Azimuthal correlations of photons produced at mid-rapidity in 200 A GeV S + Au collisions have been studied using a preshower photon multiplicity detector in the WA93 experiment. The Fourier ...expansion method has been employd to estimate the event plane via the anisotropy of the event as a function of centrality. The event plane correlation technique has been used to determine the true event anisotropy, beyond the anisotropy which arises due to finite multiplicity. The VENUS event generator with rescattering and proper simulation of the detector response can explain only a portion of the observed anisotropy. The residual anisotropy is found to be of the order of 5% for semi-central collisions. This suggests that directed collective flow of the produced particles is present at SPS energies.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The cross section and decay angular distributions for the coherent {phi}-meson photoproduction on the deuteron have been measured for the first time up to a squared four-momentum transfer t=(p{sub ...{gamma}}-p{sub {phi}}){sup 2}=-2 GeV{sup 2}/c{sup 2}, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are compared with predictions from a rescattering model. In a framework of vector meson dominance, the data are consistent with the total {phi}-N cross section {sigma}{sub {phi}}{sub N} at about 10 mb. If vector meson dominance is violated, a larger {sigma}{sub {phi}}{sub N} is possible by introducing a larger t slope for the {phi}N{yields}{phi}N process than that for the {gamma}N{yields}{phi}N process. The decay angular distributions of the {phi} are consistent with helicity conservation.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
We searched for the Phi--(1860) pentaquark in the photoproduction process off the deuteron in the Xi- pi- decay channel using CLAS. The invariant mass spectrum of the Xi- pi- system does not indicate ...any statistically significant enhancement near the reported mass M = 1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90% confidence level upper limit of 0.7 nb for the photoproduction cross section of Phi--(1860) with a consecutive decay into Xi- pi- in the photon energy range 4.5 GeV < Egamma < 5.5 GeV.
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