Nambu-Goldstone mesons in strong magnetic field

Abstract

We study the q \bar q structure embedded in chiral mesons in response to external magnetic fields, using the chiral Lagrangian with q \bar q degrees of freedom derived earlier. We show that GMOR relations hold true for neutral chiral mesons, while they are violated for the charged ones for eB>sigma=0.2 GeV^2. The standard chiral perturbation theory also fails in this region. Masses of pi^+ and pi^0 mesons are calculated and compared to lattice data.

Comments: 21 pages, 3 figures