  Photoemission spectra of Bi_2Sr_2CaCu_2O_{8+delta} below T_c show two
features near the (pi,0) point of the zone: a sharp peak at low energy and a
higher binding energy hump. We find that the sharp peak persists at low energy
even as one moves towards (0,0), while the broad hump shows significant
dispersion which correlates well with the normal state dispersion. We argue
that these features are naturally explained by the mixing of electrons with a
bosonic mode which appears only below T_c, and speculate that the latter may be
related to the resonance seen in recent neutron data.
