28650811
Crossing intrinsic depolarizing resonances by varying a partial Siberian snake.
We recently forced a 140 MeV polarized proton beam to cross intrinsic depolarizing resonances by varying a partial Siberian snake{close_quote}s strength for different values of the vertical and horizontal betatron tunes {nu}{sub {ital y}} and {nu}{sub {ital x}}. A weak second-order intrinsic resonance was observed in the {nu}{sub {ital x}} sweep; moreover, an unexpected partial spin flip was found in the {nu}{sub {ital y}} sweep. We also varied the snake ramp time to identify the {nu}{sub {ital y}} and {nu}{sub {ital x}} regions where the resonance crossings occurred during the snake variation; in these crossings the polarization partially deviated from Froissart-Stora behavior. {copyright} {ital 1996 The American Physical Society.}
122534152
Doubler system quench detection threshold
The experimental study leading to the determination of the sensitivity needed for protecting the Fermilab Doubler from damage during quenches is presented. The quench voltage thresholds involved were obtained from measurements made on Doubler cable of resistance × temperature and voltage × time during quenches under several currents and from data collected during operation of the Doubler Quench Protection System as implemented in the B-12 string of 20 magnets. At 4kA, a quench voltage threshold in excess of 5.0V will limit the peak Doubler cable temperature to 452K for quenches originating in the magnet coils whereas a threshold of 0.5V is required for quenches originating outside of coils.
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.
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.
123199387
Design of the Fermilab Main Injector Lambertson
A common design has been adopted for a high field (1.1 T) Lambertson magnet for use in the four injection/extraction channels of the Main Injector (MI) as well as the Tevatron injection channel. To support the extraction/injection of 150 GeV/c protons and pbars, the field within the "field region" of the Lambertson should reach 1.1 Tesla with less than 0.3% variation in a 2 by 12 inch good field aperture. Utilization for the 8.9 GeV/c pbars and resonant extraction of 120 GeV/c protons place stringent aperture requirements on the magnet design. In addition, this magnet must simultaneously support circulating beam in the energy range of 8.9 GeV/c to 900 GeV/c, through its "field free" region. At maximum excitation, the leakage field in this region must be kept to a minimum to avoid any deleterious effects on the circulating beam. The magnet design parameters which meet the aperture, magnetic, and structural requirements as well as the selection criteria of the steel are 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.
11226857
Dynamical electroweak symmetry breaking with top-quark and neutrino condensates.
Recently it has been suggested that electroweak symmetry is broken by a top-quark vacuum condensate. In that model, the prediction for the top-quark mass seems to be in conflict with indirect experimental upper bounds. We propose a new scenario in which electroweak symmetry is broken by a combination of top-quark and third-generation neutrino condensates, involving a right-handed gauge-singlet neutrino. We show that the top-quark mass comes out smaller in this model and can easily lie in the experimentally favored window. The resulting neutrino spectrum is phenomenologically acceptable if we make the natural assumption that the right-handed neutrino has a large Majorana mass.
17649647
Variational approximation for two-time correlation functions in Phi 4 theory: Optimization of the dynamics.
We apply the time-dependent variational principle of Balian and Veneroni to {Phi}{sup 4} theory. An appropriate parametrization for the variational objects allows us to write coupled dynamical equations from which we derive approximations for the two-time correlation functions involving two, three, or four field operators. {copyright} 1995 The American Physical Society.
41996012
Stability of systems of three arbitrary charges: General properties.
The stability of systems consisting of a negative charge {minus}{ital q}{sub 1} and two positive charges {ital q}{sub 2} and {ital q}{sub 3} is discussed as a function of the values of the charges {ital q}{sub {ital i}} and of the constituent masses {ital m}{sub {ital i}}. We give general results and list some open questions of interest, which hopefully will stimulate further investigations.
15021862
Low-energy supersymmetry with D-term contributions to scalar masses.
We investigate how the predictions of the Minimal Supersymmetric Standard Model are modified by D-term contributions to soft scalar masses, which arise whenever the rank of the gauge group at very high energies is greater than four. We give a parameterization of the most general such contributions that can occur when the unbroken gauge symmetry is an arbitrary subgroup of E_6, and show how the D-term contributions leave their imprint on physics at ordinary energies. We impose experimental constraints on the resulting parameter space and discuss some features of the resulting supersymmetric spectrum which differ from the predictions obtained with universal boundary conditions on scalar masses near the Planck scale. These include relations between squark and slepton masses; the behavior of $\sin^2 (\beta-\alpha)$ (which determines the production cross-section for the lightest Higgs scalar boson at an e+e- collider) and the mass of the pseudoscalar Higgs bosons; R_b [the ratio $\Gamma(Z -> b\overline b)/\Gamma(Z -> hadrons)$; and mass differences between charginos and neutralinos.
36873731
Interference radiative phenomena in the production of heavy unstable particles.
We discuss the characteristic interference phenomena, including real as well as virtual radiative corrections, to the inclusive cross sections for production of heavy unstable systems such as {ital t{bar t}} or {ital W}{sup +}{ital W{minus}} pairs. We demonstrate explicitly the (fortunate) cancellation between emissions associated with the production of unstable particles and with their decays, and between emissions accompanying the decay stages. As a result the total interference effect is shown to be of {ital O}({alpha}{sub {ital i}}{Gamma}/{ital M}) or better (where {alpha}{sub {ital i}}={alpha} or {alpha}{sub {ital s}} as appropriate).