Anisotropy of the quark-antiquark potential in a magnetic field

Abstract

We investigate the static Q¯Q potential for Nf=2+1 QCD at the physical point in the presence of a constant and uniform external magnetic field. The potential is found to be anisotropic and steeper in the directions transverse to the magnetic field than in the longitudinal one. In particular, when compared to the standard case with zero background field, the string tension increases (decreases) in the transverse (longitudinal) direction, while the absolute value of the Coulomb coupling and the Sommer parameter show an opposite behavior

Screening masses in strong external magnetic fields

“…As regards the effects more directly related to color interactions, various studies have considered the possible influence of an external magnetic field on the static quark-antiquark potential [14][15][16][17][18][19], which has been clarified by recent lattice results [20,21], and might have consequences relevant to the spectrum of heavy quark bound states [22][23][24][25][26][27][28][29][30][31][32]. At zero temperature, the potential becomes anisotropic and the string tension σ is larger (smaller) in the direction orthogonal (parallel) to the magnetic field B [20,21]; at finite T , in particular in the region right below the pseudocritical temperature T c , the magnetic field induces a general suppression of σ [21], leading to an early onset of deconfinement, in agreement with the observed dependence of T c on B [33][34][35] In this paper we extend the study to the region of temperatures above T c , in order to investigate the effects of a magnetic background on the interactions between heavy quarks in the Quark-Gluon Plasma. In this phase, the effective interaction is no longer confining and can instead be described by a screened Coulomb form, with two different screening lengths/masses characterizing the (color)electric and the (color)magnetic sectors.…”

The evolution of meson masses in a strong magnetic field

“…The dependence of the string tension σ on the MF is caused by the fluctuating qq pairs embedded to the string and provides a correction about ∆σ σ ∼ 15% at eB ∼ 1 GeV 2 . This phenomenon was studied on the lattice in [65] and was confirmed within PIH formalism in [66]. The correction to the ground state caused by this effect is beyond the declared accuracy and is neglected in what follows.…”

Confinining properties of QCD in strong magnetic backgrounds

“…The effects of the magnetic field on it have been predicted by model computations [29][30][31][32][33] and may have various phenomenological consequences, especially for heavy quark bound states [34][35][36][37][38][39][40][41][42][43]. Exploratory lattice results, in particular, have shown the presence of anisotropies, at zero temperature, both in the string tension and in the Coulomb coupling [21]. Our purpose is to refine such results in various directions.…”

“…Quarks are directly coupled to magnetic fields, through their electric charges, however many interesting effects emerge also in the gluon sector, mediated by quark loops. Lattice QCD simulation have proved to be a viable and effective tool to investigate such effects, both at zero and finite temperature [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”