Models of $n\bar{n}$ transition in medium

TL;DR

This paper reviews models of neutron-antineutron transition in medium, emphasizing the importance of a field-theoretical approach, and provides a lower limit estimate for the oscillation time based on current theoretical frameworks.

Contribution

It demonstrates that a field-theoretical approach is essential for modeling $n\bar{n}$ transitions in medium and estimates a new lower limit on the oscillation time.

Findings

Field-theoretical models are preferred for $n\bar{n}$ transition in medium.

Lower limit on free-space $n\bar{n}$ oscillation time is between 1.2×10^9 s and 10^16 years.

The study refines the theoretical understanding of $n\bar{n}$ oscillation constraints.

Abstract

The present state of the $n\bar{n}$ transition problem is briefly outlined. The models based on the diagram technique for direct reactions, potential description of $\bar{n}$-medium interaction and field-theoretical approach are considered. It is shown that for the $n\bar{n}$ transition in medium field-theoretical approach should be used. The lower limit on the free-space $n\bar{n}$ oscillation time $\tau_{{\rm min}}$ is found to be: $10^{16}\; {\rm yr}>\tau_{{\rm min}}>1.2\cdot 10^{9}\; {\rm s}$.