3,037 research outputs found

    A Necessary And Sufficient Condition of Distillability with unite fidelity from Finite Copies of a Mixed State: The Most Efficient Purification Protocol

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    It is well known that any entangled mixed state in 222\otimes 2 systems can be purified via infinite copies of the mixed state. But can one distill a pure maximally entangled state from finite copies of a mixed state in any bipartite system by local operation and classical communication? This is more meaningful in practical application. We give a necessary and sufficient condition of this distillability. This condition can be expressed as: there exists distillable-subspaces. According to this condition, one can judge whether a mixed state is distillable or not easily. We also analyze some properties of distillable-subspaces, and discuss the most efficient purification protocols. Finally, we discuss the distillable enanglement of two-quibt system for the case of finite copies.Comment: a revised versio

    Investigation on the sampling size optimisation in gear tooth surface measurement using a Co-ordinate Measuring Machine

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    Co-ordinate Measuring Machines (CMMs) are widely used in gear manufacturing industry. One of the main issues for contact inspection using a CMM is the sampling technique. In this paper the gear tooth surfaces are expressed by series of parameters and inspection error compensation and initial value optimisation method are presented. The minimum number of measurement points for 3D tooth surfaces are derived. If high precision is required, more points need to be inspected. The sampling size optimisation is obtained from the criterion equation. The surface form deviation and initial values are optimised using the minimum zone method and Genetic Algorithms. A feature based inspection system for spur/helical gears is developed and trials and simulations demonstrated the developed method is very effective and suitable

    Impact of Subleading Corrections on Hadronic B Decays

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    We study the subleading corrections originating from the 3-parton (q\bar q g) Fock states of final-state mesons in B decays. The corrections could give significant contributions to decays involving an \omega or \eta^{(\prime)} in the final states. Our results indicate the similarity of \omega K and \omega \pi^- rates, of order 5\times 10^{-6}, consistent with the recent measurements. We obtain a_2(B\to J/\psi K)\approx 0.27+0.05i, in good agreement with data. Without resorting to the unknown singlet annihilation effects, 3-parton Fock state contributions can enhance the branching ratios of K\eta' to the level above 50\times 10^{-6}.Comment: 5 pages, 5 figures, revtex4; some typos corrected, a new figure and a reference added, more explanations for the calculation provided, to appear in Phys. Rev.

    Perturbative QCD analysis of BϕKB \to \phi K^* decays

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    We study the first observed charmless BVVB\to VV modes, the BϕKB\to\phi K^* decays, in perturbative QCD formalism. The obtained branching ratios B(BϕK)15×106B(B\to\phi K^*)\sim 15 \times 10^{-6} are larger than 9×106\sim 9\times 10^{-6} from QCD factorization. The comparison of the predicted magnitudes and phases of the different helicity amplitudes, and branching ratios with experimental data can test the power counting rules, the evaluation of annihilation contributions, and the mechanism of dynamical penguin enhancement in perturbative QCD, respectively.Comment: 14 pages, 2 tables, brief disscussion on hard sacle added, version to appear in PR

    B_c meson rare decays in the light-cone quark model

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    We investigate the rare decays BcDs(1968)ˉB_c \rightarrow D_s(1968) \ell \bar{\ell} and BcDs(2317)ˉB_c\rightarrow D_s^*(2317) \ell \bar{\ell} in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful to investigating the structure of BcB_c meson and to testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC.Comment: 9 pages, 11 figures, version accepted for publication in EPJ

    Study of f_0(980) and f_0(1500) from B_s \to f_0(980)\pi, f_0(1500)\pi Decays

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    In this paper, we analyze the scalar mesons f0(980)f_0(980) and f0(1500)f_0(1500) from the decays Bˉs0f0(980)π0,f0(1500)π0\bar B^0_s \to f_0(980)\pi^0, f_0(1500)\pi^0 within Perturbative QCD approach. From the leading order calculations, we find that (a) in the allowed mixing angle ranges, the branching ratio of Bˉs0f0(980)π0\bar B^0_s\to f_0(980)\pi^0 is about (1.01.6)×107(1.0\sim1.6)\times 10^{-7}, which is smaller than that of Bˉs0f0(980)K0\bar B^0_s\to f_0(980)K^0 (the difference is a few times even one order); (b) the decay Bˉs0f0(1500)π0\bar B^0_s \to f_0(1500)\pi^0 is better to distinguish between the lowest lying state or the first excited state for f0(1500)f_0(1500), because the branching ratios for two scenarios have about one-order difference in most of the mixing angle ranges; and (c) the direct CP asymmetries of Bˉs0f0(1500)π0\bar B^0_s \to f_0(1500)\pi^0 for two scenarios also exists great difference. In scenario II, the variation range of the value ACPdir(Bˉs0f0(1500)π0){\cal A} ^{dir}_{CP}(\bar B^0_s \to f_0(1500)\pi^0) according to the mixing angle is very small, except for the values corresponding to the mixing angles being near 9090^\circ or 270270^\circ, while the variation range of ACPdir(Bˉs0f0(1500)π0){\cal A} ^{dir}_{CP}(\bar B^0_s \to f_0(1500)\pi^0) in scenario I is very large. Compared with the future data for the decay Bˉs0f0(1500)π0\bar B^0_s \to f_0(1500)\pi^0, it is ease to determine the nature of the scalar meson f0(1500)f_0(1500).Comment: 16 pages, 3 figures, Revte

