17 research outputs found
The glasma initial state and JIMWLK factorization
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.Comment: 4 pages, 2 figures. Talk given by T.L. at Strong and Electroweak
Matter 2008 (SEWM08), August 26-29, 2008, Amsterdam, The Netherland
High energy factorization in nucleus-nucleus collisions II - Multigluon correlations
We extend previous results (arXiv:0804.2630 [hep-ph]) on factorization in
high-energy nucleus-nucleus collisions by computing the inclusive multigluon
spectrum to next-to-leading order. The factorization formula is strictly valid
for multigluon emission in a slice of rapidity of width \Delta Y< 1/\alpha_s.
Our results show that often neglected disconnected graphs dominate the
inclusive multigluon spectrum and are essential to prove factorization for this
quantity. These results provide a dynamical framework for the Glasma flux tube
picture of the striking "ridge"-like correlation seen in heavy ion collisions.Comment: 29 page
From Glasma to Quark Gluon Plasma in heavy ion collisions
When two sheets of Color Glass Condensate collide in a high energy heavy ion
collision, they form matter with very high energy densities called the Glasma.
We describe how this matter is formed, its remarkable properties and its
relevance for understanding thermalization of the Quark Gluon Plasma in heavy
ion collisions. Long range rapidity correlations contained in the near side
ridge measured in heavy ion collisions may allow one to directly infer the
properties of the Glasma.Comment: Plenary Topical Overview Talk, Quark Matter 2008; 10 pages 8 figure
Non-perturbative computation of double inclusive gluon production in the Glasma
The near-side ridge observed in A+A collisions at RHIC has been described as
arising from the radial flow of Glasma flux tubes formed at very early times in
the collisions. We investigate the viability of this scenario by performing a
non-perturbative numerical computation of double inclusive gluon production in
the Glasma. Our results support the conjecture that the range of transverse
color screening of correlations determining the size of the flux tubes is a
semi-hard scale, albeit with non-trivial structure. We discuss our results in
the context of ridge correlations in the RHIC heavy ion experiments.Comment: 25 pages, 11 figures, uses JHEP3.cls V2: small clarifications,
published in JHE
CGC, Hydrodynamics, and the Parton Energy Loss
Hadron spectra in Au+Au collisions at RHIC are calculated by hydrodynamics
with initial conditions from the Color Glass Condensate (CGC). Minijet
components with parton energy loss in medium are also taken into account by
using parton density obtained from hydrodynamical simulations. We found that
CGC provides a good initial condition for hydrodynamics in Au+Au collisions at
RHIC.Comment: Quark Matter 2004 contribution, 4 pages, 2 figure
QCD at small x and nucleus-nucleus collisions
At large collision energy sqrt(s) and relatively low momentum transfer Q, one
expects a new regime of Quantum Chromo-Dynamics (QCD) known as "saturation".
This kinematical range is characterized by a very large occupation number for
gluons inside hadrons and nuclei; this is the region where higher twist
contributions are as large as the leading twist contributions incorporated in
collinear factorization. In this talk, I discuss the onset of and dynamics in
the saturation regime, some of its experimental signatures, and its
implications for the early stages of Heavy Ion Collisions.Comment: Plenary talk given at QM2006, Shanghai, November 2006. 8 pages, 8
figure
Large mass Q-Qbar production from the Color Glass Condensate
We compute quark-antiquark pair production in the context of the Color Glass
Condensate model for central heavy-ion collisions. The calculation is performed
analytically to leading order in the density of hard sources present in the
projectiles, and is applicable to quarks with a mass large compared to the
saturation momentum. The formulas derived in this paper are compared to
expressions derived in the framework of collinearly factorized perturbative QCD
and in kt factorization models. We comment on the breaking of kt factorization
which occurs beyond leading order in our approach.Comment: 24 pages, 3 postscript figure