2,901 research outputs found

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    The 2001 Mars In-Situ-Propellant-Production Precursor (MIP) Flight Demonstration

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    The successful performance of the five individual demonstrations of MARS IN-SITU-PROPELLANT-PRODUCTION PRECURSOR (MIP) will provide both knowledge of and confidence in the reliability of this technology. At the completion of this flight demonstration, the MIP Team will be able to: a) recommend preferred hardware configurations for the intake and adsorption of carbon dioxide from the Martian atmosphere; b) understand the performance characteristics of zirconia cells to generate propellant-grade oxygen; c) understand long-term performance characteristics of advanced solar cells/arrays operated in the actual Mars environment; d) evaluate the functionality of methods to mitigate the deposition of airborne dust onto solar arrays; and e) recommend preferred hardware designs for innovative thermal management including the radiation of heat to the outside environment

    Assessment of cognitive self-statements during marital problem solving: A comparison of two methods

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    Twenty maritally distressed couples (DC) and 20 nondistressed couples (NDC) were recruited and asked to undertake 10 minutes of problem-solving discussions, which were videotaped. Each individual partner’s cognitive self-statements during the interaction were assessed using two methods: video-assisted recall (VR) and thought listing (TL). Reported cognitions from each method were content- analysed and classified into five categories: partner- referent positive, partner- referent negative, self-referent positive, self- referent negative, and other. Proportions of reported cognitions falling into each category were analysed in two separate two-way MANOVAs (marital distress/ nondistress x sex) for the VR and TL measures. Results of each MANOVA indicated a highly significant effect of marital distress on cognitions, and a significant effect of sex on the VR but not the TL measure. Discriminant analyses showed that the VR and TL methods both discriminated between DC and NDC groups. Post hoc univariate ANOVAs indicated that DC had significantly higher proportions of negative partner- referent cognitions, and lower proportions of positive partner- referent cognitions, than NDC while problem solving. The relative merits of each cognitive assessment method, and their potential use in increasing marital therapy effectiveness, are discussed
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