Quasi Three-Body Decay of D Meson

The aim of this work is to provide a phenomenological analysis of the contribution of D~0 meson to K*(892)~0π~+π~-(K*(892)~0-→π~+K~-), K~-π~+ω(ω-→π~+π~-π~0) and K~-π~+?(?(1020)-→ K~+K~-) quasi-three-body decays. The analysis of mentioned multi-body decays is such as to factorize into the three-body decay and several channels observed. Hadronic three-body decays receive both resonant and non-resonant contribution. Based on the factorization method, there are tree and emission annihilation diagrams for these decay modes. In the case of D~0 to vector pseudoscalar states appeared in factored terms, the matrix elements of the vector and axial vector currents between the D~0 and PV mesons can be computed by using D~(*+)pole. Considering the non-resonant and resonant amplitude in our computation,the theoretical values of the branching ratio are(9.78 ± 0.46) × 10~(-3),(2.74 ± 0.17) × 10~(-2), and(3.53 ± 0.23) × 10~(-5), while the experimental results of them are(9.9 ±2.3) × 10~(-3),(2.7 ± 0.5) × 10~(-2), and(4 ± 1.7) × 10~(-5) respectively. Comparing computational analysis values with experimental values show that our results are in approximately agreement with them.     

The decay ω(782)→5π in chiral theory.

The arguments are put forward that the many pion decays ω→2π⁺2π⁻π⁰ and π⁺π⁻3π⁰ provide an ideal test site for testing the predictions of chiral models of the vector meson decays into many pions. Using the approach based on the Weinberg Lagrangian or, in a new language, the Lagrangian of hidden local symmetry added with the term induced by the anomalous Lagrangian of Wess and Zumino, the partial widths of these decays are evaluated, and their excitation curves in e⁺e⁻ annihilation are obtained. The discussed are the perspectives of the experimental study of the decays ω→5π in e⁺e⁻ annihilation and photoproduction.     

A Study on Radiative Dileptonic Decays B0(Bs)→γ l+l-

We study the rare radiative dileptonic decays B⁰(B_s)→γ l⁺l^- (l=e,μ) in the standard model. By using the B meson wave function constrained by non-leptonic decays, the branching ratios turn out to be of the order of 10^-9 for B_s→γ μ⁺μ^-, γe⁺e^-, and 10^-10 for B⁰→γμ⁺μ^-, γe⁺e^-. Based on the study, these decays are accessible at the near future LHC-b experiment, which are useful to determine the B(B_s) wave function.     

正负电子湮灭过程的核子激发态N*产生(英文)

目前,正负电子湮灭过程的核子激发态N*产生的实验数据主要来自于粲偶素能区。粲偶素衰变到核子激发态过程类似于其类时电磁形状因子测量过程,正反粲夸克短程湮灭提供了近乎于点源的胶子强子化过程。与γN,eN,πN反应互补,这一新的N*产生源具有同位旋和低自旋筛选的优势。综述了正负电子湮灭过程的核子激发态N*产生的实验情况和相关的唯象进展,同时讨论未来发展的一些新方向,如正负电子湮灭过程的核子激发态N*产物的一些新来源等。Up to now, the N* production from e+e- annihilations has been studied only around charmonium region. Charmonium decays to N*s are analogous to (time-like) EM form factors in that the charm quark annihilation provides a nearly pointlike (ggg) current. Complementary to other sources, such as πN, eN and γN reactions, this new source for N* spectroscopy has a few advantages, such as an isospin filter and a low spin filter. The experimental results on N* from e+e- annihilations and their phenomenological implications are reviewed. Possible new sources on N* production from e+e- annihilations are discussed.     

ξ(2230) Is Likely to Be a Glueball

On the basis of the recent results of ξ(2230) → π⁺π^-, pp and ξ(2230) → K⁺K^-, K_sK_s, measured by the BES Collaboration in J/ψ radiative decays, combined with the PSI85 experiment of pp → ξ(2230) → KK we argue that because of its very narrow partial decay widths to nn and KK (less than 1 MeV), its large production rate in J/ψ radiative decays (BR(J/ψ → γξ> 2.3×10^-3), and its flavor-symmetric couplings to ππ and KK, the ξ(2230) is very likely to to be a J^PC= (even)⁺⁺ glueball.     

