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Wee partons in large nuclei: From virtual dream to hard reality

Description: We construct a weak coupling, many body theory to compute parton distributions in large nuclei for x {much_lt} A{sup {minus} 1/3}. The wee partons are highly coherent, non-Abelian Weizsaecker-Williams fields. Radiative corrections to the classical results axe discussed. The parton distributions for a single nucleus provide the initial conditions for the dynamical evolution of matter formed in ultrarelativistic nuclear collisions.
Date: June 1, 1995
Creator: Venugopalan, R.
Partner: UNT Libraries Government Documents Department

From many body wee partons dynamics to perfect fluid: a standard model for heavy ion collisions

Description: We discuss a standard model of heavy ion collisions that has emerged both from experimental results of the RHIC program and associated theoretical developments. We comment briefly on the impact of early results of the LHC program on this picture. We consider how this standard model of heavy ion collisions could be solidified or falsified in future experiments at RHIC, the LHC and a future Electro-Ion Collider.
Date: July 22, 2010
Creator: Venugopalan, R.
Partner: UNT Libraries Government Documents Department

Inclusive hadron distributions in p+p collisions from saturation models of HERA DIS data.

Description: Dipole models based on various saturation scenarios provide reasonable fits to small-x DIS inclusive, diffractive and exclusive data from HERA. Proton un-integrated gluon distributions extracted from such fits are employed in a k{sub {perpendicular}}-factorization framework to calculate inclusive gluon distributions at various energies. The n-particle multiplicity distribution predicted in the Glasma flux tube approach shows good agreement with data over a wide range of energies. Hadron inclusive transverse momentum distributions expressed in terms of the saturation scale demonstrate universal behavior over a wider kinematic range systematically with increasing center of mass energies.
Date: December 6, 2010
Creator: Tribedy, P. & Venugopalan, R.
Partner: UNT Libraries Government Documents Department

WHAT IS NEW AT SMALL X*

Description: The authors discuss some recent developments in small x physics. Current understanding of small x physics is that pQCD works at HERA and the Tevatron, but perhaps even better than expected. There is much flexibility in parton distributions to hide interesting new effects. Indeed, there are strong hints from HERA that one is on the threshold of a new regime of truly high parton densities, where one may expect qualitative changes in the behavior of distributions.
Date: January 3, 2000
Creator: VENUGOPALAN,R.
Partner: UNT Libraries Government Documents Department

PARTON SATURATION, PRODUCTION, AND EQUILIBRATION IN HIGH ENERGY NUCLEAR COLLISIONS

Description: Deeply inelastic scattering of electrons off nuclei can determine whether parton distributions saturate at HERA energies. If so, this phenomenon will also tell us a great deal about how particles are produced, and whether they equilibrate, in high energy nuclear collisions.
Date: March 20, 1999
Creator: VENUGOPALAN,R.
Partner: UNT Libraries Government Documents Department

DEEPLY INELASTIC SCATTERING OFF NUCLEI AT RHIC.

Description: In this talk, we discussed the physics case for an eA collider. We emphasized the novel physics that might be studied at small x. The interesting physics at intermediate x's has been discussed elsewhere [3]. Plans for an electron-ion collider include, as a major part of the program, the possibility of doing polarized electron-polarized proton/light ion scattering. A discussion of the combined case for high energy electron nucleus and polarized electron-polarized proton scattering will be published separately [66].
Date: September 14, 2001
Creator: VENUGOPALAN, R.
Partner: UNT Libraries Government Documents Department

HADRONIC SCATTERING IN THE COLOR GLASS CONDENSATE.

Description: Multi-particle production in QCD is dominated by higher twist contributions. The operator product expansion is not very effective here because the number of relevant operators grow rapidly with increasing twist. The Color Glass Condensate (CGC) provides a framework in QCD to systematically discuss ''classical'' (multiple scattering) and ''quantum'' evolution (shadowing) effects in multi-particle production. The apparently insuperable problem of nucleus-nucleus scattering in QCD simplifies greatly in the CGC. A few examples are discussed with emphasis on open problems.
Date: May 15, 2005
Creator: Venugopalan, R.
Partner: UNT Libraries Government Documents Department

Ekpyrosis and inflationary dynamics in heavy ion collisions: the role of quantum fluctuations

Description: We summarize recent significant progress in the development of a first-principles formalism to describe the formation and evolution of matter in very high energy heavy ion collisions. The key role of quantum fluctuations both before and after a collision is emphasized. Systematic computations are now feasible to address early time isotropization, flow, parton energy loss and the Chiral Magnetic Effect.
Date: May 23, 2011
Creator: Dusling, K.; Venugopalan, R. & Gelis, F.
Partner: UNT Libraries Government Documents Department

Nuclear diffractive structure functions at high energies

Description: A future high-energy electron-ion collider would explore the non-linear weakly-coupled regime of QCD, and test the Color Glass Condensate (CGC) approach to high-energy scattering. Hard diffraction in deep inelastic scattering off nuclei will provide many fundamental measurements. In this work, the nuclear diffractive structure function F{sub 2,A}{sup D} is predicted in the CGC framework, and the features of nuclear enhancement and suppression are discussed.
Date: August 8, 2008
Creator: Marquet,C.; Kowalski, H.; Lappi, T. & Venugopalan, R.
Partner: UNT Libraries Government Documents Department

