xc0→BB^-MM衰变中的重子共振态

基于SU（3）对称性研究了Xc0的遍举多体衰变xc0→BB^-MM（B：重子，M：介子），通过同位旋耦合常数构造了xc0→BB^-→BB^-MM衰变的跃迁振幅．基于这些跃迁振幅，发现N^＊共振态对xc0→BB^-ππ的贡献相对较大，这个衰变道可以在实验上用来研究N^＊共振态．     

How and when can one identify hadronic molecules in the baryon spectrum<Superscript>⋆</Superscript>

A method to identify hadronic molecules in the particle spectrum is reviewed and the conditions for its applicability discussed. Special emphasis is put on the discussion of molecule candidates in the baryon spectrum.     

在T2HDM模型中中性希格斯粒子对B→X_s1 1-衰变过程的影响(英文)

在T2HDM模型中计算了中性希格斯粒子圈图对稀有衰变过程B→X_s1 1-的贡献.通过计算发现:(a)中性希格斯粒子对衰变过程B→X_s1 1-的修正能够增强其标准模型的预言,但增幅很小;(b)在中性希格斯玻色子的质量大于100GeV和tanβ<40的情况下,中性希格斯粒子对稀有衰变过程B→X_s1 1-的分支比的贡献可忽略.     

The radiative decay of the <Emphasis Type="Italic">Λ</Emphasis>(1405) and its two-pole structure

We evaluate theoretically the radiative decay widths into γΛ and γΣ ⁰ of the two poles of the Λ(1405) found in chiral unitary theories and we find quite different results for each of the two poles. We show that, depending on which reaction is used to measure the Λ(1405) radiative decays, one gives more weight to one or the other pole, resulting in quite different shapes in the γΛ(Σ ⁰) invariant-mass distributions. Our results for the high-energy pole agree with those of the empirical determination of the γΛ and γΣ ⁰ radiative widths (based on an isobar model fitting of the K^-p atom data), which are sometimes referred to as “experimental data”. We have made a detailed study of the K ^- p→π ⁰ γΛ(Σ ⁰) and π ^- p→K ⁰ γΛ(Σ ⁰) reactions and have shown that they, indeed, lead to different shapes for the γΛ(Σ ⁰) invariant-mass distributions.     

Quark models<Superscript>⋆</Superscript>

The scope of a relativistically covariant constituent quark model of baryons based on the Bethe-Salpeter equation in instantaneous approximation is illustrated by a discussion of various baryon resonance observables such as static electromagnetic moments --including a novel calculational procedure-- form factors and helicity amplitudes, semileptonic decays as well as the systematics of two-body strong decay widths.     

Covariant tensor formalism for partial-wave analyses of ψ decay to mesons

J/ψ and decays to mesons are a good place to look for glueballs, hybrids and for extracting strange and non-strange components in mesons. Abundant J/ψ and events have been collected at the Beijing Electron Positron Collider (BEPC). More data will be collected at upgraded BEPC and CLEO-C. Here we provide explicit PWA formulae for many interesting channels in the covariant tensor formalism. Received: 29 November 2002 / Accepted: 20 December 2002 / Published online: 25 March 2003 RID="a" ID="a"e-mail: zoubs@mail.ihep.ac.cn Communicated by V.V. Anisovich     

Bound-state versus collective-coordinate approaches in chiral soliton models and the width of the Θpentaquark

We thoroughly compare the bound-state and rigid-rotator approaches to three-flavored chiral solitons. We establish that these two approaches yield identical results for the baryon spectrum and kaon-nucleon S-matrix in the limit that the number of colors (N_C) tends to infinity. After proper subtraction of the background phase shift the bound-state approach indeed exhibits a clear resonance behavior in the strangeness S = + 1 channel. We present a first dynamical calculation of the widths of the Θ⁺ and Θ^* pentaquarks for finite N_C in a chiral soliton model.     

Study of D±s→μ±vμ at Belle

We present a preliminary measurement of the B(Ds→μvμ) with the Belle experiment at the KEKB collider. We select Ds→μvμ decays with a method that provides a high-purity of the selected sample and an absolute measurement of the branching fraction. The results are based on a data sample of 550 fb-1 and are compared to similar measurements by other experiments as well as to the predictions of LQCD. We conclude with short prospects for improvements in the accuracy of the measurement.     

A bag model study ofD mesons

An investigation of the newly discovered charmed mesonsD 0 andD +, particularly their non-leptonic decay modes, is carried out in the framework of the MIT bag model. The amplitude for a number of two-body final state decays are explicitly evaluated and compared with other available estimates.     

An explanation of the beam dump experiment

The production of prompt neutrinos in the beam dump experiment is explained in a cluster model, by postulating the emission of strange clusters in hadron collisions, besides the usual non-strange clusters. The low mass strange clusters can decay only by the weak interaction. The leptonic and semi-leptonic decay modes of these clusters give rise to prompt neutrinos. A prediction of the model is that the ratios <v _e>/π ⁺ at PS energies would be the same as SPS energies.