1,162 research outputs found

    Anyonic order parameters for discrete gauge theories on the lattice

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    We present a new family of gauge invariant non-local order parameters for (non-abelian) discrete gauge theories on a Euclidean lattice, which are in one-to-one correspondence with the excitation spectrum that follows from the representation theory of the quantum double D(H) of the finite group H. These combine magnetic flux-sector labeled by a conjugacy class with an electric representation of the centralizer subgroup that commutes with the flux. In particular cases like the trivial class for magnetic flux, or the trivial irrep for electric charge, these order parameters reduce to the familiar Wilson and the 't Hooft operators respectively. It is pointed out that these novel operators are crucial for probing the phase structure of a class of discrete lattice models we define, using Monte Carlo simulations.Comment: 14 pages, 1 figur

    Study of the Linked Dipole Chain Model in heavy quark production at the Tevatron

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    We present calculations of charm and beauty production at Tevatron within the framework of kT-factorization, using the unintegrated gluon distributions as obtained from the Linked Dipole Chain model. The analysis covers transverse momentum and rapidity distributions and the azimuthal correlations between b and bbar quarks (or rather muons from their decay) which are powerful tests for the different unintegrated gluon distributions. We compare the theoretical results with recent experimental data taken by D0 and CDF collaborations at the Tevatron Run I and II.Comment: 16 page

    Anticipated regret to increase uptake of colorectal cancer screening (ARTICS):a randomised controlled trial

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    Objective. Screening is key to early detection of colorectal cancer. Our aim was to determine whether a simple anticipated regret (AR) intervention could increase colorectal cancer screening uptake. Methods. We conducted a randomised controlled trial of a simple, questionnaire-based AR intervention, delivered alongside existing pre-notification letters. 60,000 adults aged 50-74 from the Scottish National Screening programme were randomised to: 1) no questionnaire (control), 2) Health Locus of Control questionnaire (HLOC) or 3) HLOC plus anticipated regret questionnaire (AR). Primary outcome was guaiac Faecal Occult Blood Test (FOBT) return. Secondary outcomes included intention to return test kit and perceived disgust (ICK). Results. 59,366 people were analysed as allocated (Intentionto- treat (ITT)); there were no overall differences between treatment groups on FOBT uptake (control: 57.3%, HLOC: 56.9%, AR: 57.4%). 13,645 (34.2%) people returned questionnaires. Analysis of the secondary questionnaire measures showed that AR had an indirect effect on FOBT uptake via intention, whilst ICK had a direct effect on FOBT uptake over and above intention. The effect of AR on FOBT uptake was also moderated by intention strength: for less than strong intenders only, uptake was 4.2% higher in the AR (84.6%) versus the HLOC group (80.4%) (95% CI for difference (2.0, 6.5)). Conclusion. The findings show that psychological concepts including anticipated regret and perceived disgust (ICK) are important factors in determining FOBT uptake. However, there was no simple effect of the AR intervention in the ITT. We conclude that exposure to AR in those with low intentions may be required to increase FOBT uptake. Current controlled trials: www.controlledtrials. com number: ISRCTN74986452

    Multifragmentation threshold in ^{93}Nb+{nat}Mg collisions at 30 MeV/nucleon

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    We analyzed the 93Nb^{93}Nb on natMg^{nat}Mg reaction at 30 MeV/nucleon in the aim of disentangling binary sequential decay and multifragmentation decay close to the energy threshold, i.e. 3\simeq 3 MeV/nucleon. Using the backtracing technique applied to the statistical models GEMINI and SMM we reconstruct simulated charge, mass and excitation energy distributions and compare them to the experimental ones. We show that data are better described by SMM than by GEMINI in agreement with the fact that multifragmentation is responsible for fragment production at excitation energies around 3 MeV/nucleon.Comment: 16 pages, 12 figures, 5 tables Soumis \`a Nuclear Physics

    Cut Diagrams for High Energy Scatterings

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    A new approach is introduced to study QCD amplitudes at high energy and comparatively small momentum transfer. Novel cut diagrams, representing resummation of Feynman diagrams, are used to simplify calculation and to avoid delicate cancellations encountered in the usual approach. Explicit calculation to the 6th order is carried out to demonstrate the advantage of cut diagrams over Feynman diagrams.Comment: uu-encoded file containing a latex manuscript with 14 postscript figure

    Mass and charge identification of fragments detected with the Chimera Silicon-CsI(Tl) telescopes

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    Mass and charge identification of charged products detected with Silicon-CsI(Tl) telescopes of the Chimera apparatus is presented. An identification function, based on the Bethe-Bloch formula, is used to fit empirical correlation between Delta E and E ADC readings, in order to determine, event by event, the atomic and mass numbers of the detected charged reaction products prior to energy calibration.Comment: 24 pages, 7 .jpg figures, submitted to Nucl.Instr.

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

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    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

    Study of CP violation in Dalitz-plot analyses of B0 --> K+K-KS, B+ --> K+K-K+, and B+ --> KSKSK+

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    We perform amplitude analyses of the decays B0K+KKS0B^0 \to K^+K^-K^0_S, B+K+KK+B^+ \rightarrow K^+K^-K^+, and B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470×106470\times 10^6 BBˉB\bar{B} decays, collected with the BABAR detector at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory. For B+K+KK+B^+ \to K^+K^-K^+, we find a direct CP asymmetry in B+ϕ(1020)K+B^+ \to \phi(1020)K^+ of ACP=(12.8±4.4±1.3)A_{CP}= (12.8\pm 4.4 \pm 1.3)%, which differs from zero by 2.8σ2.8 \sigma. For B0K+KKS0B^0 \to K^+K^-K^0_S, we measure the CP-violating phase βeff(ϕ(1020)KS0)=(21±6±2)\beta_{\rm eff} (\phi(1020)K^0_S) = (21\pm 6 \pm 2)^\circ. For B+KS0KS0K+B^+ \to K^0_S K^0_S K^+, we measure an overall direct CP asymmetry of ACP=(45+4±2)A_{CP} = (4 ^{+4}_{-5} \pm 2)%. We also perform an angular-moment analysis of the three channels, and determine that the fX(1500)f_X(1500) state can be described well by the sum of the resonances f0(1500)f_0(1500), f2(1525)f_2^{\prime}(1525), and f0(1710)f_0(1710).Comment: 35 pages, 68 postscript figures. v3 - minor modifications to agree with published versio

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
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