> >9. (a little off the line) radiative correction in generators.
> >
> >
> I started looking at that. I read Plaster's theses and there they
> simply did an elastic N(e,e'N) reaction radiative correction, based on
> POLRAD, that Chris knows a lot about. The question is whether this
> would be sufficient for our quasielastic reaction, since in our low q^2
> kinematics we hardly have quasielastic reaction. Secondly, I wonder how
> large this correction would be in first place. Plaster quotes something
> like: ~1.9%, ~3.7%, ~4.4% difference in polarization measurements for
> Q^2 = 0.447, 1.132, 1.450 . Shouldn't it be even lower at our Q^2s?
The definition of missing energy is different for elastic and QE.
People usually use a pertinent Emiss definition but the old calculation
of radiative corrections ala mo-tsai (+ maximon) which were all done for
elastic scattering. This is a good starting point, but there is no "right
way to do it"...
For clarity, keep in mind that the size of the correction you mention
above absolutely depends on the Emiss cut applied to the data (implicitly
or not) and it is advisable to keep the effect below 5-10 % typically.
You have to understand the formalism for elastic scattering first, before
looking at what to do with an A(eeX)B reaction. It is a broad topic
Believe it or not, there was a first paper by Borie and Drechsel,
NPA (in 1974...) discussing this issue, but not conclusively. Maybe it was
drechsel's thesis ! Their result was (somewhat pedantically) repeated by
Sarty, Templon, Vellidis (see Mainz 4H(ee'p) from Florizone, MIT, and some
NIM paper by them, ca 1999), which seemed to be succesful in an extensive
simulation into the continuum part of the spectrum.
These are the classic references and definitely a starting point, although
if you read this stuff nicely summarized in a chpater in some thesis you
may be better off than going through some 30 pages of a 1969 Reviews of
Modern physics !! The manual for MCEEP (Ulmer, et al) is also very clear,
and it is attached for your pleasure. It deals with both the elastic
and QE case. I also looked it up in some pre-print of Franz Gross book: if
you have it, go for it. He is very clear (and original in his demonstration)
in giving you the physics (but not a practical formula -> Mo and Tsai!)
Nobody does really take into account a polarized beams. I think
the best place to look is LvBuuren thesis (/home/blast/blast/....) but
they were also not very sastisfied with their approach. Finally, I noticed
(and keep a copy somewhere) a paper from Hall-B discussing again the issue
taking pion production as the example, but I never took the time to see
how useful it were.
>
> Cheers, Vitaliy
>
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