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NuFact 2021 is the twentysecond in the series of yearly international workshops which started in 1999. The main goal of the workshop is to review the progress of current and future facilities able to improve on measurements of the properties of neutral and charged lepton flavor violation, as well as searches for new phenomena beyond the capabilities of presently planned experiments. A special session on Diversity, Outreach & Education will also be held as well as a poster session.
For the 2021 edition, to comply with the different situation in the various countries concerning vaccines and travel regulations, we will hold the conference in mixed mode: the participants and speakers having the opportunity to travel to Cagliari (Italy) may attend the conference in person, while the others may attend and give their talks remotely.
Please, visit the main website here.
The NuFact 2021 workshop program consists of plenary sessions, parallel sessions with six Working Groups covering the following topics:
and dedicated workshops.
The recordings of the plenary sessions and the satellite workshops are available at the link:
https://www.youtube.com/channel/UCAvQIvnouQPVXRPOevlxuYQ/videos
NEW: Results of the survey https://indico.cern.ch/event/855372/attachments/1938507/3947348/NuFact_feedback.pdf
The ICARUS collaboration employed the 760-ton T600 detector in 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. ICARUS performed a sensitive search for LSND-like anomalous νe appearance in the CNGS beam, which contributed to the constraints on the allowed parameters to a narrow region around 1 eV$^2$, where all the experimental results can be coherently accommodated at 90% C.L. After a significant overhaul at CERN, the T600 detector has been installed at Fermilab. In 2020 cryogenic commissioning began with detector cool down, liquid Argon filling and recirculation. ICARUS has started operations and is presently in its commissioning phase, collecting the first neutrino events from the Booster Neutrino Beam and the NuMI off-axis. The main goal of the first year of ICARUS data taking will then be the definitive verification of the recent claim by NEUTRINO-4 short baseline reactor experiment both in the $\nu_\mu$ channel with the BNB and in the $\nu_e$ with NuMI. After the first year of operations, ICARUS will commence its search for evidence of a sterile neutrino jointly with the SBND near detector, within the Short Baseline Neutrino (SBN) program. The ICARUS exposure to the NuMI beam will also give the possibility for other physics studies such as light dark matter searches and neutrino-Argon cross section measurements. The proposed contribution will address ICARUS achievements, its status and plans for the new run at Fermilab and the ongoing developments of the analysis tools needed to fulfill its physics program.
MicroBooNE is a Liquid Argon Time Projection Chamber detector that has been taking data since 2015. One of its primary goals is to investigate the unexplained excess of electromagnetic events in the lowest energy ranges observed in the same neutrino beamline in the MiniBooNE experiment. While one leading interpretation of this anomaly is electron neutrino appearance due to sterile neutrino oscillations, a viable Standard Model explanation is neutrino-induced single photon events. The MicroBooNE single photon analysis looks to test this interpretation by measuring the rate of neutrino-induced resonant neutral current (NC) delta baryon production and subsequent delta radiative decay with a single photon in the final state, NC $\Delta$ $\to$ N$\gamma$. This search for a process that has never been observed before in neutrino scattering is projected to improve upon the current experimental limit from T2K by greater than a factor of thirty. This talk will present the status of the MicroBooNE single photon analysis and the outlook for subsequent measurements.
The IceCube Neutrino Observatory has detected hundreds of thousands of atmospheric neutrinos at propagation baselines from 100 to 12,800 km and energies from a few GeV to 100 TeV. Above 100 GeV where ordinary oscillation effects become vanishingly small, this data sample offers the opportunity to search for and set constraints on a wide range of beyond-standard-model oscillation mechanisms. These include the effects of sterile neutrinos, non-standard interactions, anomalous decoherence, and Lorentz violation. In this presentation I will update on the latest IceCube results and ongoing searches for Beyond-Standard-Model oscillation physics at high energy, with a particular focus on recent studies of neutrino nucleus non-standard interactions.
We continue our discussions [1-4] on neutrino electromagnetic properties. In the present talk we start with a short introduction to the derivation of the general structure of the electromagnetic form factors of Dirac and Majorana neutrinos.
Then we consider experimental constraints on neutrino magnetic and electric dipole moments, electric millicharge, charge radii and anapole moments from the terrestrial laboratory experiments (the bounds obtained by the reactor MUNU, TEXONO and GEMMA experiments and the solar Super-Kamiokande and the recent Borexino experiments). A special credit is done to the most severe constraints on neutrino magnetic moments, millicharge and charge radii [5-9]. The world best reactor [5] and solar [6] neutrino and astrophysical [10,11] bounds on neutrino magnetic moments, as well as bounds on millicharge from the reactor neutrinos [7] are included in the recent issues of the Review of Particle Physics (see the latest Review: P.A. Zyla et al. (Particle Data Group), Prog. Theor. Exp. Phys. 2020, 083C01). The best astrophysical bound on neutrino millicharge was obtained in [12].
In the recent studies [13] it is shown that the puzzling results of the XENON1T collaboration [14] at few keV electronic recoils could be due to the scattering of solar neutrinos endowed with finite Majorana transition magnetic moments of the strengths lie within the limits set by the Borexino experiment with solar neutrinos [6]. The comprehensive analysis of the existing and new extended mechanisms for enhancing neutrino transition magnetic moments to the level appropriate for the interpretation of the XENON1T data and leaving neutrino masses within acceptable values is provided in [15].
Considering neutrinos from all known sources, as well as including all available data from XENON1T and Borexino, the strongest up-to-date exclusion limits on the active-to-sterile neutrino transition magnetic moment are derived in [16] .
A comprehensive analisys of constraints on neutrino electric millicharge from experiments of elastic neutrino-electron interaction and future prospects involving coherent elastic neutrino-nucleus scattering is presented in [17].
We also present results of the recent detailed study [18] of the electromagnetic interactions of massive neutrinos in the theoretical formulation of low-energy elastic neutrino-electron scattering. 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. Using the derived new expression for a neutrino electromagnetic scattering cross section [18], we further developed studies of neutrino electromagnetic properties using the COHERENT data [8] and obtained [9] new bounds on the neutrino charge radii from the COHERENT experiment. Worthy of note, our paper [9] has been included by the Editors Suggestion to the Phys. Rev. D “Highlights of 2018”, and the obtained constraints on the nondiagonal neutrino charge radii since 2019 has been included by the Particle Data Group to the Review of Particle Physics.
The main manifestation of neutrino electromagnetic interactions, such as: 1) the radiative decay in vacuum, in matter and in a magnetic field, 2) the neutrino Cherenkov radiation, 3) the plasmon decay to neutrino-antineutrino pair, 4) the neutrino spin light in matter, and 5) the neutrino spin and spin-flavour precession are discussed. Phenomenological consequences of neutrino electromagnetic interactions (including the spin light of neutrino [19]) in astrophysical environments are also reviewed.
The second part of the proposed talk is dedicated to results of our mostly recently performed detailed studies of new effects in neutrino spin, spin-flavour and flavor oscillations under the influence of the transversal matter currents [20] and a constant magnetic field [21,22], as well as to our newly developed approach to the problem of the neutrino quantum decoherence [23] and also to our recent proposal [24] for an experimental setup to observe coherent elastic neutrino-atom scattering (CEνAS) using electron antineutrinos from tritium decay and a liquid helium target that as we have estimated opens a new frontier in constraining the neutrino magnetic moment.
The discussed in the second part of the talk new results include two new effects that can be summarized as follows:
1) it is shown [20] that neutrino spin and spin-flavor oscillations can be engendered by weak interactions of neutrinos with the medium in the case when there are the transversal matter currents; different possibilities for the resonance amplification of oscillations are discussed, the neutrino Standard Model and non-standard interactions are accounted for;
2) within a new treatment [21] of the neutrino flavor, spin and spin-flavour oscillations in the presence of a constant magnetic field, that is based on the use of the exact neutrino stationary states in the magnetic field, it is shown that there is an interplay of neutrino oscillations on different frequencies. In particular: a) the amplitude of the flavour oscillations νLe↔ νLμ at the vacuum frequency is modulated by the magnetic field frequency μB , and b) the neutrino spin oscillation probability (without change of the neutrino flavour) exhibits the dependence on the neutrino energy and mass square difference Δm2 .
The discovered new phenomena in neutrino oscillations should be accounted for reinterpretation of results of already performed experiments on detection of astrophysical neutrino fluxes produced in astrophysical environments with strong magnetic fields and dense matter. These new neutrino oscillation phenomena are also of interest in view of future experiments on observations of supernova neutrino fluxes with large volume detectors like DUNE, JUNO and Hyper-Kamiokande.
Two other new results discussed in the concluding part of the talk are as follows:
3) a new theoretical framework, based on the quantum field theory of open systems applied to neutrinos, has been developed [23] to describe the neutrino evolution in external environments accounting for the effect of the neutrino quantum decoherence; we have used this approach to consider a new mechanism of the neutrino quantum decoherence engendered by the neutrino radiative decay to photons and dark photons in an astrophysical environment, the corresponding new constraints on the decoherence parameter have been obtained;
4) in [24] we have proposed an experimental setup to observe coherent elastic neutrino-atom scattering (CEνAS) using electron antineutrinos from tritium decay and a liquid helium target and shown that the sensitivity of this apparatus (when using 60 g of tritium) to a possible electron neutrino magnetic moment can be of order about 7×10−13μB at 90% C.L., that is more than one order of magnitude smaller than the current experimental limit.
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:
[1] C. Guinti and A. Studenikin, Neutrino electromagnetic interactions: A window to new physics, Rev. Mod. Phys. 87 (2015) 531-591.
[2] C. Giunti, K. Kouzakov, Y. F. Li, A. Lokhov, A. Studenikin, S. Zhou, Electromagnetic neutrinos in laboratory experiments and astrophysics, Annalen Phys. 528 (2016) 198.
[3] A. Studenikin, Neutrino electromagnetic interactions: A window to new physics - II,
PoS EPS-HEP2017 (2017) 137.
[4] A. Studenikin, Electromagnetic neutrino properties: new constraints and new effects,
PoS ICHEP2020 (2021)180.
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moment in GEMMA experiment , Adv. High Energy Phys. 2012 (2012) 350150.
[6] M. Agostini et al (Borexino coll.), Limiting neutrino magnetic moments with Borexino Phase-II solar neutrino data, Phys. Rev. D 96 (2017) 091103.
[7] A. Studenikin, New bounds on neutrino electric millicharge from limits on neutrino magnetic moment, Europhys. Lett. 107 (2014) 21001.
[8] D. Papoulias, T. Kosmas, COHERENT constraints to conventional and exotic neutrino physics, Phys. Rev. D 97 (2018) 033003.
[9] M. Cadeddu, C. Giunti, K. Kouzakov, Y.F. Li, A. Studenikin, Y.Y. Zhang, “Neutrino charge radii from COHERENT elastic neutrino-nucleus scattering”, Phys. Rev. D 98 (2018) 113010.
[10] N. Viaux, M. Catelan, P. B. Stetson, G. G. Raffelt et al., Particle-physics constraints from the globular cluster M5: neutrino dipole moments, Astron. & Astrophys. 558 (2013) A12.
[11] S. Arceo-Díaz, K.-P. Schröder, K. Zuber and D. Jack, Constraint on the magnetic dipole moment of neutrinos by the tip-RGB luminosity in ω-Centauri, Astropart. Phys. 70 (2015) 1.
[12] A. Studenikin, I. Tokarev, Millicharged neutrino with anomalous magnetic moment in rotating magnetized matter, Nucl. Phys. B 884 (2014) 396-407.
[13] O. G. Miranda, D. K. Papoulias, M. Tórtola, J. W. F. Valle, XENON1T signal from transition neutrino magnetic moments , Phys.Lett. B 808 (2020) 135685.
[14] E. Aprile et al. [XENON], Observation of excess electronic recoil Events in XENON1T, Phys. Rev. D 102 (2020) 072004.
[15] K. Babu, S. Jana, M. Lindner, Large neutrino magnetic moments in the light of recent experiments, JHEP 2010 (2020) 040.
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[17] A. Parada, Constraints on neutrino electric millicharge from experiments of elastic neutrino-electron interaction and future experimental proposals involving coherent elastic neutrino-nucleus scattering, Adv.High Energy Phys. 2020 (2020) 5908904.
[18] K. Kouzakov, A. Studenikin, Electromagnetic properties of massive neutrinos in low-energy
elastic neutrino-electron scattering, Phys. Rev. D 95 (2017) 055013.
[19] A. Grigoriev, A. Lokhov, A. Studenikin, A. Ternov, Spin light of neutrino in astrophysical environments, JCAP 1711 (2017) 024 (23 p.).
[20] P. Pustoshny, A. Studenikin, Neutrino spin and spin-flavour oscillations in transversal
matter currents with standard and non-standard interactions, Phys. Rev. D 98 (2018) 113009.
[21] A. Popov, A. Studenikin, Neutrino eigenstates and flavour, spin and spin-flavour oscillations in a constant magnetic field, Eur. Phys. J. C 79 (2019) 144.
[22] P. Kurashvili, K. Kouzakov, L. Chotorlishvili, A. Studenikin, Spin-flavor oscillations of ultrahigh-energy cosmic neutrinos in interstellar space: The role of neutrino magnetic moments”, Phys. Rev. D 96 (2017) 103017.
[23] K. Stankevich, A. Studenikin, Neutrino quantum decoherence engendered by neutrino radiative decay, Phys. Rev. D 101 (2020) 056004.
[24] M. Cadeddu, F. Dordei, C. Giunti, K. Kouzakov, E. Picciau, A. Studenikin, Potentialities of a low-energy detector based on 4He evaporation to observe atomic effects in coherent neutrino scattering and physics perspectives, Phys. Rev. D 100 (2019) 073014.
[25] A. Popov, A. Studenikin, Manifestations of non-zero Majorana CP violating phases in oscillations of supernova neutrinos, accepted for publ. in Phys. Rev. D, arXiv: 2102.07991 [hep-ph].
A measurement of the transmission coefficient for neutrons through a thick ($\sim 3$ atoms/b) liquid natural argon target in the energy range 30-70 keV was performed by the Argon Resonance Transmission Interaction Experiment (ARTIE) using a time of flight neutron beam at Los Alamos National Laboratory. In this energy range theory predicts an anti-resonance in the $^{40}$Ar cross section near $57$ keV, but the existing data, coming from an experiment performed in the 90s (Winters. et al.), does not support this. This discrepancy gives rise to significant uncertainty in the penetration depth of neutrons through liquid argon, an important parameter for next generation neutrino and dark matter experiments. In this talk, the first results from the ARTIE experiment will be presented. The ARTIE measurement of the total cross section as a function of energy confirms the existence of the anti-resonance near $57$ keV, but not as deep as the theory prediction. This measurement is important for the Deep Underground Neutrino Experiment since it could allow a viable means of calibration and a deeper understanding of signals and backgrounds for the neutrino science program.
The long-baseline neutrino oscillation experiments rely on detailed models of neutrino interactions on nuclei. These models constitute an important source of systematic uncertainty, driven in part because detectors to date have been blind to final state neutrons. We are proposing a three-dimensional projection scintillator tracker as a near detector component in the next generation long-baseline neutrino experiments such as T2K upgrade and DUNE. Due to the good timing resolution and fine granularity, this technology is capable of measuring neutrons in neutrino interactions on an event-by-event basis and will provide valuable data for refining neutrino interaction models and ways to reconstruct neutrino energy. Two prototypes have been exposed to the neutron beamline in Los Alamos National Lab (LANL) in both 2019 and 2020 with neutron energy ranging from 0 to 800 MeV. In order to demonstrate the capability of the neutron detection, a total neutron-scintillator cross section is measured with one of the prototypes and compared to external measurements. In this presentation, the details of the cross section measurement and the systematic uncertainty handling will be presented.
Nuclear reactors offer a great opportunity to study neutrinos due to their high antineutrino flux, but their detection through coherent elastic neutrino-nucleus scattering (CEvNS) is challenging given the need for sub-keV thresholds and great background identification.
