56362095
Measurement and simulation of nonlinear beam-beam mode coupling in the Fermilab Tevatron
The Tevatron beam dynamics has been studied from the "weak-strong" representation of the beam-beam effects for various octupole field settings. A single particle is tracked using TEAPOT in the presence of the other beam. The nonlinearities introduced by the beam-beam forces introduces two unwanted effects: (1) it excites nonlinear resonances; (2) it introduces dispersion of the tunes with amplitude. The strength of nonlinear three mode coupling satisfying the sum rules v/sub 3/=v/sub 1//spl plusmn/v/sub 2/ for various octupole settings are calculated. The higher order spectral analysis results are presented.
54946396
Study of stability of beam in the Fermilab main injector
The Fermilab Main Injector is a new 150‐GeV proton synchrotron, designed to replace the Main Ring and improve the high energy physics potential of Fermilab. The status of the Fermilab accelerator complex upgrade will be discussed. Study of the stability of the beam in the Main injector will be discussed. Detuning and corrector schemes to improve the dynamic aperture of the Main Injector will be presented. Tune modulation caused by octupolar detuning will be discussed.
54609000
Strength and shape of the magnetic field of the Fermilab Main Injector dipoles
Measurements of 230 6-meter and 136 4-meter dipoles constructed for the Fermilab Main Injector were carried out as part of the magnet production effort. An automated measurement system provided data on magnetic field strength and shape using several partially redundant systems. Results of these measurements are available for each individual magnet for use in accelerator modelling. In this report we will summarise the results on all of the magnets to characterise the properties which will govern accelerator operation.
45590013
Indication of pionic-atom anomalies in pion-nucleus elastic scattering.
Elastic cross sections for the scattering of positive and negative pions from /sup 58/Ni were measured at 30 MeV incident pion energy. Statistical errors of +- 3% and normalization errors of +- 6% were achieved. These data appear to confirm the theoretical construct that the physics which explains anomalously small shifts and widths in pionic atoms would be manifested in low energy pion-nucleus elastic scattering. The data show good agreement with the cross sections calculated assuming s and p partial waves are anomalous. Here anomalous refers to partial waves that are calculated from an optical potential which reproduces anomalously small level shifts and widths in pionic atoms. Conventional optical potentials do not agree as well with both the ..pi../sup +/ and ..pi../sup -/ data. Various conventional possibilities such as a larger neutron radius than proton radius in the nuclear density were tried, but these did not result in good agreement with the data.
122682011
Magnetic field measurements of the initial Fermilab Main Injector production quadrupoles
A large sample of the 2.54-meter quadrupoles for lattice matching in the Fermilab Main Injector have been fabricated and measured. The resulting properties are reported and compared to the accelerator requirements.
120282931
Fermilab Main Injector commissioning status
The Fermilab Main Injector construction project is nearing completion. The commissioning of the Main Injector began in late 1998. The status of the beam studies and fulfilment of the project commissioning milestones is presented.
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.
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.
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.
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.