Hi Aki,
which cuts are you exactly using? Is a cut on coincidence time included?
Regards,
Michael
On Fri, 11 Mar 2005, Akihisa Shinozaki wrote:
> Hi Vitality,
>
> Thank you for your feedback. I am using the empty runs including the
> deuterium periods. I will try the stricter z-cut, since I am using a
> very loose cut (|z|<35 cm) now, and see if the error bars shrink.
>
> Thank you,
> aki
>
> vitalik wrote:
>
> > Aki,
> > I'm familiar with this background. In fact this is not the background
> > from the empty cell, but the electromagnetic shower events. They
> > separate well from the quasielastic peak but clash with the pion
> > production region. One thing you can do is try to restrict the
> > z-cut. A big source of those showers is the collimator upstream.
> > Ultimately, I believe that you will have to rely on the subtraction of
> > the empty cell rate. The good news is that I believe that you can use
> > empty runs from deuterium running period also, to increase your empty
> > run set. Aaron has a comprehensive empty run list.
> > Cheers,
> > Vitaliy
> >
> > Akihisa Shinozaki wrote:
> >
> >> Hi Tavi,
> >>
> >> Please never mind my previous results. I found at least four mistakes
> >> in my code. Both data and simulations were not right results. I was
> >> basically collecting the "garbages" for the data. Also, the
> >> simulations did not took the pi+ channel into account by my mistakes.
> >> I am sorry if I made another confusions for you.
> >>
> >> So this is my another attempt for the p(e',e) results for you. This
> >> time only trigger 7 is considered. For e' selection, Cerenkov hits
> >> were required for the corresponding TOF counters.
> >>
> >> The file, asymmetryi.ps, shows the asymmetries from all the data
> >> obtained from last October to December (48 deg. only). The data are
> >> compared with my MAID and SL simulations. The simulated curves assume
> >> the dilution factor = 0.5 with no asymmetry offset. The data make
> >> good agreement with the simulations. It *seems* to me that your data
> >> do not quite match with mine in the left sector since your data do
> >> not go beyond the zero as much as my current result. I think we can
> >> discuss this later.
> >>
> >> peei_md.ps and peei_sl.ps show the data distributions of W, Q^2,
> >> Ee'(lab), and, Theta^e'(lab) . The blue (red) + points are the
> >> counting rate in events per Coulomb in the electron left (right)
> >> sector. The thiner lines are background (empty target spectrum). The
> >> thick curves are my MAID or SL simulations. The data spectra in
> >> peei_md.ps and peei_sl.ps are not the same because W<1.4 GeV is
> >> applied for MAID while the SL simulation requires W<1.3 GeV. There is
> >> no radiative process considered and this should be one of the sources
> >> of the differences between the data and simulations. Since you are
> >> doing with GEANT, you could tell me more on the characteristics of my
> >> simulations.
> >>
> >> It is quite striking that the background rates are as high as the
> >> foreground, which is the main source of the error in the asymmetries.
> >> I am using the all empty target runs available but the statistics is
> >> still about one tenth of the foreground.
> >>
> >> I think that is all for now. Thank you!
> >> aki
> >>
> >
>
--+-------------------------------------+--------------------------+ | Office: | Home: | |-------------------------------------|--------------------------| | Dr. Michael Kohl | Michael Kohl | | Laboratory for Nuclear Science | 5 Ibbetson Street | | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 | | Middleton, MA 01949 | U.S.A. | | U.S.A. | | | - - - - - - - - - - - - | - - - - - - - - -| | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de | | Work: +1-617-253-9207 | Home: +1-617-629-3147 | | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 | | http://blast.lns.mit.edu | | +-------------------------------------+--------------------------+
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