An analysis of inclusive pion production in proton-beryllium collisions at 6.4, 12.3, and 17.5 GeV/c proton beam momentum has been performed. The data were taken by Experiment 910 at the Alternating Gradient Synchrotron at the Brookhaven National Laboratory. The differential pi(+) and pi(-) production cross sections (d(2)sigma/dpd Omega) were measured up to 400 mrad in theta(pi) and up to 6 GeV/c in p(pi). The measured cross section was fit with a Sanford-Wang parametrization.

Source images extracted from two-particle correlations were constructed from strange and nonstrange hadrons produced in 6A GeV Au+Au collisions. Small-angle correlations for pλ, pp, and π-π - pairs produced in 6A GeV Au+Au reactions were also measured. The pp and π-π- pairs reflect a small homogeneity length caused by flow focusing the source.

Differential cross-sections are presented for the inclusive production of charged pions in the momentum range 0.1 to 1.2 GeV/c in interactions of 12.3 and 17.5 GeV/c protons with Be, Cu, and Au targets. The measurements were made by Experiment 910 at the Alternating Gradient Synchrotron in Brookhaven National Laboratory. The cross-sections are presented as a function of pion total momentum and production polar angle $\theta$ with respect to the beam.

The E895 experiment at the AGS measured strange particle production and collective behavior in An + Au collisions between 2-8 AGeV. The production of A Baryons: and K-0 Mesons as a function of energy rises smoothly and exhibits a nonlinear impact: parameter dependence. Neutral and positively charged Kaons exhibit a strong anti-flow behavior. A Baryons show a smaller flow signal than protons.The production of strange particles in relativistic heavy, ion collisions is an important probe for high density nuclear matter. Of particular interest are suggestions that strange particle yields can be used to investigate the nuclear equation of state [1] or possible signatures of a change of the in-medium mass [2]. The flow effects of strange particles offer a good probe for their in-medium potentials [3,4].Motivated by these suggestions the E895 collaboration has performed an extensive set of measurements at the Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratory. These measurements were performed for Au+Au collisions in a beam energy range of 2-8 AGeV. Charged reaction products were detected in the EOS Time Projection Chamber (TPC) [5] situated in a uniform magnetic field. The TPC provides continuous 3D tracking and particle identification for charged: particles (-1 less than or equal to Z less than or equal to 6) with full azimuthal coverage. The method of identification via the rigidity of the track and the energy loss in the TPC gas leads to ambiguities for certain rigidities, thus restricting the identification of charged kaons to low transverse momenta at backward rapidities. This restriction does not affect our neutral strange particles measurements (A Baryons and K-s(0) Mesons) which were reconstructed from their charged decay products by means of a neural network [6-8].

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-p correlation function.

We report a particle source imaging analysis based on two-pion correlations in high multiplicity $\mathrm{Au}+\mathrm{Au}$ collisions at beam energies between $2A$ and $8A\mathrm{GeV}$. 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 Hanburg-Brown--Twiss analysis.

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, $ _{L}$, as a function of the logarithm of beam energy.

Inclusive and semi-inclusive measurements are presented for antiproton ((p) over bar) production in proton-nucleus collisions at the Alternating Gradient Synchrotron (AGS), The inclusive yields per event increase strongly with increasing beam energy and decrease slightly with increasing target mass. The (p) over bar yield in 17.5 GeV/c p +Au collisions decreases with grey track multiplicity. N-g, for N-g>O, consistent with annihilation within the target nucleus. The relationship between N-g and the number of scatterings of the proton in the nucleus is used to estimate the (p) over bar annihilation cross section in the nuclear medium, The resulting cross section is at least a factor of 5 smaller than the free (p) over bar -p annihilation cross section when assuming a small or negligible formation time. Only with a long formation time can the data be described with the free (p) over bar -p annihilation cross section.

