44,373 research outputs found

    Model-independent Study on Magnetic Dipole Transition in Heavy Quarkonium

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    Some new results on magnetic dipole (M1) transitions in heavy quarkonium from nonrelativistic effective field theories of QCD are briefly reported. This model-independent approach not only facilitates a systematic and lucid way to investigate the relativistic corrections, it also clarifies some inconsistent treatment in previous potential model approach. The impact of our formalism on J/Psi -> eta_c gamma, Upsilon(Upsilon') -> eta_b gamma and h_c -> chi_{c0} gamma are discussed.Comment: 7 pages and 3 figures. Talk presented at QCD@Work 2005, Conversano, June 16-20, 2005 and QCD05, Montpellier, July 4-8, 200

    Inclusive hch_c production at BB factories

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    Within the nonrelativistic QCD (NRQCD) factorization framework, we investigate the inclusive production of the hch_c meson associated with either light hadrons or charmed hadrons at BB factory energy s=10.58\sqrt{s}=10.58 GeV. Both the leading color-singlet and color-octet channels are included. For the hch_c production associated with light hadrons, the total production rate is dominated by the color-octet channel, thus the future measurement of this process may impose useful constraint on the value of the color-octet matrix element ; for the hch_c production associated with charmed hadrons, the total production rate is about one order of magnitude smaller, and dominated by the color-singlet channel.Comment: v2, 23 pages, 1 table, 6 figures. Minor corrections, and a note added, accepted for publication in PR

    Which hadronic decay modes are good for ηb\eta_b searching: double J/ψJ/\psi or something else?

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    It has been controversial whether ηb\eta_b can be discovered in Tevatron Run 2 through the decay ηbJ/ψJ/ψ\eta_b\to J/\psi J/\psi followed by J/ψμ+μJ/\psi\to \mu^+\mu^-. We clear this controversy by an explicit calculation which predicts Br[ηbJ/ψJ/ψ]{\rm Br}[\eta_b\to J/\psi J/\psi] to be of order 10810^{-8}. It is concluded that observing eta_b through this decay mode in Tevatron Run 2 is rather unrealistic. The eta_b may be observed in the forthcoming LHC experiments through the 4-lepton channel, if the background events can be significantly reduced by imposing some kinematical cuts. By some rough but plausible considerations, we find that the analogous decay processes eta_b to VV, D^*\bar{D}^* also have very suppressed branching ratios, nevertheless it may be worth looking for \eta_b at LHC and Super B factory through the decay modes \eta_b \to K_S K^{\pm}\pi^{\mp}, D^*\bar{D}.Comment: v2; 28 pages, 2 figures. References added, presentation improved. Discussion on possible nonperturbative mechanism for eta_b->VV added, analysis for eta_b->VP updated by incoprating the U-spin violation effec
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