Charmless non-leptonic B s decays to P P , P V and V V final states in the pQCD approach AbstractWe calculate the CP-averaged branching ratios and CP-violating asymmetries of a number of two-body charmless hadronic decays B 0 s → P P, P V, V V in the perturbative QCD (pQCD) approach to leading order in α s (here P and V denote light pseudo-scalar and vector mesons, respectively). The mixinginduced CP violation parameters are also calculated for these decays. We also predict the polarization fractions of B s → V V decays and find that the transverse polarizations are enhanced in some penguin dominated decays such as B 0 s → K * K * , K * ρ. Some of the predictions worked out here can already be confronted with the recently available data from the CDF collaboration on the branching ratios for the

We calculate next-to-leading-order (NLO) corrections to the B ! transition form factors at leading twist in the k T factorization theorem. Light partons off shell by k 2 T are considered in the quark diagrams, in the effective diagrams for the B-meson wave function defined with the effective heavy-quark field, and in the effective diagrams for the pion wave function. It is explicitly demonstrated that the infrared logarithms lnk 2 T cancel between the above sets of diagrams, as deriving the k T -dependent NLO hard kernel from their difference. The infrared finiteness of the hard kernel confirms the application of the k T factorization theorem to B-meson semileptonic decays. The NLO pion wave function is identical to those constructed from the pion transition and electromagnetic form factors, consistent with its universality. Choosing the renormalization and factorization scales lower than the B-meson mass, the NLO corrections are under control: they amount only up to 30% of the form factors at large recoil of the pion, when varying models for the meson wave functions.

These predictions will be tested on the ongoing and forthcoming hadron colliders.

We compute perturbative corrections to B → π form factors from QCD light-cone sum rules with B-meson distribution amplitudes. Applying the method of regions we demonstrate factorization of the vacuum-to-B-meson correlation function defined with an interpolating current for pion, at one-loop level, explicitly in the heavy quark limit. The short-distance functions in the factorization formulae of the correlation function involves both hard and hard-collinear scales; and these functions can be further factorized into hard coefficients by integrating out the hard fluctuations and jet functions encoding the hard-collinear information. Resummation of large logarithms in the short-distance functions is then achieved via the standard renormalization-group approach. We further show that structures of the factorization formulae for f + Bπ (q 2 ) and f 0 Bπ (q 2 ) at large hadronic recoil from QCD light-cone sum rules match that derived in QCD factorization. In particular, we perform an exploratory phenomenological analysis of B → π form factors, paying attention to various sources of perturbative and systematic uncertainties, and extract |V ub | = 3.05 +0.54 −0.38 | th. ± 0.09| exp. × 10 −3 with the inverse moment of the B-meson distribution amplitude φ + B (ω) determined by reproducing f + Bπ (q 2 = 0) obtained from the light-cone sum rules with π distribution amplitudes. Furthermore, we present the invariant-mass distributions of the lepton pair for B → πℓν ℓ (ℓ = µ , τ ) in the whole kinematic region. Finally, we discuss non-valence Fock state contributions to the B → π form factors f + Bπ (q 2 ) and f 0 Bπ (q 2 ) in brief.

We calculate next-to-leading-order (NLO) correction to the pion electromagnetic form factor at leading twist in the kT factorization theorem. Partons off-shell by k 2 T are considered in both quark diagrams and effective diagrams for the transverse-momentum-dependent (TMD) pion wave function. The light-cone singularities in the TMD pion wave function are regularized by rotating the Wilson lines away from the light cone. The soft divergences from gluon exchanges among initialand final-state partons cancel exactly. We derive the infrared-finite kT -dependent NLO hard kernel for the pion electromagnetic form factor by taking the difference of the above two sets of diagrams. Varying the renormalization and factorization scales, we find that the NLO correction is smaller, when both the scales are set to the invariant masses of internal particles: it becomes lower than 40% of the leading-order (LO) contribution for momentum transfer squared Q 2 > 7 GeV 2 . It is observed that the NLO leading-twist correction does not play an essential role in explaining the experimental data, but the LO higher-twist contribution does.

Applying the method of light-cone sum rules with photon distribution amplitudes, we compute the subleading-power correction to the radiative leptonic B → γ ν decay from the twist-two hadronic photon contribution at next-to-leading order in QCD; and further evaluate the higher-twist "resolved photon" corrections at leading order in α s , up to twist-four accuracy. QCD factorization for the vacuum-to-photon correlation function with an interpolating current for the B-meson is established explicitly at leading power in Λ/m b employing the evanescent operator approach. Resummation of the parametrically large logarithms of m 2 b /Λ 2 entering the hard function of the leading-twist factorization formula is achieved by solving the QCD evolution equation for the light-ray tensor operator at two loops. The leading-twist hadronic photon effect turns out to preserve the symmetry relation between the two B → γ form factors due to the helicity conservation, however, the higher-twist hadronic photon corrections can yield symmetry-breaking effect already at tree level in QCD. Using the conformal expansion of photon distribution amplitudes with the non-perturbative parameters estimated from QCD sum rules, the twist-two hadronic photon contribution can give rise to approximately 30% correction to the leading-power "direct photon" effect computed from the perturbative QCD factorization approach. In contrast, the subleading-power corrections from the higher-twist two-particle and three-particle photon distribution amplitudes are estimated to be of O(3 ∼ 5%) with the light-cone sum rule approach. We further predict the partial branching fractions of B → γ ν with a photonenergy cut E γ ≥ E cut , which are of interest for determining the inverse moment of the leading-twist B-meson distribution amplitude thanks to the forthcoming high-luminosity Belle II experiment at KEK.

We compute radiative corrections to Λ b → Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ b -baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ b -baryon correlation function is justified at leading power in Λ/m b , with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to-B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at O(α s ) shift the Λ b → Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ b → Λ from factors we further investigate several decay observables in the electro-weak penguin Λ b → Λ + − transitions in the factorization limit (i.e., ignoring the "non-factorizable" hadronic effects which cannot be expressed in terms of the Λ b → Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.

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 Bmeson 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 . 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-toleading-logarithmic sum rules for the form factors of B → D ν 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 → D ν 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 +,0 BD (q 2 ) are explored by investigating the (differential) branching fractions and the R(D) ratio of B → D ν and by determining the CKM matrix element |V cb | from the total decay rate of B → Dµν µ .