arXiv subjects

Wen-Fei Wang

Publications and source records attributed to Wen-Fei Wang.

45 records · Page 3Linked to original sources

arXiv2014

Direct CP asymmetries of three-body $B$ decays in perturbative QCD

We propose a theoretical framework for analyzing three-body hadronic $B$ meson decays based on the perturbative QCD approach. The crucial nonperturbative input is a two-hadron distribution amplitude for final states, whose involved time-like form factor and rescattering phase are fit to relevant experimental data. Together with the short-distance strong phase from the $b$-quark decay kernel, we are able to make predictions for direct CP asymmetries in, for example, the $B^\pm \to π^+ π^- π^\pm$ and $π^+π^-K^\pm$ modes, which are consistent with the LHCb data in various localized regions of phase space. Applications of our formalism to other three-body hadronic and radiative $B$ meson decays are mentioned.

hep-ph↗

arXiv2014

Semileptonic decays $B \to D^{(*)} lν$ in the perturbative QCD factorization approach

In this paper, we study the $B \to D^{(*)} l^- \barν_{\rm l}$ semileptonic decays and calculate the branching ratios ${\cal B}(B \to D^{(*)} l^- \barν_{\rm l})$ and the ratios $R(D^{(*)})$ and $R_{\rm D}^{\rm l,τ}$ by employing the perturbative QCD (pQCD) factorization approach. We find that (a) for $R(D)$ and $R(D^*)$ ratios, the pQCD predictions are $R(D)=0.430^{+0.021}_{-0.026}$, $R(D^*)=0.301 \pm 0.013$ and agree well with BaBar's measurements of $R(D^{(*)})$; (b) for the newly defined $R_{\rm D}^{\rm l}$ and $R_{\rm D}^{\rm τ}$ ratios, the pQCD predictions are $R_{\rm D}^{\rm l} = 0.450^{+0.064}_{-0.051}$ and $R_{\rm D}^{\rm τ} =0.642^{+0.081}_{-0.070}$, which may be more sensitive to the QCD dynamics of the considered semileptonic decays than $R(D^{(*)})$ and should be tested by experimental measurements.

hep-ph↗

arXiv2013

Study of $\bar{B}_s^0 \to (D_s^+,D_s^{*+}) l^-\barν_l$ decays in the pQCD factorization approach

The $\bar{B}_s^0 \to D_s^{(*)+} l^- \barν_l$ semileptonic decays were calculated in the framework of the standard model (SM) by employing the perturbative QCD (pQCD) factorization approach. We defined four ratios of the branching ratios of the considered decays $R(D_s^{(*)})$ and $R_{D_s}^{l,τ}$. From the numerical results and phenomenological analysis we found that: (a) The pQCD predictions for the branching ratios $Br(\bar{B}_s^0 \to D_s^{(*)+} l^-\barν_l)$ generally agree well with the previous theoretical predictions; (b) For the four ratios, the pQCD predictions are $R(D_s)= 0.392 \pm 0.022$, $R(D_s^{*})= 0.302\pm 0.011$, $R_{D_{s}}^l=0.448^{+0.058}_{-0.041}$ and $R_{D_{s}}^τ=0.582^{+0.071}_{-0.045}$, which show a very good $SU(3)_F$ flavor symmetry with the corresponding ratios for $B\to D^{(*)} l^- \barν_l$ decays; and (c) we strongly suggest the measurements of the new ratios $R(D_s^{(*)})$ and $R_{D_{s}}^{l,τ}$ in the forthcoming Super-B experiments.

hep-ph↗

arXiv2013

Revisiting $Kπ$ puzzle in the pQCD factorization approach

In this paper, we calculated the branching ratios and direct CP violation of the four $B\to Kπ$ decays with the inclusion of all currently known next-to-leading order (NLO) contributions by employing the perturbative QCD (pQCD) factorization approach. We found that (a) Besides the 10% enhancement from the NLO vertex corrections, the quark-loops and magnetic penguins, the NLO contributions to the form factors can provide an additional $\sim 15%$ enhancement to the branching ratios, and lead to a very good agreement with the data; (b) The NLO pQCD predictions are $\acp^{dir}(B^0\to K^+π^-)=(-6.5\pm 3.1)%$ and $\acp^{dir}(B^+\to K^+ π^0)=(2.2\pm 2.0)%$, become well consistent with the data due to the inclusion of the NLO contributions.

