIMPs (Weakly Interacting Massive Particles) using atmospheric neutrino data of Super-Kamiokande-I,-II,–III and -IV (1996-2016). The latest results of the search for WIMP-induced neutrinos from the Sun, the Earth’s core and the Milky Way are discussed.
We search for an excess of neutrinos as compared to the expected level of atmospheric neutrino background using a fit method. The fit is based on angular and momentum distributions of simulated background and various signal hypotheses of DM-induced neutrinos. It includes all event samples of fully-contained, partially-contained and upward-going muons. This allowed us to test wide range of WIMP masses spanning in maximum from 1 GeV up to 10 TeV, varying and depending on WIMP annihilation source and assumed annihilation channel. Super-Kamiokande sensitivity for masses of DM particles in the GeV scale is the best among neutrino experiments. In case of Solar/Earth WIMP search, obtained limit on DM-induced neutrino flux was related to limit on spin-dependent (Solar/Earth) and spin-independent (Solar) WIMP-nucleon cross section and compared against results of direct detection experiments. In case of Milky Way analysis, the upper limits on the self-annihilation cross-section were derived.
The IceCube Neutrino Observatory searches for a neutrino signal from dark matter self-annihilations in the Sun, the Earth, and the halo of the Milky Way among other targets. The signal neutrinos are identified as events with reconstructed energies and arrival directions that correspond to the distribution expected in dark matter self-annihilations. The latest results from IceCube will be presented with focus on the recent updates of the search from the center of the Milky Way. Two new analyses have been carried out that are sensitive to different energy scales and together cover an energy range from 10 GeV to 300 TeV in dark matter particle mass. Sensitivities as well as experimental exclusion limits will be presented for both analyses.
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a continuously operated, wide field-of-view (FOV) observatory sensitive to 100 GeV - 100 TeV gamma rays and cosmic rays. HAWC has been making observations since summer 2012 and officially commenced data-taking operations with the full detector in March 2015. With a FOV of 2 steradians, HAWC observes 2/3 of the sky in 24 hours and can be used to search for astrophysical signatures of dark matter (DM) and primordial black holes (PBHs). Within HAWC’s field of view there are many dark matter candidate sources for which the upper limits from HAWC are the most sensitive for dark matter of mass > 10 TeV. I will present HAWC's latest results on searches for dark matter signals from dwarf spheroidal galaxies and galaxy clusters, and for evaporating PHBs. HAWC’s measurement of TeV gamma ray emission from the region surrounding nearby pulsars is also relevant to interpretation of the excess of positrons observed at Earth, and I will present our measurements on emission near Geminga and the Monogem pulsars.
In a dedicated run where protons from the Fermilab Booster were
delivered directly to the steel beam dump of the Booster Neutrino
Beamline, the MiniBooNE detector was used to search for the
production of dark matter particles via vector-boson mediators,
as predicted by vector portal models of dark matter. In the
scenario that was considered, the interactions of the dark matter
particles are mediated by a "dark photon" that kinetically mixes
with the ordinary photon, and four parameters determine the
physics: the dark matter mass, the mediator mass, the kinetic
mixing parameter, and the dark sector coupling. The signal
searched for was the elastic scattering of dark matter particles
off nucleons in the detector mineral oil, with neutrinos being an
irreducible background. Within the model considered, the results
obtained provide the best limits on the dark matter annihilation
parameter, in the dark matter mass range from 0.01 to 0.3 GeV, for
a value of the dark sector coupling consistent with theoretical
bounds. The result also excludes a vector mediator particle solution
to the g-2 anomaly. Our analysis was motivated by the vector portal
model, however, other low-mass dark matter models are also possible.
In this talk we will review the experiment, the analysis methods,
and present the results, which demonstrate that beam dump experiments
provide a novel and promising approach to dark matter searches.
