639 research outputs found

    Addendum: New approach to the resummation of logarithms in Higgs-boson decays to a vector quarkonium plus a photon [Phys. Rev. D 95, 054018 (2017)]

    Full text link
    In this addendum to Phys.\ Rev.\ D {\bf 95}, 054018 (2017) we recompute the rates for the decays of the Higgs boson to a vector quarkonium plus a photon, where the vector quarkonium is J/ψJ/\psi, Υ(1S)\Upsilon(1S), Υ(2S)\Upsilon(2S), or Υ(3S)\Upsilon(3S). We correct an error in the Abel-Pad\'e summation formula that was used to carry out the evolution of the quarkonium light-cone distribution amplitude in Phys.\ Rev.\ D {\bf 95}, 054018 (2017). We also correct an error in the scale of quarkonium wave function at the origin in Phys.\ Rev.\ D {\bf 95}, 054018 (2017) and introduce several additional refinements in the calculation.Comment: 7 pages, [v2] Abel-Pade summation formula corrected, [v3] PRD versio

    ZZ-boson decays to a vector quarkonium plus a photon

    Full text link
    We compute the decay rates for the processes ZV+γZ\to V+\gamma, where ZZ is the ZZ boson, γ\gamma is the photon, and VV is one of the vector quarkonia J/ψJ/\psi or Υ(nS)\Upsilon(nS), with n=1n=1, 22, or 33. Our computations include corrections through relative orders αs\alpha_s and v2v^2 and resummations of logarithms of mZ2/mQ2m_Z^2/m_Q^2, to all orders in αs\alpha_s, at NLL accuracy. (vv is the velocity of the heavy quark QQ or the heavy antiquark Qˉ\bar{Q} in the quarkonium rest frame, and mZm_Z and mQm_Q are the masses of ZZ and QQ, respectively.) Our calculations are the first to include both the order-αs\alpha_s correction to the light-cone distributions amplitude and the resummation of logarithms of mZ2/mQ2m_Z^2/m_Q^2 and are the first calculations for the Υ(2S)\Upsilon(2S) and Υ(3S)\Upsilon(3S) final states. The resummations of logarithms of mZ2/mQ2m_Z^2/m_Q^2 that are associated with the order-αs\alpha_s and order-v2v^2 corrections are carried out by making use of the Abel-Pad\'e method. We confirm the analytic result for the order-v2v^2 correction that was presented in a previous publication, and we correct the relative sign of the direct and indirect amplitudes and some choices of scales in that publication. Our branching fractions for ZJ/ψ+γZ\to J/\psi+\gamma and ZΥ(1S)+γZ\to \Upsilon(1S)+\gamma differ by 2.0σ2.0\,\sigma and 4.0σ-4.0\,\sigma, respectively, from the branching fractions that are given in the most recent publication on this topic (in units of the uncertainties that are given in that publication). However, we argue that the uncertainties in the rates are underestimated in that publication.Comment: 26 pages, [v2] references added / [v3] Equation (27) modified, 3 sentences added after Eq. (27), Reference [17] added / [v4] PRD versio

    New approach to the resummation of logarithms in Higgs-boson decays to a vector quarkonium plus a photon