In this talk we will discuss the physics potential of a liquid argon scintillating bubble chamber, a novel CEvNS reactor detector currently under construction by the SBC collaboration. With a one-year exposure, a 100 kg chamber placed at 30 m from a 2 GWth power reactor has the potential to achieve world-leading sensitivities.
The T2K experiment aims to measure CP violation in the lepton sector and the latest T2K results show that CP symmetry is violated at 90% confidence level. To achieve higher significance in this measurement it is essential to reduce both statistical and systematic uncertainties. The T2K-WAGASCI detectors have been introduced to T2K experiment as new near detectors to reduce the systematic uncertainty related to the neutrino-nucleus interactions. They are located at 1.5 degree from the neutrino beam axis, a different off-axis angle with respect to the ND280 detector, and T2K-WAGASCI is therefore exposed to a different neutrino flux and will make new measurements of neutrino-nucleus interactions at the JPARC neutrino beam.
The T2K-WAGASCI consists of two kinds of neutrino target detectors and muon range detectors. WAGASCI modules have a three-dimensional grid structure of plastic scintillator bars and water target. The Proton Module is a fully-active tracking detector consisting of only scintillator strips. These neutrino detectors are surrounded by two side muon range detectors and Baby MIND, a magnetised downstream muon range detector. Baby MIND consists of iron-core magnet planes, with a magnetic field strength of 1.5 T, and scintillator tracking planes. It enables a reduction of the neutrino background for measurements of antineutrinos and vice versa.
In this talk the analysis status on the cross section measurement on H2O and CH target in the 1 GeV energy region with data set corresponding to 6.5 × 10^20 protons on target will be shown and the potential impact on the T2K oscillation measurement will be discussed.
The ESS neutrino superbeam (ESSνSB) project is being studied as an upgrade to the European Spallation Source (ESS). This proposed upgrade consists of adding an H⁻ source to the existing beamline in order to send H⁻ pulses in between proton pulses, effectively doubling the beam power from 5 MW to 10 MW. In this contribution, we present the 2.5 GeV linear accelerator (linac) lattice and the design of the transfer line from the linac to the accumulator ring, where pulses would be stacked to achieve short proton pulses of high intensity. The results of error studies, quantifying the effect of accelerator imperfections on the beam transport through the linac and transfer line, are also presented.
The commissioning of the European Spallation Source (ESS) linac has started and that marks another important step towards the completion of the most powerful proton driver in the world with 5 MW of average beam power on target. Such impressive beam power could also be used for particle physics experiments at the intensity frontier. In particular, the ESS based super-beam project ESSnuSB plans to use the ESS linac as a driver for a long baseline neutrino oscillation experiment to measure, with precision, the charge-parity violation phase.
In order not to interfere with the neutron production, the ESSnuSB will increase the beam duty cycle of the linac from 4% to 8% by accelerating pulses of H$^-$ ions interleaved with the proton pulses used for neutron production. Each H$^-$ pulse will be extracted at the end of the linac in four batches, transported to a 384 m circumference storage ring, where the batches will be accumulated over 600 turns and then extracted in a single turn. In this way, we form highly compressed 1.2 ${\rm \mu s}$ pulses carrying almost 90 kJ each. On average, another 5 MW of beam power will be used for producing the neutrino super beam.
We present the design and expected performance of the accumulator ring with details on the charge-exchange injection, the fast extraction, the two-stage collimation and the RF systems.
The goal of the ESSνSB project is to discover and measure neutrino CP Violation with unprecedented sensitivity. The associated ESSνSB H2020 Design Study is aimed at investigating and proposing a conceptual design of a new neutrino superbeam in Europe. The Target Station is a key element of this project, since it will produce a high intensity neutrino superbeam from a 5 MW proton beam delivered by the European Spallation Source at Lund. Work Package 4 of this project focuses on the optimization of the physics performance of the elements producing the beam, such as the targets and the magnetic horns, as well as on the technical aspects related to the Target Station design. The 5 MW proton beam will be split laterally into four 1.25 MW beams, each with 1.3 μs proton pulses and 14 Hz repetition rate, that will hit four separate targets inserted into four horns. The production of the neutrino beams under such conditions requires the development of technologies capable of working at a MW power scale, both for the target and for the other components of the target station facility. The status of the target station will be presented, with some possible future opportunities offered by this facility to develop complementary R&D.
This project has received funding from the European Union Horizon 2020 research and innovation program under grant agreement No 777419, and in part from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Projektnummer 423761110 and from the Polish Ministry of Science and Higher Education grant No W129/H2020/2018 from the resources for the years 2018-2021 for the realization of co-funded projects.
The ENUBET project intends to reduce the flux related systematics in an accelerator neutrino beam to the 1% level by monitoring associated charged leptons produced in a narrow band meson beam. Large angle leptons from kaon decays are measured in an instrumented decay tunnel, while low angle muons from pions can be monitored after the hadron dump.
A general overwiev of the ENUBET physics program will be presented with particular focus on the beamline design.
A key element of the project is the design of a meson transfer line with conventional magnets that maximizes the yield of K+ and π+, while minimizing the total length to reduce meson decays in the not instrumented region. In order to limit particle rates on the tunnel instrumentation, a high level of beam collimation is needed, thus allowing undecayed mesons to reach the end of the tunnel. At the same time a fine tuning of the shielding and the collimators is required to minimize any beam induced background in the decay region.
The transfer line is optimized with TRANSPORT and G4beamline simulations for 8.5 GeV/c mesons with a momentum bite of 10%, considering various proton drivers and target designs. Doses are estimated with a full FLUKA model. The current envisaged beamline is based on conventional quadrupoles and dipoles and provides a large bending angle that can ensure a reduced background from the untagged neutrino component at the neutrino detector. This contribution will report details on the up-to-date design in terms of particle yields at the decay tunnel and expected neutrino fluxes at the far detector.
Doses at the second dipole do not prevent the use of a superconducting magnet, that, increasing the bending angle, could improve the background suppression and the separation of the monitored neutrino component from other neutrinos: glimpses of such a design will be also shown.
In addition, studies on an alternative secondary site-dependent beamline with a broad momentum range (4, 6, 8.5 GeV/c), that could enhance the physics reach of the facility, will be discussed.
https://kassiopeagroup.zoom.us/j/89432151923?pwd=dzB2RG5JOGRmeGRETGJ5Z2lTeFB1QT09
The MEG II experiment at Paul Scherrer Institute (PSI) in Switzerland aims to achieve a sensitivity of $6\times10^{-14}$ on the charged lepton flavor violating decay $\mu \rightarrow e \gamma$. The current upper limit on this decay is $4.2\times10^{-13}$ at 90 % C.L., set by the first phase of MEG. This limit was set using the PSI muon beam at a reduced intensity, $3\times10^7~\mu^+/$s, to keep the background at a manageable level. The upgraded detectors in MEG II can cope with a higher intensity, thus the experiment is expected to run with a $7\times10^7~\mu^+/s$ beam. The new low mass, single volume, high granularity tracker, together with a new highly segmented timing counter, guarantees better resolutions for the positron detection. Moreover, the replacement of the old PMTs with MPPCs in the inner face of the liquid Xenon calorimeter improved the photon detection. We will present the details of the upgraded detectors, including their performances calculated from the data collected in the past years. We will also discuss the latest results from last year pre-engineering run and the perspective for the 2021 run, the first with all the detectors and electronics installed.
The Mu3e experiment is designed to search for the lepton flavor violating decay $\mu \rightarrow e^+ e^+ e^-$.
The ultimate aim of the experiment is to reach a branching ratio sensitivity of 10$^{−16}$.
The experiment is located at the Paul Scherrer Institute (Switzerland) and an existing beam line providing 10$^{8}$ muons per second will allow to reach a sensitivity of a few 10$^{−15}$ in the first phase of the experiment.
The muons with a momentum of about 28 MeV/c are stopped and decay at rest on a target.
The decay products (positrons and electrons) with energies below 53 MeV are measured by a tracking detector consisting of two double layers of 50 $\mu$m thin high-voltage monolithic active pixel sensors.
The high granularity of pixel detector with a pixel size of 80$\mu$m×80$\mu$m together with the small material budget allows for a precise track reconstruction.
Two timing detectors (scintillating tiles and fibres) provide precise timing information, allowing to further suppress combinatorial background.
The full Geant4-based detector simulation with the final geometry and reconstruction software indicate that a background-free measurement is possible.
The design and prototyping of the detector are finalized, the solenoid magnet is installed, and the integration and commissioning has started with this year.
The talk presents the detector and readout system design, as well as performance studies of the first phase of the experiment.
The plans for commissioning and first data taking will be discussed.
he Mu2e experiment, under construction at Fermilab, will search for the neutrinoless coherent conversion of the muon into an electron in the field of an aluminum nucleus. This Charged Lepton Flavor Violating (CLFV) process has a very clear signature, a single monoenergetic electron with energy slightly below the muon rest mass. The Mu2e experiment aims to improve by four orders of magnitude the current best limit on the ratio (Rμe) between the conversion and muon capture rates and reach a single event sensitivity of 3×10−17 on Rμe.
Another important physics goal would be that of searching for a Lepton Number Violating (LNV) process. Neutrinoless double beta decay (0νββ) has set the most stringent limit on this kind of process. The conversion of stopped negative muons to positrons in the field of a nucleus, μ−+N(A,Z)→e++N(A,Z−2), is an example of both CLFV and LNV.
Mu2e will use a intense, pulsed, negative muon beam sent to an aluminum target for a total number of 1018 stopped muons. The production and transport of the muons is achieved with a sophisticated magnetic system comprised of a production, a transport and a detector solenoid. The Detector Solenoids hosts the stopping target made of aluminum followed by a straw-tube tracker and electromagnetic calorimeter. The entire detector region is surrounded by a Cosmic Ray Veto system.
Mu2e is under construction at the Muon Campus at Fermilab. Requirements, tests on prototypes, and status of the production will be discussed. The experiment will start in late 2023 and will take 4-5 years of data-taking to reach our goal.
https://www.wonder.me/r?id=8c4ab10d-737f-4fdf-8990-4d8915e57ea4
NOvA is a long-baseline neutrino oscillation experiment. Its large tracking calorimeters
can detect and identify muon and electron neutrino interactions with high efficiency.
Neutrinos produced by the NuMI beam are detected by a near detector, located at Fermilab,
and a much larger far detector, located 810 km away in Ash River, Minnesota. NOvA can
measure the electron neutrino and antineutrino appearance rates, as well as the muon
neutrino and antineutrino disappearance rates, in order to constrain neutrino oscillations
parameters, including the neutrino mass hierarchy and the CP-violating phase δCP.
This talk will present NOvA's latest results combining both neutrino data (13.6×10^20POT)
and antineutrino data (12.5×10^20 POT).
The Deep Underground Neutrino Experiment (DUNE) is a next generation, long-baseline neutrino oscillation experiment which will utilize high-intensity $\nu_{\mu}$ and $\bar{\nu}_{\mu}$ with peak neutrino energies of ~2.5 GeV produced at Fermilab, over a 1285 km baseline, to carry out a detailed study of neutrino mixing. The neutrino beam has an initial design intensity of 1.2 MW, but has a planned upgrade to 2.4 MW. The unoscillated neutrino flux will be sampled with a near detector complex at Fermilab, and oscillated at the DUNE far detector at the Sanford Underground Research Facility, which will ultimately consist of four modules each containing a total liquid argon mass of 17 kt.
Here, the long-baseline neutrino oscillation sensitivity of DUNE is determined, using a full simulation, reconstruction, and event selection of the far detector and a full simulation and parameterized analysis of the near detector. Detailed uncertainties due to the flux prediction, neutrino interaction model, and detector effects are included. DUNE is able to resolve the neutrino mass ordering to a 5$\sigma$ precision, for all values of the CP-phase, after a 66 kiloton-megawatt-year exposure (kt-MW-yr). It has the potential to observe charge-parity violation in the neutrino sector to a precision of 3$\sigma$ (5$\sigma$) after an exposure of 197 (646) kt-MW-yr, for 50% of all values of the CP-violating phase. DUNE's sensitivity to other oscillation parameters of interest have been explored.
Neutrino oscillation physics is entering the precision measurement
era. The focus of next generation neutrino experiments will be to
determine the parameters governing neutrino oscillations precisely.
The Hyper-Kamiokande experiment, currently under construction in
Japan, includes a long-baseline neutrino oscillations program. Its
main goals will be to determine whether CP violation occurs in
neutrino oscillations and to provide precise neutrino oscillation
parameters. To achieve this, Hyper-Kamiokande will have a large
fiducial volume (8 times that of Super-Kamiokande) and will benefit
from the upgrade of the J-PARC neutrino beam, enabling it to collect an
unprecedented amount of statistics. A thorough knowledge of systematic
effects and powerful near detectors are needed to match this level of
precision. This talk presents the expected sensitivity of
Hyper-Kamiokande to oscillation parameters, notably CP violation,
using a combination of accelerator and atmospheric neutrino information.
NuWro is a versatile Monte Carlo neutrino event generator, applicable for simulations in the energy range of the accelerator-based neutrino oscillation experiments. Since 2005, the theoretical group of the University of Wrocław, Poland, has been extensively working on its development, successfully comparing to various neutrino cross section measurements. NuWro is a vital tool for event generation in many experimental collaborations, providing a lightweight framework for model development and original solutions.
In this talk, we will present recent developments and advances in model implementations conducted within NuWro. Among others, we will demonstrate the phenomenological 2p2h model, hyperon production, and neutrino scattering off atomic electrons. We will emphasise the new philosophy of implementing more exclusive, computationally demanding models. Then, we will show the results of the Ghent low-energy model of single-pion production implemented within this strategy of using precomputed assets and importance sampling methods
[Phys.Rev. D 103 (2021) 053003].
NEUT is a neutrino-nucleus interaction simulation program library and used for the analyses of Super-K and T2K. Recently, NEUT is also used to simulate pion interactions with the nucleus in the detector simulation. In order to make the users access various functions in NEUT, we have started a project to design
a set of new APIs for easy access to the implemented total and interaction channel-level cross-sections, simulation of individual interaction to generate kinematics functions, and so on. At the same time, we also plan to update the existing detector geometry and flux handling programs for the T2K experiment
to make it more generic.
In this talk, we will also report the recent status and plan to implement new physics models, like SuSAv2/RMF CCQE models, MK and DCC 1pi models, improvements of the NC DIS implementation, together with the direction of future development.
The next generation of neutrino oscillation experiments rely on the precise understanding of neutrino interactions in a wide energy range. The GENIE collaboration is constantly engaged in an effort to improve interaction models and fit them against available datasets. A lot of effort is going into pion producing processes, so far focusing on the resonant component of the pion production. This is not enough as pion production is entangled with hadronisation models due to the interplay between deep inelastic scattering and resonant processes. In particular, the knowledge of the exact mixture of hadrons in showers affects the efficiency to distinguish between NC/CC events, the topological characterization, and impacts the estimation of backgrounds. The GENIE neutrino Monte Carlo [2] employs an effective low-mass hadronization model known as AGKY [5] whose validity spans from low to high W. At low invariant mass (W < 2.3 GeV/c2), the model is based on the Koba-Nielsen-Olesen (KNO) scaling low while it gradually switches over to PYTHIA6 (W > 3 GeV/c2) [4]. The default AGKY model parameters controlling hadronization at low invariant masses were extracted from some of the FNAL 15” bubble chamber and the Big European Bubble Chamber analysis [6, 1] but PYTHIA has never been tuned to low energy neutrino-hadroprodution data. Moreover, comparisons of the GENIE model against neutrino-induced hadron shower data exposed disagreements between different datasets, which further deteriorates at the PYTHIA region. The GENIE Collaboration addressed this issue by tuning the hadronization model against charged averaged multiplicity data on hydrogen and deuterium targets from bubble chamber experiments. All the experimental procedures followed in the original analysis have been taken into account in the simulation. The tune has been done using the Professor Framework [3] providing with a complete error estimation of the parameters and the correlation between the low-W AGKY parameters and PYTHIA parameters. In this talk, we focus on the discussion of the tuning procedure as well as the impact of the tune on other observables.
