Lepton flavour violating top decays at the LHC

摘要

We consider lepton-flavour violating decays of the top quark, mediated by 4-fermion operators. We compile constraints on a complete set of SU(3)  ×  U(1)-invariant operators, arising from their loop contributions to rare decays and from HERA’s single-top search. The bounds on e–μ flavour change are more restrictive than on ℓ–τ; nonetheless the top could decay to a jet +eμ¯ with a branching ratio of order 10^-3. We estimate that the currently available LHC data (20 fb^-1 at 8 TeV) could be sensitive to BR(t→eμ¯+ jet)  ∼ 6 × 10^-5, and we extrapolate that 100 fb^-1 at 13 TeV could reach a sensitivity of  ∼ 1 × 10^-5.