Narrow Results

We analyze the D→ππ decay channels at the leading order, α_s corrections with the QCD factorization and the soft-gluon corrections with the light cone QCD sum rule. Comparing with the experimental result, the calculations of the D⁰→π⁺π^- and D⁺→π⁺π⁰ decay are much better under the consideration of the contributions of factorization parts, α_s corrections and soft-gluon effects. However, the calculation result is one order less than the experimental result in D⁰→π⁰π⁰ decay. It may have large effects of final state interaction in the decay channel.

Single transverse-spin asymmetry in high energy hadronic reaction has been greatly investigated from both experiment and theory sides in the last few years. In this talk, I will summarize some recent theoretical developments, which, in my opinion, help to unvail the mysterious of the single spin asymmetry.

We study the effects of the fourth quark generation model in B_d→ϕK_S decay. With the up-to-date experimental data of Br(B_d → ϕK_S), S_ϕKS and A_ϕKS, we derive the new bound of the new weak phase ϕ_sb, which is much more stringent than the existing one. At the same time, the theoretical predictions within the SM for Br(B_d → ϕK_S), S_ϕKS and A_ϕKS agree with the current experimental data within errors.

In this paper, the hadronic decays B⁺→J/ψρ⁺ and B⁰→J/ψρ⁰ have been analyzed in "QCD factorization" method. The effective coefficients have been calculated for three helicity states (h = 0, +, -) which given three contributions of amplitude. We have assumed two scenarios for J/ψ. First, we have considered that J/ψ behaves as a light meson in comparison with B-meson and in other scenario, we have considered mass of J/ψ in our calculations. The branching ratios are calculated in these conditions and also in different energy scales. The obtained results are in agreement with available experimental data at second scenario and μ = m_b/2.

In this paper, the non-leptonic three-body decays $B\to K^{\ast }(892)K\pi$, $\pi \pi$, $KK$ are studied by introducing two-meson distribution amplitude for the $K\pi$, $\pi \pi$ and $KK$ pairs in naive and QCD factorization (QCDF) approaches, such that the analysis is simplified into quasi-two body decays. By considering that the vector meson is being ejected in factorization, the resonant and non-resonant contributions are analyzed by using intermediate mesons in Breit–Wigner resonance formalism and the heavy meson chiral perturbation theory (HMChPT), respectively. The calculated values of the resonant and non-resonant branching ratio of $B\to K^{\ast }(892)\pi \pi$, $B\to K^{\ast }(892)K\pi$ and $B\to K^{\ast }(892)KK$ decay modes are compared with the experimental data. For $B\to K^{0\ast }(892){\pi }^{+}{\pi }^{-}$ and $B\to K^{0\ast }(892)K^{+}{K}^{-}$, the non-resonant contributions are about 70–80% of experimental data, for which the total results by considering resonant contributions are in good agreement with the experiment.

We present an analytic calculation of Branching Ratio (BR) and Charge-Parity (CP) violating asymmetries of the $B_s^0$ meson decay into the two light vectors $K^{\ast 0}{\bar{K}}^{\ast 0}$ by calculating the helicity amplitude in the framework of quantum chromodynamics (QCD) factorization approach. We find the BR of $B_s^0\to K^{\ast 0}{\bar{K}}^{\ast 0}=(1.13\pm 0.18)\times 10^{-5}$ which is in full agreement with the recent theoretical predictions and experimental measurements. We also calculate the direct CP violation, CP violation in mixing and CP violation due to interference which are ${{𝒜}}_{CP}^{\text{dir}}=0.00353\pm 0.00154$, $({{𝒜}}_{CP}^{\text{mix}})=-0.00686\pm 0.03119$, and $({{𝒜}}_{CP}^{\mathrm{\Delta }\mathrm{\Gamma }})=0.99997\pm 0.00021$, respectively.

We study analytically the Branching Ratio (BR) and Charge-Parity (CP) asymmetries of the $\overline{B_s^0}\to \omega \varphi$ decay mode within QCDF approach. We find the $BR(\overline{B_s^0}\to \omega \varphi )=(0.51\pm 0.12)\times 10^{-6}$. We also find the values of CP asymmetries are ${{𝒜}}_{CP}^{\text{dir}}(\overline{B_s^0}\to \omega \varphi )=0.080\pm 0.008$, ${{𝒜}}_{CP}^{\text{mix}}(\overline{B_s^0}\to \omega \varphi )=0.184\pm 0.035$ and ${{𝒜}}_{CP}^{\mathrm{\Delta }\mathrm{\Gamma }}(\overline{B_s^0}\to \omega \varphi )=0.980\pm 0.006$. The reported results are consistent with the recent theoretical predictions and can be used as a reference values in the forthcoming experiments.

