The signature of charge dependent directed flow observables by electromagnetic fields in heavy ion collisions
Laboratori Nazionali del Sud, INFN-LNS, Via S. Sofia 62, I-95123, Catania, Italy
2 Department of Physics and Astronomy, University of Catania, Via S. Sofia 64, 1-95125, Catania, Italy
Accepted: 22 June 2021
Published online: 6 July 2021
We discuss the generation of the directed flow induced by the electromagnetic field as a function of and . Despite the complex dynamics of charged particles due to strong interactions generating several anisotropies in the azimuthal angle, it is possible at to directly correlate the splitting in of heavy quarks with different charges to some main features of the magnetic field, and in particular its values at formation and freeze-out time. We further found that the slope of the splitting of positively and negatively charged particles at high can be formulated as , where f is the spectra of the charged particles and the constants and (order of MeV) are constrained by the y component of magnetic fields and the sign of is simply determined by the difference in the center of colliding systems at the formation time of particles and at the time when particles leave the effective range of electromagnetic fields or freeze out. The formula is derived from general considerations and is confirmed by several related numerical simulations; it supplies a useful guide to quantify the effect of different magnetic field configurations and provides an evidence of why the measurement of of charm, bottom and leptons from decay and their correlations are a powerful probe of the initial e.m. fields in ultra-relativistic collisions.
© The Author(s) 2021
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