Search for charged lepton flavor violating decays of Upsilon(1S)

Abstract

We present a search for the charged lepton-flavor-violating decays Upsilon(1S) -> l(+/-)l'(-/+) and radiative charged lepton-flavour-violating decays Upsilon(1S) -> gamma l(+/-)l'(-/+) [l, l' = e, mu, tau] using the 158 million Upsilon(2S) sample collected by the Belle detector at the KEKB collider. This search uses Upsilon(1S) mesons produced in Upsilon(2S) -> pi(+)pi(-)Upsilon(1S) transitions.

We do not find any significant signal, so we provide upper limits on the branching fractions at the 90% confidence level.

Keywords

• e(+)-e(-) Experiments