Forward-backward multiplicity correlations for identified particles at STAR
Abstract
Kinematic observables of charged particles from relativistic heavy-ion collisions are measured in search of quark-gluon degrees of freedom. Long-Range Forward-Backward multiplicity correlations (LRC) may be a signal for multiple partonic interactions in dense matter, as predicted by the Dual Parton Model (DPM), Color String Percolation Model (CSPM), and the Color Glass Condensate (CGC) picture. Previously, a strong LRC for inclusive charged hadrons was measured as a function of pseudorapidity gap (Δη) in Au+Au collisions at [special characters omitted] = 200 GeV, and were shown to decrease with decreasing centrality. In this dissertation, the forward-backward correlation strength is studied with respect to its particle species dependence (pions, kaons, protons and anti-protons), and is measured as a function of rapidity gap (Δy) in Au+Au collisions at [special characters omitted] = 200 GeV. The CGC picture, which describes particle sources as longitudinal flux tubes, predicts that the correlation will grow with centrality. Furthermore, fluctuations in the number of gluons at early times will produce a long range correlation strength significantly larger for pions than for baryons. A strong, long-range (Δy > 1.0) correlation is measured for pions in central Au+Au collisions at [special characters omitted] = 200 GeV, which decreases with decreasing centrality. The measured small short-range correlation compared to pions for protons and antiprotons suggests their long-range component will also be small. The forward-backward multiplicity correlation measurements for identified particles indicate multiple partonic interactions in high-energy, central Au+Au collisions, and the possible formation of the quark-gluon plasma.
Degree
Ph.D.
Advisors
Scharenberg, Purdue University.
Subject Area
Nuclear physics|Particle physics
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