Study on Production of Exotic 0^＋ Meson D＇^＊aj（2317） in Decays of ψ（4415）

The newly observed D^＊aj family containing D^＊aj（2317）, Daj（2460）, and Daj（2632） attracts great interests. Determining their structures may be an important task for both theorists and experimentalists. In this work we use a non-relativistic model （the harmonic oscillator model） to evaluate the production rate of D^＊aj （2317） from the decays of ψ（4415）. For a comparison, we a/so employ the widely adopted heavy quark effective theory to repeat the calculation. We lind that the rate is sizable and may be observed at BES III and CLEO, if it is a p-wave excited state of Da（1968）. Unfortunately, the other two members of the family cannot be observed through decays of charmonia, because of the constraints from the final state phase space.     

Study of ψ(4415) in the QPC model

Some authors consider the ψ(4415) to be the 4S or 5S excited tate of a cc pair. Starting from this assumption, we study he decays of the ψ(4415) to DD, D^*D^*, D_SD_S, D_S^*D_S^*, and get the corresponding branching ratios in terms of the Quark-Pair-Creation (QPC) model. Compared with the experimental data, we find that the results of 4S state agree much better than those of the 5S state. Therefore, it is more reasonable to assume the ψ(4415) to be a 4S state.     

Abnormal Suppression of Vector-Tensor Decays of ψ(2S)

The hadronic decays ψ(2S)→ρα₂ and K^*0K₂^*0+c.c. have been studied in a sample of 3.6×10⁶ ψ(2S) events.Measurements of their branching fractions are presented.Both channels violate the “15% rule” predicted by perturbative QCD compared with the corresponding J/ψ decays.These results serve as new examples of abnormal suppression of ψ(2S) decays into vector-tensor final states that was first observed in ψ(2S)→ωf₂     

Study of ψ(2S)Decays into pπ and KK

From a study of(2S)decays into vector-pseudoscalar final states,ρπ and KK*,based on a sample of 1.27×10⁶ produced (2S) events,we have set upper limits at 90% confidence level on the branching fractions into ρπof 3.6×10^－5, into K⁺K^*+c.c.of 2.5×10^－5,and into K⁰K^*0+c.c.of 1.2×10^－4.We find that all these decays are substantially suppressed relative to the corresponding J/ψ decays in comparison with PQCD predictions.Our results confirm the MARK Ⅱ measurements at an improved sensitivity level.     

Dissociation cross sections of ψ(3770), ψ(4040), ψ(4160), and ψ(4415) mesons with nucleons

We study the dissociation of ψ(3770), ψ(4040), ψ(4160), and ψ(4415) mesons in collision with nucleons, which takes place in high-energy proton-nucleus collisions. The quark interchange between a nucleon and a ■ meson leads to the dissociation of the ■ meson. We consider the reactions:■, and■, where R stands for ψ(3770), ψ(4040), ψ(4160), or ψ(4415). A reaction of a neutron and a ■ meson corresponds to a reaction of a proton and the ■ meson by replacing the up quark with the down quark and vice versa. Transition-amplitude formulas are derived from the S-matrix element.Unpolarized cross sections are calculated with the transition amplitudes for scattering in the prior form and in the post form. The cross sections relate to nodes in the radial wave functions of ψ(3770), ψ(4040), ψ(4160), and ψ(4415) mesons.     

Role of Electromagnetic Dipole Operator in the Electroweak Penguin Dominated Vector Meson Decays of B Meson

The pure annihilation type decays Dd^0→Фγand Bs→ργ receive only colour suppressed penguin contributions with a very small branching ratio in the standard model. When we include the previously neglected electromagnetic dipole operator, the branching ratios can be enhanced to R（^-Bd^0→Фγ）≈ 1×10^-11 and R（^-Bs→ργ）～（6 - 16） ×10^-10, which are one order magnitude larger than previous study using the QCD factorization approach. The new effect can also give a large contribution, of order 10^-9, to transverse polarization of B→Фρ and B →ωФ, which is comparable to the longitudinal part. These effects can be detected in the LHCb experiment and the super-B factories.     

Pseudoscalar-Meson Mixing in ψ(2S)→VP Decays

Based on the branching ratios of ψ(2S)→VP given by the BES collaboration, we make a new analysis to study the mixing of pseudoscalars. The mixing angle of η and η_p, θ_p is determined to be (－7.54±1.52)° which is consistent with the value obtained from quadratic Gell-Mann-Okubo formula. From this work we also know that the strength of DOZI to SOZI is about 14% in ψ(2S)→VP, and the phase angle of electromagnetic amplitude to strong amplitude is (156±89)°.     

