MEG: Muon to Electron and Gamma

Baldini, Alessandro MAssimo; Mori, Toshinori

doi:10.21468/SciPostPhysProc.5.019

SciPost Physics Proceedings

MEG: Muon to Electron and Gamma

A.M. Baldini, T. Mori

SciPost Phys. Proc. 5, 019 (2021) · published 6 September 2021

doi: 10.21468/SciPostPhysProc.5.019
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Abstract

The possible existence of the muon to electron and gamma decay predicted by many new physics scenarios is investigated by stopping positive muons in a very thin target and measuring emitted photons and positrons with the best possible resolutions. Photons are measured by a 2.7 ton ultra pure liquid xenon detector while positron trajectories are measured in a specially designed gradient magnetic field by low-mass drift chambers and precisely timed by scintillation counters. A first phase of the experiment (MEG) ended in 2016, and excluded the existence of the decay with branching ratios larger than 4.2x10**(-13) (90% C.L.). This provides approximately 30 times stronger constraints on a variety of new physics models than previous experiments. In the second phase (MEG II), most of the detectors have been upgraded by adopting up-to-date technologies to improve the search sensitivity by another order of magnitude down to O(10**(-19) ). MEG II will pursue new physics beyond the Standard Model complementary to high energy collider experiments with a compatible or even higher sensitivity.

TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhysProc.5.019
TI  - MEG: Muon to Electron and Gamma
PY  - 2021/09/06
UR  - https://www.scipost.org/SciPostPhysProc.5.019
JF  - SciPost Physics Proceedings
JA  - SciPost Phys. Proc.
VL  - 
IS  - 5
SP  - 019
A1  - Baldini, Alessandro MAssimo
AU  - Mori, Toshinori
AB  - The possible existence of the muon to electron and gamma decay predicted by many new physics scenarios is investigated by stopping positive muons in a very thin target and measuring emitted photons and positrons with the best possible resolutions. Photons are measured by a 2.7 ton ultra pure liquid xenon detector while positron trajectories are measured in a specially designed gradient magnetic field by low-mass drift chambers and precisely timed by scintillation counters. A first phase of the experiment (MEG) ended in 2016, and excluded the existence of the decay with branching ratios larger than 4.2x10**(-13) (90% C.L.). This provides approximately 30 times stronger constraints on a variety of new physics models than previous experiments. In the second phase (MEG II), most of the detectors have been upgraded by adopting up-to-date technologies to improve the search sensitivity by another order of magnitude down to O(10**(-19) ). MEG II will pursue new physics beyond the Standard Model complementary to high energy collider experiments with a compatible or even higher sensitivity.
ER  -

@Article{10.21468/SciPostPhysProc.5.019,
	title={{MEG: Muon to Electron and Gamma}},
	author={A.M. Baldini and T. Mori},
	journal={SciPost Phys. Proc.},
	pages={019},
	year={2021},
	publisher={SciPost},
	doi={10.21468/SciPostPhysProc.5.019},
	url={https://scipost.org/10.21468/SciPostPhysProc.5.019},
}

Cited by 3

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¹ Alessandro MAssimo Baldini,
² Toshinori Mori