We calculate the corrections to the partial widths of the light Higgs boson in the Littlest Higgs model due to effects of the TeV-scale physics. We focus on the loop-induced Higgs coupling to photon pairs, which is especially sensitive to the effects of new particles running in the loop. This coupling can be probed with high precision at a photon collider in the process $\gamma \gamma \to H\to b\overline{b}$ for a light Higgs boson with mass $115\mathrm{G}\mathrm{e}\mathrm{V}\le M_H\lesssim 140\mathrm{G}\mathrm{e}\mathrm{V}$. Using future LHC measurements of the parameters of the Littlest Higgs model, one can calculate a prediction for this process, which will serve as a test of the model and as a probe for a strongly coupled UV completion at the 10 TeV scale. We outline the prospects for measuring these parameters with sufficient precision to match the expected experimental uncertainty on $\gamma \gamma \to H\to b\overline{b}$.

• Received 26 July 2004

DOI:https://doi.org/10.1103/PhysRevD.70.115003