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arXiv · 2308.05064

Search for a Non-Relativistic Boson in Two-Body Antimuon Decay

J. I. Collar·P. S. Cooper·C. M. Lewis
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Abstract

We demonstrate the feasibility of probing the charged lepton flavor violating decay $\mu^{+}\!\!\rightarrow \!e^{+} X^{0}$ for the presence of a slow-moving neutral boson $X^{0}$ capable of undergoing gravitational binding to large structures, and as such able to participate in some cosmological scenarios. A short exposure to surface antimuons from beamline M20 at TRIUMF generates a branching ratio limit of $\lesssim 10^{-5}$. This is comparable or better than previous searches for this channel, although in a thus-far unexplored region of $X^{0}$ phase space very close to the kinematic limit of the decay. The future improved sensitivity of the method using a customized p-type point contact germanium detector is described.

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J. I. Collar, P. S. Cooper, C. M. Lewis. 2023-08-09. Search for a Non-Relativistic Boson in Two-Body Antimuon Decay. https://doi.org/10.1103/physrevlett.131.241802

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