4,679 research outputs found

    Effect of radiation-like solid on CMB anisotropies

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    We compute the power in the lowest multipoles of CMB anisotropies in the presence of radiation-like solid, a hypothetical new kind of radiation with nonzero shear modulus. If only the ordinary Sachs-Wolfe effect is taken into account, the shear modulus to energy density ratio must be in absolute value of order 10510^{-5} or less for the theory to be consistent with observations within cosmic variance. With the integrated Sachs-Wolfe effect switched on, the constraint is relaxed almost by two orders of magnitude.Comment: 24 pages, 3 figure

    Measurement of the nuclear modification factor for high-pTp_{\mathrm{T}} charged hadrons in pp+Pb collisions with the ATLAS detector

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    The charged hadron spectra in pp+Pb and pppp collisions at sNN=s=5.02\sqrt{s_{NN}}=\sqrt{s}=5.02TeV are measured with the ATLAS experiment at the LHC. The measurements are performed with pp+Pb data recorded in 2013 with an integrated luminosity of 25nb1{}^{-1} and pppp data recorded in 2015 with an integrated luminosity of 28pb1{}^{-1}. The pp+Pb results are compared to pppp spectra, presented as a ratio of transverse momentum distributions in the two systems scaled by the number of binary nucleon-nucleon collisions, the nuclear modification factor RpPbR_{p \mathrm{Pb}}. The study of RpPbR_\mathrm{pPb} allows a detailed comparison of the collision systems in different centrality intervals and in a wide range of transverse momentum. It is shown that the nuclear modification factor does not have any significant deviation from unity in the high transverse momentum region.Comment: 4 pages, 4 figures, presented at Hard Probes 201

    Evolution of a black hole-inhabited brane close to reconnection

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    Last moments of a mini black hole escaping from a brane are studied. It is argued that at the point of reconnection, where the piece of the brane attached to the black hole separates from the rest, the worldsheet of the brane becomes isotropic (light-like). The degenerate mode of evolution, with the worldsheet isotropic everywhere, is investigated. In particular, it is shown that the brane approaches the reconnection point from below if it reconnects within a certain limit distance, and from above if it reconnects beyond that distance. The rate of relaxation to the degenerate mode is established. If the dimension of the brane is pp, the nondegeneracy, measured by the determinant of the relevant part of the induced metric tensor, falls down as (latitudinal angle)2(p1)^{2(p - 1)}.Comment: 20 pages, 4 figure

    Coleman - de Luccia instanton of the second order in a brane world

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    The second order Coleman - de Luccia instanton and its action in the Randall - Sundrum type II model are investigated and the comparison with the results in Einstein's general relativity is done in the present paper.Comment: 4 pages, accepted in IJT
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