References
[1] Amsterdam-Bologna-Padova-Pisa-Saclay-Torino Collaboration et al. Charged hadron multiplicities in high energy ν ̄μn and ν ̄μp interactions. Zeitschrift fu ̈r Physik C Particles and Fields, 11(4):283–292, Dec 1982.
[2] C. Andreopoulos et al. The GENIE Neutrino Monte Carlo Generator. Nucl. Instrum. Meth., A614:87–104, 2010.
[3] Andy Buckley, Hendrik Hoeth, Heiko Lacker, Holger Schulz, and Jan Eike von Seggern. Systematic event generator tuning for the lhc. 2009.
[4] Torbj ̈orn Sj ̈ostrand, Stephen Mrenna, and Peter Skands. Pythia 6.4 physics and manual. Journal of High Energy Physics, 2006(05):026–026, May 2006.
[5] T. Yang, C. Andreopoulos, H. Gallagher, K. Hofmann, and P. Kehayias. A hadronization model for few-gev neutrino interactions. The European Physical Journal C, 63(1):1–10, Aug 2009.
[6] D. Zieminska et al. Charged-particle multiplicity distributions in νn and νp charged-current interactions. Phys. Rev. D, 27:47–57, Jan 1983.
[1] C. Andreopoulos et al. The GENIE Neutrino Monte Carlo Generator. Nucl.
Instrum. Meth., A614:87–104, 2010.
[2] T. Yang, C. Andreopoulos, H. Gallagher, K. Hofmann, and P. Kehayias.
A hadronization model for few-gev neutrino interactions. The European
Physical Journal C, 63(1):1–10, Aug 2009.
[3] Torbjörn Sjöstrand, Stephen Mrenna, and Peter Skands. Pythia 6.4 physics
and manual. Journal of High Energy Physics, 2006(05):026–026, May 2006.
[4] D. Zieminska et al. Charged-particle multiplicity distributions in νn and νp
charged-current interactions. Phys. Rev. D, 27:47–57, Jan 1983.
[5] D. Zieminska, et al., Charged-particle multiplicity distributions in $\nu_\mu$ n and $\nu_\mu$ p charged-current interactions, Phys. Rev. D 27 (1983) 47–57
[6] Andy Buckley, Hendrik Hoeth, Heiko Lacker, Holger Schulz, and Jan Eike
von Seggern. Systematic event generator tuning for the lhc. 2009.
The generation of accurate neutrino-nucleus cross section models needed for neutrino oscillation experiments requires simultaneously the description of many degrees of freedom and precise calculations to model nuclear responses. The detailed calculation of complete models makes the Monte Carlo generators slow and impractical. We present exhaustive neural importance sampling, a method based on normalizing flows to find a suitable proposal density for rejection sampling automatically and efficiently, and discuss how this technique solves common issues of the rejection algorithm
We report on an update (2021) of a phenomelogical model for inelastic neutrino- and electron- nucleon scattering cross sections using effective leading order parton distribution functions with a new scaling variable ξw. Non-perturbative effects are well described using the ξw scaling variable in combination with multiplicative K factors at low Q2. The model describes all inelastic charged lepton-nucleon scattering data (HERA/NMC/BCDMS/SLAC/JLab) ranging from very high Q2 to very low Q2 and down to the Q2 = 0 photo-production region. The model has been developed to be used in analysis of neutrino oscillation experiments in the few GeV region. The 2021 update accounts for the difference between axial and vector structure function which brings it into better agreement with existing inelastic neutrino-nucleon scattering measurements.
The European Spallation Source (ESS), currently under construction in Lund, Sweden, will be the brightest spallation neutron source in the world, when its driving proton linac. Such a high power requires production, efficient acceleration, and almost no-loss transport of a high current beam, thus making design and beam commissioning of this machine challenging. achieves the design power of 5 MW at 2 GeV. The linac could be used for projects like the ESS Neutrino Super Beam (ESSNuSB), currently, an ongoing project to study the viability of using the ESS linac as a driver for a neutrino beam by interleaving a H- beam with the protons and further increasing the machine average power to 10MW. The ion source and LEBT commissioning happened already in 2018/2019 and will continue with the RFQ in 2021, MEBT and all DTL tanks in the following year. This talk will summarise the status of the linac project and commissioning, with focus on the normal conducting linac plans.
The COMET experiment aims to search for the neutrinoless conversion of a muon to an electron in muonic atoms. This experiment utilizes a slow-extracted pulsed proton beam at 8 GeV from the J-PARC main ring synchrotron (MR). To achieve a sensitivity of $10^{-17}$, an extremely clean pulsed beam is required. In particular, an intensity ratio of leakage protons to the main pulsed beam, called EXTINCTION, must be less than $10^{-10}$. This beam is critical in the pursuit of the highest level of sensitivity.
The MR nominally accelerates the protons up to 30 GeV with 600 ns bunch intervals and extracts them slowly after forming the continuous beam. Instead, the COMET requires the acceleration of protons up to 8 GeV with 1.2 $\mu$s bunch intervals and slow-extraction with keeping the bunch separations, called bunched slow-extraction (bunched-SX). A 1.2 $\mu$s bunch separation is realized by arranging the proton-filled bucket and the empty bucket alternately. Although both buckets are injected into the MR by once excitation of the injection kicker, there are some protons with the extinction of $10^{-6}$ in the empty bucket at the rapid cycling synchrotron for the MR. To achieve excellent extinction, the injection kicker excitation timing is shifted such that particles remaining in the empty bucket are not injected into the MR. It is essential to measure the extinction with such customized MR operations.
An extinction measurement with a bunched-SX beam was performed with $O(10^{10})$ statistics in May 2021. The extinction was measured by counting all secondary pions of a bunched-SX beam in the K1.8BR secondary beamline in the hadron experimental facility of J-PARC. The result of extinction measurement will be presented.
https://kassiopeagroup.zoom.us/j/89432151923?pwd=dzB2RG5JOGRmeGRETGJ5Z2lTeFB1QT09
The DeeMe experiment aims to search for one of the charged lepton flavor violating processes, muon to electron conversion in the field of a nucleus. Our goal is to measure the process with a single event sensitivity of $1 \times 10^{-13}$ for a graphite target with a novel method, with which the final sensitivity could reach down to a level of $10^{-15}$ for a silicon carbide target. That is one or two orders of magnitude better than the current upper limits, $7 \times 10^{-13}$ for a gold target by the SINDRUM-II experiment at PSI and $4.6 \times 10^{-12}$ for a titanium target by the experiment at TRIUMF. The construction of the secondary beamline, H Line, is now in progress. Meanwhile, we measured the momentum spectrum of electrons through muon decay-in-orbit (DIO) for the momentum region 48--62 $\ \mathrm{MeV/}c$ at the D2 area, MLF. I will present the preparation status of DeeMe, the detector development, and the measurement of the DIO spectrum.
The Mu2e experiment, currently in advance stages of construction, is using a
novel technique to search for new physics through lepton flavor violation in
the direct conversion of a stopped muon into an electron. The goal is to obtain
sensitivities of a factor of 10,000 over existing limits. We discuss an evolution
of Mu2e, called Mu2e-II, that would profit from the increased proton intensity
provided by the Fermilab PIP-II accelerator upgrade to increase the sensitivity
by up to an additional order of magnitude. The opportunities and challenges of
harnessing this increased intensity to further the reach of Mu2e will be discussed.
Muon to electron conversion in a muonic atom is a process of charged lepton flavor violation (CLFV). It is not allowed in the Standard Model (SM) and known to be one of the best processes to search for new physics beyond the SM. The COMET experiment aims to search for this process at J-PARC with single-event sensitivity of $3\times10^{-17}$, which is about 10,000 improvement over the current limit. The COMET experiment has taken a staged approach. COMET Phase-I, as the first phase, aims at a single-event sensitivity of $3\times10^{-15}$ with the partial muon beam line and a Phase-I dedicated detector. The construction of COMET Phase-I has started and its physics run is expected to start in 2022-23. The COMET Phase-II will follow immediately. In this talk, we will describe the physics motivation of CLFV, and the details of COMET Phase-I / Phase-II together with the current status of the experiment preparation.
We study the status of the reactor antineutrino anomaly in light of new reactor flux models from both conversion and summation methods. In order to unify the calculation of IBD yields for different model predictions, we recalculate IBD yields with 1-order Vogel-Beacom IBD cross section and PDG 2020 inputs at first. And then our global fitting work shows that both the reactor rate and fuel evolution data are consistent with the predictions from both the conversion model of Kopeikin et al. and the summation model of Estienne et al. We also apply the Kurchatov Institute (KI) measurement into the conversion model of Hayen et al. including forbidden transitions which can partially explain the shape anomaly, and the rate anomaly is decreasing. The convergence of these model predictions indicates the robustness for the solution to the reactor anomaly in terms of flux model refinements. Our work also implies that the rate anomaly might stem from an inappropriate normalization of ILL measurements if the KI measurement is confirmed.
I discuss the sensitivity to parameters describing large extra dimensions (LED) at the next generation reactor experiment JUNO, in combination with its near detector TAO. After an introduction to neutrino oscillations with LED parameters, I discuss the effect of systematic uncertainties on the sensitivity. I show how well JUNO+TAO could measure LED parameters if large extra dimensions were present in nature. I also show that the light sterile neutrino scenario produces a nearly identical signal at JUNO+TAO as the LED scenario.
We present new results of the DANSS experiment on the searches for sterile neutrinos. They are based on approximately 4 million of inverse beta decay events collected at 10.9, 11.9 and 12.9 meters from the reactor core of the 3.1 GW Kalinin Nuclear Power Plant in Russia. The neutrino spectrum dependence on the fuel composition is also presented. We have also measured the reactor power using the IBD event rate during 38 months with the statistical accuracy 1.5% in 2 days and with the relative systematic uncertainty of about 0.5%. Plans for the DANSS upgrade will be presented. This upgrade should allow DANSS to test the Neutrino-4 claim of observation of sterile neutrinos.
The SoLid experiment intends to search for active-to-sterile anti-neutrino oscillations at the very short baseline (6.3-8.9 m) of the SCK•CEN BR2 research reactor (Mol, Belgium) to address the so-called “Reactor Anti-neutrino Anomaly”. This anomaly arose from the reevaluation of the predicted reactor anti-neutrino flux which resulted in a deficit observed by very short baseline experiments. This deficit could be explained by flavor oscillations to a new type of neutrino: the sterile neutrino.
High experimental sensitivity to inverse beta decay interactions can be achieved thanks to the innovative combination of highly segmented PVT scintillator that will serve as neutrino target and to measure the positron with a high neutron-gamma discrimination 6LiF:ZnS(Ag) scintillator. This technology offers precise time and space localization of the IBD signals. The reconstruction of the full topology of the events allows a strong background rejection, necessary given the low overburden at the reactor building and the presence of 214BiPo background from the 238U decay chain in the neutron screens. From the analysis point of view many variables can be reconstructed and exploited with multivariates and boosted decision trees analysis to improve the background rejections.
The detector has been taking a first phase of physics data from 2018 to 2020. In this contribution we will present an overview of the experiment, the background rejections capabilities, the extraction of the reactor anti-neutrino signal and in particular for the first time the physics results with two years of data. The ability to probe the RAA with this result will be investigated. Finally the perspective of a full event topology analysis will be presented on the first opened dataset of 2018.
The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector that will study reactor antineutrinos emitted from two nuclear power plants in the south of China at a baseline of about 53 km. Thanks to its 2 photon detection systems (18000 20” PMTs and 25600 3” PMTs), JUNO will achieve an unprecedented 3% energy resolution at 1 MeV with an energy scale calibration uncertainty of 1%. Such a powerful detector capability will resolve, for the first time, the interference pattern between the solar and atmospheric oscillation modes. Therefore, the primary physics goals of JUNO include the determination of the neutrino mass ordering at a 3-sigma confidence level and the measurement of three neutrino oscillation parameters, $\sin^2\theta_{12}$, $\Delta m^2_{21}$ and $\Delta m^2_{32}$, with sub-percent precision. This talk will cover the JUNO expected sensitivity in terms of neutrino oscillation physics, showing the impact of JUNO future results within the global neutrino framework.
The latest data of the two long-baseline accelerator experiments NOνA and T2K, interpreted in the standard 3-flavor scenario, display a discrepancy. A mismatch in the determination of the standard CP-phase $\delta_{CP}$ extracted by the two experiments is evident in the normal neutrino mass ordering. While NOνA prefers values close to $\delta_{CP}$ ∼ $0.8\pi$, T2K identifies values of $\delta_{CP}$ ∼ 1.4$\pi$. Such two estimates are in disagreement at more than 90% C.L. for 2 degrees of freedom. We show that such a tension can be resolved if one hypothesizes the existence of complex neutral-current non-standard interactions (NSI) of the flavor changing type involving the $e − \mu$ or the $e − \tau$ sectors with couplings $|\varepsilon_{e\mu}|$ ∼ $|\varepsilon_{e\tau}|$ ∼ 0.2. Remarkably, in the presence of such NSI, both experiments point towards the same common value of the standard CP-phase $\delta_{CP}$ ∼ $3\pi/2$. Our analysis also
highlights an intriguing preference for maximal CP-violation in the non-standard sector with the NSI CP-phases having best fit close to $\phi_{e\mu}$ ∼ $\phi_{e\tau}$ ∼ $3\pi/2$, hence pointing towards imaginary NSI couplings.
In this work, an analytical expression for appearance probability has been derived for neutrino (anti-neutrino) oscillations in matter, including non-standard interactions (NSI-propagation). We consider two NSI parameters $\epsilon_{e\mu}$ and $\epsilon_{e\tau}$ to obtain the expression for $\nu_{\mu}\rightarrow\nu_{e}$ ( $\bar{\nu}_{\mu}\rightarrow\bar{\nu}_{e}$) transition, relevant to the ongoing and upcoming accelerator neutrino experiments. We also compare our result to that of exact expression of the oscillation probability.
MicroBooNE is a liquid argon time projection chamber that operates in the Booster Neutrino Beam at Fermilab. The detector provides high-resolution imaging of neutrino interactions with a low threshold and full angular coverage. Thanks to a high event rate and several years of continuous operation, the MicroBooNE collaboration has obtained the world's largest dataset of neutrino-argon scattering events. A detailed understanding of these interactions, especially the impact of nuclear physics effects, will be critical to the success of future precision neutrino oscillation efforts, particularly the argon-based Deep Underground Neutrino Experiment (DUNE) and the Short-Baseline Neutrino (SBN) program. This talk presents some of the latest neutrino-argon cross section measurements in MicroBooNE: new measurements of the inclusive electron neutrino and muon neutrino cross sections, a new measurement of the eta production cross section, and progress towards a measurement of lambda baryon production in muon antineutrino interactions.
The MicroBooNE detector is the world's longest-running liquid argon time projection chamber (LArTPC), currently installed in the Booster Neutrino Beam at Fermilab. One of the primary physics goals of MicroBooNE is to perform detailed studies of neutrino-argon scattering cross sections, which are critical for the success of future neutrino oscillation experiments. At neutrino energies relevant for the Short-Baseline Neutrino Program, the most plentiful event topology involves mesonless final states containing one or more protons. A low reconstruction threshold enabled by LArTPC technology has allowed MicroBooNE to pursue various analyses studying neutrino-induced proton production at accelerator energies. This talk presents several recent results from that effort, including a neutral-current elastic differential cross section as a function of Q^2, as well as charged-current measurements examining exclusive final states containing protons.
