Introduction for Exotics Hadron production in HIC Exotics from RHIC

1. Hadron Physics at RHIC Su Houng Lee Yonsei Univ., Korea • Introduction for Exotics • Hadron production in HIC • Exotics from RHIC Thanks to: Former collegues and students Present students: Y. Park, Y. Sarac, Y. Heo, K. Kim Post doc: K. Ohnishi

2. Introduction for Exotics

3. Definition of Exotics • Hadrons that can not be explained by quark-antiquark, or 3 quarks • That are bound by strong interaction • Reasons for its search are similar to that for superheavy Element in low energy nuclear Physics •  Understand QCD sQGP

4. Experiment - First claim 1. LEPS coll., Nakano et.al. PRL 91 012002 (2003) Mass= 1.54 GeV , width <25 MeV , quark content= uudds

5. Experiment - Recent claim In Carbon target , but

6. Positive results Negative results Recent CLAS experiments find no Q+ in g+d or g+p  Give up, more experiment or theoretical guideline?

7. Theory : prediction (Diakanov, Petrov, Polyakov 97) 1. SU(3) soliton I=J Hedghog 2. Quantizing the 8 angles, the Hamiltonian becomes

8. 3. With constraint coming from WZ term 1. only SU(3) representations containing Y=1 are allowed moreover, the number of states 2I+1 at S=0 or Y= Nc/3 must determine the spin of the representation through 2J+1 because I=J in the SU(2) soliton  one spin state for given representation 4. Diakanov Petrov Polyakov applied it toAnti-decuplet which predicted MQ= 1540, GQ=30 MeV

9. Theory: why it can be wrong (T. Cohen) 1. Soliton picture is valid at large Nc: Semi-classical quantization is valid for slow rotation: ie. Valid for describing excitations of order 1/N_c, so that it does not mix and breakdown with vibrational modes of order 1 2. Lowest representation SU(3)f (p,q)at large Nc Quantization constraint requires • Octet • Decuplet • Anti decuplet • (lowest representation containing s=1)

10. 3. Mass splitting in large Nc: Anit decuplet octet mass splitting is mixes with vibrational mode and inconsistent with original assumption and has undetermined correction of same order  Rotation is too fast and may couple to vibrational modes, which might be important to excite q qbar mode, hence describing anti decuplet state with naive soliton quantization might be wrong

11. Theory: Quark model of a pentaquark Strong diquark correlation Karlinear, Lipkin model u d diquark: C=3,F=3,S=0 triquark: C=3,F=6,S=1/2 s u d Jaffe, Wilczek model u d 2 diquark: C=3,F=3,S=0 relative p wave s d u

12. Color Spin Interaction in QCD 1. In QCD q-q are also attractive if in color anti-triplet channel. In perturbative QCD, 2CB=CM This term is called color spin interaction

13. Color spin interaction explains hadron spectrum u u d Nucleon Baryon Mass difference Meson Mass difference Works very well with 3CB=CM = constant

14. Why there should be a heavy pentaquark 1. For a charmed Pentaquark c 3. If recombined into a D-meson and a Nucleon c 1. For a Pentaquark u u s d d 2. If recombined into a Kaon and a Nucleon u u d s d

15. Other possible states - Tetraquark 1. For a Tetraquark 2. For the meson and meson u d A u B A B d DD- BB-

16. Where to search: Baryonic decay mode of B+ decay in hadronic language Larger By Nc

17. Pentaquark decay mode of B+ Weak decay Branching ratio is 0.092 Qc lower limit in B-factory Can search for it in Belle S.H.Lee. Y. Kown. Y. Kwon , PRL (06) Using pevious fit, we find the branching ratio to be 14.4x10-7 gDpL x gKpQ/gKpL

18. Hadron Production in HIC

19. Success of statistical model P. Braun-Munzinger, J. Stachel (95 …)

20. Recent Star data - I

21. Theoretical Explanation – Muller, Kanada-En’yo u d s Quark Coalescence model = Statitical model + overlap integral QGP u u s d d s

22. Statistical model = quark coalescence + overlap Explicit example Exotic production in HIC will follow statistical model modified only by the wave function overlap integral and hadronic phase

23. Exotic particle production: elementary vs HIC Exotic particle production from elementary processes Exotic particle production from Heavy Ion collision Q+ QGP u u u u s s d d d d

24. Example Q+(1540) production in Au+Au at RHIC in central rapidity region Statistical model J. Randrup, PRC 68 (2003) 031903, NQ =1 Coalescence model Chen, Greco, Ko, Lee, Liu, PLB 601 (2004) 34, NQ =0.2 Hadronic regeneration or dissociation is not so large

25. Exotics from RHIC • RHIC (STAR)FAIR (GSI)

26. Possible Decay mode of charmed Pentaquark Q+ u u c d d L=1

27. Rough estimate of events at RHIC Q+ u u c d d Central collision (0-10%) dNcc/dy = 2.2 (phenix)

28. Possible Decay mode of Tetra-quark u d c c

29. Who can do it : STAR collaboration?

30. Who can do it : FAIR ?

31. Summary • While controvery exist over light pentaquark, Many Theories consistently predict bound heavy pentaquark 2. Quark model also predict metastable tetraquark • RHIC can be a very useful exotic factory  If found the first exotic ever, will tell us about QCD and dense matter  color superconductivity

32. References • Experiments • T. Nakano , Phys. Rev. Lett. 91 (03) 012002. • K.~H.~Hicks, Prog. Part. Nucl. Phys. 55 (05) 647. • Skyrme model controversy • T.D.Cohen, Phys. Lett. B 581 (04) 175 • H. Walliser and H. Weigel, Eur. Phys. J. A 26 (05) 361. • D.Diakonov, V.Petrov and M.V.Polyakov, Z. Phys.A 359 (97) 305 • Theory • H. J. Lipkin, Phys. Lett. B 195 (87) 484. • Fl. Stancu, Phys. Rev. D 58 (98) 111501. • D. O. Riska, N. N. Scoccola, Phys. Lett. B 299 (93) 338. • Y.Oh, B.Y. Park, D.P. Min, Phys. Lett. B 331 (94) 362. Phys. Rev. D 50 (94) 3350. • R.L.Jaffe, F.Wilczek, Phys. Rev.Lett. 91(2003) 232003. • present work • H. Kim, Y. Oh, S.H.Lee, PLB 595 (04) 293: • Y. Sarac, H.Kim, S.H.Lee, PRD 73 (06) 014009 • S.H.Lee, Y. Kown, Y. Kown, PRL 96 (06) 102001