Parallel Neutrino Talks
The neutrino spectra and flux were reevaluated during the preparation of the current experiments devoted to the measurement of $\theta_{13}$. Some discrepancies between data and the theoretical predictions in some neutrino experiments at short distances were observed when using the new predicted flux and spectra. This problem has been called the Reactor Antineutrino Anomaly (RAA), which together with the gallium anomaly, both show discrepancies with respect to the expectations at the $\sim$ 3 $\sigma$ level. Oscillations into a light sterile neutrino state ($\Delta m^{2} \sim 1eV^{2}$) could account for such deficits. The SoLid experiment has been conceived to give an unambiguous response to the hypothesis of a light sterile neutrino as the origin of the RAA. To this end, SoLid is searching for an oscillation pattern at short baselines (5-9 m) in the energy spectrum of the electron antineutrinos emitted by the SCK•CEN BR2 reactor in Belgium.
The detector uses a novel technology, combining PVT (cubes of 5 cm3) and $^6$LiF:ZnS (sheets) scintillators. The PVT acts as an antineutrino target for Inverse Beta Decay (IBD) process, which yields a positron plus a neutron. The positron interacts mostly in the PVT, while the neutron thermalize and is captured some $\mu$s later on the $^6$Li, giving rise to a prompt-delayed signal correlated in time and distance.
The detector is highly segmented (modules of 10 planes of 16x16 cubes), and is read out by a network of wavelength shifting fibers and MPPCs. Then, high experimental sensitivity can be achieved, which allows to the precise localization of the IBD products, increasing the power of the background discrimination through topological cuts. A 300 kg prototype was deployed in 2015, showing the feasibility of the detection principle. A full scale detector (~2 tons) is currently under construction and data taking with the first detector modules will start by summer of 2017.
The CeSOX experiment will search for light sterile neutrinos with an intense 144Ce-144Pr antineutrino generator deployed next to the Borexino detector located at the Laboratory Nazionali del Gran Sasso. Data taking is expected to start during spring 2018.
The main goal of the DANSS project is to probe SBL reactor antineutrino
oscillations to the sterile state with a compact cubic meter highly
segmented neutrino spectrometer made of 2500 plastic scintillator strips
(100 x 4 x 1 cm^3) covered with gadolinium loaded reflective coating and
read out by 2500 SiPMs and 50 PMTs via WLS-fibers. The DANSS detector has
been built under a 3 GW commercial reactor (the Kalinin NPP, Russia). The
spectrometer has passive shield, active muon veto, and can be positioned
in 10-12 m from the center of the reactor due to a vertically mobile
platform. It is registering 5000 reactor antineutrinos per day via inverse
beta decay with an excellent discrimination of all types of background.
Preliminary results of analysis of one year data collected in 2016-2017
will be presented. These data provide sensitivity in the most interesting
region of the phase space, where sterile neutrino is predicated by RNA and
other anomalies in SBL oscillation data.
In the recent years, major milestones in neutrino physics were accomplished at nuclear reactors: the smallest neutrino mixing angle $\theta_{13}$ was determined with high precision and the emitted antineutrino spectrum was measured at unprecedented resolution. However, two anomalies, the first one related to the absolute flux and the second one to the spectral shape, have yet to be solved. The flux anomaly is known as the Reactor Antineutrino Anomaly and could be caused by the existence of a light sterile neutrino eigenstate participating in the neutrino oscillation phenomenon. Introducing a sterile state implies the presence of a fourth mass eigenstate, while global fits favour oscillation parameters around $\sin^{2}(2\theta)=0.09$ and $\Delta m^{2} = 1.8 \textrm{eV}^{2}$.
The Stereo experiment was built to finally solve this puzzle. It is one of the first running experiments built to search for eV sterile neutrinos and takes data since end of 2016 at ILL Grenoble (France). At a short baseline of 10 metres, it measures the antineutrino flux and spectrum emitted by a compact research reactor. The segmentation of the detector in six target cells allows for independent measurements of the neutrino spectrum at multiple baselines. An active-sterile flavour oscillation could be unambiguously detected, as it distorts the spectral shape of each cell's measurement differently.
