An analysis of $\Lambda_b^0 \rightarrow \Lambda\mu^+\mu^-$ decays at the LHCb experiment

TL;DR

This paper reports the first evidence of the decay $ Lambda_b^0 ightarrow Lambda mu^+ mu^-$ in specific $q^2$ regions, measuring branching fractions and angular asymmetries using LHCb data, advancing understanding of rare baryonic decays.

Contribution

It provides the first evidence of this decay mode in certain $q^2$ regions and measures angular asymmetries, offering new insights into rare baryonic decay processes.

Findings

Evidence of decay in low $q^2$ region

First measurements of angular asymmetries

Branching fraction as a function of $q^2$

Abstract

The branching fraction of the rare decay $\Lambda_b^0 \rightarrow \Lambda \mu^+ \mu^-$ is measured as a function of $q^2$, the square of the dimuon invariant mass. The analysis is performed using proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected by the LHCb experiment. Evidence of signal is found for the first time in the $q^2$ region below the square of the J/$\psi$ mass. In the $q^2$ intervals where the signal is observed, angular distributions are studied and two forward-backward asymmetries, in the dimuon and hadronic systems, are measured for the first time.