T. Case

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,

Azimuthal dependence of pion interferometry at the AGS

E_{tr} sim

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

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

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

4 AGeV) where the calculated baryon density

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

rho sim 4 rho_0

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

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Antiflow of K(0)(s) mesons in 6A GeV Au + Au 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.

Results from the experiment E895 at the BNL AGS

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.

Collective flow and particle spectra in relativistic heavy ion collisions

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.

Comparison of source images for protons, [formula presented]’s, and [formula presented]’s in [formula presented] [formula presented] collisions

Proton elliptic flow is studied as a function of impact-parameter