Study of excited $\Lambda_\mathrm{b}^0$ states decaying to $\Lambda_\mathrm{b}^0\pi^+\pi^-$ in proton-proton collisions at $\sqrt{s}=$ 13 TeV

Bruno, Giacomo [UCL] Caputo, Claudio [UCL] David, Pieter [UCL] Delaere, Christophe [UCL] Delcourt, Martin [UCL] Giammanco, Andrea [UCL] Lemaitre, Vincent [UCL] Prisciandaro, Jessica [UCL] Saggio, Alessia [UCL] Vischia, Pietro [UCL] Zobec, Joze [UCL] CMS Collaboration et al.

A study of excited Λb0 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 140 fb−1 . The existence of four excited Λb0 states: Λb0(5912)0 , Λb0(5920)0 , Λb0(6146)0 , and Λb0(6152)0 in the Λb0π+π− mass spectrum is confirmed, and their masses are measured. The Λb0π+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.