[NT/RBRC] Searching for missing direct photons with P and CP violation

by Jonathan D Kroth (Iowa State University)

Friday 24 Oct 2025, 11:00 → 13:00 US/Eastern

https://bnl.zoomgov.com/j/1614715193?pwd=WkwxODVWdzZzb29zQnZRVGp3VTBDQT09 (CFNS Library)

The spectrum of direct photons from the quark-gluon plasma produced at RHIC has defied the efforts of theorists to describe it. In particular, a significant increase in the number of photons produced at low $p_T$ and the correct non-zero $v_2$ flow coefficient have yet to be predicted simultaneously. In an attempt to investigate possible solutions, we study synchrotron radiation from massive fermions in a medium with a chiral chemical potential and a chiral gradient parallel to the magnetic field. In the limit of a non-interacting plasma, these parameters increase the number of photons produced at low $p_T$ while suppressing the traditionally large synchrotron radiation flow coefficient $v_2$ to levels comparable to those seen in experiments. Given these results, we suggest that P- or CP-violating domains, long conjectured to exist in quark-gluon plasma and recently suggested by results from the STAR collaboration, may be a solution to the problem of missing direct photons.