The first detailed measurements of the centrality dependence of strangeness production in p-A collisions are presented. Lambda and K(S) dn/dy distributions from 17.5 GeV/ c p-Au collisions are shown as a function of "grey" track multiplicity and the estimated number of collisions, nu, made by the proton. The nu dependence of the Lambda yield deviates from a scaling of p-p data by the number of participants, increasing faster than this scaling for nu=5 and saturating for larger nu. A slower growth in K(S) multiplicity with nu is observed, consistent with a weaker nu dependence of K&Kmacr; production than YK production.

Experiment E910 has measured slow protons and deuterons from collisions of 18 GeV/c protons with Be, Cu, and Au targets at the BNL AGS. These correspond to the "grey tracks" first observed in emulsion experiments. We report on their momentum and angular distributions and investigate their use in measuring the centrality of a collision, as defined by the mean number of projectile-nucleon interactions. The relation between the measured N-grey and the mean number of interactions <(nu)over bar>(N-grey) is studied using several simple models, one newly proposed, as well as the RQMD event generator. RQMD is shown to reproduce the N-grey distribution, and exhibits a dependence of N-grey on centrality that is similar to the behavior of the simple models. We find a strong linear dependence of N-grey on nu, with a constant of proportionality that varies with target. For the Au target, we report a relative systematic error for extracting <(nu)over bar>(nu)over bar>(N-grey) that lies between 10 and 20 % over all N-grey. [S0556-2813(99)02508-X].

A method for plasma delay and pulse-height defect corrections for Si surface barrier detectors (SBD) is presented. Based on known empirical formulae, simple approximations involving the measured time of flight (TOF) and energy of the ions were found and a mass reconstruction procedure was developed. The procedure was applied for obtaining the fission fragment mass and angular distributions from the 64Ni+197Au reaction at 418 and 383 MeV incident energy using an array of eight SBDs.

Fission fragment mass and angular distributions were measured from the ^{64}Ni+^{197}Au reaction at 418 MeV and 383 MeV incident energy. A detailed data analysis was performed, using the one-body dissipation theory implemented in the code HICOL. The effect of the window and the wall friction on the experimental observables was investigated. Friction stronger than one-body was also considered. The mass and angular distributions were consistent with one-body dissipation. An evaporation code DIFHEAT coupled to HICOL was developed in order to predict reaction time scales required to describe available data on pre-scission neutron multiplicities. The multiplicity data were again consistent with one-body dissipation. The cross-sections for touch, capture and quasi-fission were also obtained.

In Experiment 910 at the Brookhaven National Laboratory AGS accelerator, we studied proton-nucleus collisions in a large-acceptance, TPC-based spectrometer using a variety of target/beam energy combinations. The experiment was designed to study strange particle production in proton-nucleus collisions and has excellent acceptance for neutral strange particles decaying at least 1 cm downstream of the target. The E910 spectrometer also has good sensitivity to Lambda p pi(-) decays and modest sensitivity to Sigma(-)p decay channels of the hypothesized H dibaryon. Preliminary results on the centrality dependence of Lambda production in 18 GeV p+Au collisions are presented along with results of our first search for H --> Lambda p pi(-) and H --> Sigma(-)p decays in the 18 GeV/c p+Au data set.

Using a relativistic hadron transport model, we investigate the utility of the elliptic flow excitation function as a probe for the stiffness of nuclear matter and for the onset of a possible quark-gluon-plasma (QGP) phasetransition at AGS energies 1 < EBeam < 11 AGeV. The excitation function shows a strong dependence on the nuclear equation of state, and exhibits characteristic signatures which could signal the onset of a phase transition to the QGP.

The mean transverse kinetic energies of the fragments formed in the interaction of 1 A GeV Au+C have been determined. An energy balance argument indicates the presence of a collective energy which increases in magnitude with increasing multiplicity and accounts for nearly half of the measured mean transverse kinetic energy. The radial flow velocity associated with the collective energy yields estimates for the time required to expand to the freeze-out volume. Isentropic trajectories in the temperature-density plane are shown for the expansion and indicate that the system goes through the critical region at the same multiplicities as deduced from a statistical analysis. Here, the expansion time is approximately 70 fm/c.