Angular analysis of the decay ${\Lambda }_b^0\to \Lambda (1520){\mu }^{+}{\mu }^{-}$

The first angular analysis of ${\Lambda }_b^0\to \Lambda (1520){\mu }^{+}{\mu }^{-}$ decays is presented, using proton-proton collision data collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb${}^{-1}$. The leptonic forward-backward asymmetry, $A_{\text{FB, 3/2}}^{\mathrm{\ell }}$, and the $CP$-averaged angular observable, $S_{1cc}$, are determined by fitting projections of the angular distributions in four intervals of the square of the dimuon invariant mass between 0.1 and 12.5 GeV${}^2\mathrm{/}{c}^4$. The results are in good agreement with predictions based on the Standard Model of particle physics.