Lepton Flavour Violation in Tau Decays: Results and Prospects at the LHC

Abstract

In this report, searches for the lepton flavour violating decays τ − → μ − μ + μ − , Z 0 → τ ± μ ∓ and D 0 → e ± μ ∓ are presented, using proton-proton collision data recorded by the LHC experiments during 2011 and 2012. The ATLAS experiment puts an upper limit on B(τ − → μ − μ + μ − ) < 3.76 × 10 −7 at 90% confidence level, and on B(Z 0 → τ ± μ ∓ ) < 1.69 × 10 −5 at 95% confidence level, based on a data sample corresponding to an integrated luminosity of 20.3 fb −1 . The LHCb experiment puts an upper limit on B(τ − → μ − μ + μ − ) < 4.6 × 10 −8 and on B(D 0 → e ± μ ∓ ) < 1.3 × 10 −8 , both at 90% confidence level, based on a data sample corresponding to an integrated luminosity of 3.0 fb −1 .

The full lepton flavor of the littlest Higgs model with T-parity

“…Belle II [107] aims to improve the precision to 10 −9 − 10 −10 in a variety of LFV processes [76] while LHCb also expects to reach a similar sensitivity [77]. The upper bound on τ → µµµ from LHCb [114] is already within a factor of 2 of its current best limit [85] (see also [115] for the LHC collaborations). For the default values in Eq.…”