This talk will give an overview on the Stereo experiment, along with details on the detector design, detection principle and the current status of data analysis.
It has been recently speculated that new “secret” interactions among sterile neutrinos, mediated by a gauge boson X, can inhibit or suppress the sterile neutrino thermalization, due to the production of a large matter potential term in the flavour evolution equation for the active-sterile system.
In this way it would be possible to relieve the tension among laboratory sterile neutrinos and cosmological data.
This scenario is particularly interesting since it could have important consequences for the small scale structure of dark matter if the mediator X couples also to dark matter.
We constrain the secret interactions scenario using the Big Bang nucleosinthesys data, the mass limit from Large Scale Structures of the Universe and the latest Planck data on Cosmic Microwave Background anisotropies.
A light sterile neutrino that mixes with the active states has been proposed to explain anomalies in short baseline neutrino oscillation data. Constraints on the mass and mixing parameters are usually presented by showing results from complementary neutrino oscillation experiments. However, measurements of the Cosmic Microwave Background, most recently by the Planck satellite, constrain the radiative degrees of freedom in the early universe, which would be affected by a sterile neutrino. We have for the first time translated these Planck constraints into the parameter space of neutrino oscillation, that of mixing angles and mass splittings. We will show these constraints from Planck compared to the muon-neutrino disappearance oscillation limits on sterile neutrinos from MINOS and IceCube, and also compare them with the recent electron-neutrino disappearance limits from reactor experiments such as Daya Bay and NEOS. Finally we will present new results of the cosmological limits in the context of muon-to-electron-neutrino appearance searches.
Super-Kamiokande (SK) is a 50 kilotonne water Cherenkov detector aiming for the detection of several physics such as solar, atmospheric, astrophysical neutrinos, proton decay, WIMP dark matter, etc. It has been running over 20 years since 1996, and achieved several remarkable outcomes in the field of the particle and astrophysics, one of which is the discovery of the neutrino oscillation, bringing the Nobel Prize in physics 2015.
SK still accumulates a large number of neutrino events, and simultaneously the physic target and its sensitivity are extended along with the improvement of the analysis method, such as event reconstruction and background rejection. For example, a new technique to detect the recoiled neutron has been developed and utilized for the atmospheric and proton decay analysis recently.
One of the strong motivations for the atmospheric neutrino oscillation measurement is to measure the mass ordering (hierarchy) between $\nu_2$ and $\nu_3$. The atmospheric neutrino is sensitive to the mass hierarchy with help of the matter effect which is given when passing through the Earth. We have performed a detailed analysis to discriminate small signature of the mass hierarchy due to the matter effect.
Proton decay is a direct signature anticipated by the grand unified theory (GUT) which is the physics beyond the standard model. Though the major decay modes and GUT models are excluded by the past searches, the efforts to search a glimpse of the proton decay signal are being continued with better event reconstruction and analysis method.
In this talk we will review the status and the results of the atmospheric neutrino measurement and proton decay search using the most updated dataset taken until 2017 spring.
ORCA is the low-energy branch of KM3NeT, the next-generation underwater Cherenkov neutrino detector currently being built in the Mediterranean Sea. The detector will be used to determine the neutrino mass hierarchy, i.e. whether the third mass eigenstate is heavier or lighter than the other two states.
Atmospheric neutrinos traversing the Earth are affected by matter effects, which lead to modifications in the oscillation probabilities that are sensitive to the mass hierarchy. The technical design of the ORCA detector foresees a dense configuration of optical modules, optimised for the study of interactions of neutrinos with energies down to a few GeV. With ORCA, both cascades events involving mostly electron neutrinos and track events of mostly muon neutrinos can be accurately reconstructed thanks to the excellent optical properties of deep-sea water. With the total instrumented volume of ORCA of several megatons of sea water, it will be possible to probe with high event statistics a wide range of baselines through the Earth allowing for a 3-sigma determination of the neutrino mass hierarchy after 3-4 years of operation.
