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arXiv · 2507.07176

Amplifying muon-to-positron conversion in nuclei with ultralight dark matter

Purushottam Sahu·Manibrata Sen
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Abstract

We present an analysis of the lepton-number and lepton-flavour-violating process of muon-to-positron conversion $\mu^- + N \rightarrow e^+ + N'$, in the presence of an ultralight scalar dark matter (ULSDM) field which couples to neutrinos. The ULSDM contributes to the effective off-diagonal Majorana mass $ m_{\mu e}$, therefore amplifying the rate of muon-to-positron conversion to experimentally observable levels. Using existing bounds from SINDRUM II, COMET, and Mu2e experiments, we derive novel constraints on the flavour-off-diagonal couplings of neutrinos to ULSDM. Our work reveals that upcoming experiments can provide stronger sensitivity to these new couplings than bounds arising from cosmological surveys and terrestrial experiments.

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Purushottam Sahu, Manibrata Sen. 2025-07-09. Amplifying muon-to-positron conversion in nuclei with ultralight dark matter. https://arxiv.org/abs/2507.07176

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