Search for the lepton-flavour violating decays B 0 → K *0 τ ± μ ∓

Abstract

A first search for the lepton-flavour violating decays B0 → K∗0 τ ±µ ∓ is presented. The analysis is performed using a sample of proton-proton collision data, collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018, corresponding to an integrated luminosity of 9 fb−1 . No significant signal is observed, and upper limits on the branching fractions are determined to be B(B0 → K∗0 τ +µ −) < 1.0 (1.2) × 10−5 and B(B0 → K∗0 τ −µ +) < 8.2 (9.8) × 10−6 at the 90% (95%) confidence level.