We study the large branching ratios of B→ηK* decays and the time-dependent CP asymmetry S_ϕKS anomaly of B→ϕK_S decay in a flavor changing Z′ model associated with flavor changing neutral currents at the tree level. Considering the right-handed flavor changing couplings and setting ξ^LL = ξ^RL = ξ^LR = ξ^RR = ξ, we obtain 0.011 < ξ < 0.0131, this parameter region could give a simultaneous explanation to these anomalies of B→ηK* and B→ϕK_S decays. The results are consistent with the constraints and the assumptions of some references.

After briefly introducing the framework of QCD factorization for B → M₁M₂ in the language of the Soft-Collinear Effective Theory, we firstly address the recent efforts on higher-order radiative corrections in QCD factorization. Then we discuss some phenomenologies in B → VV within the framework of QCD factorization.

Using the factorization approach and considering the contributions of the current–current, QCD penguin and electroweak penguin operators at the leading approximation, the decay amplitudes and decay widths of and transitions, where q = u, d, s and P and V are pseudoscalar and vector mesons, are calculated in terms of the transition form factors of the B_q→D_q and . Having computed those form factors in three-point QCD sum rules, the branching fraction for these decays are also evaluated. A comparison of our results with the predictions of the perturbative QCD as well as the existing experimental data is presented.

The charmless bottom meson decays are systematically investigated based on an approximate six-quark operator effective Hamiltonian from perturbative QCD. It is shown that within this framework the naive QCD factorization method provides a simple way to evaluate the hadronic matrix elements of two-body mesonic decays. The singularities caused by on mass-shell quark propagator and gluon exchanging interaction are appropriately treated. Such a simple framework allows us to make theoretical predictions for the decay amplitudes with reasonable input parameters. The resulting theoretical predictions for all the branching ratios and CP asymmetries in the charmless B⁰, B⁺, B_s → ππ, πK, KK decays are found to be consistent with the current experimental data except for a few decay modes. The observed large branching ratio in B→π⁰π⁰ decay remains a puzzle though the predicted branching ratio may be significantly improved by considering the large vertex corrections in the effective Wilson coefficients. More precise measurements of charmless bottom meson decays, especially on CP violations in B → KK and B_s → ππ, πK, KK decay modes, will provide a useful test and guide us to a better understanding on perturbative and nonperturbative QCD.

In this research, the hadronic decay of is analyzed by using "QCD factorization" (QCDF) method and final state interaction (FSI). First, the decay is calculated via QCDF method and only the annihilation graphs exist in that method. Then, FSI is considered to solve the decay as a sizable correction and the D^+*K⁰, D^0*K⁺ and via the exchange of , K^-(*) and mesons are chosen for the intermediate states. To estimate the intermediate states amplitudes, QCDF method is again used. These amplitudes are used in the absorptive part of the diagrams. The experimental branching ratio of decay is less than 1.9×10^-6 and our results according to QCDF method and FSI effects are 0.16×10^-6 and 1.86×10^-6, respectively.

In this paper, the hadronic decay has been analyzed in naive and QCD factorization methods. The simplest approach to obtain the amplitude of the hadronic B decays is naive factorization, where the matrix elements have been parametrized into products of decay constant and form factors. We have calculated the factorizable amplitudes and nonfactorizable contributions corresponding to the vertex corrections and the hard spectator interactions in QCD factorization. We treat the charm quark as light, compared to the large scale provided by the mass of the decaying b quark (m_c ≪m_b and m_c fixed as m_b→∞). Our obtained branching ratio of is (1.36±0.02)×10^-5 using naive factorization, which is smaller than the experimental data: (1.2±0.4)×10^-4. On the other hand, by considering QCD corrections in QCDF and by treating D-meson as a light, we have obtained the value (2.57±0.01)×10^-5, which has been used to decrease the discrepancy between the theoretical and experimental data.

Motivated by the recent measurements on nonleptonic J/ψ weak decays at BESIII and the potential prospects of J/ψ meson at the high-luminosity heavy-flavor experiments, the branching ratios of the two-body nonleptonic J/ψ → DP, DV decays are estimated quantitatively by considering the QCD radiative corrections to hadronic matrix elements with the QCD factorization approach. It is found that the Cabibbo favored , , decays have branching ratios ≳ 10^-10, which might be promisingly detectable in the near future.

