55,000 research outputs found

    Quaternions and Kudla's matching principle

    No full text

    The study of BJ/Ψη()B\to J/\Psi \eta^{(\prime)} decays and determination of ηη\eta-\eta^{\prime} mixing angle

    Full text link
    We study BJ/Ψη()B\to J/\Psi \eta^{(\prime)} decays and suggest two methods to determine the ηη\eta-\eta^{\prime} mixing angle. We calculate not only the factorizable contribution in QCD facorization scheme but also the nonfactorizable hard spectator corrections in pQCD approach. We get the branching ratio of BJ/ΨηB\to J/\Psi \eta which is consistent with recent experimental data and predict the branching ratio of BJ/ΨηB\to J/\Psi \eta^{\prime} to be 7.59×1067.59\times 10^{-6}. Two methods for determining ηη\eta-\eta^{\prime} mixing angle are suggested in this paper. For the first method, we get the ηη\eta-\eta^{\prime} mixing angle to be about 13.1-13.1^{\circ}, which is in consistency with others in the literature. The second method depends on less parameters so can be used to determine the ηη\eta-\eta^{\prime} mixing angle with better accuracy but needs, as an input, the branching ratio for BJ/ΨηB\to J/\Psi \eta^{\prime}which should be measured in the near future.Comment: 16pages,4figure

    Assessment of treatment response in tuberculosis

    Get PDF
    Antibiotic treatment of tuberculosis has a duration of several months. There is significant variability of the host immune response and the pharmacokinetic-pharmacodynamic properties of Mycobacterium tuberculosis sub-populations at the site of disease. A limitation of sputum-based measures of treatment response may be sub-optimal detection and monitoring of Mycobacterium tuberculosis sub-populations. Potential biomarkers and surrogate endpoints should be benchmarked against hard clinical outcomes (failure/relapse/death) and may need tailoring to specific patient populations. Here, we assess the evidence supporting currently utilized and future potential host and pathogen-based models and biomarkers for monitoring treatment response in active and latent tuberculosis. Biomarkers for monitoring treatment response in extrapulmonary, pediatric and drug resistant tuberculosis are research priorities

    Dynamical Behavior of a stochastic SIRS epidemic model

    Full text link
    In this paper we study the Kernack - MacKendrick model under telegraph noise. The telegraph noise switches at random between two SIRS models. We give out conditions for the persistence of the disease and the stability of a disease free equilibrium. We show that the asymptotic behavior highly depends on the value of a threshold λ\lambda which is calculated from the intensities of switching between environmental states, the total size of the population as well as the parameters of both SIRS systems. According to the value of λ\lambda, the system can globally tend towards an endemic case or a disease free case. The aim of this work is also to describe completely the omega-limit set of all positive solutions to the model. Moreover, the attraction of the omega-limit set and the stationary distribution of solutions will be pointed out.Comment: 16 page

    Recent results in Euclidean dynamical triangulations

    Get PDF
    We study a formulation of lattice gravity defined via Euclidean dynamical triangulations (EDT). After fine-tuning a non-trivial local measure term we find evidence that four-dimensional, semi-classical geometries are recovered at long distance scales in the continuum limit. Furthermore, we find that the spectral dimension at short distance scales is consistent with 3/2, a value that is also observed in the causal dynamical triangulation (CDT) approach to quantum gravity.Comment: 7 pages, 3 figures. Proceedings for the 3rd conference of the Polish society on relativit

    Power Corrections in Charmless B Decays

    Full text link
    In this paper, we focus on the role of power corrections in QCD factorization(QCDF) method in charmless two-body nonleptonic BB meson decays. We use the ratio of the branching fraction of B+π+K0B^+ \to \pi^+ K^{\ast 0} to that of B0πρ+B^0 \to \pi^- \rho^+, for which the theoretical uncertainties are greatly reduced, to show clearly that the power corrections in charmless B decays are probably large. With other similar ratios considered, for example, for the B0Kρ+B^0 \to K^- \rho^+ decay, it is very likely that, among various sources of power corrections, annihilation topology plays an indispensable role at least for penguin dominated PV\rm PV channels. We also consider some selective ratios of direct CP asymmetries. Among these, we find that, if power corrections other than the chirally enhanced power corrections and annihilation topology were negligible, QCDF would predict the direct CP asymmetry of Bπ+πB \to \pi^+ \pi^- to be about 3 times larger than that of Bπ±KB \to \pi^\pm K^\mp, with opposite sign. Experimentally any significant deviation from this prediction would suggest either new physics or possibly the importance of long-distance rescattering effects.Comment: references and note added, to appear in Phys. Rev.