First observation of the decay $D^{0}\rightarrow K^{-}\pi^{+}\mu^{+}\mu^{-}$ in the $\rho^{0}$-$\omega$ region of the dimuon mass spectrum

TL;DR

This paper reports the first observation of the decay $D^{0}\rightarrow K^{-}\pi^{+}\mu^{+}\mu^{-}$ in the $ ho^{0}$-$\omega$ resonance region, measuring its branching fraction using LHCb data, confirming Standard Model predictions.

Contribution

The study provides the first experimental observation and measurement of the decay $D^{0}\rightarrow K^{-}\pi^{+}\mu^{+}\mu^{-}$ in a specific resonance region.

Findings

Branching fraction measured as $(4.17 \pm 0.12 \text{(stat)} \pm 0.40 \text{(syst)})\times10^{-6}$.

Decay observation is consistent with Standard Model expectations.

First experimental evidence of this decay mode.

Abstract

A study of the decay $D^{0}\rightarrow K^{-}\pi^{+}\mu^{+}\mu^{-}$ is performed using data collected by the LHCb detector in proton-proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2.0 fb$^{-1}$. Decay candidates with muon pairs that have an invariant mass in the range 675--875 MeV$/c^2$ are considered. This region is dominated by the $\rho^{0}$ and $\omega$ resonances. The branching fraction in this range is measured to be ${\cal B}$($D^{0}\rightarrow K^{-}\pi^{+}\mu^{+}\mu^{-}$) = $(4.17 \pm 0.12(stat) \pm 0.40(syst))\times10^{-6}$. This is the first observation of the decay $D^{0}\rightarrow K^{-}\pi^{+}\mu^{+}\mu^{-}$. Its branching fraction is consistent with the value expected in the Standard Model.