Two Nucleon (B-L)-Conserving Reactions Involving Tau Leptons

TL;DR

This paper explores tau lepton production in two-nucleon disappearance reactions within nuclei that conserve B-L, applying existing proton decay limits to set bounds on such processes involving tau leptons.

Contribution

It extends current limits on nucleon decay to include reactions with tau leptons, providing estimates and suggesting re-analysis of data for improved sensitivity.

Findings

Estimated limit for $np\to\tau^+ \overline\nu_\tau$ partial lifetime is >10^{30} years.

Existing proton decay data can constrain tau-involving two-nucleon disappearance.

Future experiments could improve sensitivity to these rare reactions.

Abstract

Tau lepton emission in two-nucleon disappearance reactions from within nuclei which conserve baryon number minus lepton number (B-L) is considered. It is shown that some existing limits on proton decay channels and two-nucleon disappearance reactions resulting in electrons and muons can be applied to $\Delta B=\Delta L=2$ decays involving $\tau$ leptons. For the two-nucleon disappearance channel $np\to\tau^+ \overline\nu_\tau$ the estimated limit for the partial mean life is $\frac{\tau}{Br}>1\times10^{30}$ yrs based on results from the IMB3 experiment. Re-analysis of existing data and future experiments could result in higher sensitivity for two-nucleon disappearance modes involving $\tau$ lepton final states.