Probing extra dimensions through the invisible Higgs decay
  In the large extra dimension model of Arkani-Hamed, Dimopoulos and Dvali the presence of an interaction between the Ricci scalar curvature and the Higgs doublet of the Standard Model makes a light Higgs boson observable at LHC at the 5 sigma level through the fusion process pp-> W*W* +X -> Higgs, graviscalars +X -> invisible+X for the portion of the Higgs-graviscalar mixing (xi) and effective Planck mass (M_D) parameter space where channels relying on visible Higgs decays fail to achieve a 5 sigma signal. However even if the LHC has a good chance of seeing a signal, it will not be able to determine the parameters of the model with any real precision.   This goal can be reached by adding the following LC measurements: gamma+missing E_T, Higgs production and decay in the visible SM-like final states and in the invisible final state. 
Daniele Dominici