Production of the top-pions at the THERA collider based γp collisions

In the framework of the topcolor-assisted technicolor (TC2) models, we study the production of the top-pions pi(1)(0), pi(1)(+/-) via the processes ep --> gammac --> pi(1)(0)c and ep --> gammac --> pi(1)(+/-)b mediated by the anomalous top coupling tcgamma. We find that the production cross section of the process ep --> gammac --> pi(1)(0)c is very small. With reasonable values of the parameters in TC2 models, the production cross section of the process ep --> gammac --> pi(1)(+/-)b can reach 1.2 pb. The charged top-pions pi(1)(+/-) might be directly observed via this process at the THERA collider based gammap collisions. (C) 2003 Published by Elsevier B.V.