Multiplicity scaling in ideal and viscous hydrodynamics
| dc.creator | Song, Huichao | |
| dc.creator | Heinz, Ulrich W. | |
| dc.date | 2008-05-13 | |
| dc.date | 2008-07-03 | |
| dc.date.accessioned | 2026-07-07T11:50:44Z | |
| dc.date.available | 2026-07-07T11:50:44Z | |
| dc.description | Using numerical results from ideal and viscous relativistic hydrodynamic simulations with three different equations of state, for Au+Au and Cu+Cu collisions at different centralities and initial energy densities, we explore the dependence of the eccentricity-scaled elliptic flow, v_2/epsilon, and the produced entropy fraction, Delta S/S_0, on the final charged hadron multiplicity density dN_ch/dy per unit transverse overlap area S, (1/S)(dN_ch/dy). The viscous hydrodynamic simulations are performed with two different versions of the Israel-Stewart kinetic evolution equations, and in each case we investigate the dependence of the physical observables on the kinetic relaxation time. We find approximate scaling of v_2/epsilon and Delta S/S_0 with (1/S)(dN_ch/dy), with scaling functions that depend on the EOS and, in particular, on the value of the specific shear viscosity eta/s. Small scaling violations are seen even in ideal hydrodynamics, caused by a breaking of the scale invariance of ideal fluid dynamics by the freeze-out condition. Viscous hydrodynamics shows somewhat larger scale-breaking effects that increase with increasing eta/s and decreasing system size and initial energy density. We propose to use precision studies of these scaling violations to help constrain the shear viscosity eta/s of the quark-gluon plasma created in relativistic heavy ion collisions. | |
| dc.description | 15 pages, incl. 9 figures. Submitted to Phys. Rev. C. Added discussion of numerical viscosity effects in Section VI, updated references | |
| dc.identifier | https://arxiv.org/abs/0805.1756 | |
| dc.identifier | http://arxiv.org/abs/0805.1756 | |
| dc.identifier | Phys.Rev.C78:024902,2008 | |
| dc.identifier | doi:10.1103/PhysRevC.78.024902 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/203659 | |
| dc.subject | Nuclear Theory | |
| dc.title | Multiplicity scaling in ideal and viscous hydrodynamics | |
| dc.type | text |