9,655 research outputs found
Jet Quenching: the medium modification of the single and double fragmentation functions
The physics of the quenching of hard jets in dense matter is briefly
reviewed. This is presented within the framework of the partonic medium
modification of the fragmentation functions. Modifications in both deeply
inelastic scattering (DIS) off large nuclei and high-energy heavy-ion
collisions are presented.Comment: 4 pages, 4 figures, Proceedings of the First Meeting of the APS
Topical Group on Hadronic Physics, Fermilab, Batavia, Illinois, Oct 24-26,
200
The Cleo III Rich Detector
CLEO III upgrade was completed with the integration of Ring Imaging
CHerenkov(RICH) detector for charged particle identification. The design of
this cylindrical detector consists of LiF crystal radiators and multi-wire
proportional chamber photon detectors coupled through a N2 filled expansion
gap. Early performance on K/pion separation is presented.Comment: Presented at Meeting of the Division of Particles and Fields of the
American Physical Society August, 200
Deciphering Deconfinement in Correlations of Conserved Charges
Diagonal and off-diagonal flavor and conserved charge susceptibilities reveal
the prevalent degrees of freedom of heated strongly interacting matter. Results
obtained from lattice simulations are compared with various model estimates in
an effort to weed down various possible pictures of a quark gluon plasma. We
argue that the vanishing of the off-diagonal quark flavor susceptibilities and
its derivatives with respect to chemical potential, at temperatures above
1.5Tc, can only be understood in a picture of a gas or liquid composed of
quasi-particles which carry the same quantum numbers as quarks and antiquarks.
A potential new observable, blind to neutral and non-strange particles, is
introduced and related via isospin symmetry to the ratio of susceptibilities of
baryonic strangeness to strangeness generated in the excited matter created at
RHIC.Comment: 5 pages, 3 figures, LATEX, To appear in the proceedings of the
International Conference on Strangeness in Quark Matter, Los Angeles, CA, Mar
26-31, 200
Extending Soft-Collinear-Effective-Theory to describe hard jets in dense QCD media
An extension to the Soft-Collinear-Effective Theory (SCET) description of
hard jets is motivated to include the leading contributions between the
propagating partons within the jet with partons radiated from a dense extended
medium. The resulting effective Lagrangian, containing both a leading and a
power suppressed (in the hard scale ) contribution, arises primarily from
interactions between the hard collinear modes in the jet with Glauber modes
from the medium. In this first attempt, the interactions between the hard jet
and soft and collinear partonic modes have been ignored, in an effort to focus
solely on the interactions with the Glauber modes. While the effect of such
modes on vacuum cross sections are suppressed by powers of the hard scale
compared to the terms from the SCET Lagrangian, such sub-leading contributions
are enhanced by the extent of the medium and result in measurable corrections.
The veracity of the derived Lagrangian is checked by direct comparison with
known results from full QCD calculations of two physical observables: the
transverse momentum broadening of hard jets in dense media and a reanalysis of
the transverse momentum dependent parton distribution function (TMDPDF).Comment: 19 pages, 6 figures, revtex4, discussion on power counting updated,
references adde
Baryon-strangeness correlations: a diagnostic of strongly interacting matter
The correlation between baryon number and strangeness elucidates the nature
of strongly interacting matter, such as that formed transiently in high-energy
nuclear collisions. This diagnostic can be extracted theoretically from lattice
QCD calculations and experimentally from event-by-event fluctuations. The
analysis of present lattice results above the critical temperature severely
limits the presence of q-qbar bound states, thus supporting a picture of
independent (quasi)quarks.Comment: 4 pages, 2 eps figures, Revised: several sign typos have been fixed
(the PRL version is correct
Parametric, Optimization-Based Study on the Feasibility of a Multisegment Antisolvent Crystallizer for in Situ Fines Removal and Matching of Target Size Distribution
Peer reviewedPostprin
Dihadron fragmentation functions and high Pt hadron-hadron correlations
We propose the formulation of a dihadron fragmentation function in terms of
parton matrix elements. Under the collinear factorization approximation and
facilitated by the cut-vertex technique, the two hadron inclusive cross section
at leading order (LO) in e+ e- annihilation is shown to factorize into a short
distance parton cross section and the long distance dihadron fragmentation
function. We also derive the DGLAP evolution equation of this function at
leading log. The evolution equation for the non-singlet quark fragmentation
function is solved numerically with a simple ansatz for the initial condition
and results are presented for cases of physical interest.Comment: Latex, 4 pages, 4 figures, talk given at Quark Matter 2004, To appear
in J. Phys.
Modified Dihadron Fragmentation Functions in Hot and Nuclear Matter
Medium modification of dihadron fragmentation functions due to gluon
bremsstrahlung induced by multiple partonic scattering is studied in both
deep-inelastic scattering (DIS) off large nuclei and high-energy heavy-ion
collisions within the same framework of twist expansion. The modified
fragmentation functions for dihadrons are found to follow closely that of
single hadrons leading to a weak nuclear suppression of their ratios as
measured by HERMES in DIS experiments. Meanwhile, a moderate medium enhancement
of the near-side correlation of two high transverse momentum hadrons with
increasing centrality is found in heavy-ion collisions because of the trigger
bias and the increase in parton energy loss with centrality. Successful
comparisons between theory and experiment for multi-hadron observables in both
confining and deconfined environments offers comprehensive evidence for
partonic energy loss as the mechanism of jet modification in dense matter.Comment: 4 pages, Revtex, 2 figures, revised figures and discussio
High Pt hadron-hadron correlations
We propose the formulation of a dihadron fragmentation function in terms of
parton matrix elements. Under the collinear factorization approximation and
facilitated by the cut-vertex technique, the two hadron inclusive cross section
at leading order (LO) in e+ e- annihilation is shown to factorize into a short
distance parton cross section and the long distance dihadron fragmentation
function. We also derive the DGLAP evolution equation of this function at
leading log. The evolution equation for the non-singlet and singlet quark
fragmentation function and the gluon fragmentation function are solved
numerically with the initial condition taken from event generators.
Modifications to the dihadron fragmentation function from higher twist
corrections in DIS off nuclei are computed. Results are presented for cases of
physical interest.Comment: 7 pages, 8 figures, Latex, Proceedings of Hot Quarks 2004, July
18-24, Taos, New Mexic
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