1,118 research outputs found

    The public production and sharing of medical information. An Australian perspective

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    There is a wealth of medical information now available to the public through various sources that are not necessarily controlled by medical or healthcare professionals. In Australia there has been a strong movement in the health consumer arena of consumer-led sharing and production of medical information and in healthcare decision-making. This has led to empowerment of the public as well as increased knowledge-sharing. There are some successful initiatives and strategies on consumer- and public-led sharing of medical information, including the formation of specialised consumer groups, independent medical information organisations, consumer peer tutoring, and email lists and consumer networking events. With well-organised public initiatives and networks, there tends to be fairly balanced information being shared. However, there needs to be caution about the use of publicly available scientific information to further the agenda of special-interest groups and lobbying groups to advance often biased and unproven opinions or for scaremongering. With the adoption of more accountability of medical research, and the increased public scrutiny of private and public research, the validity and quality of medical information reaching the public is achieving higher standards

    J/ψ+c+cˉJ/\psi + c + \bar{c} Photoproduction in e+ee^+ e^- Scattering

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    We investigate the J/ψJ/\psi + c + cˉ\bar{c} photoproduction in e+ee^+ e^- collision at the LEP II energy. The physical motivations for this study are: 1) such next-to-leading order(NLO) process was not considered in previous investigations of J/ψJ/\psi photoproduction in e+ee^+ e^- interaction, and it is worthwhile to do so in order to make sound predictions for experimental comparison; 2) from recent Belle experiment results, the process with same final states at the BB factory has a theoretically yet unexplainable large fraction; hence it is interesting to see what may happen at other colliders; 3) the existing LEP data are marginal in observing such process, and at the planed Linear Colliders(LCs) this process can be measured with high accuracy; 4) it is necessary to take this process into consideration in the aim of elucidating the quarkonium production mechanism, especially in testing the universality of NRQCD nonperturbative matrix elements via J/ψJ/\psi photoproduction in electron-position collisions.Comment: 15 pages, 3 figure

    Analysis of the doubly heavy baryons in the nuclear matter with the QCD sum rules

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    In this article, we study the doubly heavy baryon states Ξcc\Xi_{cc}, Ωcc\Omega_{cc}, Ξbb\Xi_{bb} and Ωbb\Omega_{bb} in the nuclear matter using the QCD sum rules, and derive three coupled QCD sum rules for the masses, vector self-energies and pole residues. The predictions for the mass-shifts in the nuclear matter ΔMΞcc=1.11GeV\Delta M_{\Xi_{cc}}=-1.11\,\rm{GeV}, ΔMΩcc=0.33GeV\Delta M_{\Omega_{cc}}=-0.33\,\rm{GeV}, ΔMΞbb=3.37GeV\Delta M_{\Xi_{bb}}=-3.37\,\rm{GeV} and ΔMΩbb=1.05GeV\Delta M_{\Omega_{bb}}=-1.05\,\rm{GeV} can be confronted with the experimental data in the future.Comment: 10 pages, 4 figure

    B --> Phi K_S and Supersymmetry

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    The rare decay B --> Phi K_S is a well-known probe of physics beyond the Standard Model because it arises only through loop effects yet has the same time-dependent CP asymmetry as B --> Psi K_S. Motivated by recent data suggesting new physics in B --> Phi K_S, we look to supersymmetry for possible explanations, including contributions mediated by gluino loops and by Higgs bosons. Chirality-preserving LL and RR gluino contributions are generically small, unless gluinos and squarks masses are close to the current lower bounds. Higgs contributions are also too small to explain a large asymmetry if we impose the current upper limit on B(B_s --> mu mu). On the other hand, chirality-flipping LR and RL gluino contributions can provide sizable effects and while remaining consistent with related results in B --> Psi K_S, Delta M_s, B --> X_s gamma and other processes. We discuss how the LR and RL insertions can be distinguished using other observables, and we provide a string-based model and other estimates to show that the needed sizes of mass insertions are reasonable.Comment: 33 pages, 32 figures, Updated version for PRD. Includes discussions of other recent works on this topic. Added discussions & plots for gluino mass dependence and effects of theoretical uncertaintie

