New gauge boson $B_{H}$ production associated with W boson pair via   $\gamma\gamma$ collision in the littlest Higgs model
  The littlest Higgs model is the most economical little Higgs model. The observation of the new gauge bosons predicted by the littlest Higgs model could serve as a robust signature of the model. The ILC, with the high energy and luminosity, can open an ideal window to probe these new gauge bosons, specially, the lightest $B_H$. In the framework of the littlest Higgs model, we study a gauge boson $B_{H}$ production process $\gamma\gamma\to W^{+}W^{-}B_H$. The study shows that the cross section of the process can vary in a wide range($10^{-1}-10^1$ fb) in most parameter spaces preferred by the electroweak precision data. The high c.m. energy(For example, $\sqrt{s}=1500$ GeV) can obviously enhance the cross section to the level of tens fb. For the favorable parameter spaces, the sufficient typical events could be assumed at the ILC. Therefore, our study about the process $\gamma\gamma\to W^{+}W^{-}B_H$ could provide a useful theoretical instruction for probing $B_H$ experimentally at ILC. Furthermore, such process would offer a good chance to study the triple and quartic gauge couplings involving $B_H$ and the SM gauge bosons which shed important light on the symmetry breaking features of the littlest Higgs model. 
Xuelei Wang, Jihong Chen, Yaobei Liu, Suzhen Liu, Hua Yang