In this contribution we review the methods and technology of ORCA and present its sensitivity to the neutrino mass hierarchy and other oscillation parameters such as theta_23. Additionally, the detector construction status and further science opportunities with ORCA are presented.
The HOLMES project aims to directly measure the electron neutrino mass using the electron capture decay (EC) of 163Ho down to the eV scale. It will perform a precise measurement of the end-point of the 163Ho calorimetric energy spectrum to search for the deformation caused by a finite electron neutrino mass. The choice of 163Ho as source is driven by the very low Q-value of the EC reaction (around 2.8keV), which allows for a high sensitivity while keeping the overall activities to reasonable value (O(10^2)Hz/detector), thus reducing the pile-up probability.
A large array made by thousands of Transition Edge Sensor based micro-calorimeters will be used for a calorimetric measurement of the EC 163Ho spectrum. The calorimetric approach, with the source embedded inside the detector, eliminates systematic uncertainties arising from the use of an external beta-source, and minimizes the effect of the atomic de-excitation process uncertainties.
The commissioning of the first implanted sub-array is scheduled for the end of 2017. It will provide useful data about the EC decay of 163Ho together with a first limit on neutrino mass. In this presentation the current status of the main tasks will be summarized: the TES array design and engineering, the isotope preparation and embedding, and the development of a high speed multiplexed SQUID read-out system for the data acquisition.
The newly established CONUS ($\bf CO$herent $\bf N$e$\bf U$trino Nucleus $\bf S$cattering) project by the Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, will be presented. The project aims at detecting coherent elastic neutrino nucleus scattering (CE$\nu$NS) with high-purity Germanium (Ge) detectors with an extremely low threshold, surrounded by an elaborated shield and exposed to a very high flux of anti-neutrinos from a nuclear power plant. CE$\nu$NS is one out of six neutrino interactions predicted by the standard model, but the only one yet to be detected. While the coherence condition, fulfilled for (anti)neutrinos with energies below 30 MeV, enhances the cross section, only a fraction of the nucleus recoil energy is available for detection via ionization (quenching). Thus, a signal is expected at energies below a few keV and for Ge detectors such low detection thresholds are just achieved in recent technological developments.
For the CONUS project, up to four of these low threshold Ge detectors are to be setup at the commercial nuclear power plant at Brokdorf (Germany). The thermal power output of the plant of 3.9 GW and a high duty cycle as well as the experimental site closer than 20 m to the reactor core guarantee a high anti-neutrino flux with energies well within the coherent regime. At the site an overburden of up to several tens of meters of water equivalent provides shielding against cosmic rays. Furthermore, a massive shell-structured shield including an active muon veto and passive shield layers is built up. With these measures it is aimed at to achieve a background index of 1 count/(daykeVkg) at energies below a few keV for a high signal-to-background ratio.
The presentation will cover the design, preparations, realization and status of the experiment.
The Project 8 collaboration aims to measure the absolute neutrino mass scale using cyclotron radiation emission spectroscopy on the beta decays of tritium. The second phase of the project will measure a continuous spectrum of molecular tritium beta decays and extract the tritium endpoint value with an eV or sub-eV scale precision. Monoenergetic electrons emitted by gaseous $^{83\mathrm{m}}$Kr atoms are used to determine the relationship between the cyclotron frequency and the electron energy and to optimize the instrument configuration for the tritium measurement and the electron signal reconstruction algorithm. Phase II will benefit from precise magnetometers and a gas system combining krypton and tritium that allow to measure and correct offline for the magnetic field fluctuations. We present the recent progress in understanding the electron kinematics and implementing the magnetic field calibration.