hep-ph↗

arXiv2013

Anatomy of $B \to K η^{(\prime)}$ decays in different mixing schemes and effects of next-to-leading order contributions in the perturbative QCD approach

In this paper we perform a comprehensive study of the four $B \to K \etap$ decays in the pQCD factorization approach. We calculate the CP-averaged branching ratios and CP-violating asymmetries of $B \to K\etap$ decays in the ordinary $η$-$\etar$, the $η$-$\etar$-$G$, and the $η$-$\etar$-$G$-$η_c$ mixing schemes. Besides the full LO contributions, all currently known NLO contributions to $B \to K \etap$ decays in the pQCD approach are taken into account. From our calculations and phenomenological analysis, we find the following. (a) The NLO contributions in general can provide significant enhancements to the LO pQCD predictions for the decay rates of the two $B \to K \etar$ decays, around $70%-89%$ in magnitude, but result in relatively small changes to $Br(B \to K η)$. (b) Although the NLO pQCD predictions in all three considered mixing schemes agree well with the data within one standard deviation, those pQCD predictions in the $η$-$\etar$-$G$ mixing scheme provide the best interpretation for the measured pattern of $Br(B \to K \etap)$: $Br(B^0 \to K^0 η) \approx 1.13\times 10^{-6}$, $Br(B^0 \to K^0 \etar) \approx 66.5 \times 10^{-6}$, $Br(B^\pm \to K^\pm η) \approx 2.36\times 10^{-6}$, and $Br(B^\pm \to K^\pm \etar) \approx 67.3 \times 10^{-6}$, which agree perfectly with the measured values. (c) The NLO pQCD predictions for the CP-violating asymmetries for the four considered decays are also in good consistent with the data. (d) The newly known NLO contribution to the relevant form factors $\calm_{FF}$ can produce about a 20% enhancement to the branching ratios $Br(B \to K \etar)$, which plays an important role in closing the gap between the pQCD predictions and the relevant data. (e) The general expectations about the relative strength of the LO and NLO contributions from different sources are examined and confirmed by explicit numerical calculations.

hep-ph↗

arXiv2013

Semileptonic decays $B/B_s \to (η,\etar, G)(l^+l^-,l\barν,ν\barν)$ in the perturbative QCD approach beyond the leading order

In this paper we make a systematic study of the semileptonic decays $B/B_s \to (η,\etar, G)(l^+l^-,l\barν,ν\barν)$ by employing the perturbative QCD (pQCD) factorization approach. The next-to-leading-order (NLO) contributions to the relevant form factors are included, and the ordinary $η$-$\etar$ mixing scheme and the $η$-$\etar$-$G$ mixing scheme are considered separately, where $G$ denotes a pseudoscalar glueball. The numerical results and the phenomenological analysis indicate that (a) the NLO contributions to the relevant form factors provide 25% enhancement to the leading-order pQCD predictions for the branching ratios $Br(B^-\to η^{(')} l^-\barν_l)$, leading to a good agreement between the predictions and the data; (b) for all considered decays, the pQCD results are basically consistent with those from other different theoretical models; (c) the pQCD predictions in the two considered mixing schemes agree well with each other within theoretical errors. The outcomes presented here can be tested by LHCb and forthcoming Super-$B$ experiments.

