There is more recent stuff on RC for both elastic and inelastic (polarized!)
processes which some of you might find useful. I attach three additional
papers and a conf. contribution. But for first orientation, it is perhaps
indeed advisable to glance at least casually at some of the early articles
TB mentioned. BTW, the Sarty++ paper is a PRC, not a NIM, and I also attach
it. While almost any electron scattering thesis deals with RC, the multi-
dimensional propagation of radiative tails in (unpolarized) QE scatt.
is perhaps most pedagogically presented in R. Florizone's MIT thesis,
including all the inconsistencies and caveats. A bit older, Quint's
thesis from NIKHEF is another place to look.
It *is* a broad topic, and I have repeatedly seen cross-section data
analyses in the past rise to full glory or fade to misery, depending
on how careful RC were understood. The Mainz/Saclay VCS folks (Marc VdH)
have polished RC to perfection so, as an option, they could later be asked
for advice or assistance.
Simon
-- Simon Sirca Dept of Physics, University of Ljubljana Tel: +386 1 4766-574 Jadranska 19 Fax: +386 1 2517-281 1000 Ljubljana, Slovenia---------- Forwarded message ---------- Date: Mon, 5 Jan 2004 23:28:25 -0500 (EST) From: Tancredi Botto <tancredi@lns.mit.edu> To: Blast_Anaware <Blast_anaware@rocko.mit.edu> Subject: Re: [BLAST_ANAWARE] Remaining tasks in sofrware
> >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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