BSM reach of rare charm decays, including the rising star $\Lambda_c\to p\mu^+\mu^-$

TL;DR

This paper conducts the first comprehensive global analysis of rare charm decays, including the promising $ ext{Lambda}_c o p ext{mu}^+ ext{mu}^-$ channel, to constrain new physics using recent experimental data and angular observables.

Contribution

It introduces the first global fit of rare charm decays incorporating recent data and angular observables, highlighting the potential of $ ext{Lambda}_c o p ext{mu}^+ ext{mu}^-$ for future new physics searches.

Findings

Angular observables in $D^0 o ext{pi}^+ ext{pi}^- ext{mu}^+ ext{mu}$ are sensitive to QCD models.

Future tests in $ ext{Lambda}_c o p ext{mu}^+ ext{mu}$ can set stronger limits due to lower hadronic uncertainties.

$ ext{Lambda}_c o p ext{mu}^+ ext{mu}$ is identified as a promising new channel for rare charm decay studies.

Abstract

We perform the first global fit of rare charm transitions using recent data on $D^0\to \mu^+\mu^-$, $D^+\to\pi^+\mu^+\mu^-$, $\Lambda_c\to p\mu^+\mu^-$ and $D^0\to\pi^+\pi^-\mu^+\mu^-$ decays, including angular observables. We work out constraints on new physics in the framework of the weak effective field theory. While angular observables in $D^0\to\pi^+\pi^-\mu^+\mu^-$ decays provide sensitivities to different QCD models, future null tests in $\Lambda_c\to p \mu^+\mu^-$ look more promising to extract limits because of less hadronic uncertainties. This marks $\Lambda_c\to p \mu^+\mu^-$ as the rising star of rare charm decays.