Angular moments of the decay Λ_b⁰ → Λμ⁺μ⁻ at low hadronic recoil

An analysis of the angular distribution of the decay Λb 0 → Λμ+μ− is presented, using data collected with the LHCb detector between 2011 and 2016 and corresponding to an integrated luminosity of approximately 5 fb−1. Angular observables are determined using a moment analysis of the angular distribution at low hadronic recoil, corresponding to the dimuon invariant mass squared range 15 < q2 < 20 GeV2/c4. The full basis of observables is measured for the first time. The lepton-side, hadron-side and combined forward-backward asymmetries of the decay are determined to beAFBℓ=−0.39±0.04(stat)±0.01(syst),AFBh=−0.30±0.05(stat)±0.02(syst),AFBℓh=+0.25±0.04(stat)±0.01(syst). The measurements are consistent with Standard Model predictions.