Search for B ( s ) ∗ 0 → μ + μ - in B c + → π + μ + μ - decays

Abstract

A search for the very rare B ∗ 0 → μ + μ - and B s ∗ 0 → μ + μ - decays is conducted by analysing the B c + → π + μ + μ - process. The analysis uses proton-proton collision data collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 \,fb - 1 . The signal signatures correspond to simultaneous peaks in the μ + μ - and π + μ + μ - invariant masses. No evidence for an excess of events over background is observed for either signal decay mode. Upper limits at the 90 % confidence level are set on the branching fractions relative to that for B c + → J / ψ π + decays, R B ∗ 0 ( μ + μ - ) π + / J / ψ π + < 3.8 × 10 - 5 and R B s ∗ 0 ( μ + μ - ) π + / J / ψ π + < 5.0 × 10 - 5.