sophisticated descriptions of the initial ground state of the nucleus; and additional nuclear effects, such as multinucleon interaction models, which go beyond interactions with a single nucleon within the nucleus. The combination of these models would allow for a consistent picture of an axial mass close to 1.00GeV/$c^{2}$, with a suppressed cross section at low-[$Q^{2}$]{}and larger cross section at higher-[$Q^{2}$]{}relative to a simple RFG model. Comprehensive reviews of available CCQE cross section models can be found in References [@review; @Morfin:2012kn; @garvey_review_2014; @hayato_review_2014].

More sophisticated descriptions of the initial state of the nucleus than the RFG model provides are available from a number of authors [@sf; @ankowski_SF; @butkevich_2009; @eff-sf]. These models, generically referred to as Spectral Functions (SF), have a more realistic nucleon momentum distribution taking into account the shell structure of the nucleus and correlated pairs of nucleons within the nucleus, and have non-constant binding energies. Note that although these models include correlations between nucleons in the initial state, they still use the impulse approximation and only consider interactions with a single nucleon. More complex models which go beyond the simple picture of non-interacting fermions are available [@leitner_2009; @madrid_2003; @meucci_2003; @lovato_2013; @pandey_2014]. However, with the exception of the GiBUU interaction 