QCD θvacuum energy and axion properties
Abstract
At low energies, the strong interaction is governed by the Goldstone bosons associated with the spontaneous chiral symmetry breaking, which can be systematically described by chiral perturbation theory. In this paper, we apply this theory to study the θvacuum energy density and hence the QCD axion potential up to nexttoleading order with N nondegenerate quark masses. By setting N = 3, we then derive the axion mass, selfcoupling, topological susceptibility and the normalized fourth cumulant both analytically and numerically, taking the strong isospin breaking effects into account. In addition, the modelindependent part of the axionphoton coupling, which is important for axion search experiments, is also extracted from the chiral Lagrangian supplemented with the anomalous terms up to O (p^{6}).
 Publication:

Journal of High Energy Physics
 Pub Date:
 May 2020
 DOI:
 10.1007/JHEP05(2020)001
 arXiv:
 arXiv:2003.01625
 Bibcode:
 2020JHEP...05..001L
 Keywords:

 Beyond Standard Model;
 Chiral Lagrangians;
 Effective Field Theories;
 High Energy Physics  Phenomenology;
 High Energy Physics  Experiment;
 High Energy Physics  Lattice
 EPrint:
 22 pages, 1 figure, 2 tables