Measurement of the $\Lambda_{b}^{0}\to \Lambda(1520) \mu^{+}\mu^{-}$ differential branching fraction

TL;DR

This paper reports the first measurement of the differential branching fraction of the rare decay $ ext{Lambda}_b^0 o ext{Lambda}(1520) ext{mu}^+ ext{mu}^-$ across different $q^2$ regions, using LHCb data, with results aligning with theoretical predictions at high $q^2$.

Contribution

It provides the first measurement of the $ ext{Lambda}_b^0 o ext{Lambda}(1520) ext{mu}^+ ext{mu}^-$ decay's differential branching fraction across $q^2$ intervals, excluding $J/ ext{psi}$ and $ ext{psi}(2S)$ regions.

Findings

First measurement of this decay's differential branching fraction.

Results agree with theoretical predictions at high $q^2$.

Data collected at 7, 8, and 13 TeV with 9 fb$^{-1}$ total luminosity.

Abstract

The branching fraction of the rare decay $\Lambda_{b}^{0}\to \Lambda(1520) \mu^{+}\mu^{-}$ is measured for the first time, in the squared dimuon mass intervals, $q^2$, excluding the $J/\psi$ and $\psi(2S)$ regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of $9\ \mathrm{fb}^{-1}$. The result in the highest $q^{2}$ interval, $q^{2} >15.0\ \mathrm{GeV}^2/c^4$, where theoretical predictions have the smallest model dependence, agrees with the predictions.