# Charm semileptonic decays at LHCb

## TL;DR

This paper assesses LHCb's potential to measure charm semileptonic decay parameters, aiming to improve the precision of CKM matrix element ratios and explore lepton universality in charm decays.

## Contribution

It provides projections for measuring the ratio of branching fractions in charm decays and discusses the potential to test lepton non-universality using LHCb data.

## Key findings

- Projected 0.2% statistical uncertainty on the branching ratio ratio
- Potential to improve CKM matrix element ratio measurements
- Motivation for searching lepton non-universality in charm decays

## Abstract

In these proceedings, we explore the possible reach of the LHCb dataset in the area of charm semileptonic decays. Specifically, we give prospects for the measurement of $|V_{cs}|/|V_{cd}|$ using $\mathcal{B}(D^0\to K^-\mu^+\nu_\mu)/\mathcal{B}(D^0\to\pi^-\mu^+\nu_\mu)$ with Run I data. Preliminary projections show that the LHCb Run I dataset would give a relative statistical uncertainty of $\sim 0.2\%$ on this ratio. We also motivate the search for lepton non-universality in the charm sector.