Removal and Binding Energies in Lepton Nucleus Scattering

We investigate the Fermi momentum and nuclear interaction energy   parameters that should be used in modeling quasielastic (QE)   electron and neutrino scattering on bound nucleons within the framework of the Relativistic Fermi Gas model (RFG).  We discuss the relation between interaction energy,  spectral functions and  shell model energy levels and extract updated interaction energy parameters from more modern  ee'p spectral function data. We  address the difference in parameters for scattering from bound protons and neutron, and the difference between the parameters for   modeling the  PEAK versus the  MEAN of distributions.    We show that different MC generators use different definitions of what is referred to as nuclear interaction energy  parameters.   For example, for neutrino scattering on bound neutrons in Oxygen the Smith-Moniz interaction energy  (43.0+-3 MeV) should be  used in NEUT, the excitation energy  ( 10.2+-3 MeV) should be used in  GENIE, and the  interaction energy  ( 27.0 +-3 MeV) should be used to calculate the neutrino energy from muon variables only.