Hi JH+EJK, Nice plots! Is it possible for you to save these as root macros, so that I can steal them? I'd like to change some purely cosmetic things so that some of these can go into the plenary talk, but I am sure you are both to busy for this. Thanks, Ian -----Original Message----- From: owner-brahms-l@bnl.gov [mailto:owner-brahms-l@bnl.gov]On Behalf Of J.H. Lee Sent: 12. juli 2002 20:55 To: brahms-l@bnl.gov Subject: net-proton at y=0 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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