5,728 research outputs found

    Azimuthal correlations of D-mesons in pp+pp and pp+Pb collisions at LHC energies

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    We study the correlations of D mesons produced in pp+pp and pp+Pb collisions. These are found to be sensitive to the effects of the cold nuclear medium and the transverse momentum (pTp_T) regions we are looking into. In order to put this on a quantitative footing, as a first step we analyse the azimuthal correlations of D meson-charged hadron(Dh), and then predict the same for D meson -anti D meson (DD‾D\overline{D}) pairs in pp+pp and pp+Pb collisions with strong coupling at leading order O\cal{O}(αs2\alpha_{s}^{2}) and next to leading order O\cal{O}(αs3\alpha_{s}^{3}) which includes space-time evolution (in both systems), as well cold nuclear matter effects (in pp+Pb). This also sets the stage and baseline for the identification and study of medium modification of azimuthal correlations in relativistic collision of heavy nuclei at the Large Hadron Collider.Comment: 12 pages, 4 figure

    Micromechanical Modeling and Design Optimization of 2-D Triaxial Braided Composites

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97106/1/AIAA2012-1257.pd

    Unified Dark Fluid and Cosmic Transit Models in Brans-Dicke Theory

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    Some dark energy cosmological models are constructed in the framework of a generalised Brans-Dicke theory which contains a self interacting potential and a dynamical coupling parameter. The dark sector of the universe is considered through a unified linear equation of state. The parameters of the unified dark fluid have been constrained from some physical basis. Since the universe is believed to have undergone a transition from an early deceleration to a late time acceleration, the deceleration parameter should have a signature flipping behaviour at the transition redshift. We have used a hybrid scale factor to simulate the dynamical behaviour of the deceleration parameter. Basing upon the observational constraints on the transition redshift, we have constructed four different transitioning dark energy models. The constructed models are confronted with observational data. For all the models, the behaviour of the dynamical scalar field, Brans-Dicke parameter, Self interacting potential are investigated. Also, on the basis of the generalised Brans-Dicke theory, we have estimated the time variation of the Newtonian gravitational constant.Comment: 17pages, 12 figure

    Evolution of Generalized Brans-Dicke parameter within a Superbounce scenario

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    We have studied a superbounce scenario in a set up of Brans-Dicke (BD) theory. The BD parameter is considered to be time dependent and is assumed to evolve with the Brans-Dicke scalar field. In the superbounce scenario, the model bounces at an epoch corresponding to a Big Crunch provided the ekpyrotic phase continues until that time. Within the given superbounce scenario, we investigate the evolution of the BD parameter for different equations of state. We chose an axially symmetric metric that has an axial symmetry along the x-axis. The metric is assumed to incorporate an anisotropic expansion effect. The effect of asymmetric expansion and the anisotropic parameter on the evolving and the non-evolving part of the BD parameter is investigated.Comment: 10 pages, 5 figures, accepted version of the journal Symmetr
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