2,049 research outputs found
B, Bs -> K form factors: an update of light-cone sum rule results
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
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
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
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
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)
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 and either or . The latter case is of
particular interest since it connects the absolute neutrino mass scale with the
size of the atmospheric mixing angle . It also relates the smallness
of with the largeness of . 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
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
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
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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