  The E12-14-012 experiment, performed in Jefferson Lab Hall A, has measured
the $(e, e'p)$ cross section in parallel kinematics using a natural argon
target. Here, we report the full results of the analysis of the data set
corresponding to beam energy 2.222 GeV, and spanning the missing momentum and
missing energy range $15 \lesssim p_m \lesssim 300$ MeV/c and $12 \lesssim E_m
\lesssim 80$ MeV. The reduced cross section, determined as a function of $p_m$
and $E_m$ with $\approx$4\% accuracy, has been fitted using the results of
Monte Carlo simulations involving a model spectral function and including the
effects of final state interactions. The overall agreement between data and
simulations turns out to be quite satisfactory ($\chi^2$/n.d.o.f.=1.9). The
resulting spectral function will provide valuable new information, needed for
the interpretation of neutrino interactions in liquid argon detectors.
