Search for Lepton Number and Flavor Violation in K+ and pi(0) Decays

Abstract

Searches for the lepton number violating K+ -> pi(-) mu(+) e(+) decay and the lepton flavor violating K+ -> pi(-) mu(+) e(+) and pi(0) -> mu(-) e(+) decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K+ -> pi(-) mu(+) e(+)) pi(+) mu(-) e(+)) mu(-) e(+)) < 3.2 x 10(-)(10).

These results improve by 1 order of magnitude over previous results for these decay modes.

Keywords

• Search
• for
• Lepton
• Number
• Flavor
• Violation
• pi0
• Decays