Photon production by chiral magnetic effect in the early stage of high-energy nuclear collisions

We present an event-by-event study of photons produced by the chiral magnetic effect in the early stage of high-energy nuclear collisions. We model the early stage with an evolving, <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>2</a:mn><a:mo>+</a:mo><a:mn>1</a:mn></a:mrow></a:math> dimensional, glasma, initialized via the McLerran-Venugopalan model. The photons are produced from the interplay of the chiral anomaly of quantum chromodynamics and the strong magnetic fields generated by the colliding nuclei. In particular, we focus on the spectrum and the elliptic flow of the produced photons. We find that the chiral magnetic effect has a minor impact on the photon spectrum compared to other production mechanisms as well as to experimental data. However, the photons produced by the present early stage mechanism can exhibit a significant elliptic flow.