Unambiguous evidence for extended s-wave pairing symmetry in hole-doped high-temperature superconductors.

We have analysed data from angle-resolved photo-emission spectroscopy, Fourier transform scanning tunneling spectroscopy, and low-temperature thermal conductivity for optimally doped Bi2Sr2CaCu2O8+y in order to discriminate between d-wave and extended s-wave pairing symmetry. The combined data are inconsistent with d-wave symmetry, but quantitatively consistent with extended s-wave symmetry with eight line nodes. We also explain all phase-sensitive experiments in a consistent manner. [ABSTRACT FROM AUTHOR]