Charged-current quasielastic scattering is the signal process in modern neutrino oscillation experiments. It also serves as the main tool for the reconstruction of the incoming neutrino energy. Exploiting effective field theory, we factorize neutrino-nucleon quasielastic cross sections into soft, collinear, and hard contributions. We evaluate soft and collinear functions from QED and provide a model for the hard contribution. Performing resummation, we account for logarithmically-enhanced higher-order corrections and evaluate cross sections and cross-section ratios quantifying the resulting error. We discuss the relevance of radiative corrections depending on conditions of modern and future accelerator-based neutrino experiments.
The data on tau neutrino is very scarce, only a few experiments have detected its interactions. At FNAL beam dump experiment DONUT, tau neutrino interaction cross-section was directly measured with a large systematical (~50%) and statistical (~30%) errors. The main source of systematical error is due to a poor knowledge of the tau neutrino flux. The effective way for tau neutrino production is the decay of Ds mesons, produced in proton-nucleus interactions. The DsTau experiment at CERN-SPS has been proposed to measure an inclusive differential cross-section of a Ds production with a consecutive decay to tau lepton in p-A interactions. The goal of experiment is to reduce the systematic uncertainty to 10% level. A precise measurement of the tau neutrino cross section would enable a search for new physics effects such as testing the Lepton Universality (LU) of Standard Model in neutrino interactions. The detector is based on nuclear emulsion providing a sub-micron spatial resolution for the detection of short length and small “kink” decays. Therefore, it is very suitable to search for peculiar decay topologies (“double kink”) of Ds→τ →X. After successful pilot runs and data analysis, CERN had approved the DsTau project as a new experiment NA65 in 2019. During the physics runs, 2.3×108 proton interactions will be collected in the tungsten target, and about 103 Ds→τ decays will be detected. In this talk, the results from the pilot run will be presented and the prospect for physics runs in 2021-2022 will be given.
Charged lepton flavor violation is heavily suppressed in the standard model, and its observation would be a clear evidence of new physics. Planned experiments in the muon sector are aiming at discovering or improving exclusion limits by several orders of magnitude by the end of the decade. New ideas and detector concepts have been recently proposed to further increase the experimental sensitivity. In this talk, we will review some of the technologies discussed for the next generation of muon CLFV experiments.
High Voltage Monolithic Active Pixel Sensors (HV-MAPS) use a commercial CMOS process qualified for voltages up to 120 V. This allows for a fast charge collection. At the same time the read-out electronics is integrating on the chip. With a very thin active region, the sensors can be thinned to below 50 μm. This makes HV-MAPS ideally suited for tracking low momentum particles at very high rates.
A HV-MAPS based tracking detector is currently being build for the upcoming Mu3e experiment, and is (among other experiments) being considered for Atlas and LHCb detector upgrades. This talk will provide an overview of the HV-MAPS technology and upcoming applications.
Author:
Hajime Nishiguchi
The COMET Experiment at J-PARC aims to search for the lepton flavour violating process of muon to electron conversion in a muonic atom, μ−N→e−N, with a 90% confedence level branching-ratio sensitivity of 6×10−17, in order to explore the parameter region predicted by most well-motivated theoretical models beyond the Standard Model. The need for this sensitivity places several stringent requirements on both the muon beam and the detector system. In order to realize the experiment effectively and timely, a staged approach to deployment is employed. At the Phase-I experiment, a precise muon-beam measurement will be conducted, and a search for μ−N→e−N will also be carried out with an intermediate sensitivity of 7×10−15.
The beam measurement in Phase-I experiment and the search for μ−N→e−N with the final sensitivity in Phase-II experiment will be performed by a combined detector system with Straw tracker and ECAL, called StrECAL system. To enable the required momentum resolution (<200 keV/c) for low energy electron signal (=105 MeV), a material budget of tracking detector is essential, i.e. thin-wall straw tracker operational in vacuum is employed. In addition, to enable good enough energy/spacial resolutions for the required trigger (σE/E =5% and σx=1cm for a 105 MeV electron), highly segmented LYSO crystal viewed with APD is employed as an electromagnetic calorimeter.
In this contribution, current status on the R&D and the construction of StrECAL system for COMET Phase-I and Phase-II both will be given.
We propose a new approach to explore the neutral-current non-standard neutrino interactions (NSI) in atmospheric neutrino experiments using oscillation dips and valleys in reconstructed muon observables, at a detector like ICAL that can identify the muon charge. We focus on the flavor-changing NSI parameter $\varepsilon_{\mu\tau}$, which has the maximum impact on the muon survival probability in these experiments. We show that non-zero $\varepsilon_{\mu\tau}$ shifts the oscillation dip locations in $L/E$ distributions of the up/down event ratios of reconstructed $\mu^-$ and $\mu^+$ in opposite directions. We introduce a new variable $\Delta d$ representing the difference of dip locations in $\mu^-$ and $\mu^+$, which is sensitive to the magnitude as well as the sign of $\varepsilon_{\mu\tau}$, and is independent of the value of $\Delta m^2_{32}$. We further note that the oscillation valley in the ($E$, $\cos \theta$) plane of the reconstructed muon observables bends in the presence of NSI, its curvature having opposite signs for $\mu^-$ and $\mu^+$. We demonstrate the identification of NSI with this curvature, which is feasible for detectors like ICAL having excellent muon energy and direction resolutions. We illustrate how the measurement of contrast in the curvatures of valleys in $\mu^-$ and $\mu^+$ can be used to estimate $\varepsilon_{\mu\tau}$. Using these proposed oscillation dip and valley measurements, the achievable precision on $|\varepsilon_{\mu\tau}|$ at 90% C.L. is about 2% with 500 kt$\cdot$yr exposure. The effects of statistical fluctuations, systematic errors, and uncertainties in oscillation parameters have been incorporated using multiple sets of simulated data. Our method would provide a direct and robust measurement of $\varepsilon_{\mu\tau}$ in the multi-GeV energy range.
We will discuss how to systematically study physics beyond the standard model (BSM) in the neutrino experiments within the standard model Effective Field Theory (SMEFT) framework. In this way, the analysis of the data can capture large classes of models, where the new degrees of freedom have masses well above the relevant energy for the experiment. Moreover, it allows to compare several experiments in a unified framework and in a systematic way. The approach could be applied to several short- and long baseline neutrino experiments. We will show the results of this approach at the FASERv experiment, installed 480 m downstream of the ATLAS interaction point. For some coupling structures, we find that FASERν will be able to constrain interactions that are almost three orders of magnitude weaker than the Standard Model weak interactions, implying that FASERν will be indirectly probing new physics at the 10 TeV scale.
The Belle II experiment at the SuperKEKB energy-asymmetric e+e− collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The target luminosity of the machine is $6\times10^{35}$ cm$^{−2}$s$^{−1}$ and the Belle II experiment aims to record 50 ab$^{−1}$ of data, a factor of 50 more than its predecessor. With this data set, Belle II will be able to measure the Cabibbo-Kobayashi-Maskawa (CKM) matrix, the matrix elements and their phases, with unprecedented precision and explore flavor physics with B and charmed mesons, and τ leptons. Belle II has also a unique capability to search for low mass dark matter and low mass mediators. We also expect exciting results in quarkonium physics with Belle II. In this presentation, we will review the status of the Belle II detector, the results of the planned measurements with the full available Belle II data set, and the prospects for physics at Belle II.
The Deep Underground Neutrino Experiment (DUNE) is an international project for neutrino physics and proton-decay searches, currently in the design and planning stages. Once built, DUNE will consist of two detectors exposed to the world's most intense neutrino beam. The near detector will record neutrino interactions near the beginning of the beamline, at Fermilab. The other, much larger, detector, comprising four 10-kton liquid argon time projection chambers (TPCs), will be installed at a depth of 1.5 km at the Sanford Underground Research Facility in South Dakota, about 1300 km away from the neutrino source.
The unique combination of the high-intensity neutrino beam with DUNE's high-resolution near detector system and massive LArTPC far detector enables a variety of probes of BSM physics, either novel or with unprecedented sensitivity, from the potential discovery of new particles (sterile neutrinos or dark matter), to precision tests of beyond the three-flavour mixing paradigm, Non-standard Neutrino Interactions, Heavy Neutral Leptons, or the detailed study of rare processes (e.g. neutrino trident production). The talk will review these physics topics and discuss the prospects for their discovery at the DUNE experiment.
ABSTRACT
The Fermi National Accelerator Laboratory (FNAL) Muon $g-2$ Experiment has measured the positive muon magnetic anomaly $a_{\mu} \equiv (g_{\mu}-2)/2$ with a precision of 0.46 parts per million, with data collected during its first physics run in 2018. The FNAL experimental result, combined with the measurement from the former experiment at Brookhaven National Laboratory, increases the tension with the Standard Model expectation to $4.2\sigma$, thus strengthening possible hints for new physics.
The magnetic anomaly is determined from the precision measurement of the muon
spin precession frequency relative to the momentum vector ($\omega_{a}$), and the average magnetic field experienced by the beam. The in situ straw-tracking detectors are crucial to the evaluation of the beam dynamics properties, by providing detailed time-dependent stored-muon spatial profiles in two areas of the storage ring.
This talk presents the beam dynamics systematic corrections that are required to adjust the measured muon precession frequency $\omega^{m}_{a}$ to its true physical value $\omega_{a}$.
The existence of sterile neutrinos is an important question in our field. IsoDAR is a cyclotron-based electron antineutrino source that produces a pure, well-understood energy spectrum. IsoDAR generates high statistics, which when coupled with an inverse beta decay detector such as KamLAND, is capable of addressing observed anomalies attributed to sterile neutrinos at the 5 sigma level using electron-flavor disappearance. To achieve this level of statistics, the IsoDAR cyclotron must produce 10 mA of protons at 60MeV. This is an order of magnitude more power than any commercially available cyclotron. To achieve this, IsoDAR takes advantage of several innovations in accelerator physics, paving the way as a new technology.
Experimental muon source (EMuS) at China’s spallation neutron source (CSNS) is a multidisciplinary project intended mainly for μSR, muon induced x-ray emission (MIXE) and imaging applications, and secondary for muonium to antimuonium conversion physics or neutrino cross sections measurements. These goals are achieved by intense beams of surface and decay muons produced by pions decaying at rest or in flight respectively, and neutrinos. At EMuS, pions are produced when a target of graphite is interacting with a 25 kW primary proton beam provided from the rapid cycling synchrotron (RCS) of CSNS at phase-II.
Two schemes of EMuS are being studied. The main scheme is called baseline and is operating in surface or decay muons modes and secondary for neutrinos. It is employing a target station with a superconducting capture solenoid and a conical target of graphite for the capture and collection of surface muons or charged pions, a long superconducting line for the transport of surface muons or the decay of charged pions, and shorter beamlines with which extracted surface or decay muons are led to μSR, MIXE and muon imaging experiments. For the neutrino cross sections measurements, a detector is examined few meters downstream from the end of the long superconducting line. In addition, upstream from the superconducting target station, a vertical μSR beamline of quadrupoles is foreseen to run in parallel, employing a thin slab of graphite for the production of surface muons with high polarization.
The secondary scheme is called simplified and operating for surface muons and possibly for MIXE experiments. It is employing a conventional rotated thick slab of graphite located sideways from a quadrupole triplet collector, a dipole and a beamline of quadrupoles for the selection and transport of surface muons respectively to μSR experiments.
In this talk, the different layouts of target stations and beamlines are discussed.
https://kassiopeagroup.zoom.us/j/89432151923?pwd=dzB2RG5JOGRmeGRETGJ5Z2lTeFB1QT09
The NA62 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2016-2018. This sample provides sensitivities to rare decays with branching ratios as low as 10$^{-11}$. Results from searches for lepton flavour/number violating decays of the charged kaon and the neutral pion to final states containing a lepton pair based on this data set are presented.
Extensive tests of standard model predictions are carried on by the CMS experiment at the CERN LHC. The observation of the violation of lepton number conservation would certainly be a signature of new physics beyond the standard model. The talk will review various tests of lepton universality and the status of the searches for charged lepton violation at CMS.
Tests of lepton flavour universality are particularly sensitive to the presence of physics beyond the Standard Model. Recent results and future prospects with semileptonic and rare heavy flavour decays at LHCb are presented.
The PIP-II complex at Fermilab is slated for operation later this decade and can support a MW-class O(1 GeV) proton fixed-target program in addition to the beam required for DUNE. Proton collisions with a fixed target could produce a bright stopped-pion neutrino source. The addition of an accumulator ring allows for a pulsed neutrino source with a high duty factor to suppress backgrounds. The neutrino source supports a program of using coherent elastic neutrino-nucleus scattering (CEvNS)to search for new physics, such as sensitive searches for active-to-sterile neutrino oscillations and accelerator-produced light dark matter. A key feature of a program at the Fermilab complex is the ability to design the detector hall specifically for HEP physics searches. In this talk I will present the PIP-II project and upgrades towards a stopped-pion neutrino source at Fermilab and studies showing the sensitivities of a O(100 ton) liquid argon scintillation detector to the physics accessible with this source.
Neutrino Oscillations have been confirmed in the last twenty years by a large amount of data and we are now entering in the precision era, when oscillation parameters are going to be determined with a great accuracy. However, current measurements still cannot exclude new physics scenarios like the presence of sterile neutrinos or Non Standard Interactions. We explore the capability of future long baseline experiments like DUNE to search for new sources of CP violation looking at the CP asymmetries of different oscillation channels. The accessibility of such measurements together with the large amount of oscillation data could in principle provide a simple but powerful method to seek for new physics effects.
Neutrino oscillations which essentially confirms neutrinos have non zero masses, is the first hint of physics beyond the Standard Model(SM). When neutrinos propagates through matter it interacts with the matter via weak interactions mediating a W or Z bosons. The study of Beyond Standard Model (BSM) physics often comes with some additional unknown coupling of neutrinos called non standard interactions(NSIs). Wolfenstein was the first to point out this type of NSIs of neutrinos with a vector field mediated by a vector boson namely vector NSI. There is also a possibility of neutrinos to couple with scalar field, which can offer rich phenomenology in neutrino oscillations. This scalar NSI effect the neutrino mass matrix instead of appearing as a matter potential. Which makes its effect interesting to probe it further.
In this work, we have explored the effect of scalar NSI at Long Baseline (LBL) Experiment (DUNE). We found that the diagonal elements of scalar NSI matrix can have a significant impact on the oscillation probabilities of DUNE. Also, as it perturbs the neutrino mass term it can fake the CP effect in LBL experiments. As the mass correction scales linearly with the matter density scalar NSI can sense the matter density variation and LBL experiments are an excellent candidate to probe it. In addition, we also put up the possibility of probing it further to various neutrino mass models.
Although the majority of neutrino oscillation data can be successfully explained by three-flavour neutrino oscillations, some data can be interpreted using short-baseline neutrino oscillations with a fourth sterile neutrino mass state with $\sim 1~\textrm{eV}^2$ mass. This data comprises the event excesses seen by the LSND and MiniBooNE experiments, and the event deficits seen by the GALLEX and SAGE experiments. However, this interpretation is complicated by null results from other short-baseline searches, and disappearance searches in long-baseline and atmospheric searches.
The NOvA (NuMI Off-axis $\nu_{e}$ Appearance) experiment can probe this tension by searching for the disappearance of active neutrinos from the NuMI (Neutrinos from the Main Injector) beam, with a near detector at a baseline of $1~\textrm{km}$ and a far detector at a baseline of $810~\textrm{km}$. This talk will present recent results from NOvA on searches for active to sterile oscillations in neutral current and charged current $\nu_{\mu}$ events using neutrino and antineutrino beam.
