2,555 research outputs found

    The cranking formula and the spurious behaviour of the mass parameters

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    We discuss some aspects of the approach of the mass parameters by means of the simple cranking model. In particular, it is well known that the numerical application of this formula is often subject to ambiguities or contradictions. It is found that these problems are induced by the presence of two derivatives in the formula. To overcome these problems, we state a useful ansatz and we develop a number of simple arguments which tend to justify the removal of these terms. As soon as this is done, the formula becomes simpler and easier to interpret. In this respect, it is shown how the shell effects affect the mass parameters. A number of numerical tests help us in our conclusions.Comment: version 3 corrigendum of the ansatz of section V, corrigendum of the legend of Fig3. Submission = text file + 5 figure

    Low-lying quadrupole collective states of the light and medium Xenon isotopes

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    Collective low lying levels of light and medium Xenon isotopes are deduced from the Generalized Bohr Hamiltonian (GBH). The microscopic seven functions entering into the GBH are built from a deformed mean field of the Woods-Saxon type. Theoretical spectra are found to be close to the ones of the experimental data taking into account that the calculations are completely microscopic, that is to say, without any fitting of parameters.Comment: 8 pages, 4 figures, 1 tabl

    Single particle calculations for a Woods-Saxon potential with triaxial deformations, and large Cartesian oscillator basis

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    We present a computer program which solves the Schrodinger equation of the stationary states for an average nuclear potential of Woods-Saxon type. In this work, we take specifically into account triaxial (i.e. ellipsoidal) nuclear surfaces. The deformation is specified by the usual Bohr parameters. The calculations are carried out in two stages. In the first, one calculates the representative matrix of the Hamiltonian in the cartesian oscillator basis. In the second stage one diagonalizes this matrix with the help of subroutines of the EISPACK library. If it is wished, one can calculate all eigenvalues, or only the part of the eigenvalues that are contained in a fixed interval defined in advance. In this latter case the eigenvectors are given conjointly. The program is very rapid, and the run-time is mainly used for the diagonalization. Thus, it is possible to use a significant number of the basis states in order to insure a best convergence of the results.Comment: no figures, but tbles in separate pdf file

    Scalar Quarkonia at Finite Temperature

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    Masses and decay constants of the scalar quarkonia, χQ0(Q=b,c)\chi_{Q0} (Q=b,c) with quantum numbers IG(JPC)=0+(0++)I^G(J^{PC})=0^{+}(0^{++}) are calculated in the framework of the QCD sum rules approach both in vacuum and finite temperature. The masses and decay constants remain unchanged up to T100 MeVT\simeq100~MeV but they start to diminish with increasing the temperature after this point. At near the critic or deconfinement temperature, the decay constants reach approximately to 25% of their values in vacuum, while the masses are decreased about 6% and 23% for bottom and charm cases, respectively. The results at zero temperature are in a good consistency with the existing experimental values and predictions of the other nonperturbative approaches. Our predictions on the decay constants in vacuum as well as the behavior of the masses and decay constants with respect to the temperature can be checked in the future experiments.Comment: 12 Pages, 9 Figures and 2 Table

    A seismic vulnerability index method for masonry schools in the province of Yazd

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    School facilities in Iran, in particular masonry schools, have shown poor performance during past earthquakes and can be identified as the most vulnerable buildings to the earthquakes. Hence, in this paper a method to perform observational-based damage assessment for brick masonry schools located in the province of Yazd, the central region of Iran, using a comprehensive database of schools is proposed. The database was obtained from the field survey forms applied for each observed school to collect the seismic influential parameters. The results of a vulnerability index method developed in Iran are employed to use in a correlation procedure as input data, aiming at obtaining the empirical fragility curves for each school inventory. The macroseismic model and GNDT II level method are two empirical methods that are combined in this procedure. The procedure is verified using damage survey data after earthquakes occurred in Iran

    Double-Lepton Polarization Asymmetries and Branching Ratio of the B\rar \gamma l^+ l^- transition in Universal Extra Dimension

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    We study the radiative dileptonic B \rar \gamma l^+ l^- transition in the presence of a universal extra dimension in the Applequist-Cheng-Dobrescu model. In particular, using the corresponding form factors calculated via light cone QCD sum rules, we analyze the branching ratio and double lepton polarization asymmetries related to this channel and compare the results with the predictions of the standard model. We show how the results deviate from predictions of the standard model at lower values of the compactification factor (1/R1/R ) of extra dimension.Comment: 20 Pages and 8 Figure

    Semileptonic Bs ->DsJ(2460)l nu decay in QCD

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    Using three point QCD sum rules method, the form factors relevant to the semileptonic Bs ->DsJ (2460)l nu decay are calculated. The q2 dependence of these form factors is evaluated and compared with the heavy quark effective theory predictions. The dependence of the asymmetry parameter alpha, characterizing the polarization of DsJ meson, on q2 is studied .The branching ratio of this decay is also estimated and is shown that it can be easily detected at LHC.Comment: 21 pages, 5 figures and 1 Tabl
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