Measurement of the shape of the Λ⁰_b → Λ⁺_c μ^-ν_μ differential decay rate

A measurement of the shape of the differential decay rate and the associated Isgur-Wise function for the decay Λ0 b → Λ+c μ- νμ is reported, using data corresponding to 3 fb-1collected with the LHCb detector in proton-proton collisions. The Λ+c μ- νμ anything final states are reconstructed through the detection of a muon and a Λ+c baryon decaying into pK-π+, and the decays Λ0 b → Λ+c π+π-μ- νμ are used to determine contributions from Λ0 b → Λ0c μ- νμ decays. The measured dependence of the differential decay rate upon the squared four-momentum transfer between the heavy baryons, q2, is compared with expectations from heavy-quark effective theory and from unquenched lattice QCD predictions.