348 research outputs found

    I'll just watch: Do the pro-social effects of coordination really generalize to non-actors?

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    Moving in time together has been shown to cultivate pro-social effects in co-actors, such as cooperation and helping. But less is known about who these effects apply to - whether they are restricted only to co-actors, or whether they generalize to those not involved in the coordination. One difference between past work finding generalized vs. restricted effects is whether these "outsiders" were present for the coordination or not. The present study explores whether the pro-social effects of coordination are seen towards observers as well as co-actors, and whether the absence or presence of observers during the coordination is a determining factor. Results show that greater cooperation following coordination is only seen amongst co- actors, regardless of whether the observers were present during the task or not. Findings are discussed in the context of the literature and alternative explanations for research showing generalized effects are suggested

    Laws and Conventions in Language-Related Behaviors

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    The goal of this article is to look at language-related behaviors in light of a strict definition of direct perception. I highlight a key dimension, conventionality, which discriminates between behaviors that are coordinated with respect to law-based information and those that are not (and, therefore, do not qualify as direct perception according to the definition used in this article). The difference between conventional and law-based information does not break down clearly along obvious lines such as natural versus human-made, social versus nonsocial, or linguistic versus nonlinguistic. Therefore, it is necessary to take a task-specific approach to deciding whether a behavior is organized with respect to conventional or law-based information. A tacit assumption in ecological psychology seems to be that anything that has an effect on behavior must be grounded in the perception of an affordance and, therefore, must be guided by law-based information. In this article, I question this assumption. I suggest, instead, that ecological information can be based on both laws and conventions. This move allows us to maintain rigorous definitions of affordances and direct perception, suitable for underpinning action-control, while still expanding the ecological study of behaviors into those that rely on conventional information

    Effects of interactive chat versus independent writing on L2 learning

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    Matching NLO parton shower matrix element with exact phase space: case of W -> l nu (gamma) and gamma^* -> pi^+pi^-(gamma)

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    The PHOTOS Monte Carlo is often used for simulation of QED effects in decay of intermediate particles and resonances. Momenta are generated in such a way that samples of events cover the whole bremsstrahlung phase space. With the help of selection cuts, experimental acceptance can be then taken into account. The program is based on an exact multiphoton phase space. Crude matrix element is obtained by iteration of a universal multidimensional kernel. It ensures exact distribution in the soft photon region. Algorithm is compatible with exclusive exponentiation. To evaluate the program's precision, it is necessary to control the kernel with the help of perturbative results. If available, kernel is constructed from the exact first order matrix element. This ensures that all terms necessary for non-leading logarithms are taken into account. In the present paper we will focus on the W -> l nu and gamma^* -> pi^+ pi^- decays. The Born level cross sections for both processes approach zero in some points of the phase space. A process dependent compensating weight is constructed to incorporate the exact matrix element, but is recommended for use in tests only. In the hard photon region, where scalar QED is not expected to be reliable, the compensating weight for gamma^* decay can be large. With respect to the total rate, the effect remains at the permille level. It is nonetheless of interest. The terms leading to the effect are analogous to some terms appearing in QCD. The present paper can be understood either as a contribution to discussion on how to match two collinear emission chains resulting from charged sources in a way compatible with the exact and complete phase space, exclusive exponentiation and the first order matrix element of QED (scalar QED), or as the practical study of predictions for accelerator experiments.Comment: 24 page

    SANC integrator in the progress: QCD and EW contributions

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    Modules and packages for the one-loop calculations at partonic level represent the first level of SANC output computer product. The next level represents Monte Carlo integrator mcsanc, realizing fully differential hadron level calculations (convolution with PDF) for the HEP processes at LHC. In this paper we describe the implementation into the framework mcsanc first set of processes: DY NC, DY CC, ff->HW(Z) and single top production. Both EW and QCD NLO corrections are taken into account. A comparison of SANC results with those existing in the world literature is given

    Theoretical Uncertainties in Electroweak Boson Production Cross Sections at 7, 10, and 14 TeV at the LHC

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    We present an updated study of the systematic errors in the measurements of the electroweak boson cross-sections at the LHC for various experimental cuts for a center of mass energy of 7, 10 and 14 TeV. The size of both electroweak and NNLO QCD contributions are estimated, together with the systematic error from the parton distributions. The effects of new versions of the MSTW, CTEQ, and NNPDF PDFs are considered.Comment: PDFLatex with JHEP3.cls. 22 pages, 43 figures. Version 2 adds the CT10W PDF set to analysis and updates the final systematic error table and conclusions, plus several citations and minor wording changes. Version 3 adds some references on electroweak and mixed QED/QCD corrections. Version 4 adds more references and acknowledgement

    Combination of electroweak and QCD corrections to single W production at the Fermilab Tevatron and the CERN LHC

