Azimuthally fluctuating magnetic field and its impacts on observables in heavy-ion collisions

TL;DR

This study investigates how azimuthal fluctuations of magnetic fields in heavy-ion collisions affect observable phenomena, highlighting the importance of impact parameter in optimizing measurements of magnetic field-induced effects.

Contribution

It introduces event-by-event simulations to analyze the correlation between magnetic field fluctuations and matter geometry, revealing impact parameter dependencies.

Findings

Suppression of magnetic field and participant plane correlations in central and peripheral collisions.

Peak correlation magnitudes around impact parameter 8-10 fm for RHIC.

Implication for selecting optimal collision events to measure magnetic field effects.

Abstract

The heavy-ion collisions can produce extremely strong transient magnetic and electric fields. We study the azimuthal fluctuation of these fields and their correlations with the also fluctuating matter geometry (characterized by the participant plane harmonics) using event-by-event simulations. A sizable suppression of the angular correlations between the magnetic field and the 2nd and 4th harmonic participant planes is found in very central and very peripheral collisions, while the magnitudes of these correlations peak around impact parameter b~8-10 fm for RHIC collisions. This can lead to notable impacts on a number of observables related to various magnetic field induced effects, and our finding suggests that the optimal event class for measuring them should be that corresponding to b~8-10 fm.