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
>
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:32 EST