Showing papers by "Ephraim Fischbach published in 1997"

Final results from the WABG tower gravity experiment

Abstract: A test of the inverse-square law, conducted on a 610 m television transmitter in Inverness, Mississippi, measured gravity at five elevations on the WABG tower, and compared these data with the Newtonian predictions using potential theory. The largest observed-minus-model discrepancy, at 493 m above ground, was (-33\ifmmode\pm\else\textpm\fi{}30) \ensuremath{\mu}Gal (1 $\ensuremath{\mu}\mathrm{Gal}{=10}^{\ensuremath{-}8}$ ${\mathrm{m}\mathrm{}\mathrm{s}}^{\ensuremath{-}2}$). These data have since been supplemented with additional gravity data taken on the tower at a higher elevation. The results confirm the predictions of Newtonian gravity, with a discrepancy of (32\ifmmode\pm\else\textpm\fi{}32) \ensuremath{\mu}Gal at 568 m. The tower experiments, along with current lake experiments, place very tight constraints on any possible non-Newtonian forces.

Neutrino Trapping and Neutrino Mass Bounds

Abstract: It has been shown recently that the exchange of virtual neutrino pairs leads to an unphysically large energy-density in neutron stars and white dwarfs, unless neutrinos have a minimum mass, m > 0.4 eV. Here we consider the possibility that the presence of trapped low-energy neutrinos can suppress the exchange of virtual neutrino pairs, thereby avoiding a large energy-density even for massless neutrinos. We show that a) there can be subvolumes in a neutron star or white dwarf where neutrino-trapping does not take place, and which can thus have an unphysically large energy density, and b) even in those volumes where trapping does occur, the resulting suppression can be too small to alter the conclusion that neutrinos must have a minimum mass.