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T: Fachverband Teilchenphysik

T 82: Calorimeters II

T 82.7: Vortrag

Donnerstag, 18. März 2021, 17:30–17:45, Tg

Neural network based pulse shape analysis with the Belle II electromagnetic calorimeter — •Stella Katharina Wermuth — DESY, Hamburg, Deutschland

The Belle II experiment, located at the SuperKEKB e⁺e⁻ collider in Japan, uses pulse shape analysis techniques to distinguish electromagnetically and hadronically interacting particles within the CsI(Tl) electromagnetic calorimeter. The pulse shapes from the particle-dependent scintillation response are nominally analyzed with a multi-template offline fit to measure the fraction of scintillation emission produced by hadrons. This fitting method allows for the determination of the total deposited energy, the total scintillation emission by hadrons, and the time of energy deposit. This presentation reports on a new approach to extract the total deposited energy, and the hadronic component of the scintillation emission from the pulse shapes using machine learning techniques. For this, a neural network is trained on pulse shapes produced in crystals from calorimeter clusters from simulated photons and pions, and is employed as a multivariate regression tool. I will show the comparison between the performance of the neural network and the performance of the current fitting method. The neural network shows an improvement in the total and hadron energy resolution, and robustness towards fluctuations in photon pile-up from beam backgrounds.