Chiral pions in a magnetic background

Abstract

We investigate the modification of the pion self-energy at finite temperature due to its interaction with a low-density, isospin-symmetric nuclear medium embedded in a constant magnetic background. To one loop, for fixed temperature and density, we find that the pion effective mass increases with the magnetic field. For the $\pi^{-}$, interestingly, this happens solely due to the trivial Landau quantization shift $\sim |eB|$, since the real part of the self-energy is negative in this case. In a scenario in which other charged particle species are present and undergo an analogous trivial shift, the relevant behavior of the effective mass might be determined essentially by the real part of the self-energy. In this case, we find that the pion mass decreases by $\sim 10%$ for a magnetic field $|eB|\sim m_\pi^2$, which favors pion condensation at high density and low temperatures.Comment: 7 pages, 5 figure

Pions in magnetic field at finite temperature

“…Our calculations here are qualitatively consistent with the results of other NJL models [39][40][41][42][43][44][45][46], hadron models [35][36][37][38] and lattice QCD simulations [34,[51][52][53].…”

“…For instance, for neutral hadrons, they do not have any interaction with electromagnetic fields, if we neglect the charged constituent quarks. Meson properties in electromagnetic fields are widely studied in effective models at hadron level, such as in chiral perturbation theory [35][36][37] and linear sigma model [38], and at quark level, such as in Nambu-Jona-Lasinio (NJL) model [39][40][41][42][43][44][45][46][47][48][49][50] and lattice QCD simulations [34,[51][52][53].…”

Magnetic structure of isospin-asymmetric QCD matter in neutron stars

“…(15) is subject to corrections due to the -dependence of the pion self-energy. These corrections are, however, small compared to the leading behavior [19]. Indeed, recent lattice QCD results [20] have confirmed Eq.…”

Meson properties in magnetized quark matter

“…For the phase transition from chiral symmetry breaking to its restoration, there are magnetic catalysis effects at the mean field level [4][5][6] and inverse magnetic catalysis effects in lattice QCD simulations [7][8][9] and effective model calculations [10][11][12][13][14]. Considering that pion mesons are the Goldstone modes corresponding to chiral symmetry breaking and dominate the QCD thermodynamics at low temperature, their properties [15][16][17][18][19][20][21][22][23][24][25][26][27] in an external magnetic field are extensively investigated.…”