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Is There A Q ++ State? & RHIC – Exotic Factory !

Is There A Q ++ State? & RHIC – Exotic Factory !. Huan Z. Huang Department of Physics and Astronomy University of California, Los Angeles Thanks: Jingguo Ma, An Tai, Haibin Zhang and Sevil Salur. Outline. Pentaquark q +  nK + or pK S Is There a Q ++ ?

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Is There A Q ++ State? & RHIC – Exotic Factory !

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  1. Is There A Q++ State? & RHIC – Exotic Factory ! Huan Z. Huang Department of Physics and Astronomy University of California, Los Angeles Thanks: Jingguo Ma, An Tai, Haibin Zhang and Sevil Salur

  2. Outline • Pentaquark q+ nK+ or pKS • Is There a Q++ ? • What may be the implication on production mechanism? • RHIC – an exotic particle factory!

  3. Q+ Spring-8 Result M = 1.540.01 GeV G < 25 MeV Gaussian significance 4.6s Q+ • + C(n/p)  K- K+ (n/ p) Cuts: no fK+K- no recoil p (gn only) Missing mass for n PRL 91, 012002 (2003)

  4. CLAS/JLAB Results g d → p K+ K-n g p → n K+ K- p+ • M = 15425 MeV • < 21 MeV 5.2 s • M = 155510 MeV • < 26 MeV 7.8 s Phys. Rev. Lett. 92, (2004) 032001 Phys.Rev.Lett.91, (2003) 252001

  5. Many Experiments Confirm Q+ *Gaussian statistical significance: estimated background fluctuation

  6. CDF p + p Very High Energy HERA-B p + A sqrt(s) 42 GeV Inclusive SPHINX p + C sqrt(s) 11.5 GeV Exclusive QK hep-ex/0407026 BES BaBar e+ + e- collisions ALEPH DELPHI Many Experiments with Null Results Noticeably (biased list)

  7. ICHEP04 Result • bump ~1480 MeV/c2 Q+K0p = (4.2+-0.9+1.2-0.9)% L ZEUS Result ??? No Q++pK+ was observed!

  8. Q+ Exotic Baryon D. Diakonov, V. Petrov, and M. Polyakov, Z. Phys. A 359 (1997) 305. • Exotic: S=+1 • Low mass: 1530 MeV • Narrow width: ~ 15 MeV • Jp=1/2+ Isospin = 0 M = [1890-180*Y] MeV

  9. Is There a q++ State (I=1, Instead 0)? The SAPHIR Collaboration at ELSA

  10. Is There a q++ State (I=1, Instead 0)? CLAS Results No signal in gpK-(K+p) channel The production of q++is not favored in photon reactions if the assumed mechanism for q production is correct !

  11. Magnet Coils Central Trigger Barrel (CTB) ZCal Time Projection Chamber (TPC) Year 2000 Barrel EM Cal (BEMC) Silicon Vertex Tracker (SVT)Silicon Strip Detector (SSD) FTPCEndcap EM CalFPD TOFp, TOFrYear 2001+ The STAR Detector DAQ: currently running at ~100x design rate for TPC

  12. Particle identification Particle Identification: dE/dx from TPC Future TOF Upgrade significantly enhances STAR PID

  13. STAR Pentaquark Searches X--  X- + p- (NA49 pentaquark state) N  L + KS Q+  p + KS Q++  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<75cm) d + Au 200 GeV run 3 (18.4 M) Au + Au 63 GeV run 4 (5.1 M) STAR can make an important contribution in this area !!

  14. A Stringent Limit from HERA-B HERA-B hep-ex/0408048 sqrt(s) 42 GeV pA (C,Ti,W) 200 M inelastic events q+/L <0.92%; 95%CL q+/L(1520) <2.7%; 95% CL Does this imply L(1520)/L ~ 34%? The Q++/L ratio should be small !

  15. D. Diakonov et al. (chiral quark soliton) Naive quark model S. Capstick et al. (isotensor formulation) Fl. Stancu, D.O. Riska (qq with p int.) A. Hosaka (chiral potential) M. Karliner et al.(qq-qqq) R. L. Jaffe et al. (qq-qq-q : 10 + 8) J. Sugiyama et al. (QCD sum rule) F. Csikor et al. (Lattice QCD) S. Sasaki (Lattice QCD) : 1/2+, I=0 : 1/2- : 1/2-, 3/2-, 5/2-, I=2 : 1/2+ : 1/2+ (strong p) : 1/2+, I=0 : 1/2+, I=0 : 1/2-, I=0 : 1/2+->1/2-, I=0 : 1/2-, I=0 Some Theory publications since 2003 ( Mass, width, Spin, Parity, Production mechanism, Partners… Q++implies I=1 and possibly invalids all these models ! Ohashi/Spring-8

  16. Possible Q+ Hadro-Production Reactions Q+ Q+ Coalescence or Secondary Production of q e+e- is not favored (deuteron is a good measure of sensitivity) very high energy (CDF) is not favored very violent collisions (central Au+Au, e.g.) not favored K+n and K+p experiments should be done again at appropriate energy !

  17. Q+ Possible Q+ Photo-Production Reactions CLAS/JLAB LEPS/SPring-8 Q+ Exclusive Channels ! Explains no Q++ in gpK-K+p

  18. Pentaquark or Molecule? If q state has isospin I = 1, there will be q0 n + KS Critical confirmation for I = 1 !! The structure of the q  NpK or DK molecule state cannot be ruled out ! A critical test of experimental sensitivity is the production of deuterons  how many (anti-)deuterons have been seen in CDF and e+e collisions?

  19. RHIC – Exotic Particle Factory • RHIC – Dense Partonic Matter and • Rapid Hadronization • Unique Production Mechanism for Possible Exotic Particles • Exotic Mesons, Pentaquarks, Di-baryons [WW] and Strangelets

  20. STAR PHENIX Empirical Quark Scaling in RAA and v2 Baryon Meson Constituent (n) Quark Scaling -- Meson n=2 and Baryon n=3 grouping Saturation of v2 at Intermediate pT

  21. PRL 92 (2004) 052302; PRL 91 (2003) 182301 Hadronization of Bulk Partonic Matter At hadron formation time there is a collective v2 among constituent quarks Recombination/coalescence provides a hadronization scheme (not necessarily related to partonic matter, works for d+Au) Possible geometrical nature of v2 saturation – surface emission

  22. Volcanic mediate pT – Spatter (clumps) Clustering and Surface Emission Enhancement of Clusters at intermediate pT ! Search for Multi-quark (>3) Cluster State at RHIC !

  23. RHIC – Exotic Particle Factory STAR – Exciting Physics Program A full TOF and Heavy Flavor Tracker upgrade will greatly enhance STAR’s capability !! Heavy Flavor Tracker Using Active Pixel Sensor two layers of thin silicon detector 1.5 cm and 4 cm radius Charmed Exotics?! Full Barrel TOF Using MRPC

  24. Exotic Particles Hadrons with internal structure beyond existing QCD qqq and q-qbar framework !! RHIC – Dedicated QCD Machine & Beyond Exotic (Deconfinement Phase Transition) AA AA pp pA pp pA (CGC,EMC) (spin)

  25. The End

  26. Embedding Theta++ Invariant Mass Kaon Momentum Proton Momentum Opening Angle ++ : Flat in rapidity –0.8<y<0.7 Flat in pt 0.4<pt<1.2

  27. ZEUS Result No Q++pK+ was observed! Why Q+, not Q++ ? Charge ordering in jet fragmentation? ???

  28. Au + Au Collisions at RHIC STAR Central Event (real-time Level 3)

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