118292450
Radial infall of two compact objects: 2.5PN linear momentum flux and associated recoil
The loss rate of linear momentum from a binary system composed of compact objects (radially falling towards each other under mutual gravitational influence) has been investigated using the multipolar post-Minkowskian approach. The 2.5PN accurate analytical formula for the linear momentum flux is provided, in terms of the separation of the two objects, in harmonic coordinates, both for a finite and infinite initial separation. The 2.5PN formulas for the linear momentum flux are finally used to estimate the recoil velocity accumulated during a premerger phase of the binary evolution.
115477379
2.5PN Kick from Black-Hole Binaries in Circular Orbit: Nonspinning Case
Using the Multipolar post-Minskowskian formalism, we compute the linear momentum flux from black-hole binaries in circular orbits and having no spins. The total linear momentum flux contains various types of instantaneous (which are functions of the retarded time) and hereditary (which depend on the dynamics of the binary in the past) terms both of which are analytically computed. In addition to the inspiral contribution, we use a simple model of plunge to compute the kick or recoil accumulated during this phase.
13362865
Parametrized tests of post-Newtonian theory using Advanced LIGO and Einstein Telescope
General relativity has very specific predictions for the gravitational waveforms from inspiralling compact binaries obtained using the post-Newtonian (PN) approximation. We investigate the extent to which the measurement of the PN coefficients, possible with the second generation gravitational-wave detectors such as the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) and the third generation gravitational-wave detectors such as the Einstein Telescope (ET), could be used to test post-Newtonian theory and to put bounds on a subclass of parametrized-post-Einstein theories which differ from general relativity in a parametrized sense. We demonstrate this possibility by employing the best inspiralling waveform model for nonspinning compact binaries which is 3.5PN accurate in phase and 3PN in amplitude. Within the class of theories considered, Advanced LIGO can test the theory at 1.5PN and thus the leading tail term. Future observations of stellar mass black hole binaries by ET can test the consistency between the various PN coefficients in the gravitational-wave phasing over the mass range of 11-44M(circle dot). The choice of the lower frequency cutoff is important for testing post-Newtonian theory using the ET. The bias in the test arising from the assumption of nonspinning binaries is indicated.
119847891
The 2.5PN linear momentum flux and associated recoil from inspiralling compact binaries in quasi-circular orbits: Nonspinning case
Anisotropic emission of gravitational waves (GWs) from inspiralling compact binaries leads to the loss of linear momentum and hence gravitational recoil of the system. The loss rate of linear momentum in the far-zone of the source (a nonspinning binary system of black holes in quasicircular orbit) is investigated at the 2.5 post-Newtonian (PN) order and used to provide an analytical expression in harmonic coordinates for the 2.5PN accurate recoil velocity of the binary accumulated in the inspiral phase. We find that the recoil velocity at the end of the inspiral phase (i.e at the innermost stable circular orbit (ISCO)) is maximum for a binary with symmetric mass ratio of \nu~0.2 and is roughly about ~4.58 km/s. Going beyond inspiral, we also provide an estimate of the more important contribution to the recoil velocity from the plunge phase. Again the recoil velocity at the end of the plunge, involving contributions both from inspiral and plunge phase, is maximum for a binary with \nu~0.2 and is of the order of ~180 km/s.
16022102
LISA as a dark energy probe
Recently, it has been shown that the inclusion of higher signal harmonics in the inspiral signals of binary supermassive black holes (SMBH) leads to dramatic improvements in the parameter estimation with Laser Interferometer Space Antenna (LISA). In particular, the angular resolution becomes good enough to identify the host galaxy or galaxy cluster, in which case the redshift can be determined by electromagnetic means. The gravitational wave signal also provides the luminosity distance with high accuracy, and the relationship between this and the redshift depends sensitively on the cosmological parameters, such as the equation-of-state parameter w = pDE/ρDE of dark energy. Using binary SMBH events at z < 1 with appropriate masses and orientations, one would be able to constrain w to within a few per cent. We show that, if the measured sky location is folded into the error analysis, the uncertainty on w goes down by an additional factor of 2–3, leaving weak lensing as the only limiting factor in using LISA as a dark energy probe.
119187532
Head-on infall of two compact objects: Third post-Newtonian Energy Flux
Head-on infall of two compact objects with arbitrary mass ratio is investigated using the multipolar post-Minkowskian approximation method. At the third post-Newtonian order the energy flux, in addition to the instantaneous contributions, also includes hereditary contributions consisting of the gravitational-wave tails, tails-of-tails, and the tail-squared terms. The results are given both for infall from infinity and also for infall from a finite distance. These analytical expressions should be useful for the comparison with the high accuracy numerical relativity results within the limit in which post-Newtonian approximations are valid.
55372519
Charm and beauty measurements at Fermilab fixed target
Eighteen months after a successful run of the Fermilab fixed target program, interesting results from several experiments are available. This is the first time that more than one Fermilab fixed target experiment has reported the observation of beauty mesons. In this paper we review recent results from charm and beauty fixed target experiments at Fermilab.
118561168
Performance of a silicon microstrip detector in a high radiation environment
The performance of a silicon microstrip detector has been studied in a high rate environment using electron, pion, and proton beams. The pulse height, time response, and leakage current have been studied as a function of particle fluence up to a total integrated flux of about 4 {times} 10{sup 14} protons/cm{sup 2}. 3 figs.
53474075
Lattice function measurements of Fermilab recycler ring
The Fermilab recycler ring, designed and built as an 8-GeV anti-proton storage ring, is at the final stage of its commissioning. Once integrated into the accelerator complex it is expected to help achieve the luminosity goal of Run II at Fermilab. The recycler ring is made up mostly of combined function magnets with a substantial sextupole component. Any orbit error could cause higher order feed-down and potentially change the machine. Lattice function measurements had been done at various stages of the machine and the results is presented here
35394655
Magnetic field measurements of Fermilab main injector dipoles
Measurements of the Fermilab Main Injector dipoles using a partially redundant system of integrated and point measurements were carried out for quality assurance. Additional special measurements studied the hysteretic field strength. Results from these measurements are presented.
122828768
Magnetic field strength and shape measurements of the Fermilab Main Injector quadrupoles
All of the new quadrupoles for the Fermilab Main Injector ring have been built and measured. The magnets are 2.95 m and 2.54 m in length with a 41.7 mm bore. In operation, the magnets run from 1.61 T/m at 8.9 GeV/c to 15.7 T/m at 120 GeV/c and 19.6 T/m at 150 GeV/c. These points correspond to injection, Main Injector fixed target physics and antiproton production, and extraction for transfer to the Tevatron. Good field uniformity is required to ensure a stable beam over the whole acceleration cycle. A significant octupole is included to assist in resonant extraction. The performance of these quadrupoles, in both integrated strength and field uniformity, is presented. All magnets produced meet the accelerator requirements.