On the Real Data Analysis Vertex efficiency resolution
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On the Real Data Analysis: Vertex efficiency /resolution, Qflag(Run) & Lumi Info. Xiangwei Meng Institute of High Energy Physics, CAS, Beijing Nov. 20 , 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 1
Contents o To study quarkonia and measure their production n Tracking efficiency n Momentum scale/resolution n I. P. resolution n Vertex efficiency/resolution* o Quality flags in DBS o Lumi info. in DBS & CMSSW 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 2
Work ongoing and people involved. . . Extract vertex resolution function from data: o QCD events b