Electronic Raman scattering in high-Tc superconductors: A probe of dx2-y2 pairing.

New measurements on the high-temperature superconductor ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8}$ are interpreted and found to be in quantitative agreement with a theory for electronic Raman scattering in superconductors with ${\mathit{d}}_{\mathit{x}}^{2}$-${\mathit{y}}^{2}$ pairing symmetry. The theory explains in a natural way, why the shape of the scattering intensity, as well as its change with temperature can be polarization (symmetry) dependent and hence resolves a controversy in previous interpretations of data on the electronic Raman effect.