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Yueling Yang

Publications and source records attributed to Yueling Yang.

At least 55 records · Page 3Linked to original sources
arXiv2016

Study of nonleptonic $B_{q}^{\ast}$ ${\to}$ $D_{q}V$ and $P_{q} D^*$ weak decays

Motivated by the powerful capability of measurement for the $b$-flavored hadron rare decays at LHC and SuperKEKB/Belle-II, the nonleptonic $\bar{B}^{\ast}$ ${\to}$ $D\bar{D}^{\ast}$, $D{ρ^-}$, $DK^{\ast-}$, $πD^{\ast}$ and $KD^{\ast}$ weak decays are studied in detail. With the amplitudes calculated with factorization approach and the form factors of $B^{\ast}$ transition into pseudoscalar meson evaluated with the BSW model, branching fractions and polarization fractions are firstly presented. Numerically, the CKM-favored $\bar{B}_{q}^{\ast}$ ${\to}$ $D_{q}D_{s}^{{\ast}-}$ and $D_{q}ρ^{-}$ decays have large branching fractions, $\sim$ $10^{-8}$, which should be sought for with priority and firstly observed by LHC and Belle-II experiments. The $\bar{B}^{\ast}_q$ ${\to}$ $D_qK^{\ast}$ and $D_qρ$ decays are dominated by the longitudinal polarization states. While, the parallel polarization fractions of $\bar{B}^{\ast}_q$ ${\to}$ $D_q\bar{D}^{\ast}$ decays are comparable with the longitudinal ones, numerically, $f_{\parallel}$ $+$ $f_{L}$ ${\simeq}$ 95\% and $f_{L}:f_{\parallel}$ $\simeq$ $5:4$. Some comparisons between $\bar{B}^{*0}_q$ $\to$ $D_q V$ and their corresponding $\bar{B}^{0}_q$ $\to$ $D^*_q V$ decays are performed, and the relation $ f_{L,\parallel}(\bar{B}^{\ast 0}\to D V)\simeq f_{L,\parallel}(\bar{B}^0\to D^{\ast +} V^-) $ is presented. Besides, with the implication of $SU(3)$ flavor symmetry, some useful ratios $ R_{\rm du}$ and $ R_{\rm ds}$ are discussed in detail, and suggested to be verified experimentally.

hep-ph↗
arXiv2016

Study of the $Υ(1S)$ ${\to}$ $B_{c}D_{s}^{\ast}$ decay with pQCD approach

The $Υ(1S)$ ${\to}$ $B_{c}D_{s}^{\ast}$ weak decay is studied with the perturbative QCD approach firstly. It is found that (1) main contributions to branching ratio come from the longitudinal and parallel helicity amplitudes, (2) branching ratio, longitudinal and parallel polarization fractions are sensitive to the wave functions of the $Υ(1S)$ meson, (3) branching ratio for the $Υ(1S)$ ${\to}$ $B_{c}D_{s}^{\ast}$ decay can reach up to $10^{-9}$, which might be promisingly measured by the future experiments.

hep-ph↗
arXiv2016

Study of the $ψ(1S,2S)$ and $η_{c}(1S,2S)$ weak decays into $DM$

Inspired by the recent measurements on the $J/ψ(1S)$ ${\to}$ $D_{s}ρ$, $D_{u}K^{\ast}$ weak decays at BESIII and the potential prospects of the charmonium at the high-luminosity heavy-flavor experiments, we study $ψ(1S,2S)$ and $η_{c}(1S,2S)$ weak decays into final states including one charmed meson plus one light meson, considering the QCD corrections to hadronic matrix elements with the QCD factorization. It is found that the Cabibbo favored $ψ(1S,2S)$ ${\to}$ $D_{s}^{-}ρ^{+}$, $D_{s}^{-}π^{+}$, $\overline{D}_{u}^{0}\overline{K}^{{\ast}0}$ decays have branching ratios ${\gtrsim}$ $10^{-10}$, which might be accessible at the future experiments.

