5,453 research outputs found

    Proper-time Resolution Function for Measurement of Time Evolution of B Mesons at the KEK B-Factory

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    The proper-time resolution function for the measurement of the time evolution of B mesons with the Belle detector at KEKB is studied in detail. The obtained resolution function is applied to the measurement of B meson lifetimes, the B0-B0bar oscillation frequency and time-dependent CP asymmetries.Comment: 25 pages, 18 figures, to be published in NIM A, replaced with revised versio

    ANOMALOUS GAUGE BOSON INTERACTIONS

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    We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge boson self-interactions. If the energy scale of the new physics is 1\sim 1 TeV, these low energy anomalous couplings are expected to be no larger than O(102){\cal O}(10^{-2}). Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed.Comment: 53 pages with 17 embedded figures, LaTeX, uses axodraw.sty, figures available on request. The complete paper, is available at ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z or http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z Summary of the DPF Working Subgroup on Anomalous Gauge Boson Interactions of the DPF Long Range Planning Stud

    Clocking hadronization in relativistic heavy ion collisions with balance functions

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    A novel state of matter has been hypothesized to exist during the early stage of relativistic heavy ion collisions, with normal hadrons not appearing until several fm/c after the start of the reaction. To test this hypothesis, correlations between charges and their associated anticharges are evaluated with the use of balance functions. It is shown that late-stage hadronization is characterized by tightly correlated charge/anticharge pairs when measured as a function of relative rapidity.Comment: 5 pages, 3 figure

    Scale Dependence of Halo Bispectrum from Non-Gaussian Initial Conditions in Cosmological N-body Simulations

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    We study the halo bispectrum from non-Gaussian initial conditions. Based on a set of large NN-body simulations starting from initial density fields with local type non-Gaussianity, we find that the halo bispectrum exhibits a strong dependence on the shape and scale of Fourier space triangles near squeezed configurations at large scales. The amplitude of the halo bispectrum roughly scales as fnl2f_nl^2. The resultant scaling on the triangular shape is consistent with that predicted by Jeong & Komatsu based on perturbation theory. We systematically investigate this dependence with varying redshifts and halo mass thresholds. It is shown that the fnlf_nl dependence of the halo bispectrum is stronger for more massive haloes at higher redshifts. This feature can be a useful discriminator of inflation scenarios in future deep and wide galaxy redshift surveys.Comment: 27 pages, 10 figures; revised argument in section 6, added appendix C, JCAP accepted versio

    Synchronization of Coupled Nonidentical Genetic Oscillators

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    The study on the collective dynamics of synchronization among genetic oscillators is essential for the understanding of the rhythmic phenomena of living organisms at both molecular and cellular levels. Genetic oscillators are biochemical networks, which can generally be modelled as nonlinear dynamic systems. We show in this paper that many genetic oscillators can be transformed into Lur'e form by exploiting the special structure of biological systems. By using control theory approach, we provide a theoretical method for analyzing the synchronization of coupled nonidentical genetic oscillators. Sufficient conditions for the synchronization as well as the estimation of the bound of the synchronization error are also obtained. To demonstrate the effectiveness of our theoretical results, a population of genetic oscillators based on the Goodwin model are adopted as numerical examples.Comment: 16 pages, 3 figure

    Measurement of the forward-backward asymmetries for charm- and bottom-quark pair productions at <s><\sqrt{s}>=58GeV with electron tagging

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    We have measured, with electron tagging, the forward-backward asymmetries of charm- and bottom-quark pair productions at =58.01GeV, based on 23,783 hadronic events selected from a data sample of 197pb1^{-1} taken with the TOPAZ detector at TRISTAN. The measured forward-backward asymmetries are AFBc=0.49±0.20(stat.)±0.08(sys.)A_{FB}^c = -0.49 \pm 0.20(stat.) \pm 0.08 (sys.) and AFBb=0.64±0.35(stat.)±0.13(sys.)A_{FB}^b = -0.64 \pm 0.35(stat.) \pm 0.13 (sys.), which are consistent with the standard model predictions.Comment: 19 pages, Latex format (article), 5 figures included. to be published in Phys. Lett.

