Neutral top-pion $pi;t0 and t$gamma;(z) production at the HERA and THERA colliders

Abstract

In the context of top-color assisted technicolor (TC2) models, we calculate the contributions of the neutral top-pion π t 0 to tγ and tz production via the processes ep → γc → tγ and ep → γc → tz at the HERA and THERA colliders. Our results show that the cross sections σ tγ ( s ) and σ tz ( s ) are very small at the HERA collider with s =320 GeV. However, in most of the parameter space, σ tγ ( s ) or σ tz ( s ) is in the range of about 0.1–1 pb at the THERA collider with s =1000 GeV.