hep-ph↗
arXiv2016

$J/ψ$ ${\to}$ $DP$, $DV$ decays in the QCD factorization approach

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 $J/ψ$ ${\to}$ $DP$, $DV$ 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 $J/ψ$ ${\to}$ $D_{s}^{-}ρ^{+}$, $D_{s}^{-}π^{+}$, $\overline{D}_{u}^{0}\overline{K}^{{\ast}0}$ decays have branching ratios ${\gtrsim}$ $10^{-10}$, which might be promisingly detectable in the near future.

hep-ph↗
arXiv2015

Probing Spectator Scattering and Annihilation Corrections in $B_{s}$ $\to$ $PV$ Decays

Motivated by the recent LHCb measurements on $\bar{B}_{s}$ $\to$ $π^{-}K^{*+}$ and $\bar{B}_{s}$ $\to$ $K^{\pm}K^{*\mp}$ decay modes, we revisit the $B_{s}$ $\to$ $PV$ decays within QCD factorization framework. The effects of hard-spectator scattering and annihilation corrections are studied in detail. After performing a $χ^2$-fit on the end-point parameters $X_A^{i,f}$ ($ρ_A^{i,f}$, $ϕ_A^{i,f}$) and $X_H$ ($ρ_H$, $ϕ_H$) with available data, it is found that although some possible mismatches exist, the universalities of $X_A^{i,f}$ and $X_H$ in $B_s$ and $B_{u,d}$ systems are still allowed within theoretical uncertainties and experimental errors. With the end-point parameters gotten from $B_{u,d}$ $\to$ $PV$ decays, the numerical results and detailed analyses for the observables of $\bar{B}_{s}$ ${\to}$ $πK^{\ast}$, $ρK$, $πρ$, $πϕ$ and $Kϕ$ decay modes are presented. In addition, we have identified a few useful observables, especially the ones of $\bar{B}_{s}$ $\to$ $π^{0}ϕ$ decay for instance, for probing hard-spectator scattering and annihilation contributions.

hep-ph↗
arXiv2015

$B_{c}$ ${\to}$ $BP$, $BV$ decays with the QCD factorization approach

We studied the nonleptonic $B_{c}$ ${\to}$ $BP$, $BV$ decay with the QCD factorization approach. It is found that the Cabibbo favored processes of $B_{c}$ ${\to}$ $B_{s}π$, $B_{s}ρ$, $B_{u}\bar{K}$ are the promising decay channels with branching ratio larger than 1\%, which should be observed earlier by the LHCb Collaboration.

hep-ph↗
arXiv2015

Constraints on hard spectator scattering and annihilation corrections in $B_{u,d}$ ${\to}$ $PV$ decays within QCD factorization

In this paper, we investigate the contributions of hard spectator scattering and annihilation in $B\to PV$ decays within the QCD factorization framework. With available experimental data on $B\to πK^{\ast}$, $ρK$, $πρ$ and $Kϕ$ decays, comprehensive $χ^2$ analyses of the parameters $X_{A,H}^{i,f}(ρ_{A,H}^{i,f},ϕ_{A,H}^{i,f})$ are performed, where $X_A^f$ ($X_A^i$) and $X_H$ are used to parameterize the endpoint divergences of the (non)factorizable annihilation and hard spectator scattering amplitudes, respectively. Based on $χ^2$ analyses, it is observed that (1) The topology-dependent parameterization scheme is feasible for $B\to PV$ decays; (2) At the current accuracy of experimental measurements and theoretical evaluations, $X_H=X_A^i$ is allowed by $B\to PV$ decays, but $X_{H}\neq X_A^f$ at $68%$ C. L.; (3) With the simplification $X_H=X_A^i$, parameters $X_A^f$ and $X_A^i$ should be treated individually. The above-described findings are very similar to those obtained from $B\to PP$ decays. Numerically, for $B\to PV$ decays, we obtain $(ρ_{A,H}^i,ϕ_{A,H}^i[^{\circ}]) =(2.87^{+0.66}_{-1.95}, -145^{+14}_{-21})$ and $(ρ_A^f,ϕ_A^f[^{\circ}]) = (0.91^{+0.12}_{-0.13}, -37^{+10}_{-9})$ at $68%$ C. L.. With the best-fit values, most of the theoretical results are in good agreement with the experimental data within errors. However, significant corrections to the color-suppressed tree amplitude $α_2$ related to a large $ρ_H$ result in the wrong sign for $A^{dir}_{CP}(B^- \to π^0 K^{{\ast}-})$ compared with the most recent BABAR data, which presents a new obstacle in solving "$ππ$" and "$πK$" puzzles through $α_2$. A crosscheck with measurements at Belle (or Belle II) and LHCb, which offer higher precision, is urgently expected to confirm or refute such possible mismatch.

