  We numerically study the spin-1/2 antiferromagnetic Heisenberg model on the
kagom\'{e} lattice using the density-matrix renormalization group (DMRG)
method. We find that the ground state is a magnetically disordered spin liquid,
characterized by an exponential decay of spin-spin correlation function in real
space and a magnetic structure factor showing system-size independent peaks at
commersurate antiferromangetic wavevectors. We obtain a spin triplet excitation
gap $\Delta E(S=1)=0.055\pm 0.005$ by extrapolation based on the large size
results, and confirm the presence of gapless singlet excitations. The physical
nature of such an exotic spin liquid is also discussed.
