10,049 research outputs found

    Accurate time-domain gravitational waveforms for extreme-mass-ratio binaries

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    The accuracy of time-domain solutions of the inhomogeneous Teukolsky equation is improved significantly. Comparing energy fluxes in gravitational waves with highly accurate frequency-domain results for circular equatorial orbits in Schwarzschild and Kerr, we find agreement to within 1% or better, which we believe can be even further improved. We apply our method to orbits for which frequency-domain calculations have a relative disadvantage, specifically high-eccentricity (elliptical and parabolic) "zoom-whirl" orbits, and find the energy fluxes, waveforms, and characteristic strain in gravitational waves.Comment: 6 pages, 9 figures, 2 tables; Changes: some errors corrected. Comparison with Frequency-domain now done in stronger fiel

    Galilei covariance and (4,1) de Sitter space

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    A vector space G is introduced such that the Galilei transformations are considered linear mappings in this manifold. The covariant structure of the Galilei Group (Y. Takahashi, Fortschr. Phys. 36 (1988) 63; 36 (1988) 83) is derived and the tensor analysis is developed. It is shown that the Euclidean space is embedded the (4,1) de Sitter space through in G. This is an interesting and useful aspect, in particular, for the analysis carried out for the Lie algebra of the generators of linear transformations in G.Comment: Late

    Analysis of direct CP violation in B−→D0Ds−,D0D−B^- \to D^0 D_s^-, D^0 D^- decays

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    We investigate the possibility of observing the direct CP violation in the decay modes B−→D0Ds−B^- \to D^0 D_s^- and D0D−D^0 D^- within the Standard Model. Including the contributions arising from the tree, annihilation, QCD as well as electroweak penguins with both time- and space-like components, we find that the direct CP asymmetry in B−→D0Ds−B^- \to D^0 D_s^- is very small ∼0.2\sim 0.2 % but in B−→D0D−B^- \to D^0 D^- decay it can be as large as 4%. Approximately 10710^7 charged BB mesons are required to experimentally observe the CP asymmetry parameter for the later case. Since this is easily accessible with the currently running B factories, the decay mode B−→D0D−B^- \to D^0 D^- may be pursued to look for CP violation.Comment: Latex, 14 page

    Black hole binary inspiral and trajectory dominance

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    Gravitational waves emitted during the inspiral, plunge and merger of a black hole binary carry linear momentum. This results in an astrophysically important recoil to the final merged black hole, a ``kick'' that can eject it from the nucleus of a galaxy. In a previous paper we showed that the puzzling partial cancellation of an early kick by a late antikick, and the dependence of the cancellation on black hole spin, can be understood from the phenomenology of the linear momentum waveforms. Here we connect that phenomenology to its underlying cause, the spin-dependence of the inspiral trajectories. This insight suggests that the details of plunge can be understood more broadly with a focus on inspiral trajectories.Comment: 15 pages, 12 figure

    Systematics of black hole binary inspiral kicks and the slowness approximation

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    During the inspiral and merger of black holes, the interaction of gravitational wave multipoles carries linear momentum away, thereby providing an astrophysically important recoil, or "kick" to the system and to the final black hole remnant. It has been found that linear momentum during the last stage (quasinormal ringing) of the collapse tends to provide an "antikick" that in some cases cancels almost all the kick from the earlier (quasicircular inspiral) emission. We show here that this cancellation is not due to peculiarities of gravitational waves, black holes, or interacting multipoles, but simply to the fact that the rotating flux of momentum changes its intensity slowly. We show furthermore that an understanding of the systematics of the emission allows good estimates of the net kick for numerical simulations started at fairly late times, and is useful for understanding qualitatively what kinds of systems provide large and small net kicks.Comment: 15 pages, 6 figures, 2 table
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