65 research outputs found

    Blast-wave snapshots from RHIC

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    I present fits with the so-called blast-wave model to single-particle spectra and HBT correlations from Au+Au collisions at a CMS energy of 130 AGeV. There is only little choice of freeze-out temperature and transverse flow velocity for which the model fits both the identified spectra and the correlation radii just well enough not to be excluded. The observed steep M_t dependence of R_side leads to a temperature which it is problematic to interpret. The applicability of the model for the freeze-out description is thus questioned.Comment: 4 pages, 2 figures, proceedings of 38 Rencontres de Moriond, QCD and hadronic interaction

    Understanding of the freeze-out in ultra-relativistic heavy-ion collisions

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    I discuss the quantities and effects important for the freeze-out and outline a formalism for the description of continuous decoupling of particles from the fireball. Then I present a calculation of the scattering rates of pions at various temperatures and argue that it is important to take continuous particle decoupling into account when modelling the collision dynamics.Comment: 4 pages, 2 figures, Talk given at the 2nd Warsaw meeting on correlations and resonances, Oct. 15-18, 2003, Warsaw, Polan

    Event shape sorting

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    We propose a novel method for sorting events of multiparticle production according to the azimuthal anisotropy of their momentum distribution. Although the method is quite general, we advocate its use in analysis of ultra-relativistic heavy-ion collisions where large number of hadrons is produced. The advantage of our method is that it can automatically sort out samples of events with histograms that indicate similar distributions of hadrons. It takes into account the whole measured histograms with all orders of anisotropy instead of a specific observable (e.g. v2v_2, v3v_3, q2q_2). It can be used for more exclusive experimental studies of flow anisotropies which are then more easily compared to theoretical calculations. It may also be useful in the construction of mixed-events background for correlation studies as it allows to select events with similar momentum distribution.Comment: 11 pages, 7 figures, to appear in European Physical Journal A, section added in v2 with analysis of AMPT-generated event

    Fine-Tuning Two-Particle Interferometry I: Effects from Temperature Gradients in the Source

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    A comprehensive model study of Bose-Einstein correlation radii in heavy ion collisions is presented. The starting point is a longitudinally and transversally expanding fireball, represented at freeze-out by an azimuthally symmetric emission function. The freeze-out temperature is allowed to feature transverse and temporal gradients. Their effects on the correlation radii are studied. In particular, we evaluate numerically their dependence on the transverse mass of the particle pairs and check a recent suggestion, based on analytical approximations, that for certain reasonable source parameters all three correlation radii satisfy simultaneously a 1/\sqrt{M_\perp} scaling.Comment: 22 pages, 8 figures, epsf; replaced with the revised first part of the original study, the revised second part (concerning opaque sources) can be found under nucl-th/980501
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