2,049 research outputs found

    B, Bs -> K form factors: an update of light-cone sum rule results

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    We present an improved QCD light-cone sum rule (LCSR) calculation of the B -> K and Bs -> K form factors, by including SU(3)-symmetry breaking corrections. We use recently updated K-meson distribution amplitudes which incorporate the complete SU(3)-breaking structure. By applying the method of the direct integration in the complex plane, which is presented in a detail, the analytical extraction of the imaginary parts of LCSR hard-scattering amplitudes becomes unnecessary and therefore the complexity of the calculation is greatly reduced. The values obtained for the relevant B_{(s)} -> K form factors are as follows: f^+_{BK}(0)= 0.36^{+0.05}_{-0.04}, f^+_{B_sK}(0)= 0.30^{+0.04}_{-0.03} and f^T_{BK}(0)= 0.38\pm 0.05, f^T_{B_sK}(0)= 0.30\pm 0.05. By comparing with the B -> pi form factors extracted recently by the same method, we find the following SU(3) violation among the B -> light form factors: f^+_{BK}(0)/f^+_{B\pi}(0) = 1.38^{+0.11}_{-0.10}, f^+_{B_sK}(0)/f^+_{B\pi}(0) = 1.15^{+0.17}_{-0.09}, f^T_{BK}(0)/f^T_{B\pi}(0) = 1.49^{+0.18}_{-0.06} and f^T_{B_sK}(0)/f^T_{B\pi}(0) = 1.17^{+0.15}_{-0.11}.Comment: 14 pages, 9 figures, some figures and discussions added; version to appear in PR

    Role of P2RY12 gene variants and biological variation in arterial thrombosis

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    Arterial thrombosis is the leading cause of morbidity and mortality in the Western world. Plaque rupture induces arterial thrombus formation, which may result in vascular occlusion. Depending on the localization of the occluded vessel, arterial thrombosis can affect the cardiovascular, cerebrovascular and peripheral arterial systems with clinical manifestations such as myocardial infarction and ischemic stroke. Arterial thrombosis is a multifactorial disease, and both genetic and environmental factors are known to contribute to its pathogenesis. In this thesis we have focused on the role of these genetic factors with an emphasis on common variation in the platelet receptor P2RY12 gene. The P2Y12 receptor plays a central role in platelet aggregation and is the pharmacologic target of widely prescribed antiplatelet drug clopidogrel (Plavix). Studies described in Part I have shown that common variation in the P2RY12 gene are a risk factor for arterial thrombosis at young age. In addition, we have shown that these genetic variations are a significant determinant of the on-clopidogrel platelet reactivity and the pharmacodynamic response to cangrelor, an alternative P2Y12 receptor antagonist. In another study we report that the com! mon variation in the P2RY12 gene is associated with the risk of restenosis within 1 year after percutaneous coronary interventions. In Part II, the biological variation of several hemostatic and inflammatory factors important in arterial thrombosis is described. In addition, we report an association between the concentrations of air pollution and a part of this biological variation, which may provide an explanation for the relationship between air pollution and cardiovascular disease

    Accuracy, gender and race in tort trials : a (behavioral) law and economics perspective

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    This thesis contributes to various streams of literature in the behavioral law and economics of tort law and judicial decisionmaking. Each chapter addresses a selected topic in this area from either a theoretical or an empirical perspective. The overarching theme of the thesis is the study of the interplay between accuracy and behavioral law and economics. The analysis reveals that, if carefully considered, behavioral law and economics can have an important role in policymaking as it sometimes allows to better predict: i) the effect of legal rules and courts’ practices on the behavior of regulatees; ii) how legal rules will be enforced by courts. The analysis shows also that the pursue of accuracy at trial does not necessarily lead to welfare improvements

    Stable periodic density waves in dipolar Bose-Einstein condensates trapped in optical lattices

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    Density-wave patterns in (quasi-) discrete media with local interactions are known to be unstable. We demonstrate that \emph{stable} double- and triple- period patterns (DPPs and TPPs), with respect to the period of the underlying lattice, exist in media with nonlocal nonlinearity. This is shown in detail for dipolar Bose-Einstein condensates (BECs), loaded into a deep one-dimensional (1D) optical lattice (OL), by means of analytical and numerical methods in the tight-binding limit. The patterns featuring multiple periodicities are generated by the modulational instability of the continuous-wave (CW) state, whose period is identical to that of the OL. The DPP and TPP emerge via phase transitions of the second and first kind, respectively. The emerging patterns may be stable provided that the dipole-dipole (DD) interactions are repulsive and sufficiently strong, in comparison with the local repulsive nonlinearity. Within the set of the considered states, the TPPs realize a minimum of the free energy. Accordingly, a vast stability region for the TPPs is found in the parameter space, while the DPP\ stability region is relatively narrow. The same mechanism may create stable density-wave patterns in other physical media featuring nonlocal interactions, such as arrayed optical waveguides with thermal nonlinearity.Comment: 7 pages, 4 figures, Phys. Rev. Lett., in pres

