Effect of magnetic field on jet transport coefficient $$\hat{q}$$

• DOI: 10.1007/s12043-023-02683-1
• Publication Date: 2023-12-11T09:02:38Z
• Authors: Debjani Banerjee; Prottoy Das; Souvik Paul; Abhi Modak; Ankita Budhraja; Sabyasachi Ghosh; Sidharth K Prasad
• Keywords: Nuclear Theory; FOS: Physical sciences; 7. Clean energy; 01 natural sciences; High Energy Physics - Experiment; Nuclear Theory (nucl-th); High Energy Physics - Phenomenology; High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); 0103 physical sciences; Nuclear Experiment (nucl-ex); Nuclear Experiment

We report the estimation of jet transport coefficient, $\hat{q}$ for quark- and gluon-initiated jets using a simple quasi-particle model in absence and presence of magnetic field. This model introduces a temperature and magnetic field-dependent degeneracy factor of partons, which is tuned by fitting the entropy density of lattice quantum chromodynamics data. At a finite magnetic field, $\hat{q}$ for quark jets splits into parallel and perpendicular components whose magnetic field dependence comes from two sources: the field-dependent degeneracy factor and the phase space part guided from the shear viscosity to entropy density ratio. Due to the electrically neutral nature of gluons, the estimation of $\hat{q}$ for gluon jets is affected only by the field-dependent degeneracy factor. In presence of a finite magnetic field, we find a significant enhancement in $\hat{q}$ for both quark- and gluon-initiated jets at low temperature, which gradually decreases towards high temperature. We compare the obtained results with the earlier calculations based on the anti-de Sitter/conformal field theory correspondence, and a qualitatively similar trend is observed. The change in $\hat{q}$ in presence of magnetic field is, however, quantitatively different for quark- and gluon-initiated jets. This is an interesting observation which can be explored experimentally to verify the effect of magnetic field on $\hat{q}$.<br/>typos corrected, references added, results updated<br/>