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MEG: Muon to Electron and Gamma

by A.M. Baldini and T. Mori

This is not the current version.

Submission summary

As Contributors: Alessandro MAssimo Baldini
Preprint link: scipost_202102_00022v2
Date submitted: 2021-03-31 13:22
Submitted by: Baldini, Alessandro MAssimo
Submitted to: SciPost Physics Proceedings
Proceedings issue: PSI Particle Physics
Academic field: Physics
  • High-Energy Physics - Experiment
Approach: Experimental


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.

Current status:
Has been resubmitted

Submission & Refereeing History

Resubmission scipost_202102_00022v3 on 15 April 2021

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Resubmission scipost_202102_00022v2 on 31 March 2021

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