The glasma initial state and JIMWLK factorization

Description: We review recent work on understanding the next to leading order corrections to the classical fields that dominate the initial stages of a heavy ion collision. We have recently shown that the leading ln 1/x divergences of these corrections to gluon multiplicities can be factorized into the JIMWLK evolution of the color charge density distributions.
Date: August 26, 2008
Creator: Gelis,F.; Lappi, T. & Venugopalan, R.
Partner: UNT Libraries Government Documents Department

Nuclear theory summer meeting on ERHIC

Description: The eRHIC BNL summer meeting was held at BNL from June 26 to July 14, 2000. The meeting was very informal with only two talks a day and with ample time for discussions and collaborations. Several of the theory talks focused on the issue of saturation of parton distributions at small x--whether screening effects have already been seen at HERA, the relation of saturation to shadowing, and on the various signatures of a proposed novel state of matter--the Colored Glass Condensate--that may be observed at eRHIC. A related topic that was addressed was that of quantifying twist four effects, and on the relevance of these for studies of energy loss. Other issues addressed were coherence effects in vector meson production, anti-quark distributions in nuclei, and the relevance of saturation for heavy ion collisions. There were, also, talks on the Pomeron--the relevance of instantons and the non-perturbative gluon condensate to constructing a Pomeron. On the spin physics side, there were talks on predictions for inclusive distributions at small x. There were also talks on Skewed Parton Distributions and Deeply Virtual Compton Scattering. Though most of the talks were theory talks, there were also several important experimental contributions. A preliminary detector design for eRHIC was presented. Studies for semi-inclusive measurements at eRHIC were also presented. The current status of pA scattering studies at RHIC was also discussed. The eRHIC summer meeting provided a vigorous discussion of the current status of eRHIC studies. It is hoped that this document summarizing these discussions will be of use to all those interested in electron nucleus and polarized electron-polarized proton studies.
Date: June 26, 2000
Creator: McLerran, L. & Venugopalan, R.
Partner: UNT Libraries Government Documents Department

MULTIPARTICLE PRODUCTION AT RHIC AND LHC: A CLASSICAL POINT OF VIEW.

Description: 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.
Date: October 9, 2000
Creator: KRASNITZ,A. & VENUGOPALAN,R.
Partner: UNT Libraries Government Documents Department

NON-PERTURBATIVE GLUODYNAMICS OF HIGH ENERGY HEAVY-ION COLLISIONS

Description: 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. The authors 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.
Date: January 3, 2000
Creator: KRASNITZ,A. & VENUGOPALAN,R.
Partner: UNT Libraries Government Documents Department

VIOLATION OF K-PERPENDICULAR FACTORIZATION IN QUARK PRODUCTION FROM THE COLOR GLASS CONDENSATE.

Description: We examine the violation of the k{sub {perpendicular}}factorization approximation for quark production in high energy proton-nucleus collisions. We comment on its implications for the open charm and quarkonium production in collider experiments.
Date: August 4, 2005
Creator: FUJII, H.; GELIS, F. & VENUGOPALAN, R.
Partner: UNT Libraries Government Documents Department

SCALING PROPERTIES OF THE TRANSVERSE MASS SPECTRA.

Description: Motivated from the formation of an initial state of gluon-saturated matter, we discuss scaling relations for the transverse mass spectra at BNL's Relativistic Heavy-Ion Collider (RHIC). We show on linear plots, that the transverse mass spectra for various hadrons can be described by an universal function in m{sub t}. The transverse mass spectra for different centralities can be rescaled into each other. Finally, we demonstrate that m{sub t}-scaling is also present in proton-antiproton collider data and compare it to m{sub t}-scaling at RHIC.
Date: January 13, 2002
Creator: SCHAFFNER-BIELICH,J.; KHARZEEV,D.; MCLERRAN,L. & VENUGOPALAN,R.
Partner: UNT Libraries Government Documents Department

ELLIPTIC FLOW FROM COLOR GLASS CONDENSATE.

Description: 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.
Date: July 18, 2002
Creator: KRASNITZ,A.; NARA,Y. & VENUGOPALAN,R.
Partner: UNT Libraries Government Documents Department

Gluons and the quark sea at high energies: distributions, polarization, tomography

Description: This report is based on a ten-week program on Gluons and the quark sea at high-energies, which took place at the Institute for Nuclear Theory (INT) in Seattle in Fall 2010. The principal aim of the program was to develop and sharpen the science case for an Electron-Ion Collider (EIC), a facility that will be able to collide electrons and positrons with polarized protons and with light to heavy nuclei at high energies, offering unprecedented possibilities for in-depth studies of quantum chromodynamics (QCD). This report is organized around the following four major themes: (i) the spin and flavor structure of the proton, (ii) three dimensional structure of nucleons and nuclei in momentum and configuration space, (iii) QCD matter in nuclei, and (iv) Electroweak physics and the search for physics beyond the Standard Model. Beginning with an executive summary, the report contains tables of key measurements, chapter overviews for each of the major scientific themes, and detailed individual contributions on various aspects of the scientific opportunities presented by an EIC.
Date: September 30, 2011
Creator: Boer, D.; Venugopalan, R.; Diehl, M.; Milner, R.; Vogelsang, W. & al., et
Partner: UNT Libraries Government Documents Department