Electronic excitations near the Brillouin zone boundary of Bi₂Sr₂CaCu₂O_8+δ

Based on angle resolved photoemission spectra measured on different dopings, momenta, and photon energies, we show that the anomalously large spectral linewidth in the (π,0) region of optimal doped and underdoped Bi₂Sr₂CaCu₂O_8+δ has significant contributions from the bilayer band splitting, and that the scattering rate in this region is considerably smaller than previosly estimated. This picture of the electronic excitation near (π,0) puts additional constraints on various microscopic theories and data analyses.