Eur. Phys. J. C 19, 323-337
DOI: 10.1007/s100520100609
Use of
polarimetry in top quark spin-correlation functions
C.A. Nelson Department of Physics, State University of New York at Binghamton, Binghamton, NY 13902-6016, USA
(Received: 26 January 2001 / Published online: 15 March 2001 -© Springer-Verlag 2001)
Abstract
Due to the absence of hadronization effects and the large mt
mass, top quark decay will be uniquely sensitive to fundamental
electroweak physics at the Tevatron, at the LHC, and at a future
linear collider. A "complete measurement" of the four helicity
amplitudes in
decay is possible by the
combined use of
and W polarimetry in stage-two
spin-correlation functions (S2SC). In this paper, the most
general Lorentz-invariant decay density matrix is obtained for the
decay sequence
where
and
[ or
] , and likewise for
. These density matrices are
expressed in terms of b-polarimetry helicity parameters which
enable a unique determination of the relative phases among the
amplitudes. Thereby, S2SC
distributions and single-sided b-W-interference distributions
are expressed in terms of these parameters. The four
b-polarimetry helicity parameters involving the
A(-1,-1/2)
amplitude are considered in detail.
polarimetry
signatures will not be suppressed in top quark analyses when final
angles-and-energy variables are used for
.
© Società Italiana di Fisica, Springer-Verlag 2001