    Charmless Exclusive Baryonic B Decays

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    We present a systematical study of two-body and three-body charmless baryonic B decays. Branching ratios for two-body modes are in general very small, typically less than 10610^{-6}, except that \B(B^-\to p \bar\Delta^{--})\sim 1\times 10^{-6}. In general, BˉNΔˉ>BˉNNˉ\bar B\to N\bar\Delta>\bar B\to N\bar N due to the large coupling constant for ΣbBΔ\Sigma_b\to B\Delta. For three-body modes we focus on octet baryon final states. The leading three-dominated modes are Bˉ0pnˉπ(ρ),npˉπ+(ρ+)\bar B^0\to p\bar n\pi^-(\rho^-), n\bar p\pi^+(\rho^+) with a branching ratio of order 3×1063\times 10^{-6} for Bˉ0pnˉπ\bar B^0\to p\bar n\pi^- and 8×1068\times 10^{-6} for Bˉ0pnˉρ\bar B^0\to p\bar n\rho^-. The penguin-dominated decays with strangeness in the meson, e.g., BppˉK()B^-\to p\bar p K^{-(*)} and Bˉ0pnˉK(),nnˉKˉ0()\bar B^0\to p\bar n K^{-(*)}, n\bar n \bar K^{0(*)}, have appreciable rates and the NNˉN\bar N mass spectrum peaks at low mass. The penguin-dominated modes containing a strange baryon, e.g., Bˉ0Σ0pˉπ+,Σnˉπ+\bar B^0\to \Sigma^0\bar p\pi^+, \Sigma^-\bar n\pi^+, have branching ratios of order (14)×106(1\sim 4)\times 10^{-6}. In contrast, the decay rate of Bˉ0Λpˉπ+\bar B^0\to\Lambda\bar p\pi^+ is smaller. We explain why some of charmless three-body final states in which baryon-antibaryon pair production is accompanied by a meson have a larger rate than their two-body counterparts: either the pole diagrams for the former have an anti-triplet bottom baryon intermediate state, which has a large coupling to the BB meson and the nucleon, or they are dominated by the factorizable external WW-emission process.Comment: 46 pages and 3 figures, to appear in Phys. Rev. D. Major changes are: (i) Calculations of two-body baryonic B decays involving a Delta resonance are modified, and (ii) Penguin-dominated modes B-> Sigma+N(bar)+p are discusse

    A Gaussian process and image registration based stitching method for high dynamic range measurement of precision surfaces

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    Optical instruments are widely used for precision surface measurement. However, the dynamic range of optical instruments, in terms of measurement area and resolution, is limited by the characteristics of the imaging and the detection systems. If a large area with a high resolution is required, multiple measurements need to be conducted and the resulting datasets needs to be stitched together. Traditional stitching methods use six degrees of freedom for the registration of the overlapped regions, which can result in high computational complexity. Moreover, measurement error increases with increasing measurement data. In this paper, a stitching method, based on a Gaussian process, image registration and edge intensity data fusion, is presented. Firstly, the stitched datasets are modelled by using a Gaussian process so as to determine the mean of each stitched tile. Secondly, the datasets are projected to a base plane. In this way, the three-dimensional datasets are transformed to two-dimensional (2D) images. The images are registered by using an (x, y) translation to simplify the complexity. By using a high precision linear stage that is integral to the measurement instrument, the rotational error becomes insignificant and the cumulative rotational error can be eliminated. The translational error can be compensated by the image registration process. The z direction registration is performed by a least-squares error algorithm and the (x, y, z) translational information is determined. Finally, the overlapped regions of the measurement datasets are fused together by the edge intensity data fusion method. As a result, a large measurement area with a high resolution is obtained. A simulated and an actual measurement with a coherence scanning interferometer have been conducted to verify the proposed method. The stitching result shows that the proposed method is technically feasible for large area surface measurement

    Spectrum of the Vortex Bound States of the Dirac and Schrodinger Hamiltonian in the presence of Superconducting Gaps

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    We investigate the vortex bound states both Schrodinger and Dirac Hamiltonian with the s-wave superconducting pairing gap by solving the mean-field Bogoliubov-de-Gennes equations. The exact vortex bound states spectrum is numerically determined by the integration method, and also accompanied by the quasi-classical analysis. It is found that the bound state energies is proportional to the vortex angular momentum when the chemical potential is large enough. By applying the external magnetic field, the vortex bound state energies of the Dirac Hamiltonian are almost unchanged; whereas the energy shift of the Schrodinger Hamiltonian is proportional to the magnetic field. These qualitative differences may serve as an indirect evidence of the existence of Majorana fermions in which the zero mode exists in the case of the Dirac Hamiltonian only.Comment: 8 pages, 9 figure

    Phenomenological constraints on SUSY SU(5) GUTs with non-universal gaugino masses

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    We study phenomenological aspects of supersymmetric SU(5) grand unified theories with non-universal gaugino masses. For large tan beta, we investigate constraints from the requirement of successful electroweak symmetry breaking, the positivity of stau mass squared and the b to s gamma decay rate. In the allowed region, the nature of the lightest supersymmetric particle is determined. Examples of mass spectra are given. We also calculate loop corrections to the bottom mass due to superpartners.Comment: 10 pages, 2 figures (8 eps files), uses REVTeX. Replaced to match the version to be published in PRD: minor corrections and addition
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