Multiple Bosonic Mode Coupling in Electron Self-Energy of   (La_2-xSr_x)CuO_4
  High resolution angle-resolved photoemission spectroscopy data along the (0,0)-($\pi$,$\pi$) nodal direction with significantly improved statistics reveal fine structure in the electron self-energy of the underdoped (La$_{2-x}$Sr$_x$)CuO$_4$ samples in the normal state. Fine structure at energies of (40$\sim$46) meV and (58$\sim$63)meV, and possible fine structure at energies of (23$\sim$29)meV and (75$\sim$85)meV, have been identified. These observations indicate that, in LSCO, more than one bosonic modes are involved in the coupling with electrons. 
X. J. Zhou, Junren Shi, T. Yoshida, T. Cuk, W. L. Yang, V. Brouet, J.   Nakamura, N. Mannella, Seiki Komiya, Yoichi Ando, F....