In this paper, we analyzed the decay $B^0\to D_s^{{-}^{\ast }}{K}^{+}$ within QCD factorization (QCDF) and final state interaction (FSI) methods. At first, we consider the QCDF approach, where the final states are a pseudoscalar meson and vector meson. Then, we consider the FSI method where the intermediate states are $D^{-}{\rho }^{+}$ and ${\bar{D}}^0{\rho }^0$ via the exchange of $K^0$, $K^{0^{\ast }}$, $K^{+}$ and $K^{{+}^{\ast }}$ to improve the branching ratio. The above intermediate states are calculated by using the QCDF method. In the FSI effects, the results of our calculations depend on $\eta$ as the phenomenological parameter. The experimental branching ratio of this decay is $(2.19\pm 0.30)\times 10^{-5}$. Our results in QCDF approach is $(0.31\pm 0.06)\times 10^{-5}$, and with $\eta =3$, the improved branching ratio is $(2.02\pm 0.10)\times 10^{-5}$.

In this paper, we analyzed the process of $B_s\to K^{{\mp }^{\ast }}{K}^{\pm }$ decay within QCD factorization (QCDF) and final state interaction (FSI) effects. At first, the $B_s\to K^{{\mp }^{\ast }}{K}^{\pm }$ decay is calculated via QCDF approach. The result that is found by using the QCDF method is less than the experimental result. Then we considered FSI effect as a sizable correction where there are the intermediate state $D_s^{-}{D}_s^{{+}^{\ast }}$ mesons via the exchange of ${\bar{D}}^0({\bar{D}}^{0^{\ast }})$. The experi mental branching ratio of $B_s\to K^{{\mp }^{\ast }}{K}^{\pm }$ decay is $(12.7\pm 1.9)\times 10^{-6}$, and our results by QCDF and FSI are $(2.79\pm 0.08)\times 10^{-6}$ and $(11.6\pm 0.11)\times 10^{-6}$, respectively.

We study analytically the branching ratio (BR) and charge parity (CP) asymmetries of the $\overline{B_s^0}\to K^{\ast 0}{\rho }^0$ and $K^{\ast 0}\omega$ decay modes within QCDF approach. We find the $\mathrm{\text{BR}}(\overline{B_s^0}\to K^{\ast 0}{\rho }^0)=(1.28\pm 0.23)\times 10^{-6}$ and $\mathrm{\text{BR}}(\overline{B_s^0}\to K^{\ast 0}\omega )=(1.12\pm 0.58)\times 10^{-6}$. We also find the values of CP asymmetries are ${{𝒜}}_{CP}^{\text{dir}}(\overline{B_s^0}\to K^{\ast 0}{\rho }^0)=0.214\pm 0.087$, ${{𝒜}}_{CP}^{\text{mix}}(\overline{B_s^0}\to K^{\ast 0}{\rho }^0)=0.377\pm 0.147$, ${{𝒜}}_{CP}^{\mathrm{\Delta }\mathrm{\Gamma }}(\overline{B_s^0}\to K^{\ast 0}{\rho }^0)=0.901\pm 0.051$, ${{𝒜}}_{CP}^{\text{dir}}(\overline{B_s^0}\to K^{\ast 0}\omega )=0.284\pm 0.038$, ${{𝒜}}_{CP}^{\text{mix}}(\overline{B_s^0}\to K^{\ast 0}\omega )=0.835\pm 0.024$, and ${{𝒜}}_{CP}^{\mathrm{\Delta }\mathrm{\Gamma }}(\overline{B_s^0}\to K^{\ast 0}\omega )=-0.471\pm 0.063$. The reported results are consistent with the recent theoretical predictions and can be used as a reference values in the forthcoming experiments.

The high-energy QCD factorization for Deep Inelastic Scattering and for proton-nucleus collisions using Wilson line formalism and factorization in rapidity is discussed. We show that in DIS the factorization in rapidity reduces to the k_T-factorization when the 2-gluon approximation is applied, provided that the composite Wilson line operator is used in the high-energy Operator Product Expansion. We then show that the inclusive forward cross-section in proton-nucleus collisions factorizes in parton distribution functions, fragmentation functions and dipole gluon distribution function at one-loop level.

We summarize a new analysis of the distribution of charged leptons produced in decays of Z and γ* bosons in the Collins-Soper-Sterman (CSS) formalism for transverse momentum resummation. By comparing the distribution measured at the Tevatron with the resummed CSS cross section with approximate Wilson coefficients, we constrain the magnitude of the nonperturbative Gaussian smearing factor and analyze its uncertainty caused by variations in scale parameters. We find excellent agreement between the data and our theoretical prediction, provided by the RESBOS resummation program. The nonperturbative factor that we obtained can be used to update resummed QCD predictions for precision measurements in inclusive W and Z production and for comparisons to various models of nonperturbative dynamics.

We provide an overview of recent investigations into hard processes where the factorization into transverse momentum dependent parton correlation functions breaks down.