    Full text link
    We present a calculation of the rates for Higgs-boson decays to a vector heavy-quarkonium state plus a photon, where the heavy quarkonium states are the J/psi and the Upsilon(nS) states, with n=1, 2, or 3. The calculation is carried out in the light-cone formalism, combined with nonrelativistic QCD factorization, and is accurate at leading order in m_Q^2/m_H^2, where m_Q is the heavy-quark mass and m_H is the Higgs-boson mass. The calculation contains corrections through next-to-leading order in the strong-coupling constant alpha_s and the square of the heavy-quark velocity v, and includes a resummation of logarithms of m_H^2/m_Q^2 at next-to-leading logarithmic accuracy. We have developed a new method, which makes use of Abel summation, accelerated through the use of Pade approximants, to deal with divergences in the resummed expressions for the quarkonium light-cone distribution amplitudes. This approach allows us to make definitive calculations of the resummation effects. Contributions from the order-alpha_s and order-v^2 corrections to the light-cone distribution amplitudes that we obtain with this new method differ substantially from the corresponding contributions that one obtains from a model light-cone distribution amplitude [M. Koenig and M. Neubert, J. High Energy Phys. 08 (2015) 012]. Our results for the real parts of the direct-process amplitudes are considerably smaller than those from one earlier calculation [G. T. Bodwin, H. S. Chung, J.-H. Ee, J. Lee, and F. Petriello, Phys. Rev. D 90, 113010 (2014)], reducing the sensitivity to the Higgs-boson--heavy-quark couplings, and are somewhat smaller than those from another earlier calculation [M. Koenig and M. Neubert, J. High Energy Phys. 08 (2015) 012]. However, our results for the standard-model Higgs-boson branching fractions are in good agreement with those in M. Koenig and M. Neubert, J. High Energy Phys. 08 (2015) 012.Comment: 40 pages, improved discussion of the convergence of the nonrelativistic expansion, minor corrections and changes in nomenclature, version published in Phys. Rev.

    Vav1 inhibits RANKL-induced osteoclast differentiation and bone resorption

    Get PDF
    Vav1 is a Rho/Rac guanine nucleotide exchange factor primarily expressed in hematopoietic cells. In this study, we investigated the potential role of Vav1 in osteoclast (OC) differentiation by comparing the ability of bone marrow mononuclear cells (BMMCs) obtained from Vav1-deficient (Vav1−/−) and wild-type (WT) mice to differentiate into mature OCs upon stimulation with macrophage colony stimulating factor and receptor activator of nuclear kappa B ligand in vitro. Our results suggested that Vav1 deficiency promoted the differentiation of BMMCs into OCs, as indicated by the increased expression of tartrate-resistant acid phosphatase, cathepsin K, and calcitonin receptor. Therefore, Vav1 may play a negative role in OC differentiation. This hypothesis was supported by the observation of more OCs in the femurs of Vav1−/− mice than in WT mice. Furthermore, the bone status of Vav1−/− mice was analyzed in situ and the femurs of Vav1−/− mice appeared abnormal, with poor bone density and fewer number of trabeculae. In addition, Vav1-deficient OCs showed stronger adhesion to vitronectin, an αvβ3 integrin ligand important in bone resorption. Thus, Vav1 may inhibit OC differentiation and protect against bone resorption

    Angiopoietin-1 is an apoptosis survival factor for endothelial cells

    Get PDF
    AbstractWe examined the effect of angiopoietin-1 (Ang1) on apoptosis in human umbilical vein endothelial cells (HUVECs). Ang1 (5–1000 ng/ml) dose-dependently inhibited apoptosis under a serum-deprived state. A significant apoptotic inhibition occurred with as low as 50 ng/ml. Two hundred ng/ml of Ang1 inhibited to approximately 50% of the control apoptotic rates for 96 h. Furthermore, an augmented antiapoptotic effect of Ang1 by the addition of 20 ng/ml vascular endothelial growth factor was observed. This Ang1-induced strong antiapoptotic effect in endothelial cells is a novel and intriguing finding and could be an additional description of Ang1-induced direct biological function

    Role of Hydrogen in Active Layer of Oxide-Semiconductor-Based Thin Film Transistors

    Get PDF
    Hydrogen in oxide systems plays a very important role in determining the major physical characteristics of such systems. In this study, we investigated the effect of hydrogen in oxide host systems for various oxygen environments that acted as amorphous oxide semiconductors. The oxygen environment in the sample was controlled by the oxygen gas partial pressure in the radio-frequency-sputtering process. It was confirmed that the hydrogen introduced by the passivation layer not only acted as a “killer” of oxygen deficiencies but also as the “creator” of the defects depending on the density of oxide states. Even if hydrogen is not injected, its role can change owing to unintentionally injected hydrogen, which leads to conflicting results. We discuss herein the correlation with hydrogen in the oxide semiconductor with excess or lack of oxygen through device simulation and elemental analysis. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.1
    corecore