ΔB=2 neutron decay into antiproton mode n → (p)over-bare+ ν((ν)over-bar)

We discuss the unique baryon number violation by two units neutron decay mode n -> (p) over bare(+) chi, with chi being the standard model (SM) neutrino nu or antineutrino (nu) over bar or any beyond the SM light fermion, in the framework of effective field theory. This mode is kinematically allowed but rarely discussed theoretically or searched for experimentally. We estimate the lower bound on its partial lifetime from that of the dinucleon decay np -> e(+) chi per oxygen nucleus O-16 set by the Super-Kamiokande experiment, with a conservative bound Gamma(-1)(n ->(p) over bare+chi) > 5.7 x 10(39) yrs. We also discuss its characteristic signature for the future experimental search and astrophysical implications. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

The unique baryon number violation in the two units neutron decay mode n -> (p) over bare(+) chi is discussed in this article, with an estimated lower bound on its partial lifetime. Also discussed are the characteristic signature for future experimental searches and astrophysical implications.