A measurement of ∆Γs

Abstract

Using a dataset corresponding to 9 fb−1 of integrated luminosity collected with the LHCb detector between 2011 and 2018 in proton-proton collisions, the decay-time distributions of the decay modes B0 s → J/ψη′ and B0 s → J/ψπ+π − are studied. The decay-width diference between the light and heavy mass eigenstates of the B0 s meson is measured to be ∆Γs = 0.087 ± 0.012 ± 0.009 ps−1 , where the frst uncertainty is statistical and the second systematic.