hep-ph↗

arXiv2013

Semileptonic decays $B_c\to(η_c,J/Ψ)lν$ in the perturbative QCD approach

In this paper we study the semileptonic decays of $B_c^- \to (η_c,J/ψ)l^-\barν_l$. We firstly evaluate the $B_c \to (η_c,J/Ψ)$ transition form factors $F_0(q^2)$, $F_+(q^2)$, $V(q^2)$ and $A_{0,1,2}(q^2)$ by employing the pQCD factorization approach, and then we calculate the branching ratios for all considered semileptonic decays. Based on the numerical results and the phenomenological analysis, we find that: (a) the pQCD predictions for the values of the $B_c \to η_c$ and $B_c \to J/Ψ$ transition form factors agree well with those obtained by using other methods; (b) the pQCD predictions for the branching ratios of the considered decays are $Br\left(B_c^- \toη_c e^-\barν_e(μ^-\barν_μ)\right) =(4.41^{+1.22}_{-1.09})\times10^{-3}$, $Br\left(B_c^- \toη_cτ^-\barν_τ\right) =(1.37^{+0.37}_{-0.34})\times10^{-3}$, $Br(B_c^- \to J/Ψe^-\barν_e(μ^-\barν_μ)) =(10.03^{+1.33}_{-1.18})\times10^{-3}$, and $Br\left(B_c^- \to J/Ψτ^-\barν_τ\right) =(2.92^{+0.40}_{-0.34})\times10^{-3}$; and (c) we also define and calculate two ratios of the branching ratios $R_{η_c}$ and $R_{J/Ψ}$, which will be tested by LHCb and the forthcoming Super-B experiments.

hep-ph↗

arXiv2012

The semileptonic decays $B/B_s \to (π, K)(l^+l^-,lν,ν\barν)$ in the perturbative QCD approach beyond the leading-order

In this paper we first calculate the form factors of $B \to (π,K)$ and $B_s \to K $ transitions by employing the perturbative QCD (pQCD) factorization approach with the inclusion of the next-to-leading-order(NLO) corrections, and then we calculate the branching ratios of the corresponding semileptonic decays $B/B_s \to (π, K)(l^+l^-,lν,ν\barν)$ (here $l$ denotes $e, μ$ and $τ$). Based on the numerical calculations and phenomenological analysis, we found the following results: (a) For $B \to (π, K)$ and $B_s \to K$ transition form factors $F_{0,+,\rmt}(q^2)$, the NLO pQCD predictions for the values of $F_{0,+,\rmt}(0)$ and their $q^2$-dependence agree well with those obtained from other methods; (b) For $\bar{B}^0 \to π^+l^-\barν_l, \bar{K}^0 l^+ l^- $ and $B^- \to π^0 l^-\barν_l, K^- l^+ l^-$ decay modes, the NLO pQCD predictions for their branching ratios agree very well with the measured values; (c) By comparing the pQCD predictions for $Br(\bar{B}^0 \to π^+l^-\barν_l)$ with the measured decay rate we extract out the magnitude of $V_{ub}$: $|V_{ub}|= (3.80^{+0.56}_{-0.50}(theor.)) \times 10^{-3}$; (d) We also defined several ratios of the branching ratios, $R_ν, R_C$ and $R_{N1,N2,N3}$, and presented the corresponding pQCD predictions, which will be tested by LHCb and the forthcoming Super-B experiments.

hep-ph↗

arXiv2012

Revisiting the pure annihilation decays $B_s\to π^+ π^-$ and $B^0 \to K^+ K^-$: the data and the pQCD predictions

In this work, we recalculate the charmless pure annihilation decays $B_s\to π^+ π^-$ and $B^0 \to K^+ K^-$ by using the perturbative QCD (pQCD) factorization approach, and compare the pQCD predictions with currently available experimental measurements. We used the same set of relevant input parameters and wave functions to make the calculations for the considered decay modes and found the following results: (a) one can provide a consistent pQCD interpretation for both the measured $Br(B_s^0 \to π^+ π^-)$ and $Br(B_d^0 \to K^+ K^-)$ simultaneously; (b) the pQCD predictions for $Br(B_s^0 \to π^+π^-)$ obtained by different authors are well consistent with each other; (c) our new pQCD prediction for $Br(B_d^0 \to K^+K^-)$ agree very well with the measured values from CDF and LHCb Collaboration; and (d) the CP-violating asymmetry ${\cal A}_{CP}(B_d^0 \to K^+K^-) \approx 16%$, which is large and may be detected at the LHCb experiment.

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