Interpretation of the Θ as an isotensor pentaquark with weakly decaying partners

The Θ⁺(1540), recently observed at LEPS, DIANA and CLAS, is hypothesized to be an isotensor resonance. This implies the existence of a multiplet where the Θ⁺⁺, Θ⁺ and Θ⁰ have isospin-violating strong decays, and the Θ⁺⁺⁺ and Θ⁻ have weak decays and so are long-lived. Production mechanisms for the weakly-decaying states are discussed. The J^P assignment of the Θ is most likely 1/2⁻ or 3/2⁻.     

Study of chiral property of nuclear matter through measurements of Φ meson decays

The experiment E325 being performed at KEK 12GeV-PS is to investigate the chiral property of QCD in dense matter through the measurements of vector mesons which decay inside nucleus. The status of the experiment and the preliminary mass distribution of Φ → K⁺K⁻ decays are presented.     

Charmless Hadronic Decays B→VV in the Topcolor－Assisted Technicolor Model

Based on the effective Hamiltonian with the generalized factorization approach, we calculate the branching ratios and CP asymmetries of B→VV decays in the Topcolor-assisted Technicolor (TC2) model. Within the considered parameter space we find that: (a) for the penguin-dominated B→K^*+φ and K^*0φ decays, the new physics enhancements to the branching ratios are around 40%; (b) the measured branching ratios of B→K^*+φ and K^*0φ decays prefer the range of 3≤N_c^eff≤5; (c) the SM and TC2 model predictions for the branching ratio B(B⁺→ρ⁺ρ⁰) are only about half of the Belle's measurement; and (d) for most B→VV decays, the new physics corrections on their CP asymmetries are generally small or moderate in magnitude and insensitive to the variation of m_π and N_c^eff.     

What can we learn from B→DsKπ, Bd→DsKπ and Bd→DsK decays?

We study the nonresonant three-body decays of B⁺→D^(*)−_sK⁺π⁺ and B_d→D_s^(*)−K⁰π⁺. We find that these decays can provide the information on the time-like form factors of D^(*)_sK. We also explicitly investigate B_d→D_s^(*)−K^*+ decays by discriminating the nonresonant contributions with the unknown D^(*)_s wave functions being fixed by the measured mode of B_d→D_s⁻K⁺.     

Baryon ＋ Baryon→（ΩΩ）J^π=0＋ ＋ X Cross Section Calculation

The cross sections of Ω Ξ→（ΩΩ）J^π=0 K(K^*) and Ω Ω→（ΩΩ）J^π=0 η‘(φ) are studied by using an effective Hamiltonian method.For the two pseudo-scalar meson production processes,the cross sections are still in the order of several μbs,but for the two vector meson production processes,the cross sections are about 10 times larger than those in pseudo-scalar meson production case when the coupling constants of vector meson fields are fixed according to gNNρ and fNNρ in NN scattering and the SU(3) relation.     

Studies of Bs^0 → η＇η＇ Decays in pQCD Approach

We calculate the CP averaged branching ratios and CP-violating asymmetries for Bs^0 → η＇η＇ and η＇η＇ decays in the perturbative QCD （pQCD） approach here. The pQCD predictions for the C P-averaged branching ratios are Br（Bs^0 → ηη）=（14.2-7.5^＋18.0） ×10^-6,Br（Bs^0 → ηη＇）=（12.4-7.0^＋18.2）×10^-6,and Br（Bs^0 → η＇η＇） =（9.2-4.9^＋15.3）×10^-6, which agree well with those obtained by employing the QCD factorization approach and also be consistent with available experimental upper limits. The gluonic contributions are small in size： less than 7% for Bs →ηηand ηη＇ decays, and around 18% for Bs →η＇η＇ decay. The CP-violating asymmetries for three decays are very small： less than 3% in magnitude.     

The use of QCD in OZI violating radiative decays of vector mesons

The spin parity (J^P) of the hadronic system produced in OZI violating vector decays V → γ + h is analyzed in the lowest order QCD approach. While the predicted rates for 0^± states agree with the data, theoretically unacceptable anomalies occur for even J ≠ 0, P = +1, channels. Experimental consequences are drawn. We argue that the rate for gluon jet emission in V → γ + 2 gluons is substantially smaller than previously stated.     

HYPERON DECAYS IN THE CNIRAL BAG MODEL

In terms of the chiral bag model and SD(3) Skyrme wave-functions of baruons, we investigate Δ⁺ →Pγ (SU(2)) and Σp⁺ → Pπ⁰ (SU(3) case) hyperon decays. We have found that for Δ⁺ →Pγ the Skyrme contribution is more important whereas in Σp⁺ → Pπ⁰ the quark content transition dominates.     