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    Precision studies of the production of a high-transverse momentum lepton in association with missing energy at hadron colliders require that electroweak and QCD higher-order contributions are simultaneously taken into account in theoretical predictions and data analysis. Here we present a detailed phenomenological study of the impact of electroweak and strong contributions, as well as of their combination, to all the observables relevant for the various facets of the p\smartpap \to {\rm lepton} + X physics programme at hadron colliders, including luminosity monitoring and Parton Distribution Functions constraint, WW precision physics and search for new physics signals. We provide a theoretical recipe to carefully combine electroweak and strong corrections, that are mandatory in view of the challenging experimental accuracy already reached at the Fermilab Tevatron and aimed at the CERN LHC, and discuss the uncertainty inherent the combination. We conclude that the theoretical accuracy of our calculation can be conservatively estimated to be about 2% for standard event selections at the Tevatron and the LHC, and about 5% in the very high WW transverse mass/lepton transverse momentum tails. We also provide arguments for a more aggressive error estimate (about 1% and 3%, respectively) and conclude that in order to attain a one per cent accuracy: 1) exact mixed O(ααs){\cal O}(\alpha \alpha_s) corrections should be computed in addition to the already available NNLO QCD contributions and two-loop electroweak Sudakov logarithms; 2) QCD and electroweak corrections should be coherently included into a single event generator.Comment: One reference added. Final version to appear in JHE

    Measurement of B0π+ππ+πB^0\to\pi^+\pi^-\pi^+\pi^- Decays and Search for B0ρ0ρ0B^0\to\rho^0\rho^0

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    We report on a search for the decay B0ρ0ρ0B^0\to\rho^0\rho^0 and other charmless modes with a π+ππ+π\pi^+\pi^-\pi^+\pi^- final state, including B0ρ0π+πB^0\to\rho^0\pi^+\pi^-, non-resonant B04π±B^0\to 4\pi^{\pm}, B0ρ0f0(980)B^0\to\rho^0f_0(980), B0f0(980)f0(980)B^0\to f_0(980)f_0(980) and B0f0(980)π+πB^0\to f_0(980)\pi^+\pi^-. These results are obtained from a data sample containing 657 million BBB \overline B pairs collected with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. We set an upper limit on B(B0ρ0ρ0)\mathcal{B}(B^0\to\rho^0\rho^0) of 1.0×1061.0\times 10^{-6} at the 90% confidence level (C.L.). From our B0ρ0ρ0B^0\to\rho^0\rho^0 measurement and an isospin analysis, we determine the Cabibbo-Kobayashi-Maskawa phase ϕ2\phi_2 to be 91.7±14.991.7 \pm 14.9 degrees. We find excesses in B0ρ0π+πB^0\to \rho^0\pi^+\pi^- and non-resonant B04π±B^0\to 4\pi^{\pm} with 1.3σ\sigma and 2.5σ\sigma significance, respectively. The corresponding branching fractions are less than 12.0×10612.0 \times 10^{-6} and 19.3×10619.3 \times 10^{-6} at the 90% C.L. In addition, we set 90% C.L. upper limits as follows: B(B0ρ0f0(980))<0.3×106\mathcal{B}(B^0\to\rho^0f_0(980))< 0.3 \times 10^{-6}, B(B0f0(980)f0(980))<0.1×106\mathcal{B}(B^0\to f_0(980)f_0(980))< 0.1 \times 10^{-6}, and B(B0f0(980)π+π)<3.8×106\mathcal{B}(B^0\to f_0(980)\pi^+\pi^-)< 3.8 \times 10^{-6}.Comment: 6 pages, 2 figures. Submitted to PRD(RC

    Simulation of the cosmic ray tau neutrino telescope (CRTNT) experiment

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    A tau lepton can be produced in a charged current interaction by cosmic ray tau neutrino with material inside a mountain. If it escapes from the mountain, it will decay and initiate a shower in the air, which can be detected by an air shower fluorescence/Cherenkov light detector. Designed according to such a principle, the Cosmic Ray Tau Neutrino Telescope (CRTNT) experiment, located at the foothill of Mt. Balikun in Xinjiang, China, will search for very high-energy cosmic tau neutrinos from energetic astrophysical sources by detecting those showers. This paper describes a Monte Carlo simulation for a detection of tau neutrino events by the CRTNT experiment. Ultra-high-energy cosmic ray events are also simulated to estimate the potential contamination. With the CRTNT experiment composed of four detector stations, each covering 64 by 14 degrees field of view, the expected event rates are 28.6, 21.9 and 4.7 per year assuming AGN neutrino flux according to Semikoz et. al. 2004, MPR AGN jet model and SDSS AGN core model, respectively. Null detection of such tau event by the CRTNT experiment in one year could set 90% C.L. upper limit at 19.9 (eV^-1 cm^-2 s^-1 sr^-1) for E^-2 neutrino spectrum.Comment: 14 page
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