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This will be the 30th meeting in this series of annual international multidisciplinary meetings, created in 1989 by Jean Tran Thân Van and which has in the past covered many topics in physics, astronomy and biology. All sessions take place in the Château of Blois, a beautiful renaissance castle which has housed many French kings, and notably François 1st. The 30th Rencontres de Blois on "Particle Physics and Cosmology" (Blois2018) will emphasize the increasing interplay between high energy accelerator based physics and cosmology. The conference will consist of plenary sessions for invited in-depth oral presentations (review talks) and contributed papers, in the form of relatively short oral papers. We will aim to achieve a balance between review talks, provocative talks given by recognized specialists, and shorter contributions. Special emphasis is being placed on active participation by younger researchers and post-docs. Parallel sessions are foreseen, and are being organised as the need arises.
Noble liquid time projection chambers (TPCs) are the leading technology in direct dark matter detection. Among the different targets, Liquid Argon (LAr) plays an important role thanks to its exceptional capabilities to distinguish between nuclear recoils and electronic recoils. The sensitivity of LAr detectors can be enhanced by constraining the parameters of the liquid argon response to interacting particles, such as the quenching of nuclear recoils and the electron-ion recombination effect.
The ARIS (Argon Response to Ionization and Scintillation) experiment has been designed to characterize the LAr response to low energy neutrons and gamma scatters with and without an electric field. A 0.5 kg LAr TPC was exposed to a highly collimated and quasi mono-energetic neutron beam produced with the LICORNE source at the IPN of Orsay and allowed to perform a precise measurement of quenching and recombination effects in LAr in the energy range of interest for dark matter searches.
The $SU_L(2)\bigotimes SU_R(2) $ gauge model of the unified theory
of the electromagnetic and weak interactions, which is free of
the auxiliary self-interaction scalar field, is developed.
Breaking the initial symmetry, the $SU_L(2)\bigotimes U_R(1) $
Lagrangian is derived. The obtained $SU_L(2)\bigotimes U_R(1) $
Lagrangian contains all of the terms, corresponding to free boson
and fermion fields as well as to interactions between them, which are in the classical Standard Model of the electroweak interaction. All boson
fields, including the Higgs one, directly arise due to violation
the initial symmetry, and are generated by the initial gauge
fields. The obtained masses of the Higgs particle and of the gauge boson fields
are in agreement with the experimental data[1,2].
1.ATLAS Collaboration, Physics Letters B, v.716, 30 (2012).
2.Particle Data Group,C. Patrignani et al., Chin.Phys. C , v.4, 100001 (2016).
ORCA is the low-energy branch of KM3NeT, the next-generation Cherenkov neutrino observatory under construction in the Mediterranean Sea. A dense configuration of optical modules is foreseen to detect neutrinos down to a few GeV energy. The detector will be able to accurately reconstruct and distinguish two event topologies: track-like signatures from mostly $\nu_\mu$ charged current interactions and cascade events dominated by the remaining neutrino interactions. With its instrumented volume of 8 Mm$^3$, ORCA will collect high statistics of atmospheric neutrinos that have traversed a wide range of baselines and matter density profiles while crossing the Earth.
These ingredients enable ORCA to resolve the neutrino mass hierarchy, i.e. determine whether the third neutrino mass eigenstate is lighter or heavier than the other two, with a significance of 3$\sigma$ after 3-4 years of operation. ORCA will also be able to constrain other neutrino oscillation parameters such as $\theta_{23}$ and - by studying the appearance of tau neutrinos - the unitarity of 3-neutrino mixing.
The contribution reviews the technology, performance and main scientific objectives of the experiment. The current construction status and further science options including a possible neutrino beam to ORCA are outlined.