In order to achieve the ambitious goal of characterising neutrino flavour oscillations with percent-level precision, it is critical for current and future long-baseline neutrino oscillation experiments to substantially reduce existing systematic uncertainties. The most impactful these uncertainties stem from the challenges of modelling few-GeV neutrino-nucleus interactions. In order to confront this challenge, the T2K experiment’s Neutrino Interaction Working Group (NIWG) aims to implement up to date theoretical models in T2K’s Monte-Carlo event generator (NEUT); to define a suitable parametrisation of the model’s uncertainties as an input for neutrino oscillation analyses; and to constrain these parameters using global lepton and hadron scattering data.
In this talk we present the latest uncertainty model from T2K’s NIWG as well as a comparison of the model to available data. Among other improvements, the latest model includes: a parametrisation offering substantial freedom to the input Spectral Function for charged-current quasi-elastic (CCQE) interactions; a momentum transfer dependent correction to the nuclear removal energy for CCQE interactions based on inclusive electron scattering data; and an updated treatment of nuclear medium effects in resonant pion production interactions.
A substantial fraction of systematic uncertainties in neutrino oscillation experiments stems from the lack of precision in modeling the nucleus when describing the neutrino-nucleus interactions. The Spectral Function (SF) model features a distribution of momenta and removal energies of nucleons inside the nucleus within the shell-model picture, and also accounts for short-range correlations between nucleons. These characteristics offer significant improvements with respect to the more commonly used Fermi gas-based models. Electron scattering experiments offer a precise probe of the structure of the nucleus and have been used to both construct and validate the SF model. SF is thus an interesting reference model for long baseline neutrino experiments.
Based on constraints from electron scattering data, we develop a set of parameters that can alter the occupancy of the nuclear shells and the distribution of the nucleon momentum within each shell. In addition, the contribution of short-range correlations and the effect of Pauli blocking can also be modified. In this talk, we will first present the impact these parameters have on several observables from quasi-elastic-like interactions, such as the transverse momentum imbalance or the muon momentum and direction. We then show fits of these parameters to available T2K and MINERvA cross-section data and discuss how they can be used to constrain the systematic uncertainties related to the SF model in neutrino oscillation analyses.
In order to make precision measurements of neutrino oscillation parameters, it is vital for T2K to have an accurate kinematic reconstruction of the neutrino energy. The uncertainty on this reconstruction has a variety of contributions. However for recent oscillation measurements, the missing energy in the nuclear response is a significant source of systematic uncertainty. T2K has recently updated its nuclear response model, yet it fails to accurately predict the evolution of inclusive electron scattering data over the relevant range of kinematic phase space for T2K - thus motivating a large systematic uncertainty.
By comparing our models to inclusive electron data, it is possible to reduce this systematic. This talk will focus on the development of an approximate electron scattering simulation in NEUT, the event generator used by T2K, and its comparison to such electron scattering data to produce a physically motivated correction to the first nucleon removal energy systematic. The sensitivity of cross-section measurements to such effects will be discussed in the context of recent T2K CC0Pi measurements.
TBA
NOvA is a neutrino oscillation experiment that has the primary goal of measuring $\delta_{CP}$, $\theta_{23}$, and $\Delta m^2_{32}$, with the potential to resolve the octant of $\theta_{23}$ and the mass ordering. NOvA seeks to achieve these goals by using a narrowband beam of muon neutrinos and muon antineutrinos with an energy peak near 2 GeV. Using this beam, NOvA observes both the disappearance of the muon neutrinos (antineutrinos) and the appearance of electron neutrinos (antineutrinos). The extraction of the oscillation parameters from these observations are dependent on the accurate modeling of neutrino cross sections. In this talk, I will discuss how NOvA constrains the cross section model used for the disappearance and appearance analyses and the impact of the model uncertainties on the extraction of the oscillation parameters.
NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double beta decay experiment located at the Laboratorio Subterráneo de Canfranc (LSC, Spain). Its aim is to demonstrate that the neutrino is a Majorana particle by detecting the neutrinoless double beta decay process in xenon gas enriched in the $^{136}$Xe isotope. The detector technology used in NEXT is that of radiopure high pressure time projection chambers with electroluminescence amplification, which provide excellent energy resolution better than 1% FWHM in the energy region of interest, topological reconstruction that allows rejecting single-electron background events and a strong potential for “in situ” tagging of the barium daughter ion. The experiment has been developing in phases.
The NEXT-White detector is currently running at the LSC and contains approximately an active Xe mass of 5 kg. Its purpose is to demonstrate the excellent energy resolution, to validate the reconstruction algorithms and the background model, and to make a measurement of the two-neutrino double beta decay of $^{136}$Xe.
The 100 kg NEXT-100 detector is under construction and is scheduled to be installed and assembled by the end of 2021. The predicted 90% CL sensitivity to the neutrinoless double beta decay half-life will reach $10^{26}$ years for an exposure of about 400 kg·year.
A vigorous program towards the development of ton-scale detectors is also under way, including extensive R&D towards the realization of in-situ Ba$^{2+}$ tagging as means to achieve virtually zero-background detection. A first module with a mass of at least 500 kg may be operating as early as 2026 at the Canfranc Underground Laboratory.
In this talk, I will report on recent results obtained with the NEXT-White detector, on the NEXT-100 construction status and on the prospects of future NEXT detectors.
Water Cherenkov neutrino experiments have played a crucial role in neutrino discoveries over the years, and provide a well established and affordable way to instrument large target masses. The largest uncertainty in the most recent T2K oscillation results are from the Super-Kamiokande detector systematic errors in the oscillated event samples. As neutrino experiments move from discovery to precision measurements, a comprehensive understanding of water Cherenkov detectors becomes increasingly important. The physics and technological development studies that WCTE will be capable of will aid future neutrino experiments such as Hyper-Kamiokande, ESSnuSB and THEIA.
The Water Cherenkov Test Experiment (WCTE) is a small scale water Cherenkov detector which will be located in the T9 experimental area at CERN. WCTE will be used to study the water Cherenkov detector response to hadron, electron and muon beams, and will use new photosensor technologies. The detector will be instrumented with multi-PMT modules consisting of 19, 3-inch PMTs each, and will test a newly developed calibration deployment system. Calibration techniques with known particle fluxes will be used to demonstrate a 1% level calibration for GeV scale neutrino interactions. Other measurements will include those of Cherenkov light production, pion scattering and secondary neutrino production, to provide direct inputs to the T2K and Super-Kamiokande experiments. This talk will describe the WCTE detector design, the newly developed mPMT and calibration hardware and the all important physics program.
ARIADNE, a state-of-the-art 1-ton dual-phase Liquid Argon Time Projection Chamber (LAr TPC), features a game-changing photographic readout utilising ultra-fast photon sensitive TPX3 cameras to image the secondary scintillation light produced in THGEM holes. ARIADNE underwent testing at the T9 beam line, CERN East Area. ARIADNE is the first dual-phase LAr TPC with photographic capabilities to be positioned at a charged particle beamline, and we successfully imaged beautiful LAr interactions with 1 mm track resolution at momenta between 0.5 GeV to 8 GeV. With this technology we have now created a dream TPC in which you can take videos of particle interactions with ns time resolution and mm spatial resolution just based on light. The system is ideal for colossal dual-phase LAr neutrino detectors at much lower cost and as such is now considered as an option for the fourth module of DUNE. Results using the upgraded system at Liverpool will be presented detailing the many benefits and capabilities of this technology. Additionally, a future larger scale detector using the ARIADNE technology is in the pipeline within the CERN neutrino platform program and will also be discussed.
http://hep.ph.liv.ac.uk/ariadne
The plastic scintillator detectors are widely used in high-energy physics, in particular in neutrino experiments.They can provide very good particle identification, sub-nanosecond time resolutions, full 3D geometrical acceptance and particle tracking and, at the same time, enough neutrino target mass to minimise the statistical uncertainties.In order to improve the knowledge of neutrino interactions, for instance particularly important for precision measurement of the CP violating phase, future neutrino experiments will require detectors with improved performances and fine granularity, whilst preserving a mass of many tons.The solution is using additive manufacturing, able to quickly make plastic-based objects of any shape with precisions better than 0.1 mm. The applicability of 3D-printing techniques to the manufacture of polystyrene-based scintillator will be discussed. The status of the R\&D and the latest results will be presented.
At the Paul Scherrer Institut (PSI) muon rates of up to 4x10^8 mu/s are available, produced by its 1.4 MW proton accelerator complex HIPA. While these are currently the highest muon rates available worldwide, projects in the US and Japan are underway that will be able to surpass these intensities by several orders of magnitude.
In order to maintain PSI’s position at the intensity frontier in muon physics and to utilize the unique DC machine structure, a project has started to assess the possibility of creating a next-generation muon beam by modifying the existing Target M station. Initial studies showed that surface muon rates of the order of 10^10 mu+/s can be achievedby placing two normal-conducting capture solenoids close to a slanted slab target and transporting the muons to the experimental areas with a beamline consisting of large-aperture solenoids and dipoles. This contribution will present these studies and the current status of the project.
High precision experiments using muons ($\mu^{+}$) and muonium atoms
($\mu^{+} e^{-}$) provide unique opportunities to test the fundamentals
of the Standard Model in a second-generation, fully-leptonic
environment, putting a broad spectrum of BSM scenarios within the reach
of next generation experiments. Such experiments include the search for
the muon electric dipole moment, measurements of the muon $g-2$, laser
spectroscopy of muonium and gravitational equivalence principle tests
using muonium. Such experiments would benefit greatly from an intense,
high quality and low energy muon beam.
At the Paul Scherrer Institute, a novel phase space compression scheme
(muCool) has been developed, which would produce such a beam, reducing
the phase space of a standard muon beam by ten orders of magnitude at
$10^{-3}$ efficiency, for a $10^7$ boost in brightness. The muon beam is
stopped in cryogenic helium gas, and using complex electric and magnetic
fields in combination with a gas density gradient the muons are steered
to a mm-size spot, where they have an eV energy spread. From here, they
are extracted through a small orifice into a vacuum and into a magnetic
field free region. The process takes less than 10 $\mu$s, critical to
achieving a good efficiency considering the short 2.2 $\mu$s muon
lifetime.
Several key steps in the phase space compression scheme within gas has
been demonstrated with high efficiency during several measurements at
the PSI muon facility. In this talk, the working principle of the
device, the results of recent measurements and prospects for the future
will be presented.
This work is supported by SNF grant 200020_172639.
Muon is an unstable particle, that plays a rather unique and versatile role in physics measurements. Fermilab has currently a very active muon program with the goal to carry out a sensitive test of the Standard Model as well as to set extraordinary limits on charged-lepton-flavor-violating processes. For instance, the Fermilab g-2 experiment will determine with unprecedented precision the anomalous magnetic moment of the muon while the Mu2e experiment will substantially improve the sensitivity on the search for Charged Lepton Flavor Violation process of a neutrinoless conversion of a muon to an electron. In this talk, I will present an overview of the involved accelerator technology in the design and construction of the aforementioned experiments. I will present recent results from commissioning the beamlines for the Muon g-2 experiment as well as discuss some innovative techniques that we have integrated so that to maximize the muon flux. Finally, I will discuss opportunities for future work.
TBA WG3 contribution
In view of the J-PARC program of upgrades of the beam intensity, the T2K collaboration is preparing towards an increase of the exposure aimed at establishing leptonic CP violation at 3 $\sigma$ level for a significant fraction of the possible $\delta_{CP}$ values. To reach this goal, an upgrade of the T2K near detector ND280 will be installed at J-PARC in 2022, with the aim of reducing the overall statistical and systematic uncertainties at the appropriate level of better than 4\%.
We have developed an innovative concept for this neutrino detection system, comprising the totally active Super-Fine-Grained-Detector (SuperFGD), two High Angle TPC (HA-TPC) and six TOF planes.
The SuperFGD, a highly segmented scintillator detector, acting as a fully active target for the neutrino interactions, is a novel device with dimensions of ~2x1.8x0.6 $m^3$ and a total mass of about 2 tons. It consists of about 2 millions of small scintillator cubes each of 1 $cm^3$. The signal readout from each cube is provided by wavelength shifting fibers connected to MPPCs. The total number of channels will be ~60,000 and the cubes have already been produced and assembled in $x-y$ layers.
The HA-TPC will be used for 3D track reconstruction, momentum measurement and particle identification. These TPC, with overall dimensions of 2x2x0.8 m3, will be equipped with 32 resistive MicroMegas (ERAM). The thin field cage (3 cm thickness, 4% rad. length) will be realized with laminated panels of Aramid and honeycomb covered with a kapton foil with copper strips. The 34x42 cm2 resistive bulk Micromegas will use a 500 kOhm/square DLC foil to spread the charge over the pad plane, each pad being ~1 $cm^2$. The electronics is based on the AFTER chips.
The time-of-flight (TOF) will consist of 6 planes with about 5 m2 surface area surrounding the SuperFGD and the TPCs. Each plane has been assembled with 2.2 m long cast plastic scintillator bars with light collected by arrays of large-area MPPCs from two ends.
In this talk we will report on the status of the construction of these detectors and their performances obtained in test beams.
With the addition of 0.02% Gd sulphate to its water in summer 2020, the Super-Kamiokande experiment entered a new phase: SK-Gd. This Gd doping allows for far greater sensitivity to the detection of neutrons emitted in inverse beta decay than with just pure water. This is thanks to gadolinium’s clear neutron capture signal and large neutron capture cross section. This long-awaited chapter in SK’s story aims to deliver exciting new results in the realm of low energy anti electron neutrinos, especially in measuring the diffuse supernova neutrino background. The Gd loading procedure and current status of the detector will be presented.
(Please update abstract)
The Deep Underground Neutrino Experiment (DUNE) will use large liquid argon (LAr) detector consisting of four modules, each with a fiducial mass of 10 ktons of LAr. One of the technology options for the far detector modules is a liquid-argon Time Projection Chamber (TPC) working in Dual-Phase mode. In a Dual-Phase TPC, ionization charge deposited in the liquid argon volume is drifted towards the liquid surface, extracted into the argon vapour, amplified by Large Electron Multipliers (LEM) and collected by an anode plane with strip readout. To validate this technology, a kton-scale prototype, ProtoDUNE Dual-Phase, has been constructed and is currently operating at the CERN neutrino platform.
In this talk, we will cover the principal features of the detector design, discuss its operation, and show some preliminary results from the collected comic ray data samples.
The single-phase liquid argon TPC at CERN (ProtoDUNE-SP) is an engineering prototype for the first module of the DUNE far detector. This prototype which has dimensions of a cube of about 10m edge provides full validation of the use of the membrane tank technology for large dimension cryostats. Furthermore, the very high performance of the protoDUNE-SP TPC with more than 500 days of continuous and stable operation, demonstrated the reliability of the LAr detection technology at a scale never tested before. In this talk, we will review the main characteristics and milestones of the construction and installation of protoDUNE-SP which provide a series of benchmarks for DUNE. The performance for several different detector working points will also be discussed.
DUNE is a long-baseline neutrino oscillation experiment that will take data in a wide-band neutrino beam at Fermilab in the latter half of the 2020s. The experiment is planning to build a very capable near detector to facilitate the high precision extraction of oscillation parameters. Part of the mission of the near detector is to acquire powerful data sets that can be used to constrain the fits used in the oscillation analyses and improve the neutrino interaction model. In this talk, the status of the DUNE near detector design is reviewed.
This talk presents the conceptual design of an alternative Liquid Argon Time Projection Chamber (LArTPC) for the Deep Underground Neutrino Experiment (DUNE).
The DUNE experiment will be a large LAr detector located at a baseline of 1300 kilometers,1.5 km deep underground. It is planned to be made up of four modules, each with a total mass of 17 kt of LAr, at least the first two of which will consist in LArTPCs. Although this technology was proposed 40 years ago and has been implemented before, it was never done at such a large scale. To prove the feasibility of the LArTPC technology at the kiloton scale, the ProtoDUNE SP and DP detectors were constructed and operated at the CERN Neutrino facility.
