53067347
New-generation large-area muon scintillation counters with wavelength shifter fiber readout for CDF II
New scintillation counters have been designed and constructed for upgrading the CDF detector at Fermilab Tevatron. A novel light collection technique using wavelength shifting fibers, together with a high-quality polystyrene-based scintillator UPS 923A, has resulted in compact counters with good and stable light collection efficiency over their lengths extending up to 320 cm. The design, construction, and performance of the counters are presented. Properties of the fibers and the scintillator, such as light output, light attenuation, decay time, and long-term stability, are investigated. It is found that the polystyrene-based scintillator, unlike the polyvinyltoluene-based one, has properties more adequate for long-term experiments.
116537730
Measurement of the top quark mass using the MINUIT fitter in dilepton events at CDF
119261939
Constraining spacetime torsion with the Moon and Mercury
We report a search for new gravitational physics phenomena based on Riemann-Cartan theory of general relativity including spacetime torsion. Starting from the parametrized torsion framework of Mao, Tegmark, Guth, and Cabi, we analyze the motion of test bodies in the presence of torsion, and, in particular, we compute the corrections to the perihelion advance and to the orbital geodetic precession of a satellite. We consider the motion of a test body in a spherically symmetric field, and the motion of a satellite in the gravitational field of the Sun and the Earth. We describe the torsion field by means of three parameters, and we make use of the autoparallel trajectories, which in general differ from geodesics when torsion is present. We derive the specific approximate expression of the corresponding system of ordinary differential equations, which are then solved with methods of celestial mechanics. We calculate the secular variations of the longitudes of the node and of the pericenter of the satellite. The computed secular variations show how the corrections to the perihelion advance and to the orbital de Sitter effect depend on the torsion parameters. All computations are performed under the assumptions of weak field and slow motion. To testmore » our predictions, we use the measurements of the Moon's geodetic precession from lunar laser ranging data, and the measurements of Mercury's perihelion advance from planetary radar ranging data. These measurements are then used to constrain suitable linear combinations of the torsion parameters.« less