n → Kℓ and the baryon asymmetry of the universe

This is the authors' abstract. We don't add key points for this paper.

A bstract The observed baryon asymmetry (BAU) of the universe puts strong constraints on any ( B − L )-violating interaction. An observation of a ( B − L )-violating nucleon decay channel would therefore have profound implications for our understanding of the BAU. Here we point out that the observation of the final state with a kaon and a charged lepton in a future nucleon decay experiment would hint at ( B − L ) violation even if the charge of the lepton is not determined experimentally. In SMEFT, this follows from the fact that n → K + ℓ − arises already at dimension seven, while the ( B − L )-conserving decay n → K − ℓ + requires dimension-ten operators that, in addition, would be accompanied by lower-dimensional ( B + L )-violating decay modes. An observation of n → Kℓ in the absence of other modes such as p → π 0 ℓ + , would then strongly suggest that ( B − L ) is violated.