The Vertical Drift concept proposes to instrument a DUNE module with a TPC where the electrons drift vertically, from a cathode suspended at mid-height, towards anodes placed at the bottom and top of the detector. The anodes would be made out of printed PCBs instead of wires, and the new disposition would allow the top readout electronics to be accessible during the lifetime of the experiment. The layout of the photo-detection system, that provides the timestamp of the event and the depth coordinate, would need to be modified with respect to the horizontal drift detector scheme. Since the PCB anodes are opaque, the photo-sensors would need to be placed on surfaces at a high voltage, such as the cathode or the field cage, posing a challenge in terms of power and signal transmission. Studies are ongoing both to overcome the technical challenges of this new design and to finalize the concept.
Super-Kamiokande is a 50 kton water Cherenkov detector located in Gifu, Japan. The detector has been running for 25 years in 6 distinct phases: SK-I to SK-V and most recently SK-Gd; in this time, it has accumulated a large dataset of atmospheric neutrinos.
The atmospheric neutrinos detected at Super-K cover a wide range of energies and path lengths and travel through various amounts of Earth’s matter. In addition to making measurements of standard three flavour neutrino oscillation parameters, the data is used to study standard and non-standard matter effects.
In this talk, improvements to the standard atmospheric neutrino analysis and additional non-standard neutrino analysis are presented.
The DeepCore sub-array within the IceCube Neutrino Observatory is a densely instrumented detector embedded in the Antarctic ice designed to observe atmospheric neutrino interactions above 5 GeV via Cherenkov radiation. At these energies, Earth-crossing muon neutrinos have a high chance of oscillating to tau neutrinos. These oscillations have been previously observed in DeepCore through both muon neutrino disappearance and tau neutrino appearance channels. DeepCore is able to measure these oscillations with precision comparable to accelerator-based experiments, but it is also complementary to accelerator measurements because it probes longer distance scales and higher energies, peaking above the tau lepton production threshold. This talk will discuss the IceCube Collaboration’s latest analyses of the atmospheric neutrino oscillation parameters using 8 years of data. In addition to several more years of data, these analyses benefit from recent significant efforts in improving background rejection, reconstruction techniques, modeling of systematic uncertainties, particle identification, and much more.
The ESSνSB project proposes to base a neutrino ”Super Beam” of unprecedented luminosity at the European Spallation Source. The original proposal identified the second peak of the oscillation probability as the optimal to maximize the discovery potential to leptonic CP violation. However this choice reduces the statistics at the detector and penalizes other complementary searches such as the determination of the atmospheric oscillation parameters, particularly the octant of θ23 as well as the neutrino mass ordering. We explore how these shortcomings can be alleviated by the combination of the beam data with the atmospheric neutrino sample that would also be collected at the detector. We find that the combination not only improves very significantly these drawbacks, but also enhances both the CP violation discovery potential and the precision in the measurement of the CP violating phase, for which the facility was originally optimized, by lifting parametric degeneracies. We then reassess the optimization of the ESSνSB setup when the atmospheric neutrino sample is considered, with an emphasis in performing a measurement of the CP violating phase as precise as possible. We find that for the presently preferred value of δ 〜 -π/2, shorter baselines like that with the Zinkgruvan detector site (360km) and longer running time in neutrino mode would be optimal. In these conditions, a measurement better than 14º would be achievable for any value of the θ23 octant and the mass ordering. Conversely, if present and next generation facilities were not able to discover CP violation, longer baselines like that with the Garpenberg detector site (540 km) and more even splitting between neutrino and neutrino modes would be preferable. The latter choices would allow a 5 σ discovery of CP violation for around a 60\% of the possible values of δ and to determine its value with a precision around 6º if it is close to 0 or π.
The KM3NeT/ORCA detector is a next-generation neutrino telescope on the bottom of the Mediterranean Sea. With a sensitivity optimized for atmospheric neutrinos between 1\,GeV to 100\,GeV, this detector will offer competitive sensitivity for measuring the neutrino mass ordering, as well as $\theta_{23}$ and $\Delta m^2_{23}$.
Currently under construction, 6 of the 115 planned Detection Units are already installed and are steadily taking data since January 2021. This contribution will present the results from the first neutrino oscillation analysis with 1 year of data. These early results already out-perform the ANTARES measurement, and approach the sensitivity of current world-leading atmospheric neutrino experiments. We will also discuss the latest estimates of the sensitivity of the complete KM3NeT/ORCA
detector.
The near future of neutrino oscillation physics will be marked with precision measurements on the standard neutrino mixing parameters. MOMENT introduces a novel method to produce a high-intensity low-energy muon-decay-based neutrino beam, which is ideal to study neutrino oscillations at medium distance. In this talk, we review the general prospects of MOMENT at the precision measurement of the standard parameters as well as in the search for new physics. We will highlight how MOMENT will perform in comparison of other next-generation experiments as well as complement them in the major goal of narrowing down the values of the neutrino mixing parameters.
The advent of high precision measurements of neutrinos and their oscillations calls for accurate predictions of their interactions with nuclear targets utilized in the detectors.
Achieving a comprehensive description of the different reaction mechanisms active in the broad range of energy relevant for oscillation experiments is a formidable challenge for both particle and nuclear Physics. I will present an overview of recent developments in the description of electroweak interactions within the spectral function approach and discuss the future perspectives to support the experimental effort in this new precision era.
T2K is a long baseline neutrino oscillation experiment, located in Japan. A muon (anti)neutrino beam peaked at 600 MeV is produced in the J-PARC facility and measured by near detectors and the Super-Kamiokande far detector. The main goal is to measure the neutrino oscillation parameters. T2K can run in both neutrino and antineutrino mode, enhancing the sensitivity to charge-parity violation (CPV) in the lepton sector. Measuring oscillation parameters requires precise knowledge of the (anti)neutrino interaction cross sections.
We present an improved cross section analysis which utilizes combined data samples of multiple detectors and in multiple beam configurations, the first of its kind. It will be used to measure the muon neutrino and antineutrino cross sections on carbon with no final state pions. This technique fully exploits the correlations between the samples' systematic uncertainties, allowing for their efficient cancellation. Since the two utilized T2K near detectors sample different neutrino energy spectra, this measurement will allow to better understand the energy dependence of neutrino interactions, thereby offering a direct probe of the physics that are responsible for the largest uncertainties in T2K oscillation analyses.
In addition, by measuring both neutrino and antineutrino cross sections, it is possible not only to better tune theoretical models of nuclear effects such as multinucleon interactions, but also to properly understand the asymmetry between neutrino and antineutrino interactions, the latter being of fundamental importance for CPV experiments that measure the asymmetry between neutrino and antineutrino oscillation rates.
The T2K experiment is a long-baseline neutrino oscillation experiment, based in Japan, which measures the oscillation probability of muon neutrinos produced at the JPARC facility, and detected at Super-Kamiokande. A detailed understanding of neutrino-nucleus cross sections is essential to measuring neutrino oscillation parameters. The off-axis near detector ND280 is used to measure a variety of neutrino interaction rates in the unoscillated beam, in order to give a better understanding of the individual cross sections. T2K has been working to add single pion production events to the oscillation analysis samples, thus increasing the impact of pion production cross section uncertainties on oscillation results.
There is an ongoing effort on T2K to measure the cross section for charged current muon neutrino events on water, with one positively charged pion in the final state ($\nu_\mu$CC$1\pi^+$) using the ND280 detector. The described measurement builds on a previous result, with significant changes to the particle kinematic ranges considered, including new reconstruction methods for accessing low energy pions using the signature of the decay chain to Michel electrons (the first instance of this technique being used in a T2K analysis.) In addition, the analysis will benefit from an increase in statistics by a factor of two, an updated treatment for unfolding, and a new treatment for the evaluation and propagation of systematic uncertainties. This talk will focus on the updated analysis techniques and simulated results for a variety of potential data sets based on simulations and previous measurements of signal and background processes.
New or updated neutrino cross section measurements can be used to compare to our current interaction models, in order to reduce model-related systematics, which will be particularly important for next generation oscillation experiments.
Current and future accelerator-based neutrino facilities utilizing intense neutrino beams and advanced neutrino detectors are focused on precisely determining neutrino oscillation properties and signals of weakly interacting Beyond the Standard Model (BSM) physics. These are all subtle effects, such as extracting the CP violation phase and disentangling parameter degeneracies between oscillation effects and BSM physics, and require an unprecedented level of precision in measurements. The potential of achieving discovery-level precision and fully exploring the physics capabilities of these experiments relies greatly on the precision with which the fundamental underlying neutrino-nucleus interaction processes are known. A non-trivial multi-scale, multi-process problem that lies in an uncharted territory that spans from low-energy nuclear physics to perturbative QCD with no known underlying unified physics. Therefore, multiple cross-community efforts are required to tackle such a problem and establish global constraints on neutrino-nucleus interaction physics that can enable desired precision in neutrino experiments. In this talk, I will discuss these challenges and highlight some of the recent cross-community experimental and theoretical efforts of tackling them.
The FCC : a (Heavy) Neutrino Factory
The Future Circular Collider is at the heart of the vision of the European Strategy for Particle Physics, who placed, as the highest priority for Europe and its international partners, a technical and financial feasibility study of the 100km infrastructure and of the colliders that would be installed in it. The physics programme is based on the sequence of a 90-400 GeV high luminosity and high precision e+e- collider, FCC-ee, followed by a 100 TeV hadron collider FCC-hh including heavy ion and optionally e-p collisions.
The physics opportunities of the two machines are remarkably complementary, both machines offering significant opportunities for discoveries in their own right, with a strong neutrino program. We will review the various neutrino physics opportunities offered by the FCC.
--Improvement in the measurement of the decay width of the Z into light active neutrinos;
-- a determination of the neutral coupling of the electron neutrino;
-- measurements of effective leptonic charged current couplings, sensitive to anomalous effective couplings of the neutrinos, and providing precision tests of lepton universality at O(10 ppm);
-- direct searches for Heavy Neutrinos in Z decays, down to the see-saw limit, describing the recent observation that the feasibility of discrimination between Dirac or Majorana neutrinos has been demonstrated;
-- similar searches in real and virtual W, Z and H decays at the FCC-hh and FCC-ep
The unique design of the LHCb detector, with a flexible trigger and a precision vertex detector, enables competitive and world-best limits on the production of heavy neutral leptons, particularly for those with low masses and produced from decays of B mesons via off-shell W decays. A review of existing results will be presented, and prospects will be discussed.
Multiple theories beyond the Standard Model predict the existence of heavy neutrinos, such as the Type I or Type III seesaw mechanisms which can explain the light neutrino masses, or left-right symmetric models which restore parity symmetry in weak interactions at higher energy scale and predict right-handed counterparts to the weak gauge bosons. Searches for such heavy Majorana or Dirac neutrinos with the ATLAS detector, which can also lead to boosted or also displaced signatures, will be presented using proton-proton data from the LHC at a center-of-mass energy of 13 TeV.
Requested by organizers.
The Jiangmen Underground Neutrino Observatory (JUNO) central detector (CD) would be the world’s largest liquid scintillator (LS) detector to probe multiple physics goals, including determining neutrino mass ordering, measuring solar neutrino, detecting supernova neutrino, etc. With an unprecedented $3\%$ effective energy resolution and an energy nonlinearity better than 1% requirement to determine neutrino mass ordering, the calibration system, including Auto Calibration Unit (ACU), Cable Loop System (CLS), Guide Tube Calibration System (GTCS), and Remotely Operated Vehicle (ROV), is designed with deploying multiple radioactive sources in various locations inside/outside of the CD. The strategy of the JUNO calibration system has been optimized based on Monte Carlo simulation results from calibration sub-systems data. This talk will present details of calibration strategy, including the JUNO calibration system design and simulation results, which help achieve an excellent energy resolution better than 3% between 1 MeV and 8 MeV.
Jiangmen Underground Neutrino Observatory (JUNO) is an up-coming experiment aiming to resolve the neutrino mass hierarchy, precisely measure $\sin^2\theta_{12}$, $\Delta m^2_{21}$ and $|\Delta m^2_{31}|$, investigate solar, atmospheric and geo-neutrinos and address other questions using optical light produced in a 20-kton liquid scintillator in response to the energy deposited by charged particles. The central detector has a spherical shape and is surrounded by about 18 thousand 20” and 26 thousand 3” photo-multiplier tubes (PMT). For achieving the physical goals it is necessary to reconstruct vertex and energy of events using the charge and time information coming from PMTs. Due to the tremendous amount of channels and variety of effects taking place in the detector this task becomes very challenging for traditional methods. Convolutional neural networks (CNN) seem to be a promising alternative. Usually CNN are working with data in Cartesian space, e.g. with rectangular images.
In JUNO the sensitive elements (PMT) are arranged on the spherical surface of the central detector. This leads to the necessity of using a projection procedure or a re-design of the neural network structure. The talk is covering different approaches to address this problem.
Hyper-Kamiokande (HK) is a next-generation neutrino experiment with a large-scale water-Cherenkov far detector approved in Japan. Its physics program addresses some of the most challenging questions in fundamental physics like the precise measurement of the neutrino oscillation parameters (solar, atmospheric, accelerator), search for leptonic CP violation, the investigation of astrophysical neutrino sources; supernovae and Diffused Supernova Bursts (DSNB), and the search for proton and exotic nucleon decays.
Since over a decade, HK’s predecessor, Super-Kamiokande, has proven the importance of neutron-tagging in a large variety of measurements, improving the limits of DSNB and proton-decay searches, and enhancing the sensitivity to the atmospheric oscillation parameters.
The neutrons produced in the interaction of an HK event thermalize and are eventually captured by hydrogen, emitting a 2.2 MeV photon. This signal is too weak for HK’s trigger threshold; therefore, the delayed neutron signal is searched by scanning all the hit PMTs of the prompt signal.
The newly developed method feeds this information into the neural network, providing as output which of the hit PMTs are more likely to receive the neutron capture signal. This not only improves the candidate selection efficiency and purity, but also provides valuable information about hit PMTs, identifying the most relevant ones for the subsequent fitting process.
In this presentation the details, features and performance of this method in the context of the Hyper-Kamiokande experiment will be shown.
DUNE is a next-generation international neutrino experiment designed to measure CP violation in neutrinos and the neutrino mass hierarchy, among other BSM goals. DUNE far detector modules are based on the liquid argon time projection chamber (LArTPC) technology, which offers an excellent spatial resolution and potentially allows excellent identification of individual particles. However, neutrino event reconstruction in LArTPC is challenging due to the complexity of the detector and topologies of the events. To address these issues, neutrino events can be reconstructed directly from images of neutrino interactions with deep learning methods, such as Convolutional Neural Networks (CNNs). In this talk, I will discuss the development of deep-learning-based reconstruction methods at DUNE. Compared with traditional reconstruction, these methods show a significantly better performance in simulated DUNE data.
In this talk, we will discuss the potential to prove "generalized neutrino interactions", exotic new physics interactions beyond the Standard Model, in the coherent-elastic neutrino-nucleus scattering (CE$\nu$NS) experiments in light of the latest COHERENT- CsI, and LAr data. We will discuss that how CE$\nu$ES processes could constrain these exotic new physics effective couplings, and the related phenomenology. Finally, a model realization will be presented that can lead to such exotic couplings.
The current and next generation experiments looking for coherent elastic neutrino-nucleus scattering (CEvNS) and neutrino-electron scattering are a unique tool for exploring exotic neutrino physics via nuclear and electron recoil measurements. In this talk, I will discuss the potential of such experiments in opening new directions on rare event searches beyond the neutrino sector. In particular, I will present the projected sensitivities of reactor neutrino experiments regarding axion-like particle (ALP) searches with a special focus on the ALP-photon, ALP-electron and ALP-nucleon couplings.
In this paper, we investigate the impact of different assumptions for the description of the QCD dynamics at high energies on the
determination of the normalization Φ and spectral index γ of the astrophysical neutrino flux. The distribution of neutrino events at the IceCube is estimated considering the DGLAP, BFKL and CGC approaches and the best estimates for Φ and γ are determined using a maximum likelihood fit comparing the predictions with the distribution of observed events at IceCube. We also investigate if the increase in the effective exposure time expected in IceCube - Gen2 will to allow us to disentangle the QCD dynamical effects from the description of the astrophysical neutrino flux.
