corresponding change in the real part of the self energy, even with a limited 5 meV energy broadening, is much weaker and will naturally appear as a much more subtle feature of the true ARPES spectra in the vicinity of the node. This is precisely what is observed in the experiment. It is thus not surprising that previous studies of Bi2212, even at reasonably high resolution, have not identified this feature in the spectrum. Certainly the reduced momentum resolution of higher energy synchrotron based ARPES studies of Bi2212, in addition to the contaminating presence of the bilayer splitting near the node, would make this feature otherwise impossible to detect. While the study of electron-phonon coupling in correlated electron materials such as the cuprates is of interest in its own right there are several ramifications as regards the more general problem of understanding the electronic structure of Bi2212. First, unlike the many high energy band renormalizations discussed in the introduction, this finding represents an unambiguous identification of such a renormalization with a particular bosonic mode. In this case the coupling of electrons in the 2D copper oxide sheets of Bi2212 to an out of plane c-axis gerade mode is clearly identified. The identification of this mode from the step in the imaginary part of the self energy is supported by the agreement between the model calculation of the scattering rate in the presence of such a mode and those measured experimentally. While the form of δ$_{⃗}$ k shown by this mode is in qualitative agreement with the prediction of Ref. $^{14}$, which takes a much more comprehensive approach to modeling the electron-phonon coupling in the presence of a d-wave superconducting gap, e.g. indicating that such a coupling is possible a priori, the data bares out an important additional observation. That is, a full theory of electron-phonon coupling in Bi2212, in the presence of the d-wave requires a proper treatment of the angular dependence of the kink as one scans around the Fermi surface. In the reference it was assumed that this effect would be small and one could well approximate the shift of the kink energy by pinning it the maximal d-wave superconducting gap Δ 0 . Here it is shown that the kink energy close to the node is pinned to the ”local” gap value Δ( φ ). In summary we have reported the observation of coupling to a zero momentum optical 12 V. DISCUSSION AND CONCLUSIONS