2018 Impact factor 4.843
Particles and Fields
Eur. Phys. J. C 17, 399-405
DOI 10.1007/s100520000476

On measurement of helicity parameters in top quark decay

C.A. Nelson - L.J. Adler, Jr.

Department of Physics, State University of New York at Binghamton, Binghamton, NY 13902-6016, USA

Received: 10 July 2000 / Published online: 8 September 2000 - © Springer-Verlag 2000

Abstract
To enable an evaluation of future measurements of the helicity parameters for $t \rightarrow W^+ b$ decay in regard to $\tilde{T}_{FS}$ violation, this paper considers the effects of an additional pure-imaginary coupling, $ i g_i / 2 \Lambda_i $ or i gi, associated with a specific, single additional Lorentz structure, $ i = S, P, S \pm P, \ldots $. Sizable $\tilde{T}_{FS}$ violation signatures can occur for low-effective mass scales (< 320 GeV), but in most cases can be more simply excluded by $ 10\% $ precision measurement of the probabilities P(WL) and P(bL). Signatures for excluding the presence of $\tilde{T}_{FS}$ violation associated with the two dynamical phase-type ambiguities are investigated.


Copyright Società Italiana di Fisica, Springer-Verlag 2000