  The explanation of heavy-fermion superconductivity is a long-standing
challenge to theory. It is commonly thought to be connected to non-local
fluctuations of either spin or charge degrees of freedom and therefore of
unconventional type. Here we present results for the Kondo-lattice model, a
paradigmatic model to describe heavy-fermion compounds, obtained from dynamical
mean-field theory which captures local correlation effects only. Unexpectedly,
we find robust s-wave superconductivity in the heavy-fermion state. We argue
that this novel type of pairing is tightly connected to the formation of heavy
quasiparticle bands and the presence of strong local spin fluctuations.
