Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at sqrts(NN)=130 GeV, have been analyzed by the STAR Collaboration using ...three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.
We present the first measurements of charge-dependent correlations on angular difference variables η1−η2 (pseudorapidity) and ϕ1−ϕ2 (azimuth) for primary charged hadrons with transverse momentum ...0.15⩽pt⩽2 GeV/c and |η|⩽1.3 from Au–Au collisions at sNN=130 GeV. We observe correlation structures not predicted by theory but consistent with evolution of hadron emission geometry with increasing centrality from one-dimensional fragmentation of color strings along the beam direction to an at least two-dimensional hadronization geometry along the beam and azimuth directions of a hadron-opaque bulk medium.
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