Phenomenology of neutron-antineutron conversion

TL;DR

This paper explores neutron-antineutron conversion mediated by external sources, linking it to neutron-antineutron oscillation, and provides a framework to interpret experimental limits using effective field theory and baryon matrix elements.

Contribution

It establishes theoretical connections between neutron-antineutron conversion and oscillation, and offers a method to relate experimental limits through effective field theory and matrix element calculations.

Findings

Conversion can occur if oscillation occurs in B-L violating theories.

Experimental limits on conversion can constrain oscillation parameters.

Effective field theory links conversion rates to oscillation phenomena.

Abstract

We consider the possibility of neutron-antineutron ($n-\bar n$) conversion, in which the change of a neutron into an antineutron is mediated by an external source, as can occur in a scattering process. We develop the connections between $n-{\bar n}$ conversion and $n-{\bar n}$ oscillation, in which a neutron spontaneously tranforms into an antineutron, noting that if $n-{\bar n}$ oscillation occurs in a theory with B-L violation, then $n-{\bar n}$ conversion can occur also. We show how an experimental limit on $n-{\bar n}$ conversion could connect concretely to a limit on $n-{\bar n}$ oscillation, and vice versa, using effective field theory techniques and baryon matrix elements computed in the M.I.T. bag model.