Chiral Properties of Strong Interactions in a Magnetic Background

Understand

We investigate the chiral properties of QCD in presence of a magnetic background field and in the low temperature regime, by lattice numerical simulations of N_f = 2 QCD.

• We adopt a standard staggered discretization, with a pion mass around 200 MeV, and explore a range of magnetic fields (180 MeV)^2 \leq|e|B \leq (700 MeV)^2, in which we study magnetic catalysis, i.e.
• the increase of chiral symmetry breaking induced by the background field.
• We determine the dependence of the chiral condensate on the external field, compare our results with existing model predictions and show that a substantial contribution to magnetic catalysis comes from the modified distribution of non-Abelian gauge fields, induced by the magnetic field via dynamical quark loop effects.