[Sane-analysis] Updated wiki section on single arm pions

[O. A. Rondon]

I've updated my SANE wiki section on inclusive pions
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Inclusive_pion_and_nucleon_electroproduction

I've expanded the discussion of pion production via Deltas, clarifying
the epc*.f code cutoff of this contribution above 500 MeV/c pion
momentum, and added two plots comparing the cross section with and
without the Delta .
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Delta_cutoff/no_cutoff

 For pion momenta above 500 MeV/c, Wiser seems to be the only
parameterization that is based on high momentum data, so extrapolating
the Delta part of epc can lead to substantial overestimates. A
comparison of Wiser to actual pion photoproduction data (Yerevan) is
available on the same wiki section.

The assumption that is made when using Wiser to estimate SANE's pion
inclusive yields is that pion photoproduction from our electron beam's
bremsstrahlung in our 4.6% X0 target (for p.f.=0.6) is the dominant
mechanism to produce high momentum pions.

It looks like other processes would be negligible at the values of
p_pi > ~ 1000 MeV/c that are required to produce pairs with
E_cluster > 700 MeV, but it would be great to have some comparison with
actual single arm pion electroproduction. In any case, it doesn't seem
like other pion production models would work for the momenta we want.

Cheers,

Oscar