Initial state fluctuations of QCD conserved charges in heavy-ion collisions

Mauricio Martinez, Matthew D. Sievert, Douglas E. Wertepny, and Jacquelyn Noronha-Hostler

1911.10272

RMS ellipticity of baryon number, strangeness, and electric charge as computed with ICCING, compared to the bulk energy density. We find that the strangeness distribution is far more eccentric than the bulk, because it originates only from hot spots in the event, rather than throughout the fireball.

We initialize the Quantum Chromodynamic conserved charges of baryon number, strangeness, and electric charge arising from gluon splitting into quark-antiquark pairs for the initial conditions of relativistic heavy-ion collisions. A new Monte Carlo procedure that can sample from a generic energy density profile is presented, called Initial Conserved Charges in Nuclear Geometry (ICCING), based on quark and gluon multiplicities derived within the color glass condensate (CGC) effective theory. We find that while baryon number and electric charge have nearly identical geometries to the energy density profile, the initial strangeness distribution is considerable more eccentric and is produced primarily at the hot spots corresponding to temperatures of T ≳ 400 MeV for PbPb collisions at \sqrt{s_NN} = 5.02 TeV.