S. Panitkin

Elliptic flow: Transition from out-of-plane to in-plane emission in Au + Au collisions

We have measured the proton elliptic flow excitation function for the Au + Au system spanning the beam energy range 2 -- 8 AGeV. The excitation function shows a transition from negative to positive elliptic flow at a beam energy,

Event anisotropy in high energy nucleus-nucleus collisions

E_{tr} sim

Azimuthal dependence of pion interferometry at the AGS

4 AGeV. Detailed comparisons with calculations from a relativistic Boltzmann-equation are presented. The comparisons suggest a softening of the nuclear equation of state (EOS) from a stiff form (K sim 380 MeV) at low beam energies (E_{Beam} le 2 AGeV) to a softer form (K sim 210 MeV) at higher energies (E_{Beam} ge

Model-independent source imaging using two-pion correlations in (2 to 8)a GeV Au+Au collisions.

4 AGeV) where the calculated baryon density

Comparison of source images for protons, pi-'s, and lambda's in 6A GeV Au+Au collisions.

rho sim 4 rho_0

Centrality and momentum-selected elliptic flow: Tighter constraints for the nuclear equation of state

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Model-Independent Source Imaging Using Two-Pion Correlations in (2 to 8)A GeV Au

The predictions of event anisotropy parameters from transport model RQMD are compared with the recent experimental measurements for 158A GeV Pb+Pb collisions. Using the same model, we study the time evolution of event anisotropy at 2A GeV and 158A GeV for several colliding systems. For the first time, both momentum and configuration space information are studied using the Fourier analysis of the azimuthal angular distribution. We find that, in the model, the initial geometry of the collision plays a dominant role in determining the anisotropy parameters.

Deuterons and space-momentum correlations in high energy nuclear collisions

Abstract Two-pion correlation functions, measured as a function of azimuthal emission angle with respect to the reaction plane, provide novel information on the anisotropic shape and orientation of the pion-emitting zone formed in heavy ion collisions. We present the first experimental determination of this information, for semi-central Au + Au collisions at 2–6xa0 A GeV. The source extension perpendicular to the reaction plane is greater than the extension in the plane, and tilt of the pion source in coordinate space is found to be opposite its tilt in momentum space.

Imaging proton sources and space-momentum correlations

We report a particle source imaging analysis based on two-pion correlations in high multiplicity Au + Au collisions at beam energies between 2 and 8A GeV. We apply the imaging technique introduced by Brown and Danielewicz, which allows a model-independent extraction of source functions with useful accuracy out to relative pion separations of about 20 fm. The extracted source functions have Gaussian shapes. Values of source functions at zero separation are almost constant across the energy range under study. Imaging results are found to be consistent with conventional source parameters obtained from a multidimensional HBT analysis.

Results from the experiment E895 at the BNL AGS

Source images are extracted from two-particle correlations constructed from strange and nonstrange hadrons produced in 6A GeV Au+Au collisions. Very different source images result from pp vs p Lambda vs pi(-)pi(-) correlations. Scaling by transverse mass can describe the apparent source size ratio for p/pi(-) but not for Lambda/pi(-) or Lambda/p. These observations suggest important differences in the space-time emission histories for protons, pions, and neutral strange baryons produced in the same events.