1,249 research outputs found

    Case Report-Right iliac fossa mass in an HIV-positive woman

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    Quark-antiquark composite systems: the Bethe-Salpeter equation in the spectral-integration technique

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    The Bethe-Salpeter equations for the light-quark composite systems, q q-bar, are written in terms of spectral integrals. For the q q-bar -mesons characterized by the mass M, spin J and radial quantum number n, the equations are presented for the following (n,M^2)-trajectories: pi_J, eta_J, a_J, f_J, rho_J, omega_J, h_J and b_J.Comment: 42 pages, 5 figures, typos correcte

    The structure of hot gas in Cepheus B

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    By observing radiation-affected gas in the Cepheus B molecular cloud we probe whether the sequential star formation in this source is triggered by the radiation from newly formed stars. We used the dual band receiver GREAT onboard SOFIA to map [C II] and CO 13--12 and 11--10 in Cep B and compared the spatial distribution and the spectral profiles with complementary ground-based data of low-JJ transitions of CO isotopes, atomic carbon, and the radio continuum. The interaction of the radiation from the neighboring OB association creates a large photon-dominated region (PDR) at the surface of the molecular cloud traced through the photoevaporation of C^+. Bright internal PDRs of hot gas are created around the embedded young stars, where we detect evidence of the compression of material and local velocity changes; however, on the global scale we find no indications that the dense molecular material is dynamically affected.Comment: Accepted for publication in A&A (SOFIA/GREAT special issue

    Universal description of S-wave meson spectra in a renormalized light-cone QCD-inspired model

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    A light-cone QCD-inspired model, with the mass squared operator consisting of a harmonic oscillator potential as confinement and a Dirac-delta interaction, is used to study the S-wave meson spectra. The two parameters of the harmonic potential and quark masses are fixed by masses of rho(770), rho(1450), J/psi, psi(2S), K*(892) and B*. We apply a renormalization method to define the model, in which the pseudo-scalar ground state mass fixes the renormalized strength of the Dirac-delta interaction. The model presents an universal and satisfactory description of both singlet and triplet states of S-wave mesons and the corresponding radial excitations.Comment: RevTeX, 17 pages, 7 eps figures, to be published in Phys. Rev.

    Measurement of ultrashort bi-photon correlation times with an integrated two-colour broadband SU(1,1)-interferometer

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    The bi-photon correlation time, a measure for the conditional uncertainty in the temporal arrival of two photons from a photon pair source, is a key performance identifier for many quantum spectroscopy applications, with shorter correlation times typically yielding better performance. Furthermore, it provides fundamental insight into the effects of dispersion on the bi-photon state. Here, we retrieve ultrashort bi-photon correlation times of around 100fs100\,\mathrm{fs} by measuring simultaneously spectral and temporal interferograms at the output of an SU(1,1) interferometer based on an integrated broadband parametric down-conversion source in a Ti:LiNbO3\mathrm{Ti:LiNbO}_3 waveguideComment: 8 pages, 5 figure

    Baryon spectra with instanton induced forces

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    Except the vibrational excitations of KK and KK^* mesons, the main features of spectra of mesons composed of quarks uu, dd, and ss can be quite well described by a semirelativistic potential model including instanton induced forces. The spectra of baryons composed of the same quarks is studied using the same model. The results and the limitations of this approach are described. Some possible improvements are suggested.Comment: 5 figure

    Quark--antiquark states and their radiative transitions in terms of the spectral integral equation. {\Huge II.} Charmonia

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    In the precedent paper of the authors (hep-ph/0510410), the bbˉb\bar b states were treated in the framework of the spectral integral equation, together with simultaneous calculations of radiative decays of the considered bottomonia. In the present paper, such a study is carried out for the charmonium (ccˉ)(c\bar c) states. We reconstruct the interaction in the ccˉc\bar c-sector on the basis of data for the charmonium levels with JPC=0+J^{PC}=0^{-+}, 11^{--}, 0++0^{++}, 1++1^{++}, 2++2^{++}, 1+1^{+-} and radiative transitions ψ(2S)γχc0(1P)\psi(2S)\to\gamma\chi_{c0}(1P), γχc1(1P)\gamma\chi_{c1}(1P), γχc2(1P)\gamma\chi_{c2}(1P), γηc(1S)\gamma\eta_{c}(1S) and χc0(1P)\chi_{c0}(1P), χc1(1P)\chi_{c1}(1P), χc2(1P)γJ/ψ\chi_{c2}(1P)\to\gamma J/\psi. The ccˉc\bar c levels and their wave functions are calculated for the radial excitations with n6n\le 6. Also, we determine the ccˉc\bar c component of the photon wave function using the e+ee^+e^- annihilation data: e+eJ/ψ(3097)e^+e^- \to J/\psi(3097), ψ(3686)\psi(3686), ψ(3770)\psi(3770), ψ(4040)\psi(4040), ψ(4160) \psi(4160), ψ(4415)\psi(4415) and perform the calculations of the partial widths of the two-photon decays for the n=1n=1 states: ηc0(1S)\eta_{c0}(1S), χc0(1P)\chi_{c0}(1P), χc2(1P)γγ\chi_{c2}(1P)\to\gamma\gamma, and n=2n=2 states: ηc0(2S)γγ\eta_{c0}(2S)\to\gamma\gamma, χc0(2P)\chi_{c0}(2P), χc2(2P)γγ\chi_{c2}(2P)\to \gamma\gamma. We discuss the status of the recently observed ccˉc\bar c states X(3872) and Y(3941): according to our results, the X(3872) can be either χc1(2P)\chi_{c1}(2P) or ηc2(1D)\eta_{c2}(1D), while Y(3941) is χc2(2P)\chi_{c2}(2P).Comment: 24 pages, 9 figure

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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