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Speaker 1: Leonardo Splendori
Title: Developments in b-tagging for the ATLAS upgrade and their impact on di-Higgs sensitivity
Abstract: The upcoming High Luminosity LHC (HL-LHC) era is expected to bring opportunities for studies involving rare processes, including di-Higgs production. Flavour tagging is going to play a crucial role in the analysis of such processes. This talk will explore the challenges we expect to encounter for flavour tagging in the HL-LHC era, with its higher luminosity, increased pile-up and upgraded ATLAS detector. The focus will be on the expected behaviour of current flavour tagging neural networks (GN2) when trained and evaluated on simulated Run 4 samples. To determine its performance and robustness against the harsher conditions associated with higher pileup. From this we will be able to compare the same model between Run 3 and Run 4 and produce predictions on the impact this new environment will have on di-Higgs analyses.
Speaker 2: Mélissa Leroy
Title: A Comprehensive Simulation Framework for Cadmium Telluride Hybrid Pixels
Abstract: Understanding and predicting the behavior of CdTe-based X-ray detectors is essential for optimizing and designing the next generation of high-performance imaging systems. However, the simulation of hybrid pixel sensors remains a challenge due to physical phenomena occurring during their operation. In the context of a CIFRE thesis carried out in partnership with Detection Technology, a manufacturer of X-ray detection systems for security, medical, and industrial applications, I will present a comprehensive simulation framework for X-ray hybrid pixels.The simulator reproduces interactions between X-rays and the sensor are modeled using Geant4-based Monte Carlo simulations, while charge drift, repulsion, and diffusion are described with an analytical approach derived from the charge continuity equation. The simulated spectra are validated against experimental data acquired with the XPAD3.2-S/CdTe hybrid pixel detector under synchrotron irradiation. The results show good agreement with measurements, demonstrating the relevance of this framework to reproduce complex physical effects such as fluorescence escape and charge sharing that strongly impact detector performance.
Speaker 3: Christian Tsava
Title: Search of Higgs Boson Pair Production in the bbττ Final State using b-jet triggers with the ATLAS Detector at the LHC
Abstract: This work summarizes the use of the b-jet trigger in the ATLAS search for non-resonant Higgs boson pair production in the bbττ final state using Run 2 and partial Run 3 data, with the aim of measuring the Higgs potential via the Higgs self-coupling. The event selection targets events with one or two hadronically decaying τ leptons. The objective is to study the impact of adding and calibrating the b-jet trigger in the analysis. This work provides a detailed overview of all the necessary steps for the inclusion and calibration required for the bbττ analysis.
Speaker 4: Francesco Magnani
Title: Multi-messenger astronomy with KM3NeT and COLIBRÍ
Abstract: Multi-messenger astronomy combines signals from different cosmic messengers emitted by the same astrophysical source. Neutrinos, in particular, travel unimpeded from their production site and can directly trace hadronic processes in extreme environments where electromagnetic observations are often challenging. This makes them ideal probes for systems where particle acceleration is still poorly understood, such as microquasars—compact binaries in which a compact object accretes matter from a companion star and can launch powerful relativistic jets, recently confirmed as high-energy emitters.
Part of this thesis focuses on the search for neutrino emission from microquasars using KM3NeT, the neutrino telescope under construction in the Mediterranean Sea, which spans energies from a few GeV to several hundred PeV thanks to its ORCA and ARCA detectors. In parallel, we are initiating an optical monitoring campaign with COLIBRÍ, a robotic 1.3-m telescope in San Pedro Mártir (Mexico). Optical data are expected to be crucial, as microquasar outbursts often show precursors in the optical band days before the X-ray flare. Combining both datasets will enable us to track the full evolution of an outburst and correlate the different emission channels to investigate its origin.
Part of this thesis focuses on the search for neutrino emission from microquasars using KM3NeT, the neutrino telescope under construction in the Mediterranean Sea, which spans energies from a few GeV to several hundred PeV thanks to its ORCA and ARCA detectors. In parallel, we are initiating an optical monitoring campaign with COLIBRÍ, a robotic 1.3-m telescope in San Pedro Mártir (Mexico). Optical data are expected to be crucial, as microquasar outbursts often show precursors in the optical band days before the X-ray flare. Combining both datasets will enable us to track the full evolution of an outburst and correlate the different emission channels to investigate its origin.
