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First Look at AN for p-Al (Day160)

Updated on Fri, 2015-06-12 09:51. Originally created by heppel on 2015-06-10 10:49.

 
We have downloaded and analyzed about 5 to 6 hours of data from Day160 (first p-Al data).
The runs are:

16160039
16160040
16160041
16160044
16160051
16160052
16160053
16160055
On the trigger page posted by Chris, these runs have index 1344-1354
The prescale factors are seen on his pages  www.star.bnl.gov/protected/spin/dilks/trgmon15pAu/200/prescale_canv_zoomed_pAl.png
We see that these are in the early fill region where prescaling is agressive.

The reconstruction of pions was done with an "all ones" set of calibration corrections. I am in the process of generating better gain correction factors for our new voltage settings.

 As I have before, I show the distribution of pi0 events as a function of pT for each of the 9 triggers (Bsum small(x3), Bsum large(x3), JetPatch(x3)).
drupal.star.bnl.gov/STAR/system/files/callptDay160_6hrs.pdf
For comparison, this is the trigger distribution at the start of pAu (Day126)
drupal.star.bnl.gov/STAR/system/files/Save128129.pdf

I also include a corresponding trigger analysis for pi0 events from Day070 at the beginning of pp running,
drupal.star.bnl.gov/STAR/system/files/callpt_0.pdf  I should note that there were hardware fixes after Day70.
 

Based on comparing rates for reconstructed forward pion production, this 5 to 6 hours of p-Al data looks like it is equivalent to between 0.7 and 1 pb^(-1) of pp data.

On figure the right, the asymmetries are shown for pions of energy 25<E<35 GeV as a function of pT. The p-Al data points are plotted with "star" markers and points are joined by solid lines.  For comparison to a 29 pb^(-1) pp data set, the pp data are plotted with circles as markers  and joined with dashed lines.

For the p-Aluminum  AN point at pT=3.2 GeV, the Cos(Phi) distribution is shown (upper left). Remember the slope of the Cos(Phi) distribution is proportional to AN.  The p-Al mass distribution for this pT=3.2 GeV point is shown in the lower left.


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