QCD tests from pion reactions on few-nucleon systems

TL;DR

This paper demonstrates how low-energy hadronic observables, specifically pion reactions on few-nucleon systems, can be used to test Quantum Chromodynamics (QCD) by analyzing charge symmetry breaking and pion-deuteron scattering.

Contribution

It introduces methods to extract quark mass differences and determine the pion-nucleon coupling constant from pion reactions on few-nucleon systems, providing new tools for QCD tests.

Findings

Extraction of quark mass difference from charge symmetry breaking

High-precision calculation of pion-deuteron scattering

Implications for pion-nucleon coupling constant

Abstract

We show on two examples, namely a calculation for charge symmetry breaking in pn->d pi^0 that allows one to extract the quark mass difference induced part of the proton--neutron mass difference and a high precision calculation for pion--deuteron scattering and its implications for the value of the charged pion--nucleon coupling constant, how QCD tests can be performed from low energy hadronic observables.