# Polarisabilities of the nucleon in baryon chiral perturbation theory and beyond

## TL;DR

This paper reviews recent baryon chiral perturbation theory results on nucleon polarisabilities across various Compton scattering regimes, emphasizing empirical verification and new constraints linking these regimes to nucleon structure insights.

## Contribution

It provides a comprehensive review of theoretical predictions for nucleon polarisabilities and introduces new constraints connecting different scattering regimes to enhance understanding of nucleon structure.

## Key findings

- Chiral perturbation theory accurately describes nucleon polarisabilities.
- Empirical verification is crucial for validating theoretical models.
- New constraints relate different Compton scattering regimes to nucleon structure.

## Abstract

We review the recent baryon chiral perturbation theory results for the nucleon polarisabilities that describe the different regimes of nucleon Compton scattering --- real, virtual, and doubly virtual. We stress the importance of the empirical verification of the theory in the context of the calculation of the inelastic nucleon structure corrections, such as the two-photon exchange contributions. We also discuss the recently obtained constraints that relate the different regimes of nucleon Compton scattering and can provide additional information on the nucleon structure.