Search for lepton-flavor-violating τ decays into a lepton and a vector meson using the full Belle data sample

Charged-lepton-flavor-violation is predicted in several new physics scenarios. We update the analysis of tau lepton decays into a light charged lepton (l = e(+/-) or mu(+/-)) and a vector meson (V-0 = rho(0), phi, omega, K-*0, or (K) over bar (*0)) using 980 fb(-1) of data collected with the Belle detector at the KEKB collider. No significant excess of such signal events is observed, and thus 90% credibility level upper limits are set on the tau -> lV(0) branching fractions in the range of (1.7- 4.3) x 10(-8). These limits are improved by 30% on average from the previous results.

Automated summary

In this study, we updated the analysis of τ lepton decays into a light charged lepton and a vector meson using data collected with the Belle detector at the KEKB collider. No significant excess of signal events was observed, and thus upper limits were set on the τ -> lV(0) branching fractions at the 90% credibility level, ranging from (1.7- 4.3) x 10(-8). These limits show an average improvement of 30% compared to previous results.