Hi Michael,
You mean Cerenkov cuts? No, timing is not considered. Only paddle number
is considered. As a matter of fact, your suggestion might also be
helpful since I am seeking better cuts. A tight z-cuts (|z|<20 cm)
indeed shorten the error bars but does not improve dramatically.
Thank you,
aki
Michael Kohl wrote:
>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
>>>>
>>>>
>>>>
>
>
>
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