High Density Matter and Searches for Huan Z. Huang Department of Physics and Astronomy University of California, Los Angeles The STAR Collaboration Outline High Density Matter and Its Hadronization at RHIC Pentaquark Searches in STAR The Puzzle Continues RHIC Exotic Particle Factory RHIC Dense Partonic Matter and Rapid Hadronization Unique Collision Environment for Possible Exotic Particles Formation Exotic Mesons, Pentaquarks, Di-baryons [ and Strangelets Formation of Dense Matter at RHIC 1)Suppression of high pT hadrons in central Au+Au collisions 2) Disappearance of back-to-back high pT jet correlations and the energy dissipation in soft particle production Empirical Quark Scaling in R AA and v 2 STAR PHENIX Baryon Meson Constituent (n) Quark Scaling -- Meson n=2 and Baryon n=3 grouping Saturation of v 2 at Intermediate p T Very different from fragmentation formation scheme !! Hadronization of Bulk Partonic Matter PRL 92 (2004) ; PRL 91 (2003) At hadron formation time there is a collective v 2 among constituent quarks Recombination/coalescence provides a hadronization scheme (not necessarily related to partonic matter, works for d+Au) Possible geometrical nature of v 2 saturation surface emission Clustering and Surface Emission Volcanic mediate p T Spatter (clumps) Enhancement of Clusters at intermediate p T ! (baryons and hyperons) Search for Multi-quark (>3) Cluster State at RHIC ! Au + Au Collisions at RHICSTAR Central Event (real-time Level 3) STAR Pentaquark Searches + p + K S ++ p + K + Data Set: Au + Au 200 GeV run 2 (~1.7 M, 30-80%) p + p data 200 GeV run 2 (~8 M, Z