Chao Kuangta

Bottomonium Spectrum with Screened Potential

As a sister work of Ref. [1], we incorporate the color-screening effect due to light quark pair creation into the heavy quark-antiquark potential, and investigate the effects of screened potential on the spectrum of bottomonium. We calculate the masses, electromagnetic decays, and E1 transitions of bottomonium states. We find that the fine splittings between χbJ (J=0,1,2) states are in good agreement with experimental data, and the E1 transition rates of Υ(2S) → γχbJ (1P ) and Υ(3S) → γχbJ (2P ) (J=0,1,2) all agree with data within experimental errors. In particular, the mass of Υ(6S) is lowered down to match that of the Υ(11020), which is smaller than the predictions of the linear potential models by more than 100 MeV. Comparison between charmonium and bottomonium in some related problems is also discussed.As a sister work of [Phys. Rev. D 79 (2009) 094004], we incorporate the color-screening effect due to light quark pair creation into the heavy quark-antiquark potential, and investigate the effects of screened potential on the spectrum of bottomonium. We calculate the masses, electromagnetic decays, and E1 transitions of bottomonium states. We find that the fine splittings between χbJ (J = 0, 1, 2) states are in good agreement with experimental data, and the E1 transition rates of γ(2S) → γχbJ (1P) and γ(3S) → γχbJ (2P) (J = 0, 1, 2) all agree with data within experimental errors. In particular, the mass of γ(6S) is lowered down to match that of the γ(11020), which is smaller than the predictions of the linear potential models by more than 100 MeV. Comparison between charmonium and bottomonium in some related problems is also discussed.

Impact of J/.PSI. pair production at the LHC and predictions in nonrelativistic QCD

For J/ψ pair production at hadron colliders, we present the full next-to-leading order (NLO) calculations in nonrelativistic QCD (NRQCD). We find that the NLO result can reasonably well describe the LHCb cross section, but exhibits very different behaviors from the CMS data in the transverse momentum distribution and mass distribution of J/ψ pair. Moreover, adding contributions of gluon and quark fragmentation is found to be unable to reduce the big differences. In particular, the observed flat distribution in the large invariant mass is hard to understand. NRQCD may face a challenge if this J/ψ pair experiment is confirmed.

Radiative Decays of Charmonium into Light Mesons

We apply perturbative QCD to the radiative decays of charmonia

SCREENED Q-(Q)OVER-BAR POTENTIAL AND SPECTRUM OF HEAVY QUARKONIUM

J/\psi

Nonfactorizable B→χc0K Decay and QCD Factorization

and

System: Mass Spectra and Decays*

\chi_{cJ}

Investigations On the Full and Reduced Salpeter Equation for the Quark-Anti Quark Bound States

into light mesons. We perform a complete numerical calculation for the quark-gluon loop diagrams involved in these processes. The calculated

Measuring gτ/gμ and the mass of ντ via the F and D leptonic decays

J/\psi

A Possible Interpretation for the ξ(2.2) Observed in the J/ψ Radiative Decays

decay branching ratios to P-wave mesons

Physics on the high intensive electron position accelerator at 2–7 GeV

f_2(1270)