2004/03/10 by Mikhail Kopytine, M. Kopytine, Kopytine, Mikhail
Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Experiment (nucl-ex) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #nucl-ex
paper · pdf · doi:10.48550/arxiv.nucl-ex/0403011
4 pages, 5 figures, presented as a poster at the 17th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter 2004)
arxiv created 2004/03/10 · openalex publication_date 2004/03/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Medium effects on charged-particle production are studied using three analysis techniques. We find angular collinearity and number correlations on pt at moderate pt<3 GeV/c. In this pt range abundant multiplicities enable precision measurements of correlations of non-identified hadrons for kinematic variables (pt,η,ϕ). Methods include (1) direct construction of two-particle correlation functions, (2) inversion of the bin-size dependence of non-statistical multiplicity fluctuations and (3) two-dimensional discrete wavelet analysis. Two-particle correlations on pt exceed expectations from a model of equilibrated events with fluctuating global temperature. A correlation excess at higher pt is interpreted as final-state remnants of initial-state semi-hard collisions. Lower-pt correlations exhibit a saddle structure varying with centrality. Variations in the forms and strengths of low and high pt correlations with centrality suggest transport of semi-hard collision products into the lower pt region as a manifestation of in-medium dissipation of minijets. Correlations on pt can be associated with angular correlations on (η,ϕ), using analysis methods (1), (2) or (3). In particular, wavelet analysis (3) is performed in the (η,ϕ) space in bins of pt (<2 GeV/c). Observed angular correlation structures include those attributed to quantum correlations and elliptic flow, as well as a localized structure, increasing in amplitude with pt, and presumed to originate with minijets. That structure evolves with increasing centrality in a way which also suggests dissipation, including an increased correlation length on η which may be related to the influence of a longitudinally expanding medium on minijet fragmentation.