Threshold neutral pion photoproduction off the tri-nucleon to O(q^4)

TL;DR

This paper calculates neutral pion production off tri-nucleon bound states using chiral effective field theory to fourth order, showing small higher-order corrections and enabling precise tests of theoretical predictions.

Contribution

It provides a detailed fourth-order calculation of neutral pion production off tri-nucleons, highlighting the smallness of two-nucleon corrections and facilitating experimental validation of chiral perturbation theory.

Findings

Fourth order two-nucleon corrections are very small.

Precise measurements of the cross section can test chiral perturbation theory.

Supports the validity of chiral EFT in few-nucleon systems.

Abstract

We calculate electromagnetic neutral pion production off tri-nucleon bound states (3H, 3He) at threshold in chiral nuclear effective field theory to fourth order in the standard heavy baryon counting. We show that the fourth order two-nucleon corrections to the S-wave multipoles at threshold are very small. This implies that a precise measurement of the S-wave cross section for neutral pion production off 3He allows for a stringent test of the chiral perturbation theory prediction for the S-wave electric multipole E_{0+}^{pi0 n}.