Prochains séminaires
Depuis plus de 20 ans, l'Accélérateur Grand Louvre d'Analyse Elémentaire (AGLAE) est exclusivement dédié à l'étude d'objets du patrimoine, à la croisée des sciences physiques et des sciences humaines. La nouvelle ligne de faisceau, complètement automatisée, a été inaugurée en 2017.
La conférence présentera les différentes étapes de l'achèvement de cet équipement d'excellence ainsi que les développements en cours et les défis à relever dans le futur.
5 derniers séminaires
The search for pevatrons (objects capable of accelerating 10$^{15}$ eV particles) has become one of the key targets of the high--energy gamma—ray community. These objects are of crucial importance in the context of the origin of cosmic rays (CRs), since the sources of Galactic CRs are expected to be pevatrons.
Currently, the most famous candidates for the origin of Galactic CRs are supernova remnants (SNRs), the shocks expanding in the interstellar medium after the explosion of massive stars. But surprisingly, all detected SNRs have been shown to not be pevatrons, making the situation somewhat bewildering.
A special attention is currently being devoted to the search of a SNR pevatron, and we will discuss the possibility of detecting and identifying one with next—generation gamma—ray instruments, such as the Cherenkov Telescope Array.
The idea to use neutrinos as cosmic messengers dates back to the 1950s,
and the concept of Cherenkov Neutrino Telescopes deep underwater to the
year 1960. It took more than half a century before a detector large
enough to detect cosmic high-energy neutrinos was built: The IceCube
Neutrino Telescope at the South Pole. I will decribe the way towards
IceCube construction and sketch IceCube's main results, starting with
the discovery of a diffuse flux of cosmic neutrinos in 2013. I will also
try a look into the near future, where IceCube will be flanked by
telescopes of similar size in the Mediterranean Sea (KM3NeT) and in Lake
Baikal.
The presentation will focus on a recent search for non-standard Higgs bosons, performed with a data sample collected by the ATLAS experiment at the CERN Large Hadron Collider between 2015 and 2018, and relying on experimental signatures containing multiple leptons. After an introduction to the theoretical and experimental contexts, the discussion will be framed in terms of the search strategies used, with details on the backgrounds present in the regions of interest and the challenges encountered to estimate them precisely. The obtained results will be presented, followed by perspectives for future improvements.
Because of its properties, liquid argon (LAr) is a conventional medium for neutrinos and dark matter detectors such that its operation in time projection chamber (TPC) detectors became quite common. Nevertheless, proving the scalability of these detectors toward their operation at giant scales is critical.
In the field of long-baseline neutrino oscillation experiments, DUNE (Deep Underground Neutrino Experiment) is the current leading-edge project; in the far detector, it envisages four 10-kton LAr-TPCs, in different configurations, but none of them ever used such a large LAr mass. Among those, a LAr-TPC based on the so-called dual-phase (DP) technology has been considered because particularly advantageous for covering longer drift paths. In order to validate the suitability of this technology for DUNE, two prototypes with an increasing LAr active volume have been operated at CERN: the WA105-DP demonstrator, of 3x1x1 m3 (~4.2 tons), and ProtoDUNE-DP, of 6x6x6 m3 (~300 tons). At the time of its operation, the WA105-DP detector was the first prototype ever worked at the ton scale, allowing the achievement of important technological milestones. In the DP LAr-TPCs, the photon detection system (PDS) is typically used for triggering but it is expected to be valuable for discriminating non-beam or low-energy events.
In this talk, the analysis of the light signal data collected during the whole WA105-DP prototype operation is discussed. The complete characterization of the two light signals produced in liquid and gas phases allowed the achievement of pioneering results deepening the understanding of the LAr micro-physics. Consequently, the knowledge of the light production and its subsequent propagation in the LAr bulk has been enhanced, improving the light simulation for physics sensitivity studies in big LAr detectors.