3,006 research outputs found

    Persistent Homology Over Directed Acyclic Graphs

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    We define persistent homology groups over any set of spaces which have inclusions defined so that the corresponding directed graph between the spaces is acyclic, as well as along any subgraph of this directed graph. This method simultaneously generalizes standard persistent homology, zigzag persistence and multidimensional persistence to arbitrary directed acyclic graphs, and it also allows the study of more general families of topological spaces or point-cloud data. We give an algorithm to compute the persistent homology groups simultaneously for all subgraphs which contain a single source and a single sink in O(n4)O(n^4) arithmetic operations, where nn is the number of vertices in the graph. We then demonstrate as an application of these tools a method to overlay two distinct filtrations of the same underlying space, which allows us to detect the most significant barcodes using considerably fewer points than standard persistence.Comment: Revised versio

    Faddeev study of heavy baryon spectroscopy

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    We investigate the structure of heavy baryons containing a charm or a bottom quark. We employ a constituent quark model successful in the description of the baryon-baryon interaction which is consistent with the light baryon spectra. We solve exactly the three-quark problem by means of the Faddeev method in momentum space. Heavy baryon spectrum shows a manifest compromise between perturbative and nonperturbative contributions. The flavor dependence of the one-gluon exchange is analyzed. We assign quantum numbers to some already observed resonances and we predict the first radial and orbital excitations of all states with J=1/2J=1/2 or 3/2. We combine our results with heavy quark symmetry and lowest-order SU(3) symmetry breaking to predict the masses and quantum numbers of six still non-measured ground-state beauty baryons.Comment: 22 pages, 4 figures, 8 tables. Accepted for publication in J. Phys.

    Analysis of Ωc(css)\Omega_c^*(css) and Ωb(bss)\Omega_b^*(bss) with QCD sum rules

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    In this article, we calculate the masses and residues of the heavy baryons Ωc(css)\Omega_c^*(css) and Ωb(bss)\Omega_b^*(bss) with spin-parity 3/2+{3/2}^+ with the QCD sum rules. The numerical values are compatible with experimental data and other theoretical estimations.Comment: 13 pages, 8 figures, slight versio

    Averages of bb-hadron, cc-hadron, and τ\tau-lepton properties as of summer 2014

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    This article reports world averages of measurements of bb-hadron, cc-hadron, and τ\tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through summer 2014. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CPCP violation parameters, parameters of semileptonic decays and CKM matrix elements.Comment: 436 pages, many figures and tables. Online updates available at http://www.slac.stanford.edu/xorg/hfag

    Determination of the Michel Parameters rho, xi, and delta in tau-Lepton Decays with tau --> rho nu Tags

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    Using the ARGUS detector at the e+ee^+ e^- storage ring DORIS II, we have measured the Michel parameters ρ\rho, ξ\xi, and ξδ\xi\delta for τ±l±ννˉ\tau^{\pm}\to l^{\pm} \nu\bar\nu decays in τ\tau-pair events produced at center of mass energies in the region of the Υ\Upsilon resonances. Using τρν\tau^\mp \to \rho^\mp \nu as spin analyzing tags, we find ρe=0.68±0.04±0.08\rho_{e}=0.68\pm 0.04 \pm 0.08, ξe=1.12±0.20±0.09\xi_{e}= 1.12 \pm 0.20 \pm 0.09, ξδe=0.57±0.14±0.07\xi\delta_{e}= 0.57 \pm 0.14 \pm 0.07, ρμ=0.69±0.06±0.08\rho_{\mu}= 0.69 \pm 0.06 \pm 0.08, ξμ=1.25±0.27±0.14\xi_{\mu}= 1.25 \pm 0.27 \pm 0.14 and ξδμ=0.72±0.18±0.10\xi\delta_{\mu}= 0.72 \pm 0.18 \pm 0.10. In addition, we report the combined ARGUS results on ρ\rho, ξ\xi, and ξδ\xi\delta using this work und previous measurements.Comment: 10 pages, well formatted postscript can be found at http://pktw06.phy.tu-dresden.de/iktp/pub/desy97-194.p

    Study of B -> \rho \pi decays at Belle

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    This paper describes a study of B meson decays to the pseudoscalar-vector final state \rho\pi using 31.9\times 10^6 B\bar{B} events collected with the Belle detector at KEKB. The branching fractions B(B^+ \to \rho^0\pi^+) = (8.0^{+2.3+0.7}_{-2.0-0.7}) \times 10^{-6} and B(B^0 -> \rho^{+-} \pi^{-+}) = (20.8^{+6.0+2.8}_{-6.3-3.1}) \times 10^{-6} are obtained. In addition, a 90% confidence level upper limit of B(B^0 \to \rho^0\pi^0) < 5.3 \times 10^{-6}is reported.Comment: 14 pages, 3 figures, to be submitted to Phys. Lett.

    Search for the h_c meson in B^+- ->h_c K^+-

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    We report a search for the hch_c meson via the decay chain B±hcK±B^{\pm}\to h_c K^{\pm}, \etac \gamma with ηcKS0K±π\eta_c \to K_S^0 K^{\pm} \pi^{\mp} and ppˉp\bar{p}. No significant signals are observed. We obtain upper limits on the branching fractions for B±ηcγK±B^{\pm} \to \eta_c\gamma K^{\pm} in bins of the ηcγ\eta_c\gamma invariant mass. The results are based on an analysis of 253 fb1^{-1} of data collected by the Belle detector at the KEKB e+ee^+e^- collider.Comment: 12 pages, 6 figures, submitted to Phys. Rev.

    Spectral Correlation in Incommensurate Multi-Walled Carbon Nanotubes

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    We investigate the energy spectra of clean incommensurate double-walled carbon nanotubes, and find that the overall spectral properties are described by the so-called critical statistics of Anderson metal-insulator transition. In the energy spectra, there exist three different regimes characterized by Wigner-Dyson, Poisson, and semi-Poisson distributions. This feature implies that the electron transport in incommensurate multi-walled nanotubes can be either diffusive, ballistic, or intermediate between them, depending on the position of the Fermi energy.Comment: final version to appear in Phys. Rev. Let
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