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Inclusive four charm hadron production at Belle

Inclusive four charm hadron production at Belle. JUNGIL LEE. June 16-20, 2005 International Conference on QCD and Hadronic Physics, Beijing. Outline. Brief Review on NRQCD and quarkonium physics Belle measurement of s [e + e -  J/ y h c ]

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Inclusive four charm hadron production at Belle

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  1. Inclusive four charm hadron production at Belle JUNGIL LEE June 16-20, 2005 International Conference on QCD and Hadronic Physics, Beijing

  2. Outline • Brief Review on NRQCD and quarkonium physics • Belle measurement of s[e+e- J/yhc] • Previous trials to resolve the large discrepancy between theory and data • A test by using four charm hadron final state • Discussion JUNGIL LEE, Korea University

  3. Brief Review on NRQCD

  4. NRQCD is an Effective Field Theory of QCD that describes Heavy Quarkonium NRQCD[Bodwin,Braaten,Lepage,PRD(‘95)] describes Quarkonium from first principles. NRQCD solved the problem of Infra-Red Divergencies in the Color-Singlet Model [Bodwin,Braaten,Lepage,PRD(‘92)] JUNGIL LEE, Korea University

  5. Experimental Verification of NRQCD Factorization Following the theoretical success that solved the Infra-Red Divergence problem, theorists applied NRQCD to issues on quarkonium decays and productions. The first experimental success of NRQCD in quarkonium production was at the Fermilab Tevatron. JUNGIL LEE, Korea University

  6. Tevatron Anomaly, resolved by NRQCD As an effective field theory of QCD, NRQCD replaced a 20-year-old phenomenological model at the Fermilab Tevatron. Braaten,Fleming(’95) JUNGIL LEE, Korea University

  7. J/y Polarization confronts NRQCD? According to NRQCD, J/y produced at large pT must be transversely polarized. However, CDF measurement seems to contradict the prediction. People have been curious about the reason. JUNGIL LEE, Korea University

  8. Lattice NRQCD calculation of Polarized matrix elements Lattice NRQCD calculation to estimate the spin-flip interaction by directly calculating non-perturbative matrix elements from first principles. Bodwin, Lee, Sinclair, hep-lat/0503032 Geoff Bodwin, Plenary Talk June 20, 3:50PM IT’S experimentalists’ (CDF/D0) TURN!  Hopefully with large statistics by a factor 20. JUNGIL LEE, Korea University

  9. Chiral perturbation theory and QuarkoniumPolarization • In Upsilon(3S)  Upsilon(1S), final quarkonium • Polarization is not described by QCD multipole expansion, but by chiral perturbation theory. • We apply the same idea to gluon fragmenation • into spin-triplet quarkonium states. • P. Ko, J. Lee, T. Kim, • Pyungwon Ko, Parallel session (Hall B) June 17, 2:30PM JUNGIL LEE, Korea University

  10. Belle J/y hc Anomaly

  11. B factories at KEK-B & SLAC * Collider : e+e- EC.M.=10.6GeV[U(4S)] * Detectors: KEK-B Belle, SLAC BaBar Main Goal CP violation in BJ/y Ks Remarkable QCD Results from Belle * Measured s(J/y hc ): Large discrepancy between theory & data * Discoveries: hc(2S), X(3872)[J/y p+p-] JUNGIL LEE, Korea University

  12. Exclusive e+e- J/yhc • Precision measurement R=s/smm~ 10-7 << Rhadron ~ 3.6 High-luminosity B factories • Theory is clear Exclusive  Color-singlet Only Long-distance factors are well determined through J/y e+e-, hc gg JUNGIL LEE, Korea University

  13. Belle Puzzle, Crisis of pQCD??? Braaten, Lee, PRD 67 (2003) Liu, He, Chao, PLB 557 (2003) JUNGIL LEE, Korea University

  14. Suggestions & a new Belle analysis People thought that J/y J/y is forbidden BUT … Gexp.~110MeV MJ/y -Mhc ~120MeV  Signals may include J/y J/y! JUNGIL LEE, Korea University

  15. New Belle Analysis • Did NOT see J/y J/y • Upper limit compatible with theory • Puzzle: s[J/yhc] ~ s[J/y J/y]. Why are ONLY J/yhc events seen? • Failure of pQCD factorization? • New Production Mechanism? • Or NEW PARTICLES? JUNGIL LEE, Korea University

  16. e+e- J/y GJ possibility? • Glue-rich process g*(Q2)J/y+gg • Safe factorization Q2 >> MG • B-factory can probe wider mass range • pQCD factorization[Brodsky,Lepage] for GJ • NRQCD factorization for J/y • Same order in as as g*(Q2)J/y+hc JUNGIL LEE, Korea University

  17. A scenario Brodsky,Goldhaber,Lee PRL91(2003) Signals may include J/y + Glueball. Belle angular distribution is compatible with Spin-2 glueball. Still to be studied JUNGIL LEE, Korea University

  18. What aboutFour D mesons ?

  19. Why 4 D final state? • Similar parton-level process  check if perturbative corrections are large • Quark hadron duality Inclusive four-charm-hadron production JUNGIL LEE, Korea University

  20. Perturbative Calculation JUNGIL LEE, Korea University

  21. DD final state study • Experimentally, inclusive production of 2 charmed hadrons can be measured with a large number of events. • By comparing the measured value with the LO QCD prediction, we can estimate if the NLO correction is large enough to explain the puzzle. JUNGIL LEE, Korea University

  22. Relative rate into charm mesons Spin singlet : Spin triplet = 1 : 3 D+ : D0 : D+* : D0* = 1 : 1 : 3 : 3 Branching fractions spin-triplet states Relative rate into 2 charm mesons D+D+ : D+D0 : D0 D0 =1 : 6 : 9 JUNGIL LEE, Korea University

  23. Br(D+ K-++)=9.2% Br(D0 K-+)=3.8% Predicted 4 charm-hadron envents Events(DD)=X-section(DD)*Br*Eff*Luminosity Efficiency per hadron = 0.8 Luminosity = 300 fb-1 Total Events ≈ 3 0 Belle Analysis is Under way JUNGIL LEE, Korea University

  24. Discussion • Belle results of exclusive two-charmonium production is a serious challenge to perturabtive QCD as well as to NRQCD factorization framework. • BaBar must confirm the Belle results. • Failure of pQCD factorization? • New Particles? New physics? • Study of the 4 charm hadrons final state will provide an independent constraint. • Belle analysis of the 4 charm events is under way. JUNGIL LEE, Korea University

  25. Large nonperturbative effect? • Ma and Si, PRD 70 (2005). • Bonder and Chernyak, PLB 612 (2005). • Braguta, Likhoded, and Luchinsky, hep-ph/0506009. Non-zero kT of the quark inside the meson may increase the cross section. JUNGIL LEE, Korea University

  26. NLO Corrections are Now Available ! ! ! • Zhang, Gao, and Chao, hep-ph/0506076. NLO correction term is as large as 80% of LO term. A large discrepancy between theory and data still exists. Is the perturbation series convergent? JUNGIL LEE, Korea University

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