Dear Collaborators,
Here are some distributions for the net-proton at y=0 for 5%.
We'll post more (5-20% and at 40 degree) soon.
Attached figures.
1. proton, pbar yields (dN/dydpt)
(Estimated integral coverage ~ 80-85%)
Please look at "integral" in statistics box.
p - pbar = 29.15 - 22.08 = 7.07 for pt 0.6 - 3GeV/c
p - pbar = 36.44 - 27.6 = 8.84 for all extrapolated phase space
assuming 80% coverage)
Estimated error is ~20% on the number.
2. proton, pbar invariant pt spectra
3. pbar/p ratio
4. pi plus invariant pt with exponential fit
5. pi minus invariant pt with exponential fit
If you are interested in more details for the analysis...
Event Selection:
- Events are required to have BB and ZDC vertex.
- Trigger6 only
- Centrality cut was only using fMultCent
Track Selection:
- Tracks have to come from BB vertex
- -17.5 < Track z < 17.5 cm
- Track matching cuts
Run-by-run fit with Gaussian + 2nd pol
* Since the distributions of the matching parameters are not exactly Gaussian,
the distribution (p2) under the Gaussian peak is overestimating background.
It's due to various reasons (especially non-uniformity of drift velocity
and the "angle problem").
If you take 3*rms, it's about 4*sigma.
Efficiency:
- Tracking
Based on the rough estimates/preliminary numbers from Oslo/hardware
performance,...
reconstruction efficiency for the events with highest number of clusters
in TPM1: 95% and TPM2: 97% at 90 degree.
This function is used for 40 degree runs, which will give ~90% for most central.
- ToF efficiency
My old estimate was around ~95%, but we took Peter's new estimate: 90% flat
Other corrections:
- multiple scattering
Acceptance:
- Each field setting, the first bin is not included in the summed distribution
to reduce acceptance edge effect.
JH + EJK
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