Extraction of Normal Electron Self-Energy and Pairing Self-Energy in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$ via Laser ARPES

Super-high resolution laser-based angle-resolved photoemission measurements have been performed on a high temperature superconductor Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$. The band back-bending characteristic of the Bogoliubov-like quasiparticle dispersion is clearly revealed at low temperature in the superconducting state which gives rise to two peaks in the momentum distribution curves. This makes it possible for the first time to experimentally extract the normal electron self-energy and pairing self-energy in the superconducting state. These information can be used to further determine the Bosonic spectral function that will provide key insight and constraints on the origin of electron pairing in high temperature superconductors.