Non-identical particle femtoscopy in models with single freeze-out

188

We study the effects of shear and bulk viscosities in the hadronic phase on the expansion of the fireball and on the particle production in relativistic heavy ion collisions. Comparing simulation with or without viscosity in the hadronic matter we find that elliptic flow observables strongly dependent on dissipative effects in the late stage. On the other hand, interferometry radii are sensitive, through the early transverse flow, on the value of the viscosity at high temperatures. We present first calculations including the effects of bulk viscosity in the hadronic phase and in the hadron emission. We find them important in obtaining a small freeze-out temperature consistent with the measured transverse momentum spectra and elliptic flow of identified particles.

Section: Resultsmentioning

confidence: 99%

Bulk and shear viscosities of matter created in relativistic heavy-ion collisions

Božek¹

2010

188

“…The basic ingredients of the Therminator model employed in the analysis are (1) Bjorken assumption of longitudinal boost invariance; (2) blast-wave (BW) expansion in the transverse direction with transverse velocity profile semilinear in transverse radius ρ [16], v r (ρ) = (ρ/ρ max )/(ρ/ρ max + v t ), where v t = 0.445 is obtained from BW fits to particle spectra [17]; (3) after a proper lifetime τ , a thermal emission of particles takes place from the source elements distributed in r (fm) S(r x ) (fm 034906-5 a cylinder of infinite longitudinal size and finite transverse dimension ρ max . At the point of source breakup, all particle emission is collectively viewed as happening from a freeze-out hypersurface defined in the ρ-τ plane as τ = τ 0 + aρ.…”

Section: Expansion Dynamics and Model Comparisonmentioning

confidence: 99%

Freeze-out dynamics via charged kaon femtoscopy insNN=200GeV central Au + Au collisions

Adamczyk¹,

Adkins²,

Agakishiev³

et al. 2013

We present measurements of three-dimensional correlation functions of like-sign, low-transverse-momentum kaon pairs from √ s NN = 200 GeV Au + Au collisions. A Cartesian surface-spherical harmonic decomposition technique was used to extract the kaon source function. The latter was found to have a three-dimensional Gaussian shape and can be adequately reproduced by Therminator event-generator simulations with resonance contributions taken into account. Compared to the pion one, the kaon source function is generally narrower and does not have the long tail along the pair transverse momentum direction. The kaon Gaussian radii display a monotonic decrease with increasing transverse mass m T over the interval of 0.55 m T 1.15 GeV/c 2 . While the kaon radii are adequately described by the m T -scaling in the outward and sideward directions, in 034906-2 FREEZE-OUT DYNAMICS VIA CHARGED KAON . . . PHYSICAL REVIEW C 88, 034906 (2013) the longitudinal direction the lowest m T value exceeds the expectations from a pure hydrodynamical model prediction.

“…For a set of generated events the correlation function is constructed from same-event and mixed-event pairs [71]. Such a general procedure allows for an easy implementation of experimental cuts, final interaction or Coulomb corrections [72,73] and can be also applied to non-identical particle correlations [74]. The extracted multidimensional correlation functions are parameterized by the Bertsch-Pratt formula [75,76] …”

Section: Particle Spectra Flow Correlation Radiimentioning

confidence: 99%

Rapid hydrodynamic expansion in relativistic heavy-ion collisions

Božek

Wyskiel

2009

Hydrodynamic expansion of the hot fireball created in relativistic Au-Au collisions at √ s = 200GeV in 3 + 1-dimensions is studied. We obtain a simultaneous, satisfactory description of the transverse momentum spectra, elliptic flow and pion correlation radii for different collision centralities and different rapidities. Early initial time of the evolution is required to reproduce the interferometry data, which provides a strong indication of the early onset of collectivity. We can also constraint the shape of the initial energy density in the beam direction, with a relatively high initial energy density at the center of the fireball.