[d2n-analysis-talk] H2 cross section

[MATTHEW R POSIK]

Hi Brad,

*>I commented on this and a couple other things in an earlier note: 'Re:
>BB/LHRS tracks' on 08:55 2010-04-20*

 I do not seem to have this replay in my inbox, if you still have it would
you mind resending it?


On Thu, Apr 22, 2010 at 11:50 AM, Brad Sawatzky <brads at jlab.org> wrote:

> On Wed, 21 Apr 2010, posik at jlab.org wrote:
>
> > So I am looking into the BBNormAna stuff now. In the mean time last
> > night I went to look at how to get the other parameters that I will
> > need to compute the H2 cross section.
> >
> > The first thing that I want to comment on is the shape of L.tr.tg_th,
> > there looks to be a dip in the center of the distribution (the middle
> > plot in the fig attached). Is this normal?, Or could something maybe
> > be blocking the angle?
>
> I commented on this and a couple other things in an earlier note: 'Re:
> BB/LHRS tracks' on 08:55 2010-04-20.  It looked strange to me too --
> check with Zein-Eddine and see if it makes sense to him.
>
> > With that said, then next thing I want to do is calculate the density
> > of our target. To do this I use the Ideal gas law and have
> [ . . . ]
>
> Check with Lamiaa for the target density stuff.  She should be able to
> point you to the correct calibrations and formulae, or put you in touch
> with one of the target experts.  (She may have even done some of the
> work already.)
>
> We had a couple of independent pressure readings.  I think they were all
> gauge pressure, but I'm not certain.  There was also an issue with the
> gauges' "zero" set point drifting over time...
>
> I did a quick search and found this talk by Yi from last month:
>  https://hallaweb.jlab.org/dvcslog//transversity/317
> And another document that might be useful:
>  https://hallaweb.jlab.org/dvcslog//transversity/351
> They are worth looking at for procedure and insight into the issues
> found during the Transversity analysis.
>
> > The next thing that shows up in the cross-section is the acceptance of
> > the LHRS which consists of 3 parameters (d_ang,d_z and d_E). In all
> > papers that I have read they calculate these quantities using Monte
> > Carlo simulation.
> > I do not have a Monte Carlo set up to simulate the angular acceptance.
> > I spoke to Huan and he had told me that there is an acceptance problem
> > with his Monte-Carlo acceptance. But he had told me to I could make
> > acceptance cuts and just assume the angular acceptance is 1.
>
> The phrase "assume the angular acceptance is 1" doesn't help much...
> "1" what?  (Do you mean a some sort of correction factor?)
>
> We're looking for a rough check here.  The nominal acceptance defined by
> the floor angle, P0 setting, and existing HRS calibrations should be
> fine.  Run the details by Zein-Eddine if you run into a snag.
>
> -- Brad
>
> --
> Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
> Ph: 757-269-5947  -<>-  Fax: 757-269-5235  -<>- Pager: brads-page at jlab.org
> The most exciting phrase to hear in science, the one that heralds new
>  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov
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-- 
Matthew Posik
Email: posik at temple.edu
Temple University Physics Dept.
Office: BA-319
Office #:  215-204-1331
WebSites:
Temple:
http://quarks.temple.edu/
d2n:
http://hallaweb.jlab.org/experiment/E06-014/
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