Pair production of charged and doubly charged Higgs bosons at ILC in the Higgs triplet model

The charged and doubly charged Higgs bosons (H± and H±±) are the typical particles predicted by the Higgs triplet model (HTM) and the observation of these particles might be regarded as direct evidence of the HTM. In this paper, we investigate the pair production of the charged and doubly Higgs bosons at the International Linear Collider (ILC): e+e−→H+H−(H++H−−) and e+e−→ZH+H−(H++H−−). We present the production cross sections and the distributions of the various observables, i.e., the distributions of the transverse momenta and the rapidity distributions for out-going particles. Our numerical results show that, as long as the charged and doubly charged Higgs bosons masses are not too heavy, their possible signals might be detected via these processes in future ILC experiments. A simply phenomenological analysis is also given. (paper)