Obtaining sigma --> gamma gamma Width from Nucleon Polarizabilities

TL;DR

This paper introduces a novel method to determine the gamma gamma decay width of the sigma resonance by utilizing nucleon polarizability data combined with principles of analyticity and unitarity, providing insights into its nature.

Contribution

The paper presents a new approach to fix the sigma resonance's two-photon coupling using nucleon polarizabilities, advancing understanding of this QCD state.

Findings

Gamma_{pole} = 1.2 ± 0.4 keV

Method leverages nucleon data and theoretical principles

Provides constraints on sigma's nature

Abstract

We propose a new method that fixes the coupling to two photons of the recently found lightest QCD resonance, the sigma. This coupling provides crucial information for discriminating the yet unknown nature of this special state. Our method uses available data on the nucleon polarizabilities together with analyticity and unitarity. Taking into account all the uncertainties, our result is Gamma_{pole}= 1.2 +- 0.4 keV.