4,496 research outputs found

    CP asymmetry and branching ratio of B -> pi pi

    Get PDF
    We investigate the branching ratios and CP asymmetries of the B -> pi pi processes measured in B factory experiments. Fits to the experimental data of this process indicate a large ratio of color-suppressed (C) to color-allowed (T) tree contributions. We investigate whether the large C/T can be explained within the QCD based model computation with i) a large effect from the end-point singularity or with ii) large final-state-interaction phase between two different isospin amplitudes. We show that the current experimental data do not exclude either possibility but we may be able to distinguish these two effects in future measurements of direct CP asymmetry of B -> pi^0 pi^0.Comment: 8 pages, 10 figure

    Anomalous enhancement of a penguin hadronic matrix element in B->K eta'

    Get PDF
    We estimate the density matrix element for the pi^0, eta and eta' production from the vacuum in the large-N_c limit. As a consequence, we find that the QCD axial anomaly leads to highly non-trivial corrections to the usual flavour SU(3) relations between B^0-> K^0 pi^0, B^0-> K^0 eta and B^0-> K^0 eta' decay amplitudes. These corrections may explain why the B-> K eta' branching ratio is about six times larger than the B-> K pi one.Comment: 5 pages, 1 figur

    The Green-function transform and wave propagation

    Get PDF
    Fourier methods well known in signal processing are applied to three-dimensional wave propagation problems. The Fourier transform of the Green function, when written explicitly in terms of a real-valued spatial frequency, consists of homogeneous and inhomogeneous components. Both parts are necessary to result in a pure out-going wave that satisfies causality. The homogeneous component consists only of propagating waves, but the inhomogeneous component contains both evanescent and propagating terms. Thus we make a distinction between inhomogenous waves and evanescent waves. The evanescent component is completely contained in the region of the inhomogeneous component outside the k-space sphere. Further, propagating waves in the Weyl expansion contain both homogeneous and inhomogeneous components. The connection between the Whittaker and Weyl expansions is discussed. A list of relevant spherically symmetric Fourier transforms is given

    Two-electron photoionization of endohedral atoms

    Full text link
    Using He@C60He@C_{60} as an example, we demonstrate that static potential of the fullerene core essentially alters the cross section of the two-electron ionization differential in one-electron energy dσ++(ω)/dϵd\sigma ^{++}(\omega )/d\epsilon . We found that at high photon energy prominent oscillations appear in it due to reflection of the second, slow electron wave on the C60% C_{60} shell, which "dies out" at relatively high ϵ\epsilon values, of about 2÷\div 3 two-electron ionization potentials. The results were presented for ratios RC60(ω,ϵ)≡dσ++(ω,ϵ)/dσa++(ω,ϵ)R_{C_{60}}(\omega ,\epsilon)\equiv d\sigma ^{++}(\omega ,\epsilon)/d\sigma ^{a++}(\omega,\epsilon), where dσa++(ω,ϵ)/dϵd\sigma ^{a++}(\omega,\epsilon)/d\epsilon is the two-electron differential photoionization cross section. We have calculated the ratio Ri,ful=σi++(ω)/σia++(ω)R_{i,ful}= \sigma_{i} ^{++}(\omega)/\sigma_{i}^{a++}(\omega), that accounts for reflection of both photoelectrons by the C60C_{60} shell. We have calculated also the value of two-electron photoionization cross section σ++(ω)\sigma ^{++}(\omega) and found that this value is close to that of an isolated HeHe atom.Comment: 13 pages, 4 figure

    A possible supersymmetric solution to the discrepancy between B -> \phi K_S and B -> \eta' K_S CP asymmetries

    Full text link
    We present a possible supersymmetric solution to the discrepancy between the observed mixing CP asymmetries in B -> \phi K_S and B -> \eta' K_S. We show that due to the different parity in the final states of these processes, their supersymmetric contributions from the R-sector have an opposite sign, which naturally explain the large deviation between S_{\phi K_S} and S_{\eta' K_S}. We also consider the proposed mechanisms to solve the puzzle of the observed large branching ratio of B -> \eta' K and study their impact on S_{eta' K_S}.Comment: 4 pages, 2 figure
    • …
    corecore