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

Abstract

In the framework of the topcolor-assisted technicolor (TC2) models, we study the production of the top-pions π 0 t , π ± t via the processes ep → γc → π 0 t c and ep → γc → π ± t b mediated by the anomalous top coupling tcγ. We find that the production cross section of the process ep → γc → π 0 t c is very small. With reasonable values of the parameters in TC2 models, the production cross section of the process ep → γc → π ±

Single top or bottom production associated with a scalar inγpcollision as a probe of topcolor-assisted technicolor

“…We should also note that in Ref. [23] the top-pion production is also discussed, however, it is based on the effective coupling t − c − γ at the one-loop level, while in our discussion, the processes are induced by the flavor changing coupling of the scalars directly t − c − π 0 t or b − c − π ± t at the tree level. Despite the small probability, however, we believe that the top-pion γp productions are almost free of SM backgrounds since the π 0 t tc and π + t bc couplings in SM are extremely small due to the GIM mechanism and the small V bc (∼ 0.04) value in the CKM matrix.…”

Lepton flavor violating signals of the neutral top-pion in future lepton colliders

“…One of the most interesting features of the top-pions π 0,± t is that they have large Yukawa couplings to the third-generation quarks and can induce the tree-level F C couplings in quark sector and in the lepton sector. The obviously phenomenological implication of this feature is that the top-pions can be significant produced via some F C processes, and their possible signatures might be observed in future hadron colliders [5,6] and lepton colliders [7,8]. Furthermore, the top-pions can generate large corrections to some observables related with the F C couplings and give characteristic signatures at various high-energy colliders [9,10].…”

Precise photoproduction of the charged top-pions at the LHC with forward detector acceptances

“…Photoproduction of the charged top-pion at leading order (LO) has been studied in Ref. [26] which proceeds via the subprocess γc → π ± t b mediated by the flavor changing couplings and through γb → π ± t t at the large hadron-electron collider (LHeC) [27]. At the LHC, in general pp collision, the charged top-pion can be produced in association with a top quark through bottom-gluon fusion, gb → tπ − t , and through gluon-gluon fusion, gg → btπ − t , phenomenologically similar to a charged Higgs boson in a two-Higgsdoublet model with low tanβ.…”