Pair production of charged top-pions associated with Z gauge boson in the topcolor-assisted technicolor model at the ILC

摘要

The top-pions (π~(0, ±)_t) are the three additional typical particles predicted by the topcolor-assisted technicolor (TC2) model and the observation of these particles can be regarded as the direct evidence of the TC2 model. In this paper, we investigate the production of a pair of charged top-pions associated with Z gauge boson at the International Linear Collider (ILC), i.e. e~+e~- → Zπ~+_tπ~-_t and γγ → Zπ~+_tπ~-_t. We calculate the production rate of the process e~+e~-→ Zπ~+_tπ~-_t and present the distributions of the transverse momenta of Z gauge boson and charged top-pion π~+_t. We find that the cross-section of the process e~+e~-→ Zπ~+_tπ ~-_t can reach 1 fb with reasonable parameter space of the TC2 model. Considering the main decay mode of charged top-pion, we find that such a production may provide copious events. While the cross-section of the process γγ → Zπ~+_tπ~-_t is below 1 fb, hence the process e~+e~-→ Zπ~+_tπ~-_t will play an important role in the test of the TC2 model at the ILC when compared with the process γγ → Zπ~+_tπ~-_t.