Classical Gluodynamics of High Energy Nuclear Collisions: an Erratum and an Update

We comment on the relation of our previous work on the classical gluodynamics of high energy nuclear collisions to recent work by Lappi (hep-ph/0303076). While our results for the non-perturbative number liberation coefficient agree, those for the energy disagree by a factor of 2. This discrepancy can be traced to an overall normalization error in our non-perturbative formula for the energy. When corrected for, all previous results are in excellent agreement with those of Lappi. The implications of the results of these two independent computations for RHIC phenomenology are noted.Comment: 6 pages, 2 figure

Elliptic Flow from Color Glass Condensate

We show that an observable fraction of the measured elliptic flow may originate in classical gluon fields at the initial stage of a peripheral high-energy nuclear collision. This mechanism complements the contribution of late stage mechanisms, such as those described by hydrodynamics, to the observed elliptic flow.Comment: 4 pages, 2 figures, talk contributed to Quark Matter-2002 conference (Nantes, France, July 2002

Non-perturbative gluodynamics of high energy heavy-ion collisions

The dynamics of low-x partons in the transverse plane of a high-energy nuclear collision is classical, and therefore admits a fully non--perturbative numerical treatment. We report results of a recent study estimating the initial energy density in the central region of a collision. Preliminary estimates of the number of gluons per unit rapidity, and the initial transverse momentum distribution of gluons, are also provided.Comment: Latex,9 pages, 4 figures, invited talk at 5th workshop on QCD (QCD2000), Villefrance-sur-Mer, Jan.3rd-7th, 2000; minor typo correcte

Multiparticle production at RHIC and LHC: a classical point of view

We report results of our ongoing nonperturbative numerical study of a classical effective theory describing low-x partons in the central region of a heavy-ion collision. In particular, we give estimates of the initial transverse energies and multiplicities for a wide range of collision regimes, including those at RHIC and at LHC.Comment: Talk given at International Symposium for Multiparticle Dynamics, Tihany, Hungary, October 2000. LaTeX using sprocl.sty, 6 pages, figures part of the LaTeX fil

Sphaleron-Like Processes in a Realistic Heat Bath

We measure the diffusion rate of Chern-Simons number in the (1+1)-dimensional Abelian Higgs model interacting with a realistic heat bath for temperatures between 1/13 and 2/3 times the sphaleron energy. It is found that the measured rate is close to that predicted by the sphaleron approximation at the lower end of the temperature range considered but falls at least an order of magnitude short of the sphaleron estimate at the upper end of that range. We show numerically that the sphaleron approximation breaks down as soon as the gauge-invariant two-point function yields correlation length close to the sphaleron size.Comment: talk given at Lattice-93 conference (Dallas, October 1993), 3 pages, uuencoded postscript file, IPS Research Report 93-1

Small x physics and the initial conditions in heavy ion collisions

At very high energies, the high parton densities (characterized by a semi-hard saturation scale \Lambda_s) ensure that parton distributions can be described by a classical effective field theory with remarkable properties analogous to those of spin glass systems. This color glass condensate (CGC) of gluons also provides the initial conditions for multi-particle production in high energy nuclear collisions. In this talk, we briefly summarize recent theoretical and phenomenological progress in the CGC approach to small x physics. In particular, we discuss recent numerical work on the real time gluodynamics of partons after a nuclear collision. The implications of this work for the theoretical study of thermalization in nuclear collisions and on the phenomenological interpretation of results of the recent RHIC experiments are also discussed.Comment: LaTex, 8 pages. Plenary talk by RV at Quark Matter 2001, Stony Brook, USA and at Workshop on Lepton Scattering, Hadrons, and QCD, CSSM, Adelaide, Australi

Sphaleron transitions in a realistic heat bath

We measure the diffusion rate of Chern-Simons number in the (1+1)-dimensional Abelian Higgs model interacting with a realistic heat bath for temperatures between 1/13 and 1/3 times the sphaleron energy. It is found that the measured rate is close to that predicted by one-loop calculation at the lower end of the temperature range considered but falls at least an orderof magnitude short of one-loop estimate at the upper end of that range. We show numerically that the sphaleron approximation breaks down as soon as the gauge-invariant two-point function yields correlation length close to the sphaleron size.Comment: 13 pages, LATeX + 3 figures included as postscript files, to be encapsulated using epsf. Also available as a compressed postscript file by anonymous ftp from maggia.ethz.ch (login ftp, pw ftp; then: cd pub, binary, get sphb.ps.Z). IPS Research Report No. 93-1

Anomalous chirality fluctuations in the initial stage of heavy ion collisions and parity odd bubbles

We compute numerically the topological charge distribution in the initial stage of a high energy heavy ion collision. This charge distribution is generated by Chern-Simons number fluctuations associated with the dynamics of strong classical fields in the initial state. The distribution is found to be quite narrow at RHIC and LHC energies reflecting a small value of the topological susceptibility. Thus the effective potential of classical fields is shallow in the $\theta$-direction likely creating favorable conditions for the subsequent generation of P-odd bubbles.Comment: 15 pages, 2 figures, 1 tabl