16160539
Searching for Superhorizon Fluctuations in Heavy-Ion Collisions
In this talk I discuss novel explanations for the azimuthal correlations observed in heavy-ion collisions. I review some ideas about correlations and the evolution of heavy-ion collisions. Some aspects of the correlations observed in heavy-ion collisions may be indicitive of the suppression of super-horizon fluctuations.
119402907
Suppression of nonphotonic electrons from enhancement of charm baryons in heavy ion collisions
In Au+Au collisions at 2<p{sub T}<6 GeV/c baryon production is enhanced compared to p+p collisions. Since charm baryon decays produce electrons less frequently than charm meson decays, the nonphotonic electron spectrum is sensitive to the {lambda}{sub c}/D ratio. In this report we study the dependence of the nonphotonic electron spectrum on the baryon-to-meson ratio for charm hadrons. As an example, we take the {lambda}{sub c}/D ratio to have the same form as the {lambda}/K{sub S}{sup 0} ratio. In this case, even if the total charm quark yield in Au+Au collisions scales with the number of binary nucleon-nucleon collisions (N{sub bin}), the electron spectrum at 2<p{sub T}<5 GeV/c is suppressed by as much as 20% relative to N{sub bin} scaled p+p collisions.
8293894
Particle dependence of elliptic flow in Au + Au collisions at s(NN)**(1/2) = 200-GeV
The elliptic flow parameter (v 2 ) for K 0 S and Λ+Λ has been measured at mid-rapidity in Au+Au collisions at √s NN = 200 GeV by the STAR Collaboration. The υ 2 values for both K 0 S and Λ+Λ saturate at moderate p T , deviating from the hydrodynamic behaviour observed in the lower p T region. The saturated v 2 values and the p T scales where the deviation begins are particle dependent. The particle-type dependence of v 2 shows features expected from the hadronization of a partonic ellipsoid by coalescence of co-moving quarks. These results will be discussed in relation to the nuclear modification factor (R CP ) which has also been measured for K 0 S and Λ+Λ by the STAR Collaboration.
118502088
The Sound of the Little Bangs
Measurements of particles emitted from collisions of heavy ions at relativistic energies show evidence for temperature-fluctuations on the freeze-out surface of the expanding fireball. These can be understood as remnants of the density inhomogeneities in the initial collision overlap region. In this paper we present an analysis of heavy-ion collisions analogous to the analysis of the cosmic microwave background radiation. We use data on transverse momentum correlations to extract a power-spectrum from heavy-ion collisions and use a Glauber model for eccentricity to extract the transfer function needed to produce the observed correlations. We also discuss the acoustic signal, the sound that an observer inside the matter would hear.
125578392
Azimuthal anisotropy of K0(S) and Lambda + anti-Lambda production at mid-rapidity from Au + Au collisions at S(NN)**(1/2) = 130-GeV
17939619
RHIC CRITICAL POINT SEARCH: ASSESSING STARs CAPABILITIES.
In this report we discuss the capabilities and limitations of the STAR detector to search for signatures of the QCD critical point in a low energy scan at RHIC. We find that a RHIC low energy scan will cover a broad region of interest in the nuclear matter phase diagram and that the STAR detector--a detector designed to measure the quantities that will be of interest in this search--will provide new observables and improve on previous measurements in this energy range.
120475304
An eikonal line-integral model and factorization in QCD
We study an approximation to perturbative QCD in which all quarks (active and spectator) move along eikonal lines. These eikonal lines are described by matrix operatorsU defined by time-ordered and path-ordered integrals. All known examples of Bloch-Nordsieck cancellations follow simply from the unitary properties ofU. In particular, when the eikonal lines are space-like, the time-ordering can be omitted and the unitarity ofU is evident. In this model, it is possible to examine rather explicitly the soft and very-soft gluons whose effects must cancel if factorization is hold (to leading twist). We can show such cancellation if there is a smooth continuation from space-like eikonal lines to time-like ones. We give some examples relevant to this conjecture, but we are unable to prove it in general.
56164482
Nuclear recoil energy scale in liquid xenon with application to the direct detection of dark matter
We show for the first time that the quenching of electronic excitation from nuclear recoils in liquid xenon is well-described by Lindhard theory, if the nuclear recoil energy is reconstructed using the combined (scintillation and ionization) energy scale proposed by Shutt et al.. We argue for the adoption of this perspective in favor of the existing preference for reconstructing nuclear recoil energy solely from primary scintillation. We show that signal partitioning into scintillation and ionization is well-described by the Thomas-Imel box model. We discuss the implications for liquid xenon detectors aimed at the direct detection of dark matter.
121037084
BACKGROUNDS AND THRESHOLD OF XENON10 DARK MATTER EXPERIMENT
118494907
Importance of upgraded energy reconstruction for direct dark matter searches with liquid xenon detectors
The usual nuclear recoil energy reconstruction employed by liquid xenon dark matter search experiments relies only on the primary scintillation photon signal. Energy reconstruction based on both the photon and electron signals yields a more accurate representation of search results. For a dark matter particle mass m~10 GeV, a nuclear recoil from a scattering event is more likely to be observed in the lower left corner of the typical search box, rather than near the nuclear recoil calibration centroid. In this region of the search box, the actual nuclear recoil energies are smaller than the usual energy scale suggests, by about a factor x2. Recent search results from the XENON100 experiment are discussed in light of these considerations.
12143325
Constraints on Jupiters from observations of Galactic Bulge microlensing events during 2000.
We present observations of 8 Galactic Bulge microlensing events taken with the 1.0m JKT on La Palma during 2000 June and July. The JKT observing schedule was optimized using a prioritizing algorithm to automatically update the target list. For most of these events we have sampled the lightcurves at times where no information was available from the OGLE alert team. We assume a point-source point-lens (PSPL) model and perform a maximum likelihood fit to both our data and the OGLE data to constrain the event parameters of the fit. We then refit the data assuming a binary lens and proceed to calculate the probability of detecting planets with mass ratio q = 10 3 . We have seen no clear signatures of planetary deviations on any of the 8 events and we quantify constraints on the presence of planetary companions to the lensing stars. For two well observed events, 2000BUL31 and 2000BUL33, our detection probabilities