108,386 research outputs found

    The puzzles in B→ππB\to \pi\pi and Ο€K \pi K decays: possible implications for R-parity violating supersymmetry

    Full text link
    Recent experiments suggest that certain data of B→ππ,Ο€KB \to \pi\pi,\pi K decays are inconsistent with the standard model expectations. We try to explain the discrepancies with R-parity violating suppersymmetry. By employing the QCD factorization approach, we study these decays in the minimal supersymmetric standard model with R-parity violation. We show that R-parity violation can resolve the discrepancies in both B→ππB \to \pi\pi and Bβ†’Ο€KB \to \pi K decays, and find that in some regions of parameter spaces all these requirements, including the CP averaged branching ratios and the direct CP asymmetries, can be satisfied. Furthermore, we have derived stringent bounds on relevant R-parity violating couplings from the latest experimental data, and some of these constraints are stronger than the existing bounds.Comment: 24 pages, 6 figures and 5 tables. Text revised. Final version to appear in PR

    Pseudo derivative evolutionary algorithm and convergence analysis

    Get PDF
    In this paper, a novel evolutionary algorithm (EA), called pseudo-derivative EA (called PDEA), is proposed. The basic idea of PDEA is to use pseudo-derivative, which is obtained based on the information produced during the evolution, and to help search the solution of optimization problem. The pseudo-derivative drives the search process in a more informed direction. That makes PDEA different from the random optimization methods. The convergence of PDEA is first analyzed based on systems theory. The convergence condition of PDEA is then derived though this condition is too strong to be satisfied. Next, this condition is relaxed based on the entropy theory. Finally, performances of PDEA are evaluated on the benchmark functions and an adaptive liquid level control system of a surge tank. The numeric simulation results show that PDEA is capable of finding the solutions to the optimization problems with good accuracy, reliability, and speed.</jats:p
    • …
    corecore