14 research outputs found
Sequential Quarkonium Suppression
We use recent lattice data on the heavy quark potential in order to determine
the dissociation temperatures of different quarkonium states in hot strongly
interacting matter. Our analysis shows in particular that certain quarkonium
states dissociate below the deconfinement point.Comment: Talk presented on the International Workshop on the Physics of the
Quark - Gluon Plasma, September 4-7, 2001, Palaisea
Quarkonium Feed-Down and Sequential Suppression
About 40-50 % of the quarkonium ground states J/psi(1S) and Upsilon(1S)
produced in hadronic collisions originate from the decay of higher excitations.
In a hot medium, these higher states are dissociated at lower temperatures than
the more tightly bound ground states, leading to a sequential suppression
pattern. Using new finite temperature lattice results, we specify the in-medium
potential between heavy quarks and determine the dissociation points of
different quarkonium states. On the basis of recent CDF data on bottomonium
production, we then obtain first predictions for sequential Upsilon suppression
in nuclear collisions.Comment: 19 pages, LaTeX, 11 figure
Charmonium dissociation temperatures in lattice QCD with a finite volume technique
Dissociation temperatures of J/\psi, \psi', and \chi_c states play key roles
in the sequential J/\psi suppression scenario for high energy heavy ion
collisions. We report on a study of charmonium dissociation temperatures in
quenched lattice QCD. On anisotropic lattices, we first subtract the effects of
the constant mode in finite temperature meson correlators, which have lead to
unphysical results in previous studies. We then extract ground and first exited
state masses by diagonalizing correlation functions among different source and
sink operators. To distinguish bound states from scattering states, we first
compare the charmonium mass spectra under different spatial boundary
conditions, and examine the shape and the volume-dependence of their
Bethe-Salpeter wave functions. From these studies, we found so far no sign of
scattering states up to about 2.3T_c.Comment: 4pages, 2figures, proceedings of Quark Matter 2008 (QM2008), Jaipur,
India, Feb 4-10, 200
String Breaking and Quarkonium Dissociation at Finite Temperatures
Recent lattice studies of string breaking in QCD with dynamical quarks
determine the in-medium temperature dependence of the heavy quark potential.
Comparing this to the binding energies of different quarkonium states, we check
if these can decay into open charm/beauty in a confined hadronic medium. Our
studies indicate in particular that the chi_c and the psi dissociate into open
charm below the deconfinement point.Comment: 8 pages LaTeX, 4 figure
Quarkonium Suppression
I discuss quarkonium suppression in equilibriated strongly interacting
matter. After a brief review of basic features of quarkonium production I
discuss the application of recent lattice data on the heavy quark potential to
the problem of quarkonium dissociation as well as the problem of direct lattice
determination of quarkonium properties in finite temperature lattice QCD.Comment: Invited plenary talk presented on 4th International Conference on
Physics and Astrophysics of Quark Gluon Plasma (ICPAQGP-2001), November
26-30, 2001, Jaipur; 12 pp, LaTeX, uses pramana.st
Parton Percolation and J/Psi Suppression
The geometric clustering of partons in the transverse plane of nuclear
collisions leads for increasing A or sqrt(s) to percolation. In the resulting
condensate, the partons are deconfined but not yet in thermal equilibrium. We
discuss quarkonium dissociation in this precursor of the quark-gluon plasma,
with an onset of dissociation when the saturation scale of the parton
condensate reaches that of the given quarkonium state.Comment: 13 pages latex file, 7 eps figure
Colour Deconfinement and Quarkonium Binding
At high temperatures, strongly interacting matter becomes a plasma of
deconfined quarks and gluons. In statistical QCD, deconfinement and the
properties of the resulting quark-gluon plasma can be investigated by studying
the in-medium behaviour of heavy quark bound states. In high energy nuclear
interactions, quarkonia probe different aspects of the medium formed in the
collision. We survey the results of recent charmonium production studies in SPS
and RHIC experiments.Comment: 50 pages, 53 figures; revised section 6.
Heavy quarkonium: progress, puzzles, and opportunities
A golden age for heavy quarkonium physics dawned a decade ago, initiated by
the confluence of exciting advances in quantum chromodynamics (QCD) and an
explosion of related experimental activity. The early years of this period were
chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in
2004, which presented a comprehensive review of the status of the field at that
time and provided specific recommendations for further progress. However, the
broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles
could only be partially anticipated. Since the release of the YR, the BESII
program concluded only to give birth to BESIII; the -factories and CLEO-c
flourished; quarkonium production and polarization measurements at HERA and the
Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the
deconfinement regime. All these experiments leave legacies of quality,
precision, and unsolved mysteries for quarkonium physics, and therefore beg for
continuing investigations. The plethora of newly-found quarkonium-like states
unleashed a flood of theoretical investigations into new forms of matter such
as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the
spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. The
intriguing details of quarkonium suppression in heavy-ion collisions that have
emerged from RHIC have elevated the importance of separating hot- and
cold-nuclear-matter effects in quark-gluon plasma studies. This review
systematically addresses all these matters and concludes by prioritizing
directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair