176,201 research outputs found

    Determination of f+K(0)f_+^K(0) and Extraction of ∣Vcs∣|V_{cs}| from Semileptonic DD Decays

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    By globally analyzing all existing measured branching fractions and partial rates in different four momentum transfer-squared q2q^2 bins of D→Ke+νeD\to Ke^+\nu_e decays, we obtain the product of the form factor and magnitude of CKM matrix element VcsV_{cs} to be f+K(0)∣Vcs∣=0.717±0.004f_+^K(0)|V_{cs}|=0.717\pm0.004. With this product, we determine the D→KD\to K semileptonic form factor f+K(0)=0.737±0.004±0.000f_+^K(0)=0.737\pm0.004\pm0.000 in conjunction with the value of ∣Vcs∣|V_{cs}| determined from the SM global fit. Alternately, with the product together with the input of the form factor f+K(0)f_+^K(0) calculated in lattice QCD recently, we extract ∣Vcs∣D→Ke+νe=0.962±0.005±0.014|V_{cs}|^{D\to Ke^+\nu_e}=0.962\pm0.005\pm0.014, where the error is still dominated by the uncertainty of the form factor calculated in lattice QCD. Combining the ∣Vcs∣Ds+→ℓ+νℓ=1.012±0.015±0.009|V_{cs}|^{D_s^+\to\ell^+\nu_\ell}=1.012\pm0.015\pm0.009 extracted from all existing measurements of Ds+→ℓ+νℓD^+_s\to\ell^+\nu_\ell decays and ∣Vcs∣D→Ke+νe=0.962±0.005±0.014|V_{cs}|^{D\to Ke^+\nu_e}=0.962\pm0.005\pm0.014 together, we find the most precisely determined ∣Vcs∣|V_{cs}| to be ∣Vcs∣=0.983±0.011|V_{cs}|=0.983\pm0.011, which improves the accuracy of the PDG'2014 value ∣Vcs∣PDG′2014=0.986±0.016|V_{cs}|^{\rm PDG'2014}=0.986\pm0.016 by 45%45\%

    Anisotropy of Resonant Inelastic X-Ray Scattering at the K Edge of Si:Theoretical Analysis

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    We investigate theoretically the resonant inelastic x-ray scattering (RIXS) at the KK edge of Si on the basis of an ab initio calculation. We calculate the RIXS spectra with systematically varying transfered-momenta, incident-photon energy and incident-photon polarization. We confirm the anisotropy of the experimental spectra by Y. Ma {\it et al}. (Phys. Rev. Lett. 74, 478 (1995)), providing a quantitative explanation of the spectra.Comment: 18 pages, 11 figure

    A stochastic user-operator assignment game for microtransit service evaluation: A case study of Kussbus in Luxembourg

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    This paper proposes a stochastic variant of the stable matching model from Rasulkhani and Chow [1] which allows microtransit operators to evaluate their operation policy and resource allocations. The proposed model takes into account the stochastic nature of users' travel utility perception, resulting in a probabilistic stable operation cost allocation outcome to design ticket price and ridership forecasting. We applied the model for the operation policy evaluation of a microtransit service in Luxembourg and its border area. The methodology for the model parameters estimation and calibration is developed. The results provide useful insights for the operator and the government to improve the ridership of the service.Comment: arXiv admin note: substantial text overlap with arXiv:1912.0198

    Scaling of Anisotropic Flows and Nuclear Equation of State in Intermediate Energy Heavy Ion Collisions

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    Elliptic flow (v2v_2) and hexadecupole flow (v4v_4) of light clusters have been studied in details for 25 MeV/nucleon 86^{86}Kr + 124^{124}Sn at large impact parameters by Quantum Molecular Dynamics model with different potential parameters. Four parameter sets which include soft or hard equation of state (EOS) with/without symmetry energy term are used. Both number-of-nucleon (AA) scaling of the elliptic flow versus transverse momentum (ptp_t) and the scaling of v4/A2v_4/A^{2} versus (pt/A)2(p_t/A)^2 have been demonstrated for the light clusters in all above calculation conditions. It was also found that the ratio of v4/v22v_4/{v_2}^2 keeps a constant of 1/2 which is independent of ptp_t for all the light fragments. By comparisons among different combinations of EOS and symmetry potential term, the results show that the above scaling behaviors are solid which do not depend the details of potential, while the strength of flows is sensitive to EOS and symmetry potential term.Comment: 5 pages, 5 figure

    Statistical nature of cluster emission in nuclear liquid-vapour phase coexistence

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    The emission of nuclear clusters is investigated within the framework of isospin dependent lattice gas model and classical molecular dynamics model. It is found that the emission of individual cluster which is heavier than proton is almost Poissonian except near the transition temperature at which the system is leaving the liquid-vapor phase coexistence and the thermal scaling is observed by the linear Arrhenius plots which is made from the average multiplicity of each cluster versus the inverse of temperature in the liquid vapor phase coexistence. The slopes of the Arrhenius plots, {\it i.e.} the "emission barriers", are extracted as a function of the mass or charge number and fitted by the formula embodied with the contributions of the surface energy and Coulomb interaction. The good agreements are obtained in comparison with the data for low energy conditional barriers. In addition, the possible influences of the source size, Coulomb interaction and "freeze-out" density and related physical implications are discussed
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