Development of a Cerenkov Trigger Detector for the COMET Experiment

Authors

Yuki Nakai¹^,^*, Kiyotomo Kawagoe¹, Yoshitaka Kuno², Kou Oishi¹, Hideyuki Sakamoto², Akira Sato², Junji Tojo¹, Kazuki Ueno³, Hiroshi Yamaguchi¹, and Tamaki Yoshioka⁴ on behalf of the COMET collaboration

Affiliations

¹Department of Physics, Kyushu University, Fukuoka 812-8581, Japan

²Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan

³Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki 305-0801, Japan

⁴Research Center for Advanced Particle Physics, Kyushu University, Fukuoka 812-8581, Japan

Journal

Published Date

DOI

Abstract

Theoretical models beyond the Standard Models predict that a branching ratio of the muon-to-electron (µ–e) conversion increases to about 10⁻¹⁵, although the Standard Model contribution restricts it to be less than 10⁻⁵⁴. The COMET experiment searches for the µ–e conversion with signal event sensitivity of 10⁻¹⁵ in the first phase (Phase-I). A cylindrical detector consisting of a cylindrical drift chamber and a trigger detector will be used for detecting signal electrons. We designed the CDC trigger detector for the COMET Phase-I, and constructed a 1st prototype. Using cosmic rays, we studied the performance of the prototype. A signal to noise ratio (S/N) of 16.9 ± 0.5 was measured. To improve S/N, we started construction of a 2nd prototype.