Study of excited Λ b 0 states decaying to Λ b 0π +π − in proton-proton collisions at s=13TeV

A study of excited Λ b 0 baryons is reported, based on a data sample collected in 2016–2018 with the CMS detector at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of up to 140fb −1. The existence of four excited Λ b 0 states: Λ b 0(5912) 0, Λ b 0(5920) 0, Λ b 0(6146) 0, and Λ b 0(6152) 0 in the Λ b 0π +π − mass spectrum is confirmed, and their masses are measured. The Λ b 0π +π − mass distribution exhibits a broad excess of events in the region of 6040–6100 MeV, whose origin cannot be discerned with the present data.