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arXiv · 1806.06750

Dilepton photoproduction measures the fluctuations of initial electromagnetic fields in nuclear collisions

Guansong Li·Kai Zhou·Baoyi Chen
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Abstract

Dilepton production from two photon interactions $\gamma\gamma\rightarrow l^+l^-$ are studied in semi-central and peripheral nuclear collisions. Based on Weizs\"acker-Williams approach, it is shown that the dilepton photoproduction is proportional to the electromagnetic (EM) fields $\sim E^2B^2$ and therefore sensitive to the magnitude and lifetime of initial EM fields which last only for a short time and are hard to be measured in experiments directly. We propose dilepton photoproduction as a probe for the nuclear charge fluctuations, which are crucial for the electric/magnetic field induced chiral and charge particle evolutions. We calculate the relative standard deviation of dilepton mass spectrum with event-by-event fluctuating nuclear charge distributions (and EM fields).

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Guansong Li, Kai Zhou, Baoyi Chen. 2018-06-18. Dilepton photoproduction measures the fluctuations of initial electromagnetic fields in nuclear collisions. https://doi.org/10.1088/1572-9494%2Fab5cff

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