Exclusive B→Mνν¯(M=π,K,ρ,K∗) decays and leptophobic Z′ model

We consider the exclusive flavor changing neutral current processes B→Mνν¯(M=π,K,ρ,K∗) in the leptophobic Z′ model, in which the charged leptons do not couple to the extra Z′ boson. We find that these exclusive modes are very effective to constrain the leptophobic Z′ model. In the leptophobic Z′ model, additional right-handed neutrinos are introduced and they can contribute to the missing energy signal in B→M+E̸ decays. Through the explicit calculations, we obtain quite stringent bounds on the model parameters, |UsbZ′|⩽0.29 and |UdbZ′|⩽0.61, from the already existing experimental data. We also briefly discuss an interesting subject of massive right-handed neutrinos, which might be connected with the dark matter problem.