    Probing seesaw at LHC

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    We have recently proposed a simple SU(5) theory with an adjoint fermionic multiplet on top of the usual minimal spectrum. This leads to the hybrid scenario of both type I and type III seesaw and it predicts the existence of the fermionic SU(2) triplet between 100 GeV and 1 TeV for a conventional GUT scale of about 10^{16} GeV, with main decays into W (Z) and leptons, correlated through Dirac Yukawa couplings, and lifetimes shorter than about 10^{-12} sec. These decays are lepton number violating and they offer an exciting signature of Delta L=2 dilepton events together with 4 jets at future pp (p\bar p) colliders. Increasing the triplet mass endangers the proton stability and so the seesaw mechanism could be directly testable at LHC.Comment: 19 pages, discussion on leptogenesis added, new references, main conclusions unchange

    Yukawa sector in non-supersymmetric renormalizable SO(10)

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    We discuss the ordinary, non-supersymmetric SO(10) as a theory of fermion masses and mixings. We construct two minimal versions of the Yukawa sector based on 126ˉH\bar{126}_H and either 10H10_H or 120H120_H. The latter case is of particular interest since it connects the absolute neutrino mass scale with the size of the atmospheric mixing angle θA\theta_A. It also relates the smallness of VcbV_{cb} with the largeness of θA\theta_A. These results are based on the analytic study of the second and third generations. Furthermore, we discuss the structure of the light Higgs and the role of the Peccei-Quinn symmetry for dark matter and the predictivity of the theory.Comment: 8 pages. Reference added, one formula correcte

    Type II Seesaw at LHC: the Roadmap

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    In this Letter we revisit the type-II seesaw mechanism based on the addition of a weak triplet scalar to the standard model. We perform a comprehensive study of its phenomenology at the LHC energies, complete with the electroweak precision constraints. We pay special attention to the doubly-charged component, object of collider searches for a long time, and show how the experimental bound on its mass depends crucially on the particle spectrum of the theory. Our study can be used as a roadmap for future complete LHC studies.Comment: 5 pages, 4 figures; added discussion on collider signatures including the impact on SM Higgs searches and accommodating Higgs to two photon rate, and references; latest version agrees with the published on

    Radiative seesaw and degenerate neutrinos

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    The radiative see-saw mechanism of Witten generates the right-handed neutrino masses in SO(10) with the spinorial 16_H Higgs field. We study here analytically the 2nd and 3rd generations for the minimal Yukawa structure containing 10_H and 120_H Higgs representations. In the approximation of small 2nd generation masses and gauge loop domination we find the following results : (1) b-tau unification, (2) natural coexistence between large theta_l and small theta_q, (3) degenerate neutrinos.Comment: 4 page

    Two-dimensional discrete solitons in dipolar Bose-Einstein condensates

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    We analyze the formation and dynamics of bright unstaggered solitons in the disk-shaped dipolar Bose-Einstein condensate, which features the interplay of contact (collisional) and long-range dipole-dipole (DD) interactions between atoms. The condensate is assumed to be trapped in a strong optical-lattice potential in the disk's plane, hence it may be approximated by a two-dimensional (2D) discrete model, which includes the on-site nonlinearity and cubic long-range (DD) interactions between sites of the lattice. We consider two such models, that differ by the form of the on-site nonlinearity, represented by the usual cubic term, or more accurate nonpolynomial one, derived from the underlying 3D Gross-Pitaevskii equation. Similar results are obtained for both models. The analysis is focused on effects of the DD interaction on fundamental localized modes in the lattice (2D discrete solitons). The repulsive isotropic DD nonlinearity extends the existence and stability regions of the fundamental solitons. New families of on-site, inter-site and hybrid solitons, built on top of a finite background, are found as a result of the interplay of the isotropic repulsive DD interaction and attractive contact nonlinearity. By themselves, these solutions are unstable, but they evolve into robust breathers which exist on an oscillating background. In the presence of the repulsive contact interactions, fundamental localized modes exist if the DD interaction (attractive isotropic or anisotropic) is strong enough. They are stable in narrow regions close to the anticontinuum limit, while unstable solitons evolve into breathers. In the latter case, the presence of the background is immaterial
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