U-spin symmetry in doubly Cabibbo-suppressed charmed meson decays

We prove a U-spin amplitude triangle relation among doubly Cabibbo-suppressed (DCS) charmed meson decays, D⁰→K⁺π⁻,D⁰→K⁰π⁰ and D⁺_s→K⁰K⁺, congruent to an isospin relation among corresponding Cabibbo-favored (CF) decays. U-spin breaking in relative phases between CF and DCS amplitudes affects time-dependent studies of D⁰– mixing. Comparison of final state phase patterns in DCS and CF amplitude triangles, which can shed some light on these phases, is carried out in a phenomenological framework incorporating resonance contributions.     

Study on υμ, υγ, Decays and CP Non-Invariance at Early Epoch of the Universe

We study the υ_μ and υ_γ decays in the early epoch of the universe. If m_υγ > 2m_e, there would be a CP asymmetry between υ_γ→e⁺+e^-+υ_e and υ_γ→e⁺+ e^-+ υ_e. The resultant CP non-invariance is a function of temperature and density and can reach l0^-7 for a reasonable temperature range, but it is noticed that if m_υγ > 2υ_μ～200 MeV, the CP non-invariance can be much larger.     

Strong Decays of Charm Mesons D1*(2680), D3*(2760), D2*(3000)

In this article, we assign the higher charm mesons D₁^*(2680), D₃^*(2760) and D₂^*(3000) to be the 2S 1^-, 1D 3^- and 1F 2⁺ states, respectively, and study the two-body strong decays to the ground state charm mesons and light pseudoscalar mesons with the heavy meson effective theory. We obtain the ratios among the strong decays, which can be confronted to the experimental data in the future and shed light on the nature of those higher charm mesons.     

Rare Decays B→K(*) e+ e- Test of the Standard Model

The exclusive B→K^(*) e⁺ e^- decays are studied in the topcolor-assisted technicolor model and in the minimal technicolor model. We find that the angular distribution and the dilepton mass distribution in B→K^(*) e⁺ e^- which can be reliably predicted in the large dilepton mass region, are very sensitive to the actual form of the new interaction. This provides a good test to physics beyond the standard model.     

B→a0(1450)ρ(ω) Decays in Perturbative QCD Approach

In the two-quark model supposition for the meson a₀(1450), which can be viewed as either the first excited state (scenario I) or the lowest lying state (scenario II), the branching ratios and the direct CP-violating asymmetries for decays B→ a₀(1450)ρ(ω) are studied by employing the perturbative QCD factorization approach. We find the following results: (a) For the decays B^- → a⁰₀(1450)ρ^- and \bar{B}⁰ → a⁺₀(1450)ρ^-, their branching ratios have large
difference between two scenarios. Although their branching ratios are larger than other considered decay modes, their direct CP-violatingasymmetries in both scenarios are small. (b) For the decays B^-→ a^-₀(1450)ρ⁰ and \bar{B}⁰→ a^-₀(1450)ρ⁺, a⁰₀(1450)ρ⁰, a⁰₀(1450)ω, their branching ratios are close to each other between two scenarios, respectively. (c) Comparing with the decays \bar{B}⁰ →π⁰ρ⁰,π⁰π⁰, the decay \bar{B}⁰→ a⁰₀(1450)ρ⁰ receives a
larger branching ratio in each scenario, which is sensitive to the variation of the Cabibbo-Kobayashi-Maskawa angleα.     

Solution of the Puzzles in D→K(K*)e+ve and Tansition Form Factors Among Heavy to Light and Heavy to Heavy to Mesons

We present a model-independent and systematic method for calculating the matrix elements among heavy to light and heavy to heavy hadrons. The new method allows us to obtain absolutely normalized form factors at the maximum momentum transfer for Q→Q' or q' induced weak transitions among meson states such as 0^-+→0^-+,1^--),0⁺⁺,1⁺⁺ etc. It is applied to the B-meson and D-meson systems and found that the puzzles in the D→K(K')_e+ve decays can be solved nicely.     

Angular Distributions for φ＇ Sequential Decays into 2（π^＋π^-）pp^-γ via XCJ

Amplitudes for φ（2S） sequential decays into 2（π^＋π^-）pp^-γ via XCJ are constructed in effective coupling scheme. A Mote-Carlo simulation is carried out to study angular distributions of the decayed particles in laboratory system. The results can be taken as a reference for measuring the decay of XCJ into at BESⅡ/BEPC in the near future.