Evidence for a New Structure in the J/ψp and J/ψ¯p Systems in B0s→J/ψp¯p Decays

An amplitude analysis of flavor-untagged B0s→J/ψp¯p decays is performed using a sample of 797±31 decays reconstructed with the LHCb detector. The data, collected in proton-proton collisions between 2011 and 2018, correspond to an integrated luminosity of 9  fb−1. Evidence for a new structure in the J/ψp and J/ψ¯p systems with a mass of 4337+7−4 +2−2  MeV and a width of 29+26−12 +14−14  MeV is found, where the first uncertainty is statistical and the second systematic, with a significance in the range of 3.1 to 3.7σ, depending on the assigned JP hypothesis.