The IceCube Neutrino Observatory is a cubic-kilometer Cherenkov neutrino detector deployed in the glacial ice at the geographic South Pole. DeepCore, its denser sub-array, lowers the energy threshold for neutrino detection to less than 10 GeV. In recent years, IceCube became one of the leading instruments measuring the neutrino mixing parameters in the atmospheric sector. In addition, its data are used to search for new physics beyond the standard three-neutrino mixing. This talk discusses the most recent neutrino oscillation results from IceCube and future of in-ice measurements of fundamental neutrino properties.
Keywords/Mots clés: CPPM, ATLAS Upgrade/Amélioration d'ATLAS, C3F8, Tracker cooling/Refroidissement du trajectographe
Gaia is an ESA astrometric mission launched end of 2013 for a nominal mission of five years. It is providing unprecedented astrometry (parallaxes and proper motions) and spectrophotometry for more than 1 billion sources brighter than G=20.7 mag.
It also provides spectrocopy for the brightest onces. By providing 3D spatial and velocity distributions of the stars combined with their astrophysical properties, Gaia is revolutionizing our knowledge of the Milky Way formation history and of stellar evolution. But it is also observing solar system objects, local group resolved stars, unresolved galaxies, quasars, it is alerting on photometric transients and will allow to perform relativistic tests.
I will present the content of the second Gaia data release together with a few of the many examples of its scientific exploitation, from survey calibration to dark matter constraints.
The recent discovery of high-energy astrophysical neutrinos has opened a new window to the Universe. Identifying the sources of those neutrinos is the most pressing question in the new field of neutrino astronomy. Combining neutrino data with electromagnetic measurements in a multi-messenger approach increases the sensitivity to identify the neutrino sources and helps to solve long-standing problems in astrophysics such as the origin of cosmic rays.
A first compelling candidate was identified on September 22, 2017, when the IceCube Neutrino Observatory observed an extremely high-energy neutrino, IceCube-170922, in spatial and temporal coincidence with a gamma-ray flaring blazar, TXS 0506+056, monitored by the Fermi Large Area Telescope. The coincidence triggered a large follow-up campaign in a broad wavelength band.
In this talk I will review the recent progress in multi-messenger astronomy using neutrino data with a focus on the candidate source, TXS 0506+056.
The origin of the astrophysical neutrino signal detected by IceCube is still mysterious. Several extragalactic sources have been proposed as possible accelerators of the high energy protons (or nuclei) whose interaction with gas or radiation is expected to trigger the neutrino emission. The detection of the well reconstructed event IC-170922A on September 2017, potentially associated with the BL Lac TXS 0506+056 is drastically changing the scenario. I will discuss the interpretation of this event in the framework of the blazar models and the consequences for our knowledge of the jet physics.
In preparation for a Lepton Collider in the multi-TeV range which will possibly be required for precision physics beyond the standard model if and when identified, novel acceleration techniques are being developed with attractive performance. After a review of the technology options being considered for an affordable e+/- linear collider at the energy frontier, the presentation will focus on Muon-based facilities which offer a unique potential to enable capabilities at both the Intensity Frontier with Neutrino Factories and the Energy Frontier with Muon Colliders ranging from Higgs to multi-TeV energies. By comparison with other technologies, through objectives Figures of Merit, a Muon Collider, is demonstrated to be the most promising option in the multi-TeV energy range. Muon based facilities rely on novel technologies with challenging parameters and critical issues from which the status and future plans of the R&D to demonstrate their feasibility is presented.
Keywords/Mots clés: Future Collider/Collisionneur Futur, Muon Collider/Collisionneur de muons, Accelerator/Accélérateur R&D, Neutrino Beam/Faisceau de Neutrinos, CERN
5 derniers séminaires
The Belle II experiment at the SuperKEKB accelerator, a super flavour factory project in KEK in Japan, has started its operation in April this year. In the seminar we will review the motivation for precision studies in flavour physics as a promising new window for New Physics, describe the accelerator and the detector, and discuss the present status, immediate plans and prospects of the project.
Keywords/Mots clés: B-Physics/Physique du B, KEK, CP Violation in B mesons/Violation de CP dans les mésons beaux, Low energy & high luminosity e+e- collider/Collisionneur e+e- de basse énergie & de haute luminosité
Six years since the discovery of the Higgs boson and the analysis of over
100fb-1 of data have been necessary for the ATLAS experiment to observe the
most abundant Higgs decay channel into b-quark pairs.
The seminar will explain the challenges of this observation, and present in
details the most sensitive search channel, where the Higgs is produced in
association with W or Z bosons. The longer-term perspectives for studies of
this part of the Higgs sector will also be discussed.
