Rare decays B→Mνν¯ in the TC2 model and the LHT model

In the framework of the topcolor-assisted technicolor (TC2) model and the littlest Higgs model with T-parity (LHT model), we consider the rare B decays B→Mνν¯ with M=π,K,ρ, or K*. We find that the contributions of the TC2 model to the branching ratios of these decay processes are larger than those for the LHT model. The experimental upper limits for some branching ratios can give severe constraints on the free parameters of the TC2 model.