Screening masses in strong external magnetic fields

Abstract

We present results for the (color)magnetic and (color)electric screening masses of the Quark-Gluon Plasma in the presence of an external magnetic field. The screening masses are extracted from the correlators of Polyakov loops, determined by lattice QCD simulations at the physical point. We explore temperatures in the range 200 MeV T 330 MeV and magnetic field intensities up to |e|B ∼ 1.3 GeV 2 . We find that both screening masses are increasing functions of the magnetic field and that the dependence on B becomes weaker for larger temperatures. In the case of the magnetic screening mass a slight anisotropy is also observable.

Gauge-invariant screening masses and static quark free energies in Nf=2+1 QCD at nonzero baryon density

“…1, we report some of the correlators obtained for lowest explored temperature, T ≃ 217 MeV. At zero chemical potential, the magnetic and electric correlators, C M þ and C E − , show the standard behavior already clarified in previous studies [5,6,10]: the magnetic correlator is larger than the electric one, by around 1 order of magnitude, and decreases more slowly as a function of the distance, in agreement with the expected hierarchy m M < m E ; best fits according to Eq. (3) are reported together with the data points.…”

“…Magnetic and electric screening masses in the presence of an external background field have been determined by lattice simulations in Ref. [10] and have indeed been shown to be increasing functions of B, in agreement with analytical studies of screening effects in the QGP [11][12][13].…”

“…As shown in Ref. [4] (and retraced in some recent lattice works [5,6,10]), it is possible to separate the contributions to screening of the color-magnetic and color-electric gluons by defining suitable combinations of Polyakov loop correlators. This is achieved by performing a symmetry decomposition involving the Euclidean time reversal (R) and the charge conjugation (C) operators.…”

“…This is achieved by performing a symmetry decomposition involving the Euclidean time reversal (R) and the charge conjugation (C) operators. As a result [4,6,10], one finds that the relevant role is played by the fluctuations of the real and imaginary parts of the Polyakov loop so that the correlators…”

Influence of magnetic fields on the color screening masses

“…[7][8][9]. In recent lattice studies [10,11] it has been shown that the potential gets modified and relevant consequences may arise at the level of heavy meson production and spectrum (see [12,13] and the references herein). In particular, at zero temperature the interaction becomes anisotropic due to the string tension σ which decreases in the direction parallel to the external field B, while it grows on the orthogonal plane; at larger T , in the confined regime below the pseudo-critical temperature T c , the external field is responsible of a precocious loss of the deconfining properties, in agreement with the picture of a decreasing T c due to the field itself.…”