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Phone bridge *number: 617-452-2163 * , time 5pm to 6:30 pm , 10 lines
Present:
Agenda:
- W AL paper: corrections to Fig3
- W x-section paper (Table of tasks)
- xxxadd more
- AOB
August 17, 2010
Present: Justin, Rosi, Jan, Gene, Joe, Ross
Agenda:
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- result of analysis of SL09b production
- Jan (Drupal blog )
- presentation of W-algo ver 4.0 using BTOW & TPC, for 1M input events
- Run 9 results as of September 1 Slides #### histogram-based dump of selected events #### Larger collections of events: di-jets , W-candidates , Z-candidates #### Matt's 3 interactive events in skechup or just one view , at Scott's angle
- sequential histograms from pass through 1M events (LT=~8/pb)
- M-C simulation analysis histograms for Pythia W-events (LT=320/pb) , filtered QCD-events LT=6.3/pb, Z-events LT=4200/pb
- Suggestions: count # of track pointing to cluster; compare ET vs. PT for electron
- Joe adopted his algo developed on M-C to work with Run 9 data
- removed BSMD, changed to tower-based center of gravity, relaxed cuts: PT>5 GeV/c, delEta & delPhi<0.5, isoFraction of 0.8
- Uber-preliminary result for 1M input events results plots
- Jan (Drupal blog )
- Run 9 data publication strategy has been discussed and in general agreed up. Use of BSMD for PRL paper 1 was discussed - it is worth trying.
- Questions/comments
- from former prominent STAR collaborator:
- Could the Z-candidates be di-jets? cosmic rays? Do you try to do any charge sign discrimination on the electrons (i.e., opposite sign on the 2 sides for "Z-candidates")? Phi distribution does not appear indicative of cosmics.
- Most importantly, is "Jacobian peak" absent when you look at 200 GeV data with the same algo and cuts?
- Lots of questions, but this does look really promising, seems to give you NN W candidates NN Z candidates in the barrel region. It's a bit surprising that such a crude isolation cut, with no away-side ET upper threshold or SMD criterion, would suppress jet background so effectively. We always thought we would have to work much harder than this to unveil a signal above background.
- Jan: Lets plan to use BFC filter to get rid of not-BHT3 events from pp200 data. Process LT~10/pb. Needs: adopted filtering code, run selection, 1mm accuracy of TPC calibration (within month), supported production request
- Joe: estimate TPC tracking efficiency difference for e+ vs. e-
- from former prominent STAR collaborator:
- Ross - vernier scan analysis
- lots of detail about how I do the fit - Ross is looking for explanation why his calculations are off by ~4 orders of magnitude. knows
- Comparison of Vernier scan from 2 pp500 runs - background visible in both
- Comments/suggestions:
- post study with eliminated TP affected the most by the beam background - no link yet. Even removing the noisiest high tower patches still leaves considerable amounts of background. ADD LINK
- post input data from Angelika Raw data from Angelika
- exercise the code on mock data to verify it reconstructs width correctly
- Joe - BTOW relative gains, not yet
- new phone meeting time moved to : Tuesday 5-6 pm EDT
- low TPC tracking efficiency at eta~0. Gene: may by a better T0 suffice to correct it - lets wait for the outcome. How can we address this issue?
August 27, 2009
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- TPC, Gene:
- non-linear SC(lumi) should provide TPC track accuracy of 2 mm at both ends of the track. We hope Joe will work on this next week, should take a week.
- We could also use Gene's PCA method of finding a linear combination of scalers (each at first order).
- since linear SC(lumi) was tuned to lumi equivalent to ZDC base rate of 70kHz, any pp500 run taken at the ZDC rate has current best TPC calibration. Jan: I'll use it for beam line constrain study, see below.
Wiki Markup *beam line constrain* : plan A is Rosi & Jan succeed with 3D beam line fit to global tracks w/o intermediate vertex finding. Here are \[[Media:Beamline-v3.pdf |details of the algo]\] as intended and not implemented. If this works Gene needs a \~day to produce beam line constrain for all 39 fills. Plane B is to use Minuit vertex finder which may require significant stats to overcome jitter due to pileup tracks. In such case we would need to provide manpower for \~week long job, Gene would only supervise it. Jan: lets go for plan A.
- conclusion: once both items are resolved we can ask for production, perhaps 2 weeks from now.
- BTOW, ETOW gains - no progress.
Wiki Markup BSMD : Willie is working '''slopes for individual strips'''. He run over 10k VPD-minB events and got this \[[Media:BSMD-strips-Picture 16.png|2D plot of module 119]\] and spectra \[[Media:BSMD-strips-Picture 15.png |individual strips]\]. The available 1.5M vpd-minB events should be enough to fit every strip. If not we will merge strips.
Wiki Markup BSMD geometry: Scott asked how well we know '''relative position of BSMD vs. TPC'''. It is [followed up on emc2-hn |http://www.star.bnl.gov/HyperNews-star/get/emc2/3250/1.html]. <p> Scott once did \[[Media:Conversions-distace-Scott.pdf | simple calculation for photons that convert to e+/e- pairs|\||]\] in the SVT, attached. <br>The relevant equation is on the bottom left. For the W -> e, we have r_1 = 0, r_2 = 2.3 m (approximate radius of BSMD planes), and B = 0.5 T. With these numbers, you get the simple relation<br> dPhi (cm) = 40 / pT (GeV)<br>For example, an electron of 40 GeV pT will deflect in the phi direction by 1 cm relative to the same e- of infinite pT. This is probably good to better than a few %.- run QA : Scott is working on his fills.
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