Mots clés: ATLAS, LHC, Higgs, b-tagging/étiquetage des jets de b
Abstract: Dark energy, the apparent accelerated expansion of the universe, constitutes one of the biggest mysteries in cosmology and particle physics. Since its discovery, 20 years ago, several astronomical observations and laboratory measurements have been performed in order to elucidate its nature. The talk will discuss how collider experiments can be used to provide complementary information on the nature of dark energy. We will present the first constraints on an effective field theory model of dark energy obtained by a search for light scalar particles produced in association with a pair of top quarks or jets, using the ATLAS detector. These results provide the most stringent constraints on the scale of disformal interactions between dark energy and Standard Model matter, improving the constraints obtained from cosmological and solar system tests by several orders of magnitude. We will also discuss about the future prospects of these searches at the LHC.
Keywords/Mots clés: ATLAS, LHC Run 2, Exotics/Exotique, Dark Energy/Energie Noire
The Axion is the hypothetical low-mass boson predicted by the Peccei-Quinn mechanism solving the strong CP problem. It is naturally also a cold dark matter candidate, thus it could simultaneously solve two major problems of nature. Up to recently there was no existing experimental effort aiming to detect QCD axions in the mass range around 100 ueV, preferred by models in which the Peccei-Quinn symmetry was restored after inflation.
The MADMAX project is designed to be sensitive for axions with masses 40ueV – 400 ueV. The experimental design is based on the idea of enhanced axion photon conversion in a system with several layers with alternating dielectric constants inside a ~10T dipole magnet.
After an introduction to axions as dark matter candidates the experimental idea and the proposed design of the MADMAX experiment will be discussed. Some results from proof of principle measurements and magnet design studies will be shown. The status of R&D towards realization of the MADMAX experiment will be discussed and the prospects for reaching sensitivity enough to cover the parameter space predicted for QCD dark matter axions with mass in the range 40-400 µeV will be presented.
Experimenters from four different argon dark matter searches have joined their forces in the the “Global Argon Dark Matter Collaboration” to carry out a unified program for dark matter direct detection. The participants are researchers currently working on the ArDM experiment at LSC; on the DarkSide-50 experiment at LNGS; on the DEAP-3600 experiment at SNOLab; and on the MiniCLEAN experiment at SNOLab.
In 2015/2016 the DarkSide-50 experiment at LNGS produced two zero-background science results, along with a comparison of the results obtained with both atmospheric and underground argon fills, demonstrating the ability of large experiments to eliminate background from betas/gammas at the tens of tonne-year exposure. Early in 2018, the DarkSide Collaboration announced results from a 2-years campaign with DarkSide-50, resulting again in a zero-background, null observation of heavy (>50 GeV/c2) dark matter and in the best exclusion limits for light (<10 GeV/c2) dark matter.
The DEAP-3600 experiment at SNOLAB is the first tonne-scale experiment to achieve both stable operations and an extended physics run. DEAP-3600 has been collecting physics data with over 3 tonnes of argon since late 2016 and published its first results in 2017.
Researchers from the four experiments will jointly carry out as the single next step at the scale of a few tens of tonnes the DarkSide-20k experiment. DarkSide-20k was approved in 2017 by the Italian INFN, by the host laboratory LNGS, and by the US NSF. DarkSide-20k is also officially and jointly supported by the three underground laboratories LNGS, LSC, and SNOLab.
DarkSide-20k is a 20-tonne fiducial volume dual-phase TPC to be operated at LNGS with an underground argon fill, designed to collect an exposure of 100 tonne×years, completely free of neutron-induced nuclear recoil background and all electron recoil background. DarkSide-20k is set to start operating by 2021 and will have sensitivity to WIMP-nucleon spin-independent cross sections of 1.2 × 10−47 cm2 for WIMPs of 1 TeV/c2 mass, to be achieved during a 5 year run. An extended 10 year run could produce an exposure of 200 tonne×years, with sensitivity for the cross-section of 7.4 × 10−48 cm2, for the same WIMP mass. DS-20k will explore the WIMP-nucleon cross-section down to the edge of the ’neutrino floor’, where coherent neutrino-nucleus scattering from environmental neutrinos induce nuclear recoils in the detector.
A second step in the program is the construction and operation of a detector with a fiducial mass of a few hundred tonnes, capable of collecting an exposure of several thousands of tonne×years, completely free of all backgrounds on top of CNNS. This follow-up experiment would also be capable of performing a set of very high precision measurement of several solar neutrino sources (location and laboratory t.b.d.). This includes exquisitely precise measurements of pep, CNO, as well as low energy 8B neutrinos, all in the region of transition between the vacuum- and matter-dominated regions of solar neutrino oscillations.