13,607 research outputs found

    Analysis of B-> \phi K Decays in QCD Factorization

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    We analyze the decay BϕKB\to \phi K within the framework of QCD-improved factorization. We found that although the twist-3 kaon distribution amplitude dominates the spectator interactions, it will suppress the decay rates slightly. The weak annihilation diagrams induced by (SP)(S+P)(S-P)(S+P) penguin operators, which are formally power-suppressed by order (Λ/mb)2(\Lambda/m_b)^2, are chirally and logarithmically enhanced. Therefore, these annihilation contributions are not subject to helicity suppression and can be sizable. The predicted branching ratio of BϕKB^-\to\phi K^- is (3.8±0.6)×106(3.8\pm0.6)\times 10^{-6} in the absence of annihilation contributions and it becomes (4.31.4+3.0)×106(4.3^{+3.0}_{-1.4})\times 10^{-6} when annihilation effects are taken into account. The prediction is consistent with CLEO and BaBar data but smaller than the BELLE result.Comment: 13 pages, 3 figures. A major change for the presentation of branching-ratio predictions. Experimental data are update

    Stabilizing yield and quality: early maturing chickpea for the prairies

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    Non-Peer ReviewedProgress in chickpea breeding has been constrained by lack of good sources of early maturity in the short-season temperate environment of western Canada. We hypothesized that the length of the chickpea life-cycle could be reduced through introgression of strategic genetic traits including short internode, double podding and early flowering. The result showed that both the double podding and early flowering traits had significant beneficial effects by reducing the duration of crop maturity in chickpea in the short-season temperate environment of western Canada. Pyramiding double podding, early flowering and other strategic genetic traits should lead to the development of extra short duration chickpea varieties more suited for cultivation in the Prairies and similar environments

    Heavy to Light Meson Exclusive Semileptonic Decays in Effective Field Theory of Heavy Quark

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    We present a general study on exclusive semileptonic decays of heavy (B, D, B_s) to light (pi, rho, K, K^*) mesons in the framework of effective field theory of heavy quark. Transition matrix elements of these decays can be systematically characterized by a set of wave functions which are independent of the heavy quark mass except for the implicit scale dependence. Form factors for all these decays are calculated consistently within the effective theory framework using the light cone sum rule method at the leading order of 1/m_Q expansion. The branching ratios of these decays are evaluated, and the heavy and light flavor symmetry breaking effects are investigated. We also give comparison of our results and the predictions from other approaches, among which are the relations proposed recently in the framework of large energy effective theory.Comment: 18 pages, ReVtex, 5 figures, added references and comparison of results, and corrected signs in some formula

    QCD factorization for B -> PP

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    In this work, we give a detailed discussion for QCD factorization involved the complete chirally enhanced power corrections for B decays to two light pseudoscalar mesons, and present some detailed calculations of radiative corrections at the order of alpha_s. We point out that the infrared finiteness of the vertex corrections in the chirally enhanced power corrections requires twist-3 light-cone distribution amplitudes (LCDAs) of the light pseudoscalar symmetric. However, even in the symmetric condition, there is also logarithmic divergence from the endpoints of the twist-3 LCDAs in the hard spectator scattering. We point out that the decay amplitudes of B --> PP predicted by QCD factorization are really free of the renormalization scale dependence, at least at the order of alpha_s. At last, we briefly compare the QCD factorization with the generalized factorization and PQCD method.Comment: 31 pages, 3 eps figure

    Testing the dynamics of high energy scattering using vector meson production

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    I review work on diffractive vector meson production in photon-proton collisions at high energy and large momentum transfer, accompanied by proton dissociation and a large rapidity gap. This process provides a test of the high energy scattering dynamics, but is also sensitive to the details of the treatment of the vector meson vertex. The emphasis is on the description of the process by a solution of the non-forward BFKL equation, i.e. the equation describing the evolution of scattering amplitudes in the high-energy limit of QCD. The formation of the vector meson and the non-perturbative modeling needed is also briefly discussed.Comment: 17 pages, 8 figures. Brief review to appear in Mod. Phys. Lett.

    Remarks on the KLS conjecture and Hardy-type inequalities

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    We generalize the classical Hardy and Faber-Krahn inequalities to arbitrary functions on a convex body ΩRn\Omega \subset \mathbb{R}^n, not necessarily vanishing on the boundary Ω\partial \Omega. This reduces the study of the Neumann Poincar\'e constant on Ω\Omega to that of the cone and Lebesgue measures on Ω\partial \Omega; these may be bounded via the curvature of Ω\partial \Omega. A second reduction is obtained to the class of harmonic functions on Ω\Omega. We also study the relation between the Poincar\'e constant of a log-concave measure μ\mu and its associated K. Ball body KμK_\mu. In particular, we obtain a simple proof of a conjecture of Kannan--Lov\'asz--Simonovits for unit-balls of pn\ell^n_p, originally due to Sodin and Lata{\l}a--Wojtaszczyk.Comment: 18 pages. Numbering of propositions, theorems, etc.. as appeared in final form in GAFA seminar note

    P-wave Quarkonium Decays to Meson Pairs

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    The processes of P-wave Quarkonium exclusive decays to two mesons are investigated, in which the final state vector mesons with various polarizations are considered separately. In the calculation, the initial heavy quarkonia are treated in the framework of non-relativistic quantum chromodynamics, whereas for light mesons, the light cone distribution amplitudes up to twist-3 are employed. It turns out that the higher twist contribution is significant and provides a possible explanation for the observation of the hadron helicity selection rule violated processes χc1ϕϕ,ωω\chi_{c1}\rightarrow \phi\phi,\omega\omega by the BESIII collaboration in recently. We also evaluate the χb1J/ψJ/ψ\chi_{b1}\to J/\psi J/\psi process and find that its branching ratio is big enough to be measured at the B-factories.Comment: more results and discussions adde

    Exploring the Unitarity Triangle through CP violation observables in BsK+KB_s \to K^+ K^-

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    We discuss the determination of the CKM parameters from the forthcoming CPCP violation observables in BsK+KB_s \to K^+ K^- decays. Combining the information on mixing induced CP violation in BsK+KB_s \to K^+ K^-, with the BdJ/ψKsB_d \to J/\psi K_s precision observable sin2β\sin 2\beta and the Bs0B^0_s--Bs0ˉ\bar{B^0_s} mixing phase ϕs\phi_s, we propose a determination of the unitarity triangle (ρˉ,ηˉ)(\bar\rho, \bar\eta). Computing the penguin parameters (r,θ)(r, \theta) within QCD factorization yield precise determination of (ρˉ,ηˉ)(\bar\rho, \bar\eta), reflected by a weak dependence on the θ\theta which is shown as a second order effect. The impact of the direct CP violation observable CKKC_{KK} on the penguin parameters are investigated and a lower bound on CKKC_{KK} is extracted. We also discuss the effect of the Bs0B^0_s--Bs0ˉ\bar{B^0_s} new physics mixing phase on the penguin parameters (r,θ)(r, \theta) and SKKS_{KK}. Using the SU(3)-flavour symmetry argument and the current BB-factories data provided by the Bdπ+πB_d \to \pi^+ \pi^- modes, we complement the BsK+KB_s \to K^+ K^- CP-violating observables in a variety of ways, in particular we find that SKK>0S_{KK}>0. Finally we analyze systematically the SU(3)-symmetry breaking factor within QCD factorization.Comment: 22 pages, 6 figures, typos corrected, reference and some remarks adde
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