    Optical photometric GTC/OSIRIS observations of the young massive association Cygnus OB2

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    In order to fully understand the gravitational collapse of molecular clouds, the star formation process and the evolution of circumstellar disks, these phenomena must be studied in different Galactic environments with a range of stellar contents and positions in the Galaxy. The young massive association Cygnus OB2, in the Cygnus-X region, is an unique target to study how star formation and the evolution of circumstellar disks proceed in the presence of a large number of massive stars. We present a catalog obtained with recent optical observations in r,i,z filters with OSIRIS, mounted on the 10.4m10.4\,m GTC telescope, which is the deepest optical catalog of Cyg OB2 to date. The catalog consist of 64157 sources down to M=0.15 solar masses at the adopted distance and age of Cyg OB2. A total of 38300 sources have good photometry in all three bands. We combined the optical catalog with existing X-ray data of this region, in order to define the cluster locus in the optical diagrams. The cluster locus in the r-i vs. i-z diagram is compatible with an extinction of the optically selected cluster members in the 2.64<AV<5.57 range. We derive an extinction map of the region, finding a median value of AV=4.33 in the center of the association, decreasing toward the north-west. In the color-magnitude diagrams, the shape of the distribution of main sequence stars is compatible with the presence of an obscuring cloud in the foreground at about 850+/-25 pc from the Sun.Comment: Accepted for publication ApJS 201

    ηη\eta-\eta^\prime mixing and the next-to-leading-order power correction

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    The next-to-leading-order O(1/Q4)O(1/Q^4) power correction for ηγ\eta\gamma and ηγ\eta^\prime\gamma form factors are evaluated and employed to explore the ηη\eta-\eta^\prime mixing. The parameters of the two mixing angle scheme are extracted from the data for form factors, two photon decay widths and radiative J/ψJ/\psi decays. The χ2\chi^2 analysis gives the result: fη1=(1.16±0.06)fπ,fη8=(1.33±0.23)fπ,θ1=9±3,θ8=21.3±2.3f_{\eta_1}=(1.16\pm0.06)f_\pi, f_{\eta_8}=(1.33\pm0.23)f_\pi, \theta_1=-9^\circ\pm 3^\circ, \theta_8=-21.3^\circ\pm 2.3^\circ, where fη1(8)f_{\eta_{1(8)}} and θ1(8)\theta_{1(8)} are the decay constants and the mixing angles for the singlet (octet) state. In addition, we arrive at a stringent range for fηc:10f_{\eta^\prime}^c:-10 MeVfηc4\le f_{\eta^\prime}^c\le -4 MeV.Comment: 23 pages, 9 figures, To be publshied in Phys. Rev.

    Determination of the η\eta and η\eta' Mixing Angle from the Pseudoscalar Transition Form Factors

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    The possible range of ηη\eta-\eta' mixing angle is determined from the transition form factors Fηγ(Q2)F_{\eta \gamma}(Q^2) and Fηγ(Q2)F_{\eta' \gamma}(Q^2) with the help of the present experimental data. For such purpose, the quark-flavor mixing scheme is adopted and the pseudoscalar transition form factors are calculated under the light-cone pQCD framework, where the transverse momentum corrections and the contributions beyond the leading Fock state have been carefully taken into consideration. We construct a phenomenological expression to estimate the contributions to the form factors beyond the leading Fock state based on their asymptotic behavior at Q20Q^2\to 0 and Q2Q^2\to\infty. By taking the quark-flavor mixing scheme, our results lead to ϕ=38.0±1.0±2.0\phi= 38.0^{\circ}\pm 1.0^{\circ}\pm 2.0^{\circ}, where the first error coming from experimental uncertainty and the second error coming from the uncertainties of the wavefunction parameters. The possible intrinsic charm component in η\eta and η\eta' is discussed and our present analysis also disfavors a large portion of intrinsic charm component in η\eta and η\eta', e.g. fηc50MeV|f^c_{\eta'}|\le 50 {\rm MeV}.Comment: 18 Pages, 3 figures. Several references added. To be published in EPJ

    A Measurement of the D±D^{*\pm} Cross Section in Two-Photon Processes

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    We have measured the inclusive D±D^{*\pm} production cross section in a two-photon collision at the TRISTAN e+ee^+e^- collider. The mean s\sqrt{s} of the collider was 57.16 GeV and the integrated luminosity was 150 pb1pb^{-1}. The differential cross section (dσ(D±)/dPTd\sigma(D^{*\pm})/dP_T) was obtained in the PTP_T range between 1.6 and 6.6 GeV and compared with theoretical predictions, such as those involving direct and resolved photon processes.Comment: 8 pages, Latex format (article), figures corrected, published in Phys. Rev. D 50 (1994) 187
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