We study production of $t\overline{t}$ via $W^{+}{W}^{-}$ fusion, including the initial state radiation background at the proposed Linear Collider (an $e^{+}{e}^{-}$ collider with $\sqrt{S}=1.5$ TeV) in the context of a standard model (SM) without a Higgs boson, i.e., a nonlinear $\mathrm{SU}{\mathrm{}\left(2\right)\mathrm{}}_L\times \mathrm{U}{\mathrm{}\left(1\right)\mathrm{}}_Y$ chiral Lagrangian, including dimension five $W^{+}{W}^{-}t\overline{t}$ interactions. Deviation from the SM total cross section can be used to constrain the coefficients of these operators to an order of $0.2$ (divided by the cutoff scale $\Lambda =3.1\mathrm{}$ TeV) with a $95\%$ C.L. However, there are three ways in which this sensitivity can be improved by a factor of two. First, by studying the deviation of the $t\overline{t}$ kinematics from what is predicted by the SM; second, by polarizing the collider electron beam; and third, by studying the polarization of the produced top quarks. In this way, we show that it is also possible to attempt to disentangle the contributions from different anomalous operators, isolating the form of new physics contributions.

• Received 12 September 1997

DOI:https://doi.org/10.1103/PhysRevD.57.3106