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

Abstract

A study of excited Λb 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 Λb 0 states: Λb 0(5912)0, Λb 0(5920)0, Λb 0(6146)0, and Λb 0(6152)0 in the Λb 0π+π− mass spectrum is confirmed, and their masses are measured. The Λb 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.