Initial conditions of QCD conserved charges in high energy nuclear collisions

Dr. Mauricio Martinez Guerrero, North Carolina State University


In the hydrodynamical modeling of heavy-ion collisions it is necessary to know the initial conditions for the full energy-momentum tensor and the baryon, strange and electric (BSQ) conserved charges of Quantum Chromodynamics (QCD). Different initial state models have been proposed to determine the initial values of the energy-momentum tensor. However, little is known for the initial conditions of the conserved charges BSQ. In this talk, I will present a new procedure for dynamically generating conserved charges BSQ to supplement an arbitrary initial condition for ultrarelativistic heavy ion collisions. This algorithm, which we denote ICCING (Initial Conserved Charges in Nuclear Geometries), treats an initial distribution of energy density as if it were composed entirely of gluons. It then samples the probabilities for a gluon to split into a quark-antiquark pair, which we have calculated in the Color-Glass Condensate (CGC) framework, to redistribute this energy density in space along with the conserved charges carried only by quarks. In this way, we provide a new tool to the community which can be incorporated into any framework to initialize the QCD conserved charges. Interestingly, we find that the quark flavors couple differently to the collision geometry: up and down quarks are produced by the bulk event geometry, while strange and charm quarks are preferentially produced from hot spots. As such, different quark flavors can possess significantly different eccentricities which drive the ensuing flavor-dependent flow response.

References:  1801.08986 [arxiv.org] ,  1808.04896 [arxiv.org] , 1911.10272 [arxiv.org] , 1911.12454 [arxiv.org]