hep-ph↗
arXiv2014

A Combined Fit on the Annihilation Corrections in $B_{u,d,s}$ $\to$ $PP$ Decays Within QCDF

Motivated by the possible large annihilation contributions implied by recent CDF and LHCb measurements on nonleptonic annihilation B meson decays, and the refined experimental measurements on hadronic B meson decays, we study the strength of annihilation contributions within QCD factorization (QCDF) in this paper. With the available measurements of two-body B_{u,d,s} -> pi pi, pi K, K K decays, a comprehensive fit on the phenomenological parameters X_A^{i,f} (or rho_A^{i,f} and phi_A^{i,f}) which are used to parameterize the endpoint singularity in annihilation amplitudes is performed with the statistical chi^2 approach. It is found that (1) flavor symmetry breaking effects are hardly to be distinguished between X_{A,s}^i and X_{A,d}^i due to the large experimental errors and theoretical uncertainties, where X_{A,s}^i and X_{A,d}^i are related to the nonfactorization annihilation contributions in B_s and B_{u,d} decays, respectively. So X_{A,s}^i = X_{A,d}^i is a good approximation by now. (2) In principle, parameter X_{A}^f which is related to the factorization annihilation contributions and independent of the initial state can be regarded as the same variable for B_{u,d,s} decays. (3) Numerically, two solutions are found, one is (rho_A^i, phi_A^i) = (2.98^+1.12_-0.86,-105^+34_-24) and (rho_A^f, phi_A^f) = (1.18^+0.20_-0.23,-40^+11_-8), the other is (rho_A^i, phi_A^i) = (2.97^+1.19_-0.90,-105^+32_-24) and (rho_A^f, phi_A^f) = (2.80^+0.25_-0.21,165^+4_-3). Obviously, nonfactorization annihilation parameter X_A^i is generally unequal to factorization annihilation parameter X_A^f, which differ from the traditional treatment. With the fitted parameters, all results for observables of B_{u,d,s} ->pi pi, pi K, K K decays are in good agreement with experimental data.

hep-ph↗
arXiv2014

B\to K_1π(K) decays in the perturbative QCD approach

Within the framework of the perturbative QCD approach, we study the two-body charmless decays $B\to K_1(1270)(K_1(1400))π(K)$. We find the following results: (i) The decays $\bar B^0\to K_1(1270)^+π^-, K_1(1400)^+π^-$ are incompatible with the present experimental data. There exists a similar situation for the decays $\bar B^0\to a_1(1260)^+K^-, b_1(1235)^+K^-$, which are usually considered that the nonperturbative contributions are needed to explain the data. But the difference is that the nonperturbative contributions seem to play opposite roles in these two groups of decays.(ii) The pure annihilation type decays $\bar B^0\to K_1^{\pm}(1270)K^{\mp}, K_1^{\pm}(1400)K^{\mp}$ are good channels to test whether an approach can be used to calculate correctly the strength of the penguin-annihilation amplitudes. Their branching ratios are predicted at $10^{-7}$ order, which are larger than the QCDF results. (iii) The dependence of the direct CP-violating asymmetries of these decays on the mixing angle $θ_{K_1}$ are also considered.

hep-ph↗
arXiv2014

Spectator Scattering and Annihilation Contributions as a Solution to the $πK$ and $ππ$ Puzzles within QCD Factorization Approach

