Forming molecular states with hadronic rescattering

A method for modelling the prompt production of molecular states using the hadronic rescattering framework of the general-purpose Pythia event generator is introduced. Production cross sections of possible exotic hadronic molecules via hadronic rescattering at the LHC are calculated for the χ_c1(3872) resonance, a possible tetraquark state, as well as three possible pentaquark states, Pc+(4312), Pc+(4440), and Pc+(4457). For the Pc+ states, the expected cross section from Λ _b decays is compared to the hadronic-rescattering production. The χ_c1(3872) cross section is compared to the fiducial χ_c1(3872) cross-section measurement by LHCb and found to contribute at a level of O(1 %). Finally, the expected yields of Pc+ production from hadronic rescattering during Run 3 of LHCb are estimated. The prompt background is found to be significantly larger than the prompt Pc+ signal from hadronic rescattering.