Top-quark polarization at the Fermilab Tevatron.

Abstract

With the prospects of finding the top quark at Fermilab comes the potential for new tests of the standard model and new probes of physics at the 100-GeV scale. Though the production rate for tt\ifmmode\bar\else\textasciimacron\fi{} pairs is expected to be small at Fermilab, it may be possible to perform a first-level study of the interactions of the top quark, including polarization effects. In this paper we discuss the standard model predictions for the polarization of a top quark produced in proton-antiproton collisions at the Fermilab Tevatron using either polarized or unpolarized hadron beams. Standard model electroweak loops predict that the single-particle polarization of the top quark perpendicular to the scatter plane is small, yet at the Born level there are a number of double-spin polarization asymmetries which produce effects observable within the statistical errors expected from a thousand events.