Experimental Study of f0 (975) in the J/ψ Decays

Based on 7.8×10⁶ J/ψ events collected by the BES at BEPC, through study of the hadronic decays J/ψ→φπ⁺π^－ and J/ψ→ωπ⁺π^－, the branching ratios of the processes and the mass positions and the widths of f0 are obtained. The angular distributions of J/ψ→φf₀,f₀→π⁺π^－, are fitted and the helicity amplitude ratio of this process is first given.     

Exclusive Ω_(ccc)~(++)Ω_(ccc)~(--) Production from Z~0/r~* Decays

Based on the quark model the cross section for the e~+e~-→ Z~0/r~*→Ω_(ccc)~(++)Ω_(ccc)~(--) exclusive process is investigated at the tree level. Compared with the Z~0→Ω~-Ω~+ decay, our result shows that the Z~0 boson favors decaying into charmed baryon pairs. The results are also compared with the calculation of inclusively charmed baryon production.     

Study of scalar meson f 0(980) from B→f 0(980)K * decays

We show how parton distributions unintegrated over the parton transverse momentum, k _t , may be generated, at NLO accuracy, from the known integrated (DGLAP-evolved) parton densities determined from global data analyses. A few numerical examples are given, which demonstrate that sufficient accuracy is obtained by keeping only the LO splitting functions together with the NLO integrated parton densities. However, it is important to keep the precise kinematics of the process, by taking the scale to be the virtuality rather than the transverse momentum, in order to be consistent with the calculation of the NLO splitting functions.     

Study of Exclusive Hadronic Decays for D0→Ks0π+π- and D0→Ks0K+K- and Their Resonant Structures

We report the results of an experimental study of the exclusive hadronic decays for D0→K0 sπ+π - and K 0 sK +K - and their resonant structures using BES-Ⅰ detector at the BEPC Collider. Using the data sample of 22.3 pb -1 collected at the center-of-mass energy s=4.03 GeV, we measured the branching fraction for D 0→K 0π +π - to be (5.32±0.53±0.40)%, the branching fractions for the decays D 0→ K *-π +, D 0→K 0ρ 0 and D 0→K 0(π +π -) non-resonant to be (6.05±0.32±0.49)%, (1.17±0.17±0.13)% and (1.35±0.22±0.17)%, respectively. We measured the branching fractions Br(D 0→f) to be (1.04±0.24± 0.16)% for f=K 0K +K -, (1.12±0.34±0.15)% for f=K0, and (0.27±0.13±0.03)% for f=K 0(K+K-)non-.     

Perturbative QCD Study of B(s)→φρ Decays

We study B_(s)→φρ decays in a perturbative QCD approach based on k_T factorization. In this approach, we calculate factorizable and non-factorizable contributions, there are no annihilation contributions due to quark content. We get the branching ratios and polarization fractions for B_(s)→φρ decays. Our predictions are consistent with the current experimental data.     

Experimental Searches for the Non-DD Decays of ψ(3770) in e+e－ Collider

The previous experiments which provide information on the ψ(3770) to non-DD decays are reviewed. Three approaches of searching for the non-DD decays are discussed in detail. It is also pointed out that the search for the non-DD decays of the ψ(3770) is very important for the understanding of the dynamics of charmonium decays.     

Erratum to: On the Dependence of the Widths of the τ → [ρ0(770), ρ0(1450)]π−ντ Decays on the Parameters of the Intermediate a1 Meson

JETP Letters - In Eqs. (12), in line 16 should be replaced by     

A study of CP asymmetry inB 0 decay at ψ(4S)

A method to look for CP violation in the neutralB-meson system using asymmetrically time-integrated decay rates is discussed. With this method, observation of CP violation may be posible at ψ(4S), where the CP asymmetry vanishes with the usual symmetric time-integrated rate. A rate estimate is made based on the standard model prediction taking the lates observation of \(B^0 - \overline {B^0 } \) oscillations into account. We confirm the previous prediction that CP violation can be large in theB-meson system.     

Measuring D~0-~0mixing in D→f_0(980)K~* and more

We investigate the D0-0 mixing through the doubly Cabibbo suppressed (DCS) channel D0 →f0(980)K0 and its charge conjugate channel, in which the K0 meson is reconstructed in both K π- and KSπ0 final state. Although the decay D0 →f0(980)K* has a small branching ratio, the final state mesons are relatively easy to identify. The f0(980) meson can be replaced by the S-wave π π- state, or a longitudinally polarized vector meson ρ0. All mixing parameters, including the mass difference and decay width difference,can be extracted by studying the time-dependent decay width of these channels. We show that the method is valid in all regions for mixing parameters and it does not depend on the strong phase difference.