Page History

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1. W x-section paper (Table of tasks)
   1. xxx
2. AOB

August 17, 2010

Present: Justin, Rosi, Jan, Gene, Joe, Ross
Agenda:

1. W x-section paper (Table of tasks)
   1. Pythia simu : done, see table (Jan)
   2. absolute lumi, Ross
   3. BTOW Longitudinal Leakage: Justin
   4. add more ...
2. AOB
3. Announcements:
   1. W AL paper posted at RHIC, intended submission to PRL : August 23, 2010. Elapsed analysis time between end of data taking (April 13,2009) and submission to PRL will be 16.5 months. Lets do better for run 11
   2. Joe is back

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1. LO interpretation of AL at mid rapidity - Bernd
2. Presentation(s) for RSC meeting at LBL#* new plots from old data replay, no spin info: PDF-1#*# Zs: inv mass, phi1 vs, phi 2
   • ## estimation of *error of AL(W+), W- Fig 3 at the bottom

November 3

Present: Rosi,Ross,Will,Joe,Jan,Ilya,Scott,Justin

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1. result of analysis of SL09b production
   1. Jan (Drupal blog )
      1. presentation of W-algo ver 4.0 using BTOW & TPC, for 1M input events
      2. Run 9 results as of September 1 Slides #### histogram-based dump of selected events #### Larger collections of events: di-jets , W-candidates , Z-candidates
         1. Matt's 3 interactive events in skechup or just one view , at Scott's angle
         2. sequential histograms from pass through 1M events (LT=~8/pb)
      3. M-C simulation analysis histograms for Pythia W-events (LT=320/pb) , filtered QCD-events LT=6.3/pb, Z-events LT=4200/pb
      4. Suggestions: count # of track pointing to cluster; compare ET vs. PT for electron
   2. 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
2. 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.
3. Questions/comments
   1. 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.
   2. 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
   3. Joe: estimate TPC tracking efficiency difference for e+ vs. e-
4. Ross - vernier scan analysis
   1. 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
   2. Comparison of Vernier scan from 2 pp500 runs - background visible in both
   3. 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
5. Joe - BTOW relative gains, not yet
6. new phone meeting time moved to : Tuesday 5-6 pm EDT
7. 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?

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   August 27, 2009

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1. 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.
2. BTOW, ETOW gains - no progress.

3. 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.

4. 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 \[[Media:Conversions-distace-Scott.pdf \|&#124; simple calculation for photons that convert to e+/e\-&#45; pairs\||]\] 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 %.

5. run QA : Scott is working on his fills.

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