The large branching ratios for pure annihilation $\bar{B}_s^0$ $\to$ $π^+ π^-$ and $\bar{B}_d^0$ $\to$ $K^+ K^-$ decays reported by CDF and LHCb collaborations recently and the so-called $πK$ and $ππ$ puzzles indicate that spectator scattering and annihilation contributions are important to the penguin-dominated, color-suppressed tree dominated, and pure annihilation nonleptonic $B$ decays. Combining the available experimental data for $B_{u,d}$ ${\to}$ $ππ$, $πK$ and $K \bar{K}$ decays, we do a global fit on the spectator scattering and annihilation parameters $X_H(ρ_H$, $ϕ_H)$, $X_A^i(ρ_A^{i},ϕ_A^{i})$ and $X_A^f(ρ_A^{f},ϕ_A^{f})$, which are used to parameterize the endpoint singularity in amplitudes of spectator scattering, nonfactorizable and factorizable annihilation topologies within the QCD factorization framework, in three scenarios for different purpose. Numerically, in scenario II, we get $(ρ_A^{i},ϕ_A^{i}[^{\circ}])=(2.88^{+1.52}_{-1.30},-103^{+33}_{-40})$ and $(ρ_A^{f},ϕ_A^{f}[^{\circ}])=(1.21^{+0.22}_{-0.25},-40^{+12}_{-8})$ at the $68\%$ confidence level, which are mainly demanded by resolving $πK$ puzzle and confirm the presupposition that $X_A^i\neq X_A^f$. In addition, correspondingly, the $B$-meson wave function parameter $λ_B$ is also fitted to be $0.18^{+0.11}_{-0.08}\, MeV$, which plays an important role for resolving both $πK$ and $ππ$ puzzles. With the fitted parameters, the QCDF results for observables of $B_{u,d}$ $\to$ $ππ$, $πK$ and $K \bar{K}$ decays are in good agreement with experimental measurements. Much more experimental and theoretical efforts are expected to understand the underlying QCD dynamics of spectator scattering and annihilation contributions.

hep-ph↗
arXiv2014

Study of the $B_{c}$ ${\to}$ $B_{s}π$ decay with the perturbative QCD approach

The $B_{c}$ ${\to}$ $B_{s}π$ decay is studied with the perturbative QCD approach. Three types of wave functions for $B_{s}$ meson are considered. The transition form factor $F_{0}^{B_{c}{\to}B_{s}}(0)$ and the branching ratio ${\cal B}r(B_{c}{\to}B_{s}π)$ are sensitive to the model of the $B_{s}$ meson wave functions. With appropriate inputs, our estimate on ${\cal B}r(B_{c}{\to}B_{s}π)$ is comparable with the recent LHCb measurement. A clear signal of $B_{c}$ ${\to}$ $B_{s}π$ decay should be easily observed at the Large Hadron Collider.

hep-ph↗
arXiv2014

Study of the $η^{\prime}$ ${\to}$ $Ve^{+}e^{-}$ decay with hidden local symmetry model

Within the hidden local symmetry framework, the Dalitz decay $η^{\prime}$ ${\to}$ $Ve^{+}e^{-}$ is studied with the vector meson dominance model. It is found that the partial width $Γ(η^{\prime}{\to}ωe^{+}e^{-})$ ${\approx}$ $40$ eV and branching ratio ${\cal B}(η^{\prime}{\to}ωe^{+}e^{-})$ ${\approx}$ $2{\times}10^{-4}$, and $Γ(η^{\prime}{\to}ρe^{+}e^{-})$ ${\approx}$ $10Γ(η^{\prime}{\to}ωe^{+}e^{-})$ and ${\cal B}(η^{\prime}{\to}ρe^{+}e^{-})$ ${\approx}$ $10{\cal B}(η^{\prime}{\to}ωe^{+}e^{-})$. The maximum position of the dilepton distribution is $m_{e^{+}e^{-}}$ ${\approx}$ $1.33$ MeV. These decays are measurable with the advent of high statistics $η^{\prime}$ experiments.

hep-ph↗
arXiv2014

Phenomenological study of the $B_{c}$ ${\to}$ $BP$, $BV$ decays with perturbative QCD approach