    Signatures of Thermal Dilepton Radiation at RHIC

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    The properties of thermal dilepton production from heavy-ion collisions in the RHIC energy regime are evaluated for invariant masses ranging from 0.5 to 3 GeV. Using an expanding thermal fireball to model the evolution through both quark-gluon and hadronic phases various features of the spectra are addressed. In the low-mass region, due to an expected large background, the focus is on possible medium modifications of the narrow resonance structures from ω\omega and ϕ\phi mesons, whereas in the intermediate-mass region the old idea of identifying QGP radiation is reiterated including effects of chemical under-saturation in the early stages of central Au+Au collisions.Comment: 17 pages ReVTeX including 16 figure

    SUSY GUT Model Building

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    I discuss an evolution of SUSY GUT model building, starting with the construction of 4d GUTs, to orbifold GUTs and finally to orbifold GUTs within the heterotic string. This evolution is an attempt to obtain realistic string models, perhaps relevant for the LHC. This review is in memory of the sudden loss of Julius Wess, a leader in the field, who will be sorely missed.Comment: 24 pages, 14 figures, lectures given at PiTP 2008, Institute for Advanced Study, Princeton, to be published in the European Physical Journal

    Observation of the ϕ(1680)\phi(1680) and the Y(2175) in e+eϕπ+πe^+ e^- \to \phi\pi^+\pi^-

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    The cross sections for e+eϕπ+πe^+ e^- \to \phi\pi^+\pi^- and e^+ e^- \to \phi \fzero are measured from threshold to s=3.0\sqrt{s}=3.0 GeV\hbox{GeV} using initial state radiation. The analysis is based on a data sample of 673 fb1^{-1} collected on and below the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. First measurements are reported for the resonance parameters of the ϕ(1680)\phi(1680) in the ϕπ+π\phi\pi^+\pi^- mode: m=(1689±7±10)m=(1689\pm 7\pm 10) MeV/c2c^2 and Γ=(211±14±19)\Gamma=(211\pm 14\pm 19) MeV/c2c^2. A structure at s=2.1GeV/c2\sqrt{s}=2.1 \hbox{GeV}/c^2, corresponding to the so called Y(2175), is observed; its mass and width are determined to be 2079±1328+792079\pm13^{+79}_{-28} MeV/c2c^2 and 192±2361+25MeV/c2192\pm23^{+25}_{-61} \hbox{MeV}/c^2, respectively.Comment: 11 pages, 6 figures. Add one plot. Accepted by Phys.Rev.D(RC

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Inclusive search for same-sign dilepton signatures in pp collisions at root s=7 TeV with the ATLAS detector

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    An inclusive search is presented for new physics in events with two isolated leptons (e or mu) having the same electric charge. The data are selected from events collected from p p collisions at root s = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb(-1). The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, e mu and mu mu channels. Four models predicting same-sign dilepton signals are constrained: two descriptions of Majorana neutrinos, a cascade topology similar to supersymmetry or universal extra dimensions, and fourth generation d-type quarks. Assuming a new physics scale of 1 TeV, Majorana neutrinos produced by an effective operator V with masses below 460 GeV are excluded at 95% confidence level. A lower limit of 290 GeV is set at 95% confidence level on the mass of fourth generation d-type quarks

    Observation of a 1750 MeV/c^2 Enhancement in the Diffractive Photoproduction of K^+K^-

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    Using the FOCUS spectrometer with photon beam energies between 20 and 160 \gev, we confirm the existence of a diffractively photoproduced enhancement in K+KK^+K^- at 1750 \mevcc with nearly 100 times the statistics of previous experiments. Assuming this enhancement to be a single resonance with a Breit-Wigner mass shape, we determine its mass to be 1753.5±1.5±2.31753.5\pm 1.5\pm 2.3 \mevcc and its width to be 122.2±6.2±8.0122.2\pm 6.2\pm 8.0 \mevcc. We find no corresponding enhancement at 1750 \mevcc in KKK^*K, and again neglecting any possible interference effects we place limits on the ratio Γ(X(1750)KK)/Γ(X(1750)K+K)\Gamma (X(1750) \to K^*K)/\Gamma (X(1750) \to K^+K^-). Our results are consistent with previous photoproduction experiments, but, because of the much greater statistics, challenge the common interpretation of this enhancement as the ϕ(1680)\phi (1680) seen in e+ee^+e^- annihilation experiments.Comment: 10 pages, 5 figure
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