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Introduction Theory survey Charmed Pentaquark Charmed Pentaquark from B decays

Physics of Pentaquarks. Su Houng Lee Yonsei Univ., Korea. Introduction Theory survey Charmed Pentaquark Charmed Pentaquark from B decays. References: Y. Oh, H. Kim, Y. Kwon, S.H.Lee, : PRD, PLB’s S.H.Lee,k Y. Kwon : charmed pentaquark: in preparation.

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Introduction Theory survey Charmed Pentaquark Charmed Pentaquark from B decays

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  1. Physics of Pentaquarks Su Houng Lee Yonsei Univ., Korea • Introduction • Theory survey • Charmed Pentaquark • Charmed Pentaquark from B decays References: Y. Oh, H. Kim, Y. Kwon, S.H.Lee, : PRD, PLB’s S.H.Lee,k Y. Kwon : charmed pentaquark: in preparation

  2. Introduction 1. LEPS coll., Nakano et.al. PRL 91 012002 (2003) Mass= 1.54 GeV , width <25 MeV , quark content= uudds

  3. Verification 2. Verification by other group

  4. 4. NA49 hep-ex/0310014 found X*(1862) in X- p- (ddss u) with width< 18 MeV 3. CLAS finds no Q++ in K+ P invariant mass  Q+(udud s) belongs to anti-decuplet

  5. Baryon Reprsentation Y d u I3 3 s • D(1232) • *(1383) X*(1532) W(1673) • (1540) X(1862) 10 N(939) S(1190) L(1115) X(1320) N ? S ? 8 10

  6. Heavy Pentaquarks (udud c) 1. H1 collaboration (Deep Inelastic scattering) Qc(3099) was found in D* p (uudd bar(c)) with width= 12+-3 MeV 2. Could not confirm in subsequent experiments CDF, ZEUS, FOCUS

  7. Experimental summary 1. Q+ controversial mass 1540 MeV> KN threshold (1435 MeV) 2. Qc+ controversial search was done with DN D*N final state (unbound) > 2800 MeV + e

  8. Theory review Soliton model + Quark model (biased and limited)

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

  10. 3. With constraint coming from WZ term 1. only SU(3) representations containing Y=NcB/3+S= Nc /3 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 mass= 1540, width=30 MeV

  11. Quark models Negative parity if all the quarks are in the lowest s-state But with this simple picture, it is not easy to understand small width Positive parity if a relative p wave • Karlinear, Lipkin • diquark: C=3,F=3,S=0 • triquark: C=3,F=6,S=1/2

  12. Positive parity if a relative p wave 2. Jaffe, Wilczek L=0, S=1/2 L=1  J=1/2 and 3/2 (higher mass)

  13. But, a closer look revealed puzzles

  14. Naive Solition model should fail (T. Cohen) 1. Soliton picture is valid at large N_c: 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 N_c Quantization constraint requires • Octet • Decuplet • Anti decuplet • (lowest representation containing s=1)

  15. 3. Mass splitting in large N_c: 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 naïve soliton quantization might be wrong

  16. Bound state approach for SU(3) soliton 1. SU(2) soliton+ Kaon 2. Successful for hyperon (attractive (s qbar) ) but no pentaquark (repulsive q sbar) from WZ term

  17. Summary of Solition approach for Q+ (ududs) 1. SU(3) Soliton Inconsistent application Can not be applied to heavy pentaquark Qc(ududc) 2. Bound state approach No bound Q+ predict a bound heavy pentaquark Qc(ududc) ie. mass is smaller than DN continuum Quark model also predict a bound heavy pentaquark Qc(ududc) but no light pentaquark Q+(ududs)

  18. Color spin interaction quark model

  19. Quark-antiquark, or Quark-Quark attaction 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

  20. Color spin interaction explains hadron spectrum Nucleon u u d Color anti-triplet Spin index  sym  s=1 In perturbative QCD 3CB=CM = 635 MeV x ( mu )2

  21. Why there should be a heavy pentaquark 1. For Pentaquark L=0, S=1/2 L=1 2. If recombined into a D meson and Nucleon

  22. Summary of Theory for Pentaquark 1. The only consistent Soliton approach predict only heavy pentaquark 2. Constituent quark model also predict only heavy pentaquark may explain null result for light pentaquark Could not observe heavy pentaqurk from DN finla state because it might be bound Heavy pentaquark can only be observed from Weak decay May be from B factory? But do we have sufficient data and can one conclude anything if one tries?

  23. Anti-Charmed pentaquark from B decays

  24. Can we understand Baryonic decay mode of B+ 1. Baryonic decay mode 2. Can we explain it using Dominant hadronic decay mode

  25. Baryonic decay mode of B+ Coupling ? Form factor? 1. Baryonic decay mode in hadronic language

  26. Effective hadronic Lagrangian for heavy hadrons Photo production of open charm, W.Liu, C.M.Ko, SHLee (03) NPA

  27. Baryonic decay mode of B+ 13.5 1. Baryonic decay mode in hadronic language Obtain branching ratio of experimental measurement

  28. Pentaquark decay mode of B+ Coupling=1 Using hadronic interactions as before, we find the branching ratio to be Branching ratio 0.092 Qc Total events

  29. Summary • Theory predicts no stable light pentaquark, but bound heavy pentaquark  might explain present null results 2. Baryonic decay mode of B+ can be sensibly estimated wit previously determined hadronic parameters • With present B+ data, can measure Qc from  If found the first exotic ever, will tell us about QCD and dense matter  color superconductivity

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