Chiral condensates in massless QCD and the $U(1{)}_A$ boson mass

Abstract

The $U(1{)}_A$ boson mass is calculated through the phenomenological characteristics of the vacuum related to spontaneous breaking of chiral symmetry in QCD. The mass is determined by the mixed quark-gluon condensate $⟨\bar{q}Gq⟩$ that emerges in an appropriate correlation function due to triangle anomaly. For three flavor QCD in chiral limit we find the numerical value for the $U(1{)}_A$ boson mass to be $M_0=310\pm 50\mathrm{MeV}$.

Comments: 5 pages, 2 figures