  We investigate the implications of the model with a SU(2)-singlet up-type
quark, heavy enough not to be produced at the LHC, namely, the contribution of
the new quark to the branching ratios of the K to \pi \nu \bar{\nu}, B to \pi
\nu \bar{\nu} and B to K \nu \bar{\nu} decays. We show that the deviation from
the Standard Model can be up to 10% in the case of a 5 TeV quark. Precise
measurements of these branching ratios at the future experiments will allow to
observe the contributions of the new quark or to impose stronger constraints on
its mass.
