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Implications of the scalar meson structure from B SP decays within PQCD approach

Implications of the scalar meson structure from B SP decays within PQCD approach. Yuelong Shen IHEP, CAS In collaboration with C. D. Lu , W. Wang…. Outline. Motivation Scalar meson production in B decays Numerical results and discussions Conclusion and outlook.

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Implications of the scalar meson structure from B SP decays within PQCD approach

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  1. Implications of the scalar meson structure from B SP decays within PQCD approach Yuelong Shen IHEP, CAS In collaboration with C. D. Lu , W. Wang… 高能物理学会第七届年会@桂林

  2. Outline • Motivation • Scalar meson production in B decays • Numerical results and discussions • Conclusion and outlook References: W. Wang, YLS, Y. Li and C. D. Lu, hep-ph/0609082; YLS, W. Wang, J. Zhu and C. D. Lu, hep-ph/0610380. 高能物理学会第七届年会@桂林

  3. Motivation • Problems in scalar meson spectroscopy • The advantages in study scalar meson in B decays • Annihilation diagrams: Why we use PQCD approach 高能物理学会第七届年会@桂林

  4. Problems in scalar meson spectroscopy • Classification of the multiplets and exotic states • One nonet below and one above 1 GeV The low mass nonet is more likely formed by the states • one nonet above or close to 1 GeV are not physical state • The existence of glueballs Lattice results: the mass of the scalar glueball lies in (1500-1800)MeV 高能物理学会第七届年会@桂林

  5. Advantages in study scalar meson in B decays • The larger phase space, S wave dominant • New source of glueballs 高能物理学会第七届年会@桂林

  6. is regarded as mixing of and in our calculation and : : Experimental data The earlier study • PQCD • QCDF, Cheng et al PRD 71,054020(2005), PRD73, 014017(2006) • Generalized factorization +new physics, A. Giri, et al, hep-ph/0608088. 高能物理学会第七届年会@桂林

  7. , and are assumed to be mixing of qark-antiquark and glueball states The mixing scheme is still under controversy Cheng et al Close and Zhao The decays have been measured in but not in BKpipi 高能物理学会第七届年会@桂林

  8. Large branching ratios of The upper limits of branching ratios for is very small. 高能物理学会第七届年会@桂林

  9. Annihilation contributions: the reason for employing PQCD In QCDF, cancels most contribution from , and the predicted branching ratio is much smaller than the experiment To fit the data, large annihilation contribution are needed. Too large annihilation contribution will overshoot the data 高能物理学会第七届年会@桂林

  10. An introduction to PQCD approach 高能物理学会第七届年会@桂林

  11. Scalar meson decay constant and distribution amplitude Definition of the decay constant Definition of the distribution amplitude normalization 高能物理学会第七届年会@桂林

  12. Hard kernel diagrams • Only the twist-3 wave function contribute to the factorizable emission diagram • There is enhancement rather than cancellation between the two nonfactorizable diagrams contribution 高能物理学会第七届年会@桂林

  13. contribution 高能物理学会第七届年会@桂林

  14. Numerical resultsfor • For : the larger decay constant leads to larger amplitudes. • For : The nonfactorizable emission diagrams and annihilation diagrams give the dominant contribution , which comes from the Gegenbauer moments of the twist 2 LCDA. 高能物理学会第七届年会@桂林

  15. Numerical resultsfor • The perturbative calculation suffices to explain the data, the FSI or new physics is not essential. 高能物理学会第七届年会@桂林

  16. Numerical resultsfor Scenario II Scenario I The qqbar ground state with the mass at about 1500 MeV is favored 高能物理学会第七届年会@桂林

  17. and The branching ratios 高能物理学会第七届年会@桂林

  18. Conclusion and outlook • Within PQCD approach, decays are consistent with the experiment • The results of and indicate that scenario II is more preferable. • If we regard as , it being a ground state is more favored. • We need more precise nonperturbative parameters, such as the twist-3 distribution amplitudes etc. • The glueball contribution should be included. • More channels should be considered to constrain the scalar meson structure. 高能物理学会第七届年会@桂林

  19. Thank you for your patience ! 高能物理学会第七届年会@桂林

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