The structure functions $F_1$, $F_2$, and $F_3$ of the nucleon were measured by neutrino deep inelastic inelastic scattering. These structure functions are expressed by collinear parton distribution functions, which indicate longitudinal momentum distributions of partons. In recent years, 3 dimensional (3D) structure functions have been investigated extensively for clarifying the transverse structure of the nucleon in addition to the longitudinal distributions and for understanding the origin of the nucleon spin including the partonic orbital-angular-momentum (OAM) contribution. The OAM contribution should be determined by generalized parton distributions (GPDs), which are measured mainly by deeply virtual Compton scattering and meson productions at lepton accelerator facilities (1). There are also possibilities of measuring the GPDs at hadron facilities by using high-energy exclusive reactions (2).
There is another important purpose to investigate the GPDs and the timelike GPDs (or generalized distribution amplitudes) for determining gravitational form factors to find the origin of hadron masses and their internal pressures in terms of quark and gluon degrees of freedom as studied in Ref. (3). Because the LBNF can supply neutrino beam in the energy region of 10 GeV, it is possible to measure the GPDs, for example, by the pion-production reaction $\nu_\mu + N \to \mu +\pi+N'$ (4,5,6) in figure 1. In general, neutrino reactions are sensitive to the quark flavor, so that their measurements are complementary to the current JLab and COMPASS measurements on the GPDs and also to the future EIC project (7). Combining both neutrino and charged-lepton measurements, we could determine the flavor dependence of the quark GPDs and the gluon GPD.
1 https://research.kek.jp/people/kumanos/tmpnufact2021/nu-gpd-2.eps
(1) M. Diehl, Phys. Rept. 388, 41 (2003).
(2) S. Kumano, M. Strikman, and K. Sudoh, Phys. Rev. D 80, 074003 (2009); T. Sawada et al., Phys. Rev. D 93, 114034 (2016).
(3) S. Kumano, Qin-Tao Song, and O. V. Teryaev, Phys. Rev. D 97, 014020 (2018).
(4) B. Z. Kopeliovich, Ivan Schmidt, and M. Siddikov, Phys. Rev. D 86, 113018 (2012).
(5) B. Pire, L. Szymanowski, and J. Wagner, Phys. Rev. D 95, 114029 (2017).
(6) S. Kumano, EPJ Web Conf. 208, 07003 (2019).
(7) Science Requirements and Detector Concepts for the Electron-Ion Collider: EIC Yellow Report, R. Abdul Khalek et al., arXiv:2103.05419, see Sec. 7.5.2, Neutrino physics.
SND@LHC is a compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity region of 7.2 < 𝜂 < 8.6, complementary to all the other experiments at the LHC. The experiment is to be located 480 m downstream of IP1 in the unused TI18 tunnel. The detector is composed of a hybrid system based on an 800 kg target mass of tungsten plates, interleaved with emulsion and electronic trackers, followed downstream by a calorimeter and a muon system. The configuration allows efficiently distinguishing between all three neutrino flavours, opening a unique opportunity to probe physics of heavy flavour production at the LHC in the region that is not accessible to ATLAS, CMS and LHCb. This region is of particular interest also for future circular colliders. The detector concept is also well suited to searching for Feebly Interacting Particles via signatures of scattering in the detector target. The first phase aims at operating the detector throughout LHC Run 3 to collect a total of 150 fb−1. The experiment was recently approved by the Research Board at CERN. A new era of collider neutrino physics is just starting.
A high-energy muon collider could be the most powerful and cost-effective collider approach in the multi-TeV regime, and a neutrino source based on decay of an intense muon beam would be ideal for measurement of neutrino oscillation parameters. Muon beams may be created through the decay of pions produced in the interaction of a proton beam with a target. The muons are subsequently accelerated and injected into a storage ring where they decay producing a beam of neutrinos, or collide with counter-rotating antimuons. Cooling of the muon beam would enable more muons to be accelerated resulting in a more intense neutrino source and higher collider luminosity. Ionization cooling is the novel technique by which it is proposed to cool the beam. The Muon Ionization Cooling Experiment collaboration has constructed a section of an ionization cooling cell and used it to provide the first demonstration of ionization cooling. Here the observation of ionization cooling is described. The cooling performance is studied for a variety of beam and magnetic field configurations. The future outlook for muon ionization cooling demonstrations is discussed.
Low emittance muon beams are central to the development of a Muon Collider and can significantly enhance the performance of a Neutrino Factory. The international Muon Ionization Cooling Experiment (MICE) has recorded several million individual muon tracks passing through a liquid hydrogen or a lithium hydride absorber and has demonstrated the ionization cooling of muon beams.
Previous analysis used a restricted data set, and the beam matching was not perfect. In this analysis, beam sampling routines were employed to account for imperfections in beam matching at the entrance into the cooling channel and enable an improvement of the cooling measurement. A study of the normalized transverse emittance change in the MICE cooling channel set up in a flipped polarity magnetic field configuration is presented. Additionally, the evolution of the canonical angular momentum across the absorber is shown and the characteristics of the cooling effect are discussed.
It is anticipated that high brightness muon beams will be needed primarily in two types of accelerators, a muon collider and a neutrino factory. The primary challenge posed by using muons for the working particle of an accelerator complex, and the reason they have not been used extensively, is the muon's short life-time (2.2μs at rest) and the relatively long cooling periods required by conventional beam cooling techniques. The Muon Ionization Cooling Experiment (MICE) is a multi-national accelerator physics initiative which has demonstrated Ionization Cooling (IC); a new, rapid beam-cooling technique suitable for the short-lived muon. The performance of IC depends on two key processes - energy loss due to collisional ionization, and Multiple Coulomb Scattering (MCS) - for which accurate models are crucial in parametrizing the method and enabling quantitative design of future muon accelerators. Experimental measurements of MCS of positive straight-track muons with momenta in the range 170-240 MeV/c in liquid H2 are reported in this study.
https://kassiopeagroup.zoom.us/j/89432151923?pwd=dzB2RG5JOGRmeGRETGJ5Z2lTeFB1QT09
The Muon g-2 experiment E989 at Fermilab measures the anomalous magnetic moment of the muon $a_\mu$ with improved precision compared to the Brookhaven (E821) experiments. The Brookhaven results are in tension with the Standard Model by more than $3\sigma$. The determination of $a_\mu$ requires the measurement of both the muon anomaly frequency $\omega_a$ and the magnetic field B that confines muons in a storage ring. The field is monitored by a set of coordinated nuclear magnetic resonance (NMR) measurements. NMR probes at fixed locations above and below the storage region constantly monitor the field. An in-vacuum trolley equipped with 17 NMR probes maps the muon storage region, and a special water-based NMR probe provides the calibration for the trolley probes. This presentation focuses on the determination of the time-dependent field maps from combining the fixed probe measurements and the trolley maps. The field maps are combined with the muon distribution to derive the average field observed by the muons during the measurement. This talk will cover the analysis from the first data run. We acknowledge support from the Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. DOE-OHEP. The author is supported by the NSF under Grant-1812314.
The presence of a permanent electric dipole moment (EDM) in any elementary particle implies CP violation and thus could help explain the matter-antimatter asymmetry observed in our universe. Within the context of the Standard Model, EDMs of SM particles are extremely small. However, in many beyond SM theories, EDMs could be within experimental reach in the near future. Recently, muon EDM is of particular interest due to the tensions in the anomalous magnetic moment of the muon and the electron, and hints of lepton flavor universality violation in B decays. Moreover, the 23 orders of magnitude difference between the current experimental limit ($10^{-19}$ e cm) and the SM prediction ($10^{-42}$ e cm) means muon EDM is one of the least tested areas of the SM and any detected signal is a strong hint of new physics. In this talk, we discuss a dedicated effort at Paul Scherrer Institute to search for the muon EDM using a 1.5 T compact muon storage ring and the frozen spin technique [F.J.M. Farley et al, PRL 93, 052001 (2004)]. This technique is more sensitive than the usual “parasitic” method utilized by the BNL/FNAL/J-PARC collaborations by several orders of magnitude, and could reach (5 x $10^{-23}$ e cm) after a year of data taking with the 125 MeV/c muon beam at PSI [A. Crivellin et al, PRD 98, 113002 (2018)].
The muon anomalous magnetic moment, $a_\mu=\frac{g-2}{2}$, can be both measured and computed with high precision, therefore it can provide an important test of the Standard Model and it is a sensitive probe for new physics.
The E989 Muon $g-2$ Experiment at Fermilab aims to measure $a_\mu$ with a precision of 140 parts per billion, four time more precisely than the previous experiment at Brookhaven National Laboratory. E989 seeks to either resolve or confirm the discrepancy between the Standard Model value and experimental one, which may be a hint of new physics. Recently E989 published a new measurement of $a_\mu$ from the Run 1 dataset, confirming the previous BNL value with comparable precision.
The $a_\mu$ measure requires a precise determination of both the muon spin anomalous precession frequency and the average magnetic field seen by the muons as they circulate in a storage ring. The anomalous precession frequency measure is based on the time distribution of high-energy decay positrons observed by 24 electromagnetic calorimeters placed around the inside of the ring, while the magnetic field is constantly monitored by NMR probes. In this talk will present the precession frequency analysis of the Run 1 data (2018), the related systematics and the latest results.
FASER$\nu$ at the CERN LHC is designed to directly detect collider neutrinos for the first time and study their cross sections at TeV energies. The detector will be located 480 m downstream of the ATLAS interaction point. With FASER$\nu$, the three-flavor neutrino cross-sections will be measured in the currently unexplored energy range between 350 GeV and 5 TeV. In particular, tau-neutrino and electron-neutrino cross sections will be measured at the highest energy ever. From the other perspective, FASER$\nu$ can measure forward neutrino production, and provide novel constraints on forward particle production.
In 2018 we performed a pilot run with the aims of measuring particle fluxes at the detector location and of detecting neutrino interactions for the first time at the LHC. We installed a 30-kg lead/tungsten emulsion detector and collected data of 12.2 fb$^{-1}$. The analysis of this data has yielded several neutrino interaction candidates, excluding the no-signal hypothesis at the 2$\sigma$ level.
During Run-3 of the LHC starting from 2022, we will deploy an emulsion detector with a target mass of 1.1 tons, coupled with the FASER magnetic spectrometer. This would yield roughly 1,300 $\nu_e$, 9,000 $\nu_{\mu}$, and 30 $\nu_{\tau}$ interacting in the detector. We present the status and plan of FASER$\nu$, as well as the neutrino detection in the 2018 data.
The NA62 experiment at CERN reports searches for K+ → e+N, K+→μ+N and K+→μ+νX decays,
where N and X are massive invisible particles, using the 2016-2018 data set.
The N particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits
of O(10−9) and O(10−8) of the neutrino mixing parameter |Ue4|2 and |Uμ4|2, improving on the earlier searches for heavy neutral lepton production and decays in the kinematically accessible mass range.
The X particle is considered a scalar or vector hidden sector mediator decaying to an invisible final state, and upper limits of the decay branching fraction for X masses in the range 10-370 MeV/c2 are reported for the first time, ranging from O(10−5) to O(10−7).
An improved upper limit of 1.0×10−6 is established at 90% CL on the K+→μ+ννν¯ branching fraction.
The SHiP Collaboration has proposed a general-purpose experimental facility operating in beam dump mode at the CERN SPS accelerator with the aim of searching for light, long-lived exotic particles of Hidden Sector models. The SHiP experiment incorporates a muon shield based on magnetic sweeping and two complementary apparatuses. The detector immediately downstream of the muon shield is optimised both for recoil signatures of light dark matter scattering and for tau neutrino physics, and consists of a spectrometer magnet housing a layered detector system with heavy target plates, emulsion film technology and electronic high precision tracking. The second detector system aims at measuring the visible decays of hidden sector particles to both fully reconstructible final states and to partially reconstructible final states with neutrinos, in a nearly background free environment. The detector consists of a 50 m long decay volume under vacuum followed by a spectrometer and particle identification with a rectangular acceptance of 5 m in width and 10 m in height. Using the high-intensity beam of 400 GeV protons, the experiment is capable of integrating $2\times 10^{20}$ protons in five years, which allows probing dark photons, dark scalars and pseudo-scalars, and heavy neutrinos with GeV-scale masses at sensitivities that exceed those of existing and projected experiments. 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 can be explained. The sensitivity to light dark matter reaches well below the elastic scalar Dark Matter relic density limits in the range from a few $\mbox{MeV/c}^2$ up to $\mbox{200 MeV/c}^2$. The tau neutrino deep-inelastic scattering cross-sections will be measured with a statistics a thousand times larger than currently available, with the extraction of the $F_4$ and $F_5$ structure functions, never measured so far, and allow for new tests of lepton non-universality with sensitivity to BSM physics. Following the review of the Technical Proposal, the Collaboration recently submitted to the CERN SPS Committee a Comprehensive Design Study. These studies have resulted in a mature proposal discussed at the European Strategy for Particle Physics Update meeting in Granada. A measurement with a SHiP target replica of the flux of muons from 400GeV proton interactions was performed at SPS during 2018 and will be reported at this conference. A measurement of charm production with a SHiP-like target interleaved with emulsion-based detectors was performed at SPS during 2018 and will be reported at this conference.
The JSNS2 (J-PARC Sterile Neutrino Search at the J-PARC Spallation Neutron Source) experiment will search for neutrino oscillations over a short 24 m baseline with delta m square near 1 eV square at the J-PARC Materials and Life Science Experimental Facility. The JSNS2 detector is filled with 17 tons of gadolinium-loaded liquid scintillator (LS) with an additional 31 tons of unloaded LS in the intermediate gamma-catcher and outer veto. A 1 MW proton beam (3 GeV) incident on a mercury target produces an intense neutrino beam from muon decay-at-rest. The experiment will search for muon antineutrino to electron antineutrino oscillations detected via the inverse beta decay reaction (electron antineutrino + proton -> positron + neutron), which is then tagged by the distinctive gammas from neutron capture on gadolinium. The JSNS2 experiment is expected to provide the ultimate test of the LSND anomaly by replicating nearly identical conditions with a much better S/N ratio. In June 2020, the JSNS2 experiment took the first 10 days of physics data after scintillator filling and extracted the scintillator for the summer maintenance of the MLF. Since January 2021 a long physics run has been started, following scintillator filling for the second time. In parallel, we are preparing the JSNS2-II experiment, the second phase of the JSNS2 experiment, with a second detector that has 35 tons of fiducial weight and a 48 m baseline. The second phase will improve the sensitivity of the search for sterile neutrino, especially in the low delta m square region. In this talk, we will summarize the detector operation and subsystems including the scintillator filling and extraction procedure, data acquisition system, preliminary data analysis status, and the prospect of the JSNS2-II experiment.
The flagship measurement of the JUNO experiment is the determination of the neutrino mass ordering. Here we revisit the prospects of the JUNO experiment to make this determination by 2030, using the current global knowledge of the relevant neutrino parameters as well as current information on the reactor configuration and the critical parameters of the JUNO detector.
We pay particular attention to the non-linear detector energy response.
Using the measurement of $\theta_{13}$ from Daya Bay, but without information from other experiments, we estimate the probably of JUNO determining the neutrino mass ordering at 3 or more sigma to be \%.
After a couple of years operation, JUNO will improve our knowledge of $\sin^2 \theta_{12}$, $\Delta m^2_{21}$ and $|\Delta m^2_{ee}|$, this will allow an updated estimate of JUNO's probability of determining the neutrino mass ordering.
Over the last two decades, the experimental understanding of three flavor oscillations has improved dramatically. However, almost all of our understanding of neutrino physics is due to the study of electron and muon neutrinos, and the tau neutrino remains the least well-studied particle in the Standard Model.
