The quantum pyrochlore antiferromagnet is studied by perturbative expa
nsions and exact diagonalization of small clusters. We find that the g
round state is a spin-liquid state: The spin-spin correlation function
s decay exponentially with distance and the correlation length never e
xceeds the interatomic distance. The calculated magnetic neutron diffr
action cross section is in very good agreement with experiments perfor
med on Y(Sc)Mn-2. The low energy excitations are singlet-singlet ones,
with a finite spin gap.