[d2n-analysis-talk] 5pass Momentum stability

[Brad Sawatzky]

BigBite sees everything so you need to constrain the expected momentum
somehow or a naive mean won't tell you much.  (Lower thresholds =>
more low momentum stuff passes trigger => mean momentum shifts down)

For this plot to be informative, you'll need to apply an energy
threshold in software to the Sh+PSh sum.  Apply a cut on the calorimeter
total energy that corresponds to -150mV (ie. above the hardware
threshold for all runs) and remake the plot.  

Bonus points if you repeat the exercise for different energy slices, ie:
  Plot the reconstructced momentum for particles depositing  700+-50 MeV.
  Plot the reconstructced momentum for particles depositing  900+-50 MeV.
  Plot the reconstructced momentum for particles depositing 1100+-50 MeV.

-- Brad

On Fri, 14 Oct 2011, posik at jlab.org wrote:

> Hi all,
> 
>    With the trigger thresholds changing so much during our 5.89 GeV data
> set,in addition to looking at the MWDC drift times and track residuals.
> I also took a look at the momentum for our 5.89 GeV target spin = 90
> deg. data. I attached a plot of the mean momentum histogram vs
> runnumber. I used the momentum variable BB.optics.p_firstorder. The
> various colors correspond to various shower threshold changes. The
> largest variation in mean momentum is ~ 130 MeV.
> 
> -Matt

-- 
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