195867607
Nonlinear mode coupling analysis in the Tevatron
Increased demand for higher luminosities from Fermilab proton-antiproton collider requires higher intensities and increased number of bunches. The performance of existing 6/spl times/6 and the proposed 36/spl times/36 collider is often limited by the non-linear effects arising from beam-beam interactions, in particular for high intensity beams. The tune shifts and spread from increased long range interactions combined with higher order multipoles complicates the frequency spectrum of the particle motions. The TEAPOT simulation program is used to generate turn by turn data that could be used in the nonlinear mode spectrum analysis. Bispectral mode analysis is discussed.
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.
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.
26286812
Elastic scattering of 65 MeV positive and negative pions from nickel isotopes.
Angular distributions of elastic differential cross sections were obtained at 65 MeV using positive and negative pions scattered from /sup 58/Ni, /sup 60/Ni, and /sup 64/Ni. The data were compared to predictions using the Michigan State University optical potential. These predictions are not in good agreement with the data. The negative pion cross sections are more poorly described than the positive pion cross sections. The p-italic-wave part of the potential is observed to be especially sensitive to this Coulomb-nuclear interference effect.
42818936
Summary of the TeV 33 Working Group
This summary of the TeV33 working group at Snowmass reports on work in the areas of Tevatron store parameters, the beam-beam interaction, Main Injector intensity (slip stacking), antiproton production, and electron cooling. I. OVERVIEW OF TEV33 The goal of the TeV33 project is to develop a plan for the Fermilab Tevatron Collider beyond the year 2000 when the Main Injector project will be finished and collider Run II is expected to be well underway. The TeV2000 committee report [1] suggests a goal of 30 fb of proton-antiproton collisions at 2 TeV in the center of mass system by the year 2006. The physics potential of such a data sample is summarized in the committee’s report and is described in more detail in the report of the TeV2000 Study Group [2]. The goal of obtaining a sample of 30 fb of protonantiproton collisions is widely believed to be technically feasible, but it is uncertain whether it can be achieved within the likely fiscal and schedule constraints. An upgrade to a higher energy or a higher luminosity proton-proton collider is also technically possible but, based on performance, cost, and schedule considerations, is judged to be an unrealistic competitor for the Large Hadron Collider (LHC). The purpose of the TeV33 group and, in particular, the Snowmass study group, is to develop a realistic plan for TeV33 that can form the basis for future decisions. The TeV33 project assumes the successful completion of the Main Injector project and other upgrade projects that are associated with Run II. Some of the important elements of the Run II upgrade are: 1. Main Injector with both physical and dynamic apertures greatly exceeding those available with the existing Main Ring. 2. Antiproton recovery, including the construction of a “Recycler” ring in the Main Injector tunnel. 3. Antiproton source improvements in targeting and beam cooling. While the details of the TeV33 plan are not well defined, many of the major considerations are already clear. These are: 1. The antiproton production rate must be improved by about a factor of 5. 2. The antiproton cooling must be improved to accommodate the increased flux. The current plan is to use a. 4-8 GHz stochastic cooling in the existing Debuncher and Accumulator Rings, and b. electron cooling in the Recycler Ring. 3. The existing detector technology (with modest upgrades) must be capable of analyzing the collisions for rare processes. The important considerations for the accelerator are: a. Limiting the number of interactions per crossing to a sufficiently small value by using roughly 100 bunches in the Tevatron, b. Reducing the peak luminosity (luminosity leveling) to further reduce the number of interactions per crossing, and c. Maintaining low backgrounds. 4. The proton and antiproton beams must be kept well separated in the Tevatron except at the desired collision points to avoid the adverse effects of the beam-beam interaction. Obtaining adequate separation becomes increasingly difficult as the number of bunches is increased to 100 or more bunches. At Snowmass we developed some of the aspects of the TeV33 plan, but not all the important issues were covered. This paper is intended to report the work completed in conjunction with Snowmass study, and is not a balanced presentation of the current thinking on all the important elements of the TeV33 project. II. ELEMENTS OF TEV33 A. Tevatron Store Parameters The performance of a TeV33 scenario is determined by the average production rate of events that can be analyzed to study interesting physics processes. The study described below considered various initial store parameters and calculated the dependence of the integrated luminosity on several possible choices of parameters. The more delicate question of whether the events produced could be analyzed by a given detector was not considered. 1. The Luminosity Calculation It is straight-forward to calculate the luminosity (L) by integrating the beam phase-space distributions. A relatively compact expression can be obtained when the distributions are assumed to be gaussian in transverse and longitudinal positions. In this case the luminosity per interaction region is given by L = + ( ) − ( )   
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.
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.
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.
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.