arXiv subjects

E895 Collaboration

Publications and source records attributed to E895 Collaboration.

7 recordsLinked to original sources

arXiv2002

Longitudinal Flow of Protons from 2-8 AGeV Central Au+Au Collisions

Rapidity distributions of protons from central $^{197}$Au + $^{197}$Au collisions measured by the E895 Collaboration in the energy range from 2 to 8 AGeV at the Brookhaven AGS are presented. Longitudinal flow parameters derived using a thermal model including collective longitudinal expansion are extracted from these distributions. The results show an approximately linear increase in the longitudinal flow velocity, $<βγ>_{L}$, as a function of the logarithm of beam energy.

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arXiv2001

Differential Elliptic Flow in 2 - 6 AGeV Au+Au Collisions: A New Constraint for the Nuclear Equation of State

Proton elliptic flow is studied as a function of impact-parameter $b$, for two transverse momentum cuts in 2 - 6 AGeV Au + Au collisions. The elliptic flow shows an essentially linear dependence on b (for $1.5 < b < 8$ fm) with a negative slope at 2 AGeV, a positive slope at 6 AGeV and a near zero slope at 4 AGeV. These dependencies serve as an important constraint for discriminating between various equations of state (EOS) for high density nuclear matter, and they provide important insights on the interplay between collision geometry and the expansion dynamics. Extensive comparisons of the measured and calculated differential flows provide further evidence for a softening of the EOS between 2 and 6 GeV/nucleon.

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arXiv2001

Laying the groundwork at the AGS: Recent results from experiment E895

The E895 Collaboration at the Brookhaven AGS has performed a systematic investigation of Au+Au collisions at 2-8 AGeV, using a large-acceptance Time Projection Chamber. In addition to extensive measurements of particle flow, spectra, two-particle interferometry, and strangeness production, we have performed novel hybrid analyses, including azimuthally-sensitive pion HBT, extraction of the six-dimensional pion phasespace density, and a first measurement of the Lambda-proton correlation function.

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arXiv2001

Model-independent source imaging using two-pion correlations in 2 to 8A GeV Au + Au collisions

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.

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arXiv2000

Azimuthal Dependence of Pion Interferometry at the AGS

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 2-6 AGeV. 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.

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arXiv2000

Sideward Flow in Au + Au Collisions Between 2A GeV and 8A GeV

Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au + Au collisions at beam energies of 2, 4, 6 and 8A GeV are presented in the form of in-plane transverse momentum and the first Fourier coefficient of azimuthal anisotropy v_1. These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none shows a consistent pattern of agreement within experimental uncertainties.

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arXiv2000

Beam Energy Evolution of HBT Systematics at the AGS

We present preliminary results of the first pion interferometry (HBT) excitation function at intermediate AGS energies. The beam energy evolution of the correlations' dependence on mT, centrality, and emission angle with respect to the reaction plane are discussed. Comparisons with predictions of the RQMD cascade model are made.

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