The Deep Underground Neutrino Experiment (DUNE) is a next-generation neutrino experiment currently under construction. DUNE will consist of two high-resolution neutrino interaction imaging detectors exposed to the world’s most intense neutrino beam with the Near Detector at Fermilab and the Far Detector 1,300 km away in the Sanford Underground Research Facility in South Dakota. DUNE is therefore ideally suited to collect a high-statistics, high-purity sample of tau neutrinos to significantly improve our understanding of electroweak interactions and will offer crucial tests of the three-flavor paradigm. This capability can be further improved using a proposed high-energy beam mode.
In this talk, I will discuss prospects for analyses using tau neutrinos to assess the validity of the three-flavor model, search for short-baseline sterile-driven tau neutrino appearance in the Near Detector, and constrain the currently unmeasured F4 and F5 structure functions.
The Hyper-Kamiokande (HK) experiment will perform a broad physics program including the study of long-baseline neutrino oscillations. This will be achieved by detecting neutrinos produced at an upgraded 1.3 MW beam at the J-PARC with a far water Cherenkov detector which will have about 8 times larger detector volume than that of the Super-Kamiokande detector, following the successful T2K experiment. To make full use of the high statistics data, an accurate prediction of neutrino interaction rates at the HK detector is essential. For this purpose, an intermediate water Cherenkov detector (IWCD) is planned as one of the HK’s near detectors, which will use a kiloton scale water Cherenkov detector to be located at around 1 km from the neutrino source at J-PARC. The unique feature of IWCD enables it to move vertically relative to the beam direction, changing the energies of neutrinos impinging the detector. By collecting data at various
vertical positions, IWCD will study the relation between neutrino energy and products of neutrino interactions directly. The detector is also planned to be operated with Gd2(SO4)3 loading, allowing IWCD to measure neutrons accompanying neutrino interactions. The measurement will provide direct inputs to analyses at the HK detector that utilize information about these neutrons to reduce systematic uncertainties on neutron production. This talk will describe the IWCD design and its physics program, including key technology, new photosensor module, and challenges for the IWCD measurements.
Matter effect plays a pivotal role in the upcoming Deep Underground Neutrino Experiment (DUNE) to address pressing fundamental issues such as leptonic CP violation, neutrino mass hierarchy, and precision measurements of the oscillation parameters in the precision era. In this paper, for the first time, we explore in detail the capability of DUNE to establish the matter oscillation as a function of $\delta_{\rm{CP}}$ and $\theta_{23}$ by excluding the vacuum oscillation. With the optimized neutrino beam design and using an exposure of 300 kt·MW·years, DUNE can confirm the presence of Earth’s matter effect at 2$\sigma$ C.L. irrespective of the choices of hierarchy, $\delta_{\rm{CP}}$, and $\theta_{23}$. Moreover, DUNE can rule out the vacuum oscillation at 3$\sigma$ (5$\sigma$ ) significance with a $\delta_{\rm{CP}}$ coverage of 64% (46%) for normal hierarchy and maximal $\theta_{23}$, whereas for inverted hierarchy, the $\delta_{\rm{CP}}$ coverage is 82% (43%). The relative 1$\sigma$ precision in the measurement of line-averaged constant Earth matter density (ρavg) for maximal CP-violating choices of $\delta_{\rm{CP}}$ is around 10% to 15% depending on the choice of neutrino mass hierarchy. The same for CP-conserving values of $\delta_{\rm{CP}}$ is around 25% to 30%. We find that if $\delta_{\rm{CP}}$ turns out to be around -90$^{\circ}$ or 90$^{\circ}$, the precision in measuring $\rho_{avg}$ in DUNE is better than that one can achieve using the atmospheric data from Super-Kamiokande, combined data from Solar and KamLand, and from the full exposure of T2K and NO$\nu$A. We also identify new degeneracies in ($\rho_{avg}$-$\delta_{\rm{CP}}$) and ($\rho_{avg}$-$\sin^2\theta_{23}$) planes and notice that the uncertainty in $\delta_{\rm{CP}}$ affects the measurement of $\rho_{avg}$ more than that of $\theta_{23}$. A detailed understanding of these degeneracies are essential to correctly assess the outcome of DUNE.
Reactor experiments are well suited to probe the possible loss of coherence of neutrino oscillations due to wave-packets separation. We will first comment on how decoherence modifies neutrino oscillation probabilities. Then we will turn our attention to the reactor experiments RENO, Daya Bay and KamLAND and discuss how well these experiments can constrain decoherence effects. We will finally present expected sensitivities for the future experiment JUNO.
Quantum decoherence in neutrino oscillations was theorized almost 50 years ago, however there is still no clear theoretical understanding of this phenomenon, there is not even agreement on whether or not it could be observed at all.
Treating all particles, including the source and detector, consistently in QFT, we study a model where the decoherence emerges from the time evolution of the initial state. We started by studying some simplified cases, obtaining nonetheless interesting results: we have shown that some of the assumptions used in many works on decoherence (such as the covariance of the wavepackets) are inconsistent, since the time evolution would break the Lorentz invariance; moreover we have seen that, contrary to the usual intuition, the uncertainty on the detector momentum does not always play a relevant role in decoherence, at least as long as the detector particle is non-relativistic, since its contribution is suppressed by a factor proportional to p/M.
Finally, we also notice the emergence of a new quantum effect: the oscillations do not starts immediately but only only starts a very short time after the first neutrinos arrives; however, since the time window when this effect would be observable is extremely small, the precision required to measure such an effect is most likely well beyond the current technical capabilities
Abstract: The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2×6.0×6.97m^3. The ProtoDUNE-SP detector also serves as a prototype for the first far detector module of the Deep Underground Neutrino Experiment (DUNE). A charged particle beam was specifically built to deliver multiple particles including charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/c to 7 GeV/c. The ProtoDUNE-SP detector also serves as a prototype for the first far detector module of the Deep Underground Neutrino Experiment. We present algorithms for particle identification (protons, pions, and showers) and cross section measurement of pion absorption in the protoDUNE pion beam events with a slicing method. This is the first measurement of pion absorption with pion momenta greater than 350 MeV.
The NOvA near detector (ND), located at Fermilab, provides an excellent opportunity to measure neutrino-nucleus interactions, which will benefit current and future neutrino experiments. The ND records a high rate of neutrino interactions with energies ranging from 1-5 GeV. In this talk, we present a measurement of the muon-neutrino charged-current inclusive cross sections as a function of the outgoing muon energy and angle, as well as cross sections in the derived neutrino energy and the square of the four-momentum transfer. We include a comparison of these results with predictions from various neutrino event generators. We also show our progress on the muon-antineutrino charged-current inclusive cross-section analysis. In addition, we present the status of the charged-current muon-neutrino with low hadronic activity analysis. This channel is particularly sensitive to nuclear effects in neutrino interactions, effects that are one of the major challenges for all neutrino experiments in the few GeV region.
The NOvA experiment is a long-baseline neutrino experiment aiming to con- strain independent elements of the PMNS matrix. The NOvA Near Detector can also serve as a way to measure many different types of neutrino-nucleus cross sections, significantly adding to the world neutrino data and helping to improve models of neutrino scattering that are critical to oscillation measure- ments. Electromagnetic showers can be produced in a variety of ways from neutrino scattering, sometimes in the final state lepton in charged current νe scattering, or through the decay of hadrons from charged- or neutral-current interactions, and also through coherent or incoherent scattering. Each of these final state configurations has different sensitivities to initial and final state nu- clear effects as well as interaction processes with nuclear constituents. This talk will discuss the status of a suite of analyses of data from the NOvA Near Detector which all have electromagnetic showers in the final state using both neutrinos and antineutrinos as a probe.
The effect of nonperturbative and higher order perturbative corrections to all the free nucleon structure functions in the deep inelastic scattering (DIS) of neutrinos on nucleon/nucleus is studied. The target mass correction and higher twist effects are incorporated following the works of Kretzer et al. and Dasgupta et al., respectively. The evaluation of the nucleon structure functions has been performed by using the MartinMotylinski Harland-LangThorne 2014 parametrization of the parton distribution functions. The calculations have been per- formed at the next-to-leading order. The results for the nucleon/nuclear structure functions shall be presented. The various effects considered in this work are effective in the different regions of x and Q2, and quite important in the few GeV energy region. The numerical calculations for the ν -A deep inelastic scattering (DIS) process have been performed by incorporating the nuclear medium effects like Fermi motion, binding energy, nucleon cor- relations, mesonic contributions, shadowing, and antishadowing in several nuclear targets such as carbon, polystyrene scintillator, iron, and lead, which are being used in MINERA, and in argon nuclei, which is relevant for the ArgoNeuT and DUNE experiments.
The Future Circular Collider is at the heart of the future vision of the European Strategy for Particle Physics, who placed, as the highest priority for Europe and its international partners, a technical and financial feasibility study of the 100km infrastructure and of the colliders that would be installed in it. The physics programme is based on the sequence of a 90-400 GeV high luminosity and high precision e+e- collider, FCC-ee, followed by a 100 TeV hadron collider including also heavy ion and optionally e-p collisions. The physics opportunities of the two machines are remarkably complementary, both machines offering significant opportunities for discovery in their own right, with a strong neutrino program.
The presentation will address the opportunities and challenges that the project presents, beginning with the implementation of a 100km infrastructure around Geneva for a > 70 years long exploitation, and possible synergies with high energy muon storage rings. The main challenges in accelerator technology are the design of a high efficiency RF system (for FCC-ee) and the design of affordable and high quality high field (16T) magnets for the FCC-hh. Some challenging aspects of the accelerator design for FCC-ee will also be discussed: crab-waist collisions and IR design, high precision centre-of-mass determination and the challenge of designing a monochromatization scheme for ee --> H s-channel production.
https://kassiopeagroup.zoom.us/j/89432151923?pwd=dzB2RG5JOGRmeGRETGJ5Z2lTeFB1QT09
In light of the recent FNAL g-2 result, the most up to date Standard Model value of the muon anomalous magnetic moment will be discussed.
The muon g-2/EDM experiment at J-PARC (E34) aims to measure
muon g-2 and EDM with unprecedented low-emittance muon beam
realized by acceleration of thermal muons.
Thanks to its low emittance, it can measure muon g-2 in a completely different way than FNAL or BNL.
The technical design of the experiment has been completed and the budget is being requested to start the experiment in 2025.
In the first phase of the experiment, measurement of g-2 with a precision of 0.45 ppm will be achieved through two years of data acquisition.
The measurement is statistically limited and the accuracy of 0.1 ppm will be achieved through subsequent upgrades of the beam intensity.
In this talk, details and current status of the experiment will be presented.
A hydrogen-like atom consisting of a positive muon and an electron is known as muonium. It is an ideal two-body system to test bound-state theory and fundamental symmetries. The MuSEUM collaboration aims to obtain the hyperfine structure (HFS) in muonium and the muon-to-electron mass ratio, which is necessary to determine the muon's anomalous magnetic moment. Our goal is to exceed the precision of the previous experiment at Los Alamos National Laboratory [1] by a factor of ten. Since most of the uncertainty was a statistical error, we expect a significant improvement in the precision by using the high-intensity pulsed muon beam at J-PARC MLF MUSE. The project is divided into two phases: proof of principle at zero field and measurements at high-field for the highest precision. We have reported the first physics results for the former [2], showing that our new method is working properly. For the latter, construction of a new beamline and R&D of high-precision magnetic field probes are in progress. In this contribution, we will present an overview of the project, the analysis results of the zero-field measurement, and the preparations for the high-field experiment.
[1] : W. Liu et al., Phys. Rev. Lett. 82 (1999) 711-714.
[2] : S. Kanda et al., Phys. Lett. B 815 (2021) 136154.
One of the most important achievements in the field of particle physics is the discovery of neutrino oscillations. Despite already awarded Nobel Prize, neutrino oscillation experiments still have a lot to offer, primarily the discovery of CP violation in the lepton sector is anticipated. The parameters entering the expression for neutrino oscillation probabilities are neutrino mixing parameters and mass squared differences. In this talk, we argue that neutrino mixing parameters at production and detection do not necessarily need to be equivalent since such parameters are subject to renormalization group evolution and the process of neutrino production and detection occurs at different energies.In this talk we discuss this in the frame of an UV compete model; in particular we demonstrate that quantum effects can yield relevant observable effects at various neutrino experiments. As an example, we consider high-energy astrophysical neutrinos at IceCube and show that neutron decay production mechanism, that is considered to be strongly disfavored by present data, becomes viable if the significant renormalization group effects are present. We also consider terrestrial experiments and show that the mismatch of neutrino parameters at production and detection can induce large effects at T2K and NOvA.
The neutrino mass determination is an open issue in particle physics. The study of the endpoint of beta decay is the best experimental way to provide a model-independent mea- surement. The HOLMES experiment aims to measure directly the neutrino mass with a calorimetric approach studying the 163Ho electron-capture decay. The very low Q-value (2.8 keV), the half-life (4570 y) and the proximity of the endpoint to M1 resonance make the 163Ho decay a very good choice. However, there are two critical steps to be considered for the realization of the experiment. The first step is embedding of the source isotope inside the cryogenic microcalorimeters so that the energy released in the decay process is entirely contained within the detectors, except for the fraction taken away by the neutrino. The second one is the rejection of 166Ho radioactive isotope that could produce false signal in the region of interest. Taking into account these two requirements, a dedicated implanter with a sputter ion source, an acceleration section (up to 50 keV) and a magnetic dipole (for ion selection and beam focusing) has been designed and developed. The implanter calibra- tion and performance have been evaluated using 63Cu/65Cu and 197Au beams. Currently, different holmium compounds are being tested to find the candidate with the best efficiency in the sputter process. This work will show the status of the machine development and commissioning.
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for 0νββ decay that has been able to reach the one-tonne mass scale. The detector, located at the LNGS in Italy, consists of an array of 988 TeO2 crystals arranged in a compact cylindrical structure of 19 towers. CUORE began its first physics data run in 2017 at a base temperature of about 10 mK and in April 2021 released its 3rd result of the search for 0νββ, corresponding to a tonne-year of TeO2 exposure. This is the largest amount of data ever acquired with a solid state detector and the most sensitive measurement of 0νββ decay in 130Te ever conducted, with a median exclusion sensitivity of 2.8×10^25 yr. We find no evidence of 0νββ decay and set a lower bound of 2.2 ×10^25 yr at a 90% credibility interval on the 130Te half-life for this process. In this talk, we present the current status of CUORE search for 0νββ with the updated statistics of one tonne-yr. We finally give an update of the CUORE background model and the measurement of the 130Te 2νββ decay half-life, study performed using an exposure of 300.7 kg⋅yr.
CUPID is a next-generation tonne-scale bolometric neutrinoless double beta decay experiment to probe the Majorana nature of neutrinos and discover Lepton Number Violation if the effective neutrino mass is greater than 10 meV. CUPID will be built on experience, expertise and lessons learned in CUORE, and will be installed in the current CUORE infrastructure in the Gran Sasso underground laboratory. The CUPID detector technology, successfully tested in the CUPID-Mo experiment, is
based on scintillating bolometers of Li2MoO4 enriched in the isotope of interest 100Mo. In order to achieve its ambitious science goals, CUPID aims to reduce the backgrounds in the region of interest by a factor 100 with respect to CUORE. This performance will be achieved by introducing the high efficiently alpha/beta discrimination demonstrated by the
CUPID-0 and CUPID-Mo experiments, and using a high transition energy double beta decay nucleus such as 100Mo to minimize the impact of the gamma background. CUPID will consist of about 1500 hybrid heat-light detectors for a total isotope mass of 250 kg. The CUPID scientific reach is supported by a detailed and safe background model that uses CUORE, CUPID-Mo and CUPID-0 results. The required performance in terms of energy resolution, alpha rejection factor and crystal purity have already been demonstrated and will be presented.