Photon energy reconstruction with the MEG II liquid xenon calorimeter

Kensuke Yamamoto; Sei Ban; Lukas Gerritzen; Toshiyuki Iwamoto; Satoru Kobayashi; Ayaka Matsushita; Toshinori Mori; Rina Onda; Wataru Ootani; Atsushi Oya

arXiv · 2407.19417

Photon energy reconstruction with the MEG II liquid xenon calorimeter

Kensuke Yamamoto·Sei Ban·Lukas Gerritzen·Toshiyuki Iwamoto·Satoru Kobayashi·Ayaka Matsushita·Toshinori Mori·Rina Onda·Wataru Ootani·Atsushi Oya

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Abstract

The MEG II experiment searches for a charged-lepton-flavour-violating $\mu \to e \gamma$ with the target sensitivity of $6 \times 10^{-14}$. A liquid xenon calorimeter with VUV-sensitive photosensors measures photon position, timing, and energy. This paper concentrates on the precise photon energy reconstruction with the MEG II liquid xenon calorimeter. Since a muon beam rate is $3\text{-}5 \times 10^{7}~\text{s}^{-1}$, multi-photon elimination analysis is performed using waveform analysis techniques such as a template waveform fit. As a result, background events in the energy range of 48-58 MeV were reduced by 34 %. The calibration of the energy scale of the calorimeter with several calibration sources is also discussed to achieve a high resolution of 1.8 %.

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Kensuke Yamamoto, Sei Ban, Lukas Gerritzen, Toshiyuki Iwamoto, Satoru Kobayashi, Ayaka Matsushita, Toshinori Mori, Rina Onda, Wataru Ootani, Atsushi Oya. 2024-07-28. Photon energy reconstruction with the MEG II liquid xenon calorimeter. https://arxiv.org/abs/2407.19417

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