Inspired by the recent LHCb measurements and forthcoming great potential on $B_{c}$ meson, we study the exclusive $B_{c}$ ${\to}$ $B_{q}P$, $B_{q}V$ decays with the perturbative QCD approach, where $q$ $=$ $u$, $d$, $s$; $P$ and $V$ denote the lightest pseudoscalar and vector $SU(3)$ nonet meson, respectively. By retaining the quark transverse momentum, employing the Sudakov factors, and choosing the typical scale as the maximum virtualities of the internal particles, we calculate the $B_{c}$ ${\to}$ $B$ transition from factors, and our results show that about 90\% contribution to form factors come from the $α_{s}/π$ $<$ $0.3$ region. The contributions of penguin and annihilation to branching ratios are very small due to the serious suppression by the CKM factors. There is some hierarchy relations among the $B_{c}$ ${\to}$ $BP$, $BV$ decays. The branching ratios for $B_{c}$ ${\to}$ $B_{d,s}π$, $B_{d,s}ρ$, $B_{s}K$ are large and could be measured by the running LHCb.

hep-ph↗
arXiv2013

Study of $B_{s}$ ${\to}$ $η_{c}(J/ψ)D$ decay with perturbative QCD approach

The $W$-exchange process $B_{s}$ ${\to}$ $η_{c}(J/ψ)D$ is studied with the perturbative QCD approach. Three kinds of wave functions for $B_{s}$ meson and two forms of wave functions for charmonium are considered. It is estimated that branching ratios for $B_{s}$ ${\to}$ $η_{c}\bar{D}$, $η_{c}D$, $J/ψ\bar{D}$, $J/ψD$ decays are the order of $10^{-7}$, $10^{-8}$, $10^{-8}$, $10^{-9}$, respectively, where the largest uncertainty is from wave functions. There is a possibility for measuring these decay in the near future.

hep-ph↗
arXiv2008

Study of Bc -> BP,BV Decays with QCD Factorization

The Bc -> BP,BV decays are studied with the QCD factorization approach (where P and V denote pseudoscalar and vector mesons, respectively). Considering the contributions of both current-current and penguin operators, the amplitudes of branching ratios are estimated at the leading approximation. We find that the contributions of the penguin operators are very small due to the serious suppression by the CKM elements. The most promising decay modes are Bc -> Bs Pi, Bs rho, which might be easily detected at hadron colliders.

hep-ph↗
arXiv2004

Detecting the neutral top-pion at $e^{+}e^{-}$ colliders

We investigate some processes of the associated production of a neutral top-pion $Π^{0}_{t}$ with a pair of fermions($e^{+}e^{-}\to f\bar{f}Π^{0}_{t}$) in the context of top-color-assisted technicolor(TC2) theory at future $e^{+}e^{-}$ colliders. The studies show that the largest cross sections of the processes $e^{+}e^{-}\to f'\bar{f'}Π^{0}_{t}(f'=u,d,c,s,μ,τ)$ could only reach the level of 0.01fb, we can hardly detect a neutral top-pion through these processes. For the processes $e^{+}e^{-}\to e^{+}e^{-}Π^{0}_{t}$, $e^{+}e^{-}\to t\bar{t}Π^{0}_{t}$ and $e^{+}e^{-}\to b\bar{b}Π^{0}_{t}$, the cross sections of these processes are at the level of a few fb for the favorable parameters and a few tens, even hundreds, of neutral top-pion events can be produced at future $e^{+}e^{-}$ colliders each year through these processes. With the clean background of the flavor-changing $t\bar{c}$ channel, the top-pion events can possibly be detected at the planned high luminosity $e^{+}e^{-}$ colliders. Therefore, such neutral top-pion production processes provide a useful way to detect a neutral top-pion and test the TC2 model directly.

hep-ph↗
arXiv2003

Probing neutral top-pion via a flavor-changing process $γγ\to t\bar{c}Π_{t}^{0}$

In the framework of topcolor-assisted-technicolor model(TC2), we study a flavor-changing neutral top-pion production process $γγ\to t\bar{c}Π_{t}^{0}$. The study shows that there exists a resonance effect which can enhance the cross section up to a few fb even tens fb. For a yearly luminosity 100 $fb^{-1}$ at future linear colliders, there might be hundreds even thousands events to be produced. On the other hand, the background of such flavor-changing process is very clean due to the GIM mechanism in SM . With such sufficient events and clean background, neutral toppion could be detected at future linear colliders with high center of energy and luminosity. Our study provides a possible way to test TC2 model.

hep-ph↗