4,239 research outputs found

    Some Remarks on the Final State Interactions in BπKB\to \pi K Decays

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    Careful discussions are made on some points which are met in studying B decay final state interactions, taking the B0π+KB^0\to \pi^+ K^- process as an example. We point out that π\pi--exchange rescatterings are not important, whereas for DD^* and DD^{**} exchanges, since the B0D+DsB^0\to D^+D_s^- decay has a large branching ratio their contributions may be large enough to enhance the BπKB\to \pi K branching ratio significantly. However our estimates fail to predict a large enhancement.Comment: 5 pages, use elsart.sty; The previous version is erroneous in explaining the "charm peguin" effects. No large enhancement to BπKB\to \pi K is found through D+DsD^+D_s^- intermediate stat

    B(s)SB_{(s)}\to S transitions in the light cone sum rules with the chiral current

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    B(s)B_{(s)} semi-leptonic decays to the light scalar meson, B(s)Slνˉl,Sllˉ(l=e,μ,τ)B_{(s)}\to S l\bar{\nu}_l, S l \bar{l}\,\,(l=e,\mu,\tau), are investigated in the QCD light-cone sum rules (LCSR) with chiral current correlator. Having little knowledge of ingredients of the scalar mesons, we confine ourself to the two quark picture for them and work with the two possible Scenarios. The resulting sum rules for the form factors receive no contributions from the twist-3 distribution amplitudes (DA's), in comparison with the calculation of the conventional LCSR approach where the twist-3 parts play usually an important role. We specify the range of the squared momentum transfer q2q^2, in which the operator product expansion (OPE) for the correlators remains valid approximately. It is found that the form factors satisfy a relation consistent with the prediction of soft collinear effective theory (SCET). In the effective range we investigate behaviors of the form factors and differential decay widthes and compare our calculations with the observations from other approaches. The present findings can be beneficial to experimentally identify physical properties of the scalar mesons.Comment: 22 pages,16 figure

    Study Majorana Neutrino Contribution to B-meson Semi-leptonic Rare Decays

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    B meson semi-leptonic rare decays are sensitive to new physics beyond standard model. We study the Bπμ+μB^{-}\to \pi^{-}\mu^{+}\mu^{-} process and investigate the Majorana neutrino contribution to its decay width. The constraints on the Majorana neutrino mass and mixing parameter are obtained from this decay channel with the latest LHCb data. Utilizing the best fit for the parameters, we study the lepton number violating decay Bπ+μμB^{-}\to \pi^{+}\mu^{-}\mu^{-}, and find its branching ratio is about 6.4×10106.4\times10^{-10}, which is consistent with the LHCb data reported recently.Comment: 10 pages, 3 figure

    Electrochemical Behavior and Electrochemical Determination of Tiamulin Fumarate at an Ionic Liquid Modified Carbon Paste Electrode

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    The electrochemical behavior of tiamulin fumarate (TF) at ionic liquid N-Butylpyridinium hexafluorophosphate (BPPF6) modified carbon paste electrode (BPPF6/CPE) was investigated and further used for tiamulin fumarate sample determination. BPPF6/CPE showed an enhanced electrochemical response towards the electrochemical oxidation of TF. A well-defined and sensitive oxidation peak was observed at BPPF6/CPE in 0.10 M phosphate buffer solution (PBS, pH = 6.80). The oxidation peak current of TF increased significantly at BPPF6/CPE compared with that at carbon paste electrode and the BPPF6/CPE was characterized by the electrochemical impedance spectroscopy (EIS). At the same time, the electrochemical kinetics parameters of TF on the BPPF6/CPE were evaluated. Under the optimized conditions, the oxidation peak currents were linearly dependent on the concentration of TF in the range of 0.3–9.0 μM and 9.0–0.3 mM, with a detection limit of 0.16 μM (S/N = 3). The proposed method has been successfully applied in the electrochemical quantitative determination of TF content in commercial injection samples

    Monitoring and analysis of blasting vibration in tunnel excavation of nuclear power plant

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    Vibration monitoring of blasting excavation of drainage tunnel in Lufeng Nuclear Power Plant is carried out and the data of blasting vibration is analyzed in this paper. The results show that: (1) The vertical vibration velocity of the rock mass is greater than the horizontal radial and horizontal tangential vibration velocity (2) The blasting vibration velocity of rock mass decreases with distance, which is affected by rock structure and explosive quantity. The monitoring research in this paper has guiding significance for vibration prediction and control in tunnel blasting excavation

    Isospin dependence of nucleon effective mass in Dirac Brueckner-Hartree-Fock approach

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    The isospin dependence of the nucleon effective mass is investigated in the framework of the Dirac Brueckner-Hartree-Fock (DBHF) approach. The definition of nucleon scalar and vector effective masses in the relativistic approach is clarified. Only the vector effective mass is the quantity related to the empirical value extracted from the analysis in the nonrelatiistic shell and optical potentials. In the relativistic mean field theory, where the nucleon scalar and vector potentials are both energy independent, the neutron vector potential is stronger than that of proton in the neutron rich nuclear matter, which produces a smaller neutron vector effective mass than that of proton. It is pointed out that the energy dependence of nucleon potentials has to be considered in the analysis of the isospin dependence of the nucleon effective mass. In the DBHF the neutron vector effective mass is larger than that of proton once the energy dependence of nucleon potentials is considered. The results are consistent with the analysis of phenomenological isospin dependent optical potentials.Comment: 4 pages, 3 Postscript figure