The breaking of exchange degeneracy in dual unitarisation

The splitting of trajectories with non-vacuum quantum numbers is discussed within the dual unitarisation scheme. The estimated difference in intercepts between vector-tensor trajectories of opposite signatures, such as ? ? A₂ and $\text{K}{}^1\text{?}\text{K}{}^7$, agrees both in sign and magnitude with that deduced from phenomenological analyses.     

Baryon exchange processes

The theory and phenomenology of baryon exchange processes are critically reviewed. As regards theory the main topics are the parity doublet problem and the patterns of exchange degenerate baryon trajectories implied by duality. In the phenomenological part, all baryon exchange reactions are considered, with the emphasis being on seeing how far simple ideas of pole exchange with the constraints implied by duality and broken SU(3) can be taken in forming an understanding of the data.     

The vertex bootstrap conditions in the dual unitarisation scheme

The bootstrap conditions for the triple- and double-Regge vertices are derived utilising the planar unitarity condition for six- and five-point amplitudes. The problem of symmetry breaking is considered within the one-dimensional approximation. It is shown that the vertex and propagator equations together predict the equal spacing rule for Regge trajectory intercepts and a well defined pattern of symmetry breaking for vertices.     

s-channel discontinuities of the torus insertion in the dual unitarisation scheme

The refined analysis of the s-channel discontinuities of the torus insertion in the topological expansion is performed. Assuming the dependence on reggeon masses of the fixed-pole residue similar to that given by the Veneziano model we obtain almost exact cancellations of the discontinuities which in the one-dimensional approximation were argued to be responsible for the exchange degeneracy breaking between ? and A₂ trajectories. Implications on different f-IP schemes are discussed.     

Asymptotics of the S-matrix and unitarisation

The manner in which the elastic scattering amplitude obeys unitarity, how it enters the circle of unitarity, and what its asymptotic limit is, remains a problem for models which include terms that rise fast with s. We have checked that the features of cross sections which come from unitarisation are present for most unitarisation schemes, e.g. those that saturate the profile function or those that describe multiple exchanges via an analytic formula. We have also obtained a scheme which interpolates between different classes of the unitarisation and found corresponding non-linear equations. Considering different forms of energy dependence of the scattering amplitude, and a variety of unitarisation schemes, we show that, in order to reproduce the data, the fits choose an amplitude that corresponds to an asymptotic value S = 0.     

衰变中的重子共振态

基于SU(3)对称性研究了χc0的遍举多体衰变χc0→B(-B)MM(B重子,M介子),通过同位旋耦合常数构造了χc0→B(-B)→B(-B)MM衰变的跃迁振幅.基于这些跃迁振幅,发现N*共振态对χc0→B(-B)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.     

J/ψ, ψ′ and related decays from dual unitarisation

The widths for about 30 decay modes of the J/ψ family are calculated from dual unitarisation. Consistency with experiment is obtained wherever such information is available.     

Baryon yields, isospin effects and strangeness production in elementary hadronic interactions

New NA49 data from hadron+proton and hadron+Pb interactions are used to extract detailed information on projectile isospin effects and baryon, baryon pair and strangeness production. Consequences for the interpretation of hadron production and strangeness enhancement in nuclear collisions are discussed.     

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.     

重子谱中的自旋–轨道耦合力

在组份夸克势模型的框架下,用几种夸克势模型对重子谱中N和Λ的几组L?=1负宇称激发态自旋轨道劈裂进行了分析,指出有的模型在引进了一项半唯象的自旋轨道耦合势后能解释这几组态的自旋轨道耦合能级劈裂的实验值     

Baryon Ratios in Quark-Gluon Plasma

A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavy ion collisions is presented. It is assumed that at the beginning of the hadronlzation there are diquarks and anti-diquarks in the quark matter. The number of three-quark states is distributed between the corresponding multiplets, and hadronic decays are taken into account. The results are shown at last.     

Baryon production in QCD jets

Recent data from several sources—Υ decays, high energy deep inelastic scattering,e ⁺ e ^? annihilation at PETRA—reveal substantial baryon production in QCD jets. We discuss the likely mechanisms within the context of QCD, and formulate experimental tests to distinguish amongst them.     

Baryon trajectories revisited

Various properties of baryon trajectories are re-examined in the light of the latest data: in particular we study trajectory assignments of the 1982 baryon resonance data and evaluate effective trajectories for backward πN scattering incorporating FNAL data. We find that all of the information is consistent with trajectories linear inu, withF/D ratios constant along the trajectories and parity doublets absent. We find that exchange degeneracy (EXD) is good for Λ and Σ trajectories and residues and shed some qualitative light on the systematics of EXD breaking.     

Baryon Ratios in Quark-Gluon Plasma

A way to calculate ratios of baryon produced from quark gluon plasma in relativistic heavyion collisionsis presented. It is assumed that at the beginning of the hadronization there are diquarks and anti-diquarks in the quarkmatter. The number of three-quark states is distributed between the corresponding multiplets, and hadronic decays aretaken into account. The results are shown at last.     

Baryon Structure in AdS/QCD

We discuss baryon structure in a soft-wall anti-de Sitter/quantum chromodynamics model. From unified point of view we describe nucleon form factors and the electroproduction of the N(1440) Roper resonance. The Roper resonance is identified as the first radially excited state of the nucleon. The obtained results for helicity amplitudes of the Roper electroproduction are in good agreement with the recent results of the CLAS Collaboration at JLab.     

Baryon poles in proton decay amplitudes

The decay rate of the p→π⁰e⁺ mode is calculated in SU(5) grand unified theory using a pole model with proton and $\text{1}\text{2}{}^{\mathrm{?}}$ baryon poles. Baryon-to-vacuum amplitudes are calculated in the framework of the MIT bag model. It is found that the partial decay rate [～(5×10³¹ yr)^?)] is close to the partial decay rates calculated by different methods.