The GERmanium Detector Array (GERDA) collaboration searches for the hypothetical lepton number violating process neutrinoless double beta decay of Germanium-76 by operating 35 kg of enriched germanium diodes acting as both source and detector. The detectors are operated directly in liquid argon, which acts both as a coolant and as background shielding. Since the start of Phase II in 2015, the liquid argon is also instrumented with light detectors to readout scintillation light for further background suppression. The most recent limit on the half-life from GERDA is $8.0 \times 10^{25}$ yr, the strongest limit set for this isotope. This was achieved with a background level of $10^{-3}$ counts/(keV kg yr), such that GERDA will remain "background-free" up to the entire design exposure. In May 2018, GERDA's projected half-life sensitivity will surpass $10^{26}$ yr, the first neutrinoless double beta decay experiment to do so. Results and analysis from this data release will be presented.
CUPID-0 is the first large array of enriched scintillating ZnSe cryogenic calorimeters implementing active particle identification. The detector consists of an array of 24 ZnSe crystals enriched in $^{82}$Se and two natural ZnSe crystals for a total mass of 10.5 kg installed in a dilution refrigerator hosted at the Laboratori Nazionali del Gran Sasso.
The heat-light readout exploited in CUPID-0 provides a unique tool for $\alpha$-particle discrimination and allows to suppress the background in the region of interest to an unprecedented level for a bolometric experiment. We will report the first results of the search for neutrinoless double beta decay ($0\nu\beta\beta$) in $^{82}$Se and a preliminary background reconstruction.
ENUBET has been designed to monitor lepton production in the decay tunnel of neutrino beams at single particle level and to provide a 1% measurement of the neutrino flux at source. In particular, the three body semileptonic decay of kaons monitored by large angle positron production offers a fully controlled $\nu_e$ source at the GeV scale for a new generation of short baseline experiments. During the last year major advances have been achieved in the design of the positron tagger and the beamline. In Blois, the ENUBET Collaboration will present the performance of the positron tagger tested at CERN in 2017-2018, the design for the Reference Beamline - with special emphasis on the static focusing system - and the expected sensitivity of ENUBET for $\nu_e$ and $\nu_\mu$ cross section measurements.
Recent observations of gamma rays with the Fermi-LAT have revealed excess emission from the centers of the Milky Way and the Andromeda galaxy, both of unknown origin. In this talk, I will briefly review the current observational status of the excess including morphological and spectral properties. Possible interpretations will be discussed, such as cosmic ray interactions with the interstellar medium, unresolved population of point sources, and dark matter annihilation or decay. Future observations at higher energies may shed light on the origin of the central emission.
Primordial black holes (PBH) are predicted to form from overdense regions in the early universe. These black holes can lose mass through Hawking radiation. Those PBHs of initial mass of $10^{15}$ g would evaporate in the current epoch, producing a bright burst of gamma rays. Despite the lack of detection from many experiments, the observations of PBH evaporation events provide constraints on their rate-density, which has cosmological implications. We search for excess of gamma-ray burst events that could be associated with primordial black hole evaporations in the archival data of VERITAS, a ground-based Cherenkov telescope array. We present new analysis techniques and search methodologies, and the new constraints on the rate-density of evaporation of primordial black holes.
Fixed target experiments are a particularly useful tool in the search of very weakly coupled particles in the MeV-GeV range,
which are of interest, e.g. as potential Dark Matter mediators. Owing to the high beam-energy and a hermetic detector coverage, NA62 also has the opportunity to directly search for a variety of long-lived beyond-the Standard Model particles, such as Axion-like Particles and Dark Photons. In this talk, we will review the status of this searches and give prospects for future data taking at NA62.
Searches for heavy neutral lepton (HNL) production in charged kaon decays using the data collected by the NA62 experiment at CERN are reported. Upper limits are established on the elements of the extended neutrino mixing matrix for heavy neutral lepton mass in the range 130-450 MeV, improving on the results from previous HNL production searches. The status and prospects of searches for lepton flavour and lepton number violation in kaon decays at the NA62 experiment is also presented.