Single top quark cross section evaluations for the complete sets of
tree-level diagrams in the e+eβ, eβeβ, Ξ³e and Ξ³Ξ³
modes of the next linear collider with unpolarized and polarized beams are
performed within the Standard Model and beyond. From comparison of all
possibilities we conclude that the process Ξ³+βeLβββeβtbΛ is
extremely favoured due to large cross section, no ttΛ background, high
degrees of beam polarization, and exceptional sensitivities to Vtbβ and
anomalous Wtb couplings. Similar reasons favour the process eβeββeβΞ½eβtΛb for probing top quark properties despite a considerably lower
cross section. Less favourable are processes like e+eβ,Ξ³Ξ³βeβΞ½eβtbΛ. Three processes were chosen to probe their sensitivity to
anomalous Wtb couplings, with best bounds found for Ξ³+βeLβββeβtbΛ and eR+βeRβββeβΞ½eβtbΛ.Comment: 23 pages, 13 figure