Speaker
Description
We study the magnetic properties of the Hadron Resonance Gas (HRG) (which is created in ultra-relativistic heavy-ion collisions or studied on the lattice) in the presence of a constant magnetic field. Instead of the simplified approach$^{1,2}$ of taking the gyromagnetic ratio of a hadron as $g=2|Q|$, we consider the physical value of $g$ as measured in experiments or estimated theoretically. By considering this, we also take into account the paramagnetic contributions from the spin magnetic moments of neutral hadrons, missed in past studies. We evaluate the conserved charge susceptibilities and correlations describing fluctuations in HRG, both in the absence and presence of a magnetic field. We quantify the sizable effects of the physical values of $g$. Additionally, we also discuss the instability and the dominance of the $\Delta$ baryons in strong magnetic fields, and propose how to tackle it phenomenologically. We compare our model results with the lattice data from various collaborations$^3$. For not too strong magnetic fields, the approach can reasonably describe the features of the lattice data related to the baryon, strangeness, and charge susceptibilities and correlations, highlighting the importance of the physical anomalous magnetic moments and a proper treatment of the $\Delta$. (Based on the work in progress)
References:
1. M. Marczenko, M. Szymanski, P. M. Lo, B. Karmakar, P. Huovinen, C. Sasaki, and K. Redlich, Phys. Rev. C 110, 065203 (2024), arXiv:2405.15745 [hep-ph].
2. V. Vovchenko, Phys. Rev. C 110, 034914 (2024), arXiv:2405.16306 [hep-ph].
3. Bollweg et al. Phys. Rev. D 104, 074512 (2021), arXiv:2107.10011 [hep-lat], Ding et al. (2025), arXiv:2503.18467 [hep-lat], Astrakhantsev et al. Phys. Rev. D 109, 094511 (2024), arXiv:2403.07783 [hep-lat].
