A search for baryon- and lepton-number violating decays of $\Lambda$ hyperons using the CLAS detector at Jefferson Laboratory

TL;DR

This study searches for rare baryon- and lepton-number violating decays of $ ext{Lambda}$ hyperons using the CLAS detector, setting upper limits on their branching fractions due to no observed signals.

Contribution

It provides the first experimental upper limits on ten specific baryon- and lepton-number violating decay modes of $ ext{Lambda}$ hyperons.

Findings

No significant signals observed for the decay modes.

Upper limits on branching fractions range from $4\times 10^{-7}$ to $200\times 10^{-7}$.

Results constrain theories predicting baryon- and lepton-number violation.

Abstract

We present a search for ten baryon-number violating decay modes of $\Lambda$ hyperons using the CLAS detector at Jefferson Laboratory. Nine of these decay modes result in a single meson and single lepton in the final state ($\Lambda \rightarrow m \ell$) and conserve either the sum or the difference of baryon and lepton number ($B \pm L$). The tenth decay mode ($\Lambda \rightarrow \bar{p}\pi^+$) represents a difference in baryon number of two units and no difference in lepton number. We observe no significant signal and set upper limits on the branching fractions of these reactions in the range $(4-200)\times 10^{-7}$ at the $90\%$ confidence level.