The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) has two main goals: (1) a precision measurement of final state neutron multiplicity in neutrino interactions as a function of momentum transfer in the range of 0.5-1.5 GeV, and (2) first deployment and performance characterization of Large Area Picosecond Photo Detectors (LAPPDs) for use in future neutrino experiments. ANNIE Phase 1 was constructed in 2015 in the Booster Neutrino Beam at Fermilab in order to measure the background neutron flux to confirm the feasibility of accomplishing these two goals. The preliminary results from Phase 1 are presented along with sensitivity studies for Phase 2.
Theia is a proposed multipurpose 50kT water-based liquid scintillator (WbLS) detector that aims to use the latest high precision photodetectors. WbLS is a novel scintillation medium that combines the high light yield and low-energy threshold properties of liquid scintillation, with the directionality and low attenuation length of water. This talk will discuss the principles of WbLS, ongoing research and development, and the expansive future physics potential of Theia.
The emission of antineutrinos from fission products in nuclear reactors offers a path to discover, monitor, or exclude the existence of reactors at distances of tens to hundreds of kilometers. The WATCHMAN (WATer Cherenkov Monitor of AntiNeutrinos) experiment is a proposed kiloton volume gadolinium-doped water Cherenkov detector designed to demonstrate this capability. Antineutrinos are detected in WATCHMAN through the delayed coincidence signal produced by an inverse beta decay event. The gadolinium acts as a neutron capture agent, boosting the delayed signal energy from a 2.2 MeV gamma (released following deuteron formation) to an average of 8 MeV released following a neutron capture on gadolinium. The boost in the delayed signal energy considerably reduces otherwise overwhelming background rates; depending on the chosen construction site, WATCHMAN will observe a few antineutrino events per day, with similar background event rates. The primary goal of the WATCHMAN experiment is to demonstrate the tracking of a nuclear reactor’s operation at a 10-25 km standoff. Successful deployment would also pave the path towards operating 100 kiloton – 1 megaton volume gadolinium-doped water antineutrino detectors, a necessary step for ~100 km distance monitoring.
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The construction of the experiment and, in particular, the installation of all towers in the cryostat was completed in August 2016. The detector was then successfully cooled down to a base temperature below 8 mK by the beginning of 2017. After few months devoted to the initial detector commissioning, calibrations started in April 2017 followed by a physics run in May 2017. A new campaign of optimization of the detector performance is now ongoing to be followed by a new physics run during the summer. The first physics results of CUORE, as well as a summary of the initial detector performance will be presented.
I will present an (entirely subjective) overview of the current status of cosmology, followed by a discussion of what we can expect in the coming years.
The realization of multimessenger astrophysics will open up a new field of exploration of the most energetic phenomena in the universe. Astrophysical messengers associated with each of the four fundamental forces reach detectors buried deep underground or underwater, spread across wide swaths of land, and orbiting high above us in space. Detecting coincident signals amongst these experiments in real time will herald the birth of high energy multimessenger astronomy and will enable us to begin exploring and understanding their astrophysical sources. The Astrophysical Multimessenger Observatory Network (AMON) is currently linking multiple current and future high-energy neutrino, cosmic ray, gamma ray and gravitational wave observatories into a single virtual system, facilitating near real-time coincidence searches for multimessenger astrophysical transients. AMON will generate alerts that will enable rapid follow-up of potential electromagnetic counterparts. In this talk, we will present the science case, design elements, partner observatories, and status of the AMON project, followed by examples of AMON-enabled multimessenger analyses with archival data.
Caio Licciardo
The EXO-200 experiment has made both the first observation of the double beta decay in Xe-136 and the most precisely measured half-life of any two-neutrino double beta decay to date. Consisting of an extremely low-background time projection chamber filled with ~150 kg of enriched liquid Xe-136, it has provided one of the most sensitive searches for the neutrinoless double beta decay using the first two years of data. After a hiatus in operations during a temporary shutdown of its host facility, the Waste Isolation Pilot Plant, the experiment has restarted data taking with upgrades to its front-end electronics and a radon suppression system. This talk will cover the latest results of the collaboration including new data with improved energy resolution.