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Abstract We investigate the subleading-power corrections to the exclusive B → Dℓν ℓ form factors at O $$ \mathcal{O} $$ ( α s 0 $$ {\alpha}_s^0 $$ ) in the light-cone sum rules (LCSR) framework by including the two- and three-particle higher-twist contributions from the B-meson light-cone distribution amplitudes up to the twist-six accuracy, by taking into account the subleading terms in expanding the hard-collinear charm-quark propagator, and by evaluating the hadronic matrix element of the subleading effective current . Employing further the available leading-power results for the semileptonic B → D form factors at the next-to- leading-logarithmic level and combining our improved LCSR predictions with the recent lattice determinations, we then carry out a comprehensive phenomenological analysis on the semi-leptonic B → Dℓν ℓ decay. We extract V cb = 40.2 − 0.5 + 0.6 th − 1.4 + 1.4 exp × 10 − 3 V cb = 40.9 − 0.5 + 0.6 th − 1.0 + 1.0 exp × 10 − 3 $$ \left|{V}_{cb}\right|=\left({40.2}_{-0.5}^{+0.6}{\left|{{}_{\mathrm{th}}}_{-1.4}^{+1.4}\right|}_{\mathrm{exp}}\right)\times {10}^{-3}\left(\left|{V}_{cb}\right|=\left({40.9}_{-0.5}^{+0.6}{\left|{{}_{\mathrm{th}}}_{-1.0}^{+1.0}\right|}_{\mathrm{exp}}\right)\times {10}^{-3}\right) $$ using the BaBar (Belle) experimental data, and particularly obtain for the gold-plated ratio R(D) = 0.302 ± 0.003.

Abstract Employing the QCD factorization formalism we compute B u − → γ ∗ ℓ v ¯ ℓ $$ {B}_u^{-}\to {\gamma}^{\ast}\mathrm{\ell}{\overline{v}}_{\mathrm{\ell}} $$ form factors with an off-shell photon state possessing the virtuality of order m b ΛQCD and m b 2 $$ {m}_b^2 $$ , respectively, at next-to-leading order in QCD. Perturbative resummation for the enhanced logarithms of m b /ΛQCD in the resulting factorization formulae is subsequently accomplished at next-to-leading logarithmic accuracy with the renormalization-group technique in momentum space. In particular, we derive the soft-collinear factorization formulae for a variety of the subleading power corrections to the exclusive radiative B u − → γ ∗ W ∗ $$ {B}_u^{-}\to {\gamma}^{\ast }{W}^{\ast } $$ form factors with a hard-collinear photon at O α s 0 $$ \mathcal{O}\left({\alpha}_s^0\right) $$ . We further construct a complete set of the angular observables governing the full differential distribution of the four-body leptonic decays B u − → ℓ ′ ℓ ¯ ′ ℓ v ¯ ℓ $$ {B}_u^{-}\to {\mathrm{\ell}}^{\prime }{\overline{\mathrm{\ell}}}^{\prime}\mathrm{\ell}{\overline{v}}_{\mathrm{\ell}} $$ with ℓ, ℓ′ ∈ {e, μ} and then perform an exploratory phenomenological analysis for a number of decay observables accessible at the LHCb and Belle II experiments, with an emphasis on the systematic uncertainties arising from the shape parameters of the leading-twist B-meson light-cone distribution amplitude in heavy quark effective theory.

Abstract We revisit the calculation of the strong couplings D ∗ Dπ and B ∗ Bπ from the QCD light-cone sum rules using the pion light-cone distribution amplitudes. The accuracy of the correlation function, calculated from the operator product expansion near the light-cone, is upgraded by taking into account the gluon radiative corrections to the twist-3 terms. The double spectral density of the correlation function, including the twist-2, 3 terms at O α s $$ \mathcal{O}\left({\alpha}_s\right) $$ and the twist-4 LO terms, is presented in an analytical form for the first time. This form allows us to use various versions of the quark-hadron duality regions in the double dispersion relation underlying the sum rules. We predict g D ∗ Dπ = 14.1 − 1.2 + 1.3 $$ {g}_{D^{\ast } D\pi}={14.1}_{-1.2}^{+1.3} $$ and g B ∗ Bπ = 30.0 − 2.4 + 2.6 $$ {g}_{B^{\ast } B\pi}={30.0}_{-2.4}^{+2.6} $$ when the decay constants of heavy mesons entering the light-cone sum rule are taken from lattice QCD results. We compare our results with the experimental value for the charmed meson coupling and with the lattice QCD calculations.

