Impact of the electromagnetic field on Z⁰ leptonic invariant mass in ultrarelativistic heavy ion collisions

¹ School of Physics and Astronomy, Shanghai Key Laboratory for Particle Physics and Cosmology, and Key Laboratory for Particle Astrophysics and Cosmology (MOE), Shanghai Jiao Tong University, Shanghai 200240, China
² Department of Physics and Astronomy, University of Catania, Via S. Sofia 64, 1-95125 Catania, Italy
³ Laboratori Nazionali del Sud, INFN-LNS, Via S. Sofia 62, I-95123 Catania, Italy
⁴ Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA

^* e-mail: sunyfphy@sjtu.edu.cn

Published online: 1 March 2023

Abstract

The extraordinary strong magnetic field generated in ultrarelativistic heavy ion collisions makes it possible to investigate many novel effects in the hot QCD matter, and a direct probe of it thus becomes an urgent task in the field. Here we report a new way to probe it, where the leptonic invariant mass distribution of Z⁰ boson will be modified in the presence of the magnetic field due to the Lorentz force on the lepton pairs from the decay of Z⁰ boson. It is found that the magnetic field can decrease the mean value of Z⁰ leptonic invariant mass and increase its width, and both shifts approximately depend on the integral of the magnetic field over its time duration quadratically.