Regarding the 21S0 and 23S1 multiplets

<正>This paper discusses the masses and possible members of 2¹S₀ and 2³S₁ meson multiplets in the framework of meson-meson mixing and Regge phenomenology.For the 2¹S₀ meson nonet,K^*（1460） may be the observed state of the 2¹S₀ isodoublet with a mass of 1400 MeV and the mass ofω（1420） is 1412 MeV.For the 2³S₁ meson nonet,K^*（1410） seems too light to be the 2³S₁ ns member.The fact that the agreement between the present findings and those given by experiments and other different approaches is satisfactory implies that the assignments in this paper may be reasonable.     

Recoil polarimetry in meson photoproduction at MAMI

The nucleon excitation spectrum remains poorly known, with the masses, widths, EM couplings and even existence of many states not well established. A program of experiments using meson photoproduction off the nucleon is being carried out to improve this situation. A new large acceptance recoil polarimeter has been developed by the Edinburgh group for use in such reactions with the Crystal Ball at MAMI. This work summarizes the procedure used to measure recoil polarization with the new device and presents some preliminary results for the double polarization observable C_x in the reaction γp→pπ~0, compared to the current partial wave analysis.     

Recent results for single meson production from the Crystal-Barrel/TAPS experiment at ELSA

The present focus of the CBELSA/TAPS experiment is on meson-photoproduction off the nucleon using polarized photons and polarized targets. Here first preliminary results on the reactions γ~→p~→→ pπ~0 and γ~→p~→pη for both circularly and linearly polarized photons and a longitudinally polarized target are presented. Preliminary results for the beam asymmetry Σ and the double polarization observable G have been extracted for both reactions using the linear polarization data. From the circular polarization data the observable E has been determined. Due to the near 4π angular coverage of the detector system these results cover almost the full solid angle.     

Charmed Baryon in Diquark Model

A diquark model is used to investigate single-charmed baryons.In this model,baryon is composed of two diquarks and an antiquark.Masses of lowest lying states with J~P=1/2~(±) are obtained.Baryons in our results are as heavy as other theoretic predictions and we suggest that the five-quark components should be considered in any three-quark model for studying the charmed baryons.     

B → ρ（ω, φ）η（＇） Decays and NLO Contributions in pQCD Approach

By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^0（ω, φ）η（＇）, induced by the vertex QCD corrections, the quark-loops as well as the chromo-magnetic penguins. From the numerical results and phenomenological analysis we find that （a） for B^± → ρ^±η（＇） （B^0 → ρ^0（ω, φ）η（＇）decays, the partial NLO contributions to branching ratios are small （large） in magnitude; and （b） the pQCD predictions for ACP^dir（B^± → ρ^±η（＇）） are consistent with the data, while the predicted .ACP（B^0 → ρ^0（ω）η（＇）） are generally large in magnitude and could be tested by the forthcoming LHCb experiments.     

Charmed Meson Production in Deep Inelastice+A Scattering at Small-x

Based on the nuclear effects considered in the Glauber-Gribov approach, charmed meson production in high energy deep inelastic e+A scattering is investigated in the color dipole formalism. Using the Peterson fragmentation function and the KLR-AdS/CFT color dipole model, which reasonably well describes the HERA data for the inclusive structure functions at small Bjorken-x, we present the predictive results for the D-meson transverse spectra at EIC and LHeC energies. The theoretical results indicate that the $x$-independence phenomena at very small-x predicted by the KLR-AdS/CFT model are not seen in our calculation.     

The Three-Pion Decays of the a1(1260)

We investigate the decay of a₁⁺ (1260)→π⁺π⁺π^- with the assumption that the a₁(1260) is dynamically generated from the coupled channel ρπ and KK^* interactions. In addition to the tree level diagrams that proceed via a₁⁺ (1260)→ρ⁰π⁺→π⁺π⁺π^-, we take into account also the final state interactions of ππ→ππ and KK→ππ. We calculate the invariant π⁺π^- mass distribution and also the total decay width of a₁⁺ (1260)→π⁺π⁺π^- as a function of the mass of a₁(1260). The calculated total decay width of a₁(1260) is significantly different from other model calculations and tied to the dynamical nature of the a₁(1260) resonance. The future experimental observations could test of model calculations and would provide vary valuable information on the relevance of the ρπ component in the a₁(1260) wave function.     

Charm hadronic decays and quantum correlations at CLEO-c

Several recent CLEO-c results on hadronic decays of charm mesons are reviewed.Topics include measurements of precision branching fractions for exclusive modes,investigations of inclusive rates,and analyses of Dalitz plots.In addition,the quantum correlations of the D pairs produced at the ψ(3770) are exploited to measure phase information that is of current interest for both D and B physics.     

Rare Decay B→Xsvv in the Two—Higgs—Doublet Model of Type—Ⅲ

In this paper, we calculated the new physics contribution to theoretically very clean rare decay B→X_sνν in the general two-Higgs-doublet model (model III). Within the considered parameter space, we found that (a) the new physics contribution can provide one to two orders of enhancement to the branching ratio B(B→X_sνν) and can saturate the experimental bound on B(B→X_sνν) in some regions of the parameter space; (b) besides the CLEO data of B→X_sγ, the ALEPH upper limit on B(B→X_sνν) also leads to further constraint on the size of the Yukawa coupling λ_tt: λ_tt< 6.4 for λ_bb=2.7 and m_H⁺=200 GeV.