Abstract Employing the systematic framework of soft-collinear effective theory (SCET) we perform an improved calculation of the leading-power contributions to the double radiative B d,s -meson decay amplitudes in the heavy quark expansion by including the perturbative resummation of enhanced logarithms of m b /ΛQCD at the next-to-leading-logarithmic accuracy. We then construct the QCD factorization formulae for the subleading power contributions arising from the energetic photon radiation off the constituent light-flavour quark of the bottom meson at tree level. Furthermore, we explore the factorization properties of the subleading power correction from the effective SCET current at O α s 0 $$ \mathcal{O}\left({\alpha}_s^0\right) $$ by virtue of the operator identities due to the classical equations of motion. The higher-twist contributions to the B d,s → γγ helicity form factors from the two-particle and three-particle bottom-meson distribution amplitudes are evaluated with the perturbative factorization technique, up to the twist-six accuracy. In addition, the subleading power weak-annihilation contributions from both the current-current and QCD penguin operators are taken into account at the one-loop accuracy. We proceed to apply the operator-production-expansion-controlled dispersion relation for estimating the power-suppressed soft contributions to the double radiative B d,s -meson decay form factors, which cannot be factorized into the light-cone distribution amplitudes of the heavy-meson and the resolved photon as well as the hard-scattering kernel calculable in perturbation theory canonically. Phenomenological explorations of the radiative B d,s → γγ decay observables in the presence of the neutral-meson mixing, including the CP-averaged branching fractions, the polarization fractions and the time-dependent CP asymmetries, are carried out subsequently with an emphasis on the numerical impacts of the newly computed ingredients together with the theory uncertainties from the shape parameters of the HQET bottom-meson distribution amplitudes.

In this review, we discuss the calculation of the B⟶P,V form factors within the framework of the light-cone sum rules with the light-cone distribution amplitudes of the B-meson. A detailed introduction to the definition, scale evolution, and phenomenological models of the B-meson distribution amplitudes is presented. We show two equivalent approaches of calculating the next-to-leading order QCD corrections to the sum rules for the form factors, i.e., the method of regions and the step-by-step matching in the soft-collinear effective theory. The power suppressed corrections to the B⟶P,V form factors especially the contributions from the higher-twist B-meson distribution amplitudes are displayed. We also present numerical results of the form factors including both the QCD and the power corrections, and phenomenological applications of the predicted form factors such as the determination of the CKM matrix element Vub.

Abstract We revisit QCD calculations of radiative heavy meson decay form factors by including the subleading power corrections from the twist-two photon distribution amplitude at next-to-leading-order in α s with the method of the light-cone sum rules (LCSR). The desired hard-collinear factorization formula for the vacuum-to-photon correlation function with the interpolating currents for two heavy mesons is constructed with the operator- product-expansion technique in the presence of evanescent operators. Applying the back- ground field approach, the higher twist corrections from both the two-particle and three- particle photon distribution amplitudes are further computed in the LCSR framework at leading-order in QCD, up to the twist-four accuracy. Combining the leading power “point- like” photon contribution at tree level and the subleading power resolved photon corrections from the newly derived LCSR, we update theory predictions for the nonperturbative couplings describing the electromagnetic decay processes of the heavy mesons H ∗± → H ± γ, H ∗0 → H 0 γ, H s ∗ ± $$ {H_s^{\ast}}^{\pm } $$ → H s ± $$ {H}_s^{\pm } $$ γ (with H = D, B). Furthermore, we perform an exploratory comparisons of our sum rule computations of the heavy-meson magnetic couplings with the previous determinations based upon different QCD approaches and phenomenological models.

Abstract We update QCD calculations of B → π, K form factors at large hadronic recoil by including the subleading-power corrections from the higher-twist B-meson light-cone distribution amplitudes (LCDAs) up to the twist-six accuracy and the strange-quark mass effects at leading-power in Λ/m b from the twist-two B-meson LCDA ϕ B + (ω, μ). The higher-twist corrections from both the two-particle and three-particle B-meson LCDAs are computed from the light-cone QCD sum rules (LCSR) at tree level. In particular, we construct the local duality model for the twist-five and -six B-meson LCDAs, in agreement with the corresponding asymptotic behaviours at small quark and gluon momenta, employing the method of QCD sum rules in heavy quark effective theory at leading order in α s . The strange quark mass effects in semileptonic B → K form factors yield the leading-power contribution in the heavy quark expansion, consistent with the power-counting analysis in soft-collinear effective theory, and they are also computed from the LCSR approach due to the appearance of the rapidity singularities. We demonstrate explicitly that the SU(3)-flavour symmetry breaking effects between B → π and B → K form factors, free of the power suppression in Λ/m b , are suppressed by a factor of α s m b Λ $$ {\alpha}_s\left(\sqrt{m_b\Lambda}\right) $$ in perturbative expansion, and they also respect the large-recoil symmetry relations of the heavy-to-light form factors at least at one-loop accuracy. An exploratory analysis of the obtained sum rules for B → π, K form factors with two distinct models for the B-meson LCDAs indicates that the dominant higher-twist corrections are from the Wandzura-Wilczek part of the two-particle LCDA of twist five g B − (ω, μ) instead of the three-particle B-meson LCDAs. The resulting SU(3)-flavour symmetry violation effects of B → π, K form factors turn out to be insensitive to the non-perturbative models of B-meson LCDAs. We further explore the phenomenological aspects of the semileptonic B → πℓν decays and the rare exclusive processes B → Kνν, including the determination of the CKM matrix element |V ub |, the normalized differential q 2 distributions and precision observables defined by the ratios of branching fractions for the above-mentioned two channels in the same intervals of q 2.

Abstract We reconsider the QCD predictions for the radiative decay B → γℓνℓ with an energetic photon in the final state by taking into account the 1/E γ , 1/m b power-suppressed hard-collinear and soft corrections from higher-twist B-meson light-cone distribution amplitudes (LCDAs). The soft contribution is estimated through a dispersion relation and light-cone QCD sum rules. The analysis of theoretical uncertainties and the dependence of the decay form factors on the leading-twist LCDA ϕ +(ω) shows that the latter dominates. The radiative leptonic decay is therefore well suited to constrain the parameters of ϕ +(ω), including the first inverse moment, 1/λ B , from the expected high-statistics data of the BELLE II experiment.

Abstract We compute perturbative QCD corrections to B → D form factors at leading power in Λ/m b , at large hadronic recoil, from the light-cone sum rules (LCSR) with B-meson distribution amplitudes in HQET. QCD factorization for the vacuum-to-B-meson correlation function with an interpolating current for the D-meson is demonstrated explicitly at one loop with the power counting scheme m c ∼ O Λ m b $$ {m}_c\sim \mathcal{O}\left(\sqrt{\Lambda {m}_b}\right) $$ . The jet functions encoding information of the hard-collinear dynamics in the above-mentioned correlation function are complicated by the appearance of an additional hard-collinear scale m c , compared to the counterparts entering the factorization formula of the vacuum-to-B-meson correction function for the construction of B → π from factors. Inspecting the next-to-leading-logarithmic sum rules for the form factors of B → Dℓν indicates that perturbative corrections to the hard-collinear functions are more profound than that for the hard functions, with the default theory inputs, in the physical kinematic region. We further compute the subleading power correction induced by the three-particle quark-gluon distribution amplitudes of the B-meson at tree level employing the background gluon field approach. The LCSR predictions for the semileptonic B → Dℓν form factors are then extrapolated to the entire kinematic region with the z-series parametrization. Phenomenological implications of our determinations for the form factors f BD +,0 (q 2) are explored by investigating the (differential) branching fractions and the R(D) ratio of B → Dℓν and by determining the CKM matrix element |V cb | from the total decay rate of B → Dμν μ .

Objective: To observe the clinical effect of Chinese medicine Sansheng Huatan Decoction combined with chemotherapy in treating advanced primary non-small-cell lung cancer and to evaluated the effect of Sansheng Huatan Decoction increasing clinical effect and decreasing toxicity in chemotherapy for non-small-cell lung cancer., Methods: One hundred and sixty patients of advanced primary non-small-cell lung cancer proved by pathological examination were randomized into two groups. The treatment group was treated with Sansheng Huatan Decoction and chemotherapy, and the control group was treated only with chemotherapy. The clinic effect, life quality, natural killer (NK) activities, liver and kidney functions, and blood routine test of the 2 groups were evaluated., Results: The clinical effective rates of the treatment and control groups were 56.7% and 48.2% respectively, and there was no statistic significance (P>0.10). The life quality, NK activities and blood routine test of the treatment group were better than those of the control group., Conclusion: Sansheng Huatan Decoction combined with chemotherapy is a better treatment for non-small-cell lung cancer as compared with chemotherapy.