240 research outputs found

    A systematic review of the anxiety-attention relationship in far-aiming skills

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    This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordTheoretical accounts of the anxiety and motor performance relationship cite disruptions to attention as a critical mediating factor. The aims of this paper were to (1) systematically review published research examining attentional mechanisms underpinning the anxiety–performance relationship in targeting skills, and (2) subsequently discuss these findings in relation to contemporary theoretical perspectives. Adhering to PRISMA guidelines, three electronic databases (PubMed, PsycInfo, and SPORTDiscus) were searched from inception until June 2017. Thirty-four articles satisfied the inclusion criteria. Overall, the research is of high methodological quality; however, there is a tendency to focus on the historical dichotomy between self-focus and distraction accounts, whereas empirical support for more contemporary theoretical perspectives is lacking. Whilst this review provides further support for the role of attentional disruptions in anxiety-induced performance degradation, the exact mechanisms still lack consensus. In addition, more innovative experimental designs and measures are required to progress our understanding of moderating variables

    A systematic review and meta-analysis of the relationship between flow states and performance

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    This is the final version. Available on open access from Routledge via the DOI in this recordData availability: All relevant data and code is available online from https://osf.io/3hfcu/Flow is an optimal experience that has received particular interest within sport because of a possible relationship with enhanced athletic performances. Yet, the strength and direction of the putative flow–performance relationship remain unclear. Consequently, a PRISMA guided systematic review was conducted in May 2020 to examine the empirical evidence for a flow–performance relationship, to examine potential mechanisms, and to assess the quality of current evidence. Peer-reviewed articles that examined the relationship between flow and performance in sport or computer gaming tasks were searched for using five online databases. The results were collated into a narrative synthesis and a meta-analysis. Twenty articles met the inclusion criteria, featuring 22 studies that were appropriate for meta-analysis. The overall quality of the studies was fairly good, with a mean quality assessment score of 76.5% (SD = 9.7). The pooled effect size (r = 0.31, 95% CI [0.24; 0.38]) indicated that across a range of sport and gaming tasks there was a medium-sized flow–performance relationship. However, current evidence is unable to determine the causal direction of this relationship or the mechanisms that mediate it. A number of conceptual and methodological challenges facing the study of flow are discussed and recommendations for future work are outlined.Royal Academy of Engineering (RAE

    Search for Pair Production of Scalar Top Quarks Decaying to a tau Lepton and a b Quark in ppbar Collisions at sqrt{s}=1.96 TeV

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    We search for pair production of supersymmetric top quarks (~t_1), followed by R-parity violating decay ~t_1 -> tau b with a branching ratio beta, using 322 pb^-1 of ppbar collisions at sqrt{s}=1.96 TeV collected by the CDF II detector at Fermilab. Two candidate events pass our final selection criteria, consistent with the standard model expectation. We set upper limits on the cross section sigma(~t_1 ~tbar_1)*beta^2 as a function of the stop mass m(~t_1). Assuming beta=1, we set a 95% confidence level limit m(~t_1)>153 GeV/c^2. The limits are also applicable to the case of a third generation scalar leptoquark (LQ_3) decaying LQ_3 -> tau b.Comment: 7 pages, 2 eps figure

    Precision measurement of the top quark mass from dilepton events at CDF II

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    We report a measurement of the top quark mass, M_t, in the dilepton decay channel of ttˉb+νbˉνˉt\bar{t}\to b\ell'^{+}\nu_{\ell'}\bar{b}\ell^{-}\bar{\nu}_{\ell} using an integrated luminosity of 1.0 fb^{-1} of p\bar{p} collisions collected with the CDF II detector. We apply a method that convolutes a leading-order matrix element with detector resolution functions to form event-by-event likelihoods; we have enhanced the leading-order description to describe the effects of initial-state radiation. The joint likelihood is the product of the likelihoods from 78 candidate events in this sample, which yields a measurement of M_{t} = 164.5 \pm 3.9(\textrm{stat.}) \pm 3.9(\textrm{syst.}) \mathrm{GeV}/c^2, the most precise measurement of M_t in the dilepton channel.Comment: 7 pages, 2 figures, version includes changes made prior to publication by journa

    Measurement of the Ratios of Branching Fractions B(Bs -> Ds pi pi pi) / B(Bd -> Dd pi pi pi) and B(Bs -> Ds pi) / B(Bd -> Dd pi)

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    Using 355 pb^-1 of data collected by the CDF II detector in \ppbar collisions at sqrt{s} = 1.96 TeV at the Fermilab Tevatron, we study the fully reconstructed hadronic decays B -> D pi and B -> D pi pi pi. We present the first measurement of the ratio of branching fractions B(Bs -> Ds pi pi pi) / B(Bd -> Dd pi pi pi) = 1.05 pm 0.10 (stat) pm 0.22 (syst). We also update our measurement of B(Bs -> Ds pi) / B(Bd -> Dd pi) to 1.13 pm 0.08 (stat) pm 0.23 (syst) improving the statistical uncertainty by more than a factor of two. We find B(Bs -> Ds pi) = [3.8 pm 0.3 (stat) pm 1.3 (syst)] \times 10^{-3} and B(Bs -> Ds pi pi pi) = [8.4 pm 0.8 (stat) pm 3.2 (syst)] \times 10^{-3}.Comment: 7 pages, 2 figure

    Cross Section Measurements of High-pTp_T Dilepton Final-State Processes Using a Global Fitting Method

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    We present a new method for studying high-pTp_T dilepton events (e±ee^{\pm}e^{\mp}, μ±μ\mu^{\pm}\mu^{\mp}, e±μe^{\pm}\mu^{\mp}) and simultaneously extracting the production cross sections of ppˉttˉp\bar{p} \to t\bar{t}, ppˉW+Wp\bar{p} \to W^+W^-, and p\bar{p} \to \ztt at a center-of-mass energy of s=1.96\sqrt{s} = 1.96 TeV. We perform a likelihood fit to the dilepton data in a parameter space defined by the missing transverse energy and the number of jets in the event. Our results, which use 360pb1360 {\rm pb^{-1}} of data recorded with the CDF II detector at the Fermilab Tevatron Collider, are σ(ttˉ)=8.52.2+2.7\sigma(t\bar{t}) = 8.5_{-2.2}^{+2.7} pb, σ(W+W)=16.34.4+5.2\sigma(W^+W^-) = 16.3^{+5.2}_{-4.4} pb, and \sigma(\ztt) =291^{+50}_{-46} pb.Comment: 20 pages, 2 figures, to be submitted to PRD-R

    Top Quark Mass Measurement from Dilepton Events at CDF II with the Matrix-Element Method

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    We describe a measurement of the top quark mass using events with two charged leptons collected by the CDF II detector from ppˉp\bar{p} collisions with s=1.96\sqrt s = 1.96 TeV at the Fermilab Tevatron. The likelihood in top mass is calculated for each event by convoluting the leading order matrix element describing qqˉttˉbνbˉνq\bar{q} \to t\bar{t} \to b\ell\nu_{\ell}\bar{b}\ell'\nu_{\ell'} with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated luminosity of 340 pb1^{-1}, we observe 33 candidate events and measure Mtop=165.2±6.1(stat.)±3.4(syst.) GeV/c2.M_{top} = 165.2 \pm 6.1(\textrm{stat.}) \pm 3.4(\textrm{syst.}) \mathrm{~GeV}/c^2. This measurement represents the first application of this method to events with two charged leptons and is the most precise single measurement of the top quark mass in this channel.Comment: 21 pages, 14 figure

    Measurement of the Dipion Mass Spectrum in X(3872) -> J/Psi Pi+ Pi- Decays

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    We measure the dipion mass spectrum in X(3872)--> J/Psi Pi+ Pi- decays using 360 pb-1 of pbar-p collisions at 1.96 TeV collected with the CDF II detector. The spectrum is fit with predictions for odd C-parity (3S1, 1P1, and 3DJ) charmonia decaying to J/Psi Pi+ Pi-, as well as even C-parity states in which the pions are from Rho0 decay. The latter case also encompasses exotic interpretations, such as a D0-D*0Bar molecule. Only the 3S1 and J/Psi Rho hypotheses are compatible with our data. Since 3S1 is untenable on other grounds, decay via J/Psi Rho is favored, which implies C=+1 for the X(3872). Models for different J/Psi-Rho angular momenta L are considered. Flexibility in the models, especially the introduction of Rho-Omega interference, enable good descriptions of our data for both L=0 and 1.Comment: 7 pages, 4 figures -- Submitted to Phys. Rev. Let

    Search for New Physics in Lepton + Photon + X Events with L=305 pb-1 of ppbar Collisions at roots=1.96 TeV

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    We present results of a search for anomalous production of events containing a charged lepton (either electron or muon) and a photon, both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (MET) and additional leptons and photons. We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb-1, a ppbar collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 Lepton+Photon+MET events versus a standard model expectation of 37.3 +- 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 +- 0.7 events (corresponding to a 2.7 sigma effect), is not supported by the new data. In the signature of Multi-Lepton+Photon+X we observe 31 events versus an expectation of 23.0 +- 2.7 events. In this sample we find no events with an extra photon or MET and so find no events like the one ee+gg+MET event observed in Run I.Comment: 7 pages, 3 figures, 1 table. Accepted to PR

    Measurement of the Lambda_b Lifetime in Lambda_b --> J/psi Lambda0 in p-pbar Collisions at sqrt(s)=1.96 TeV

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    We report a measurement of the Lambda_b lifetime in the exclusive decay Lambda_b --> J/psi Lambda0 in p-pbar collisions at sqrt(s) = 1.96 TeV using an integrated luminosity of 1.0 fb^{-1} of data collected by the CDF II detector at the Fermilab Tevatron. Using fully reconstructed decays, we measure tau(Lambda_b) = 1.593 ^{+0.083}_{-0.078} (stat.) +- 0.033 (syst.) ps. This is the single most precise measurement of tau(Lambda_b) and is 3.2 sigma higher than the current world average.Comment: 7 Pages, 2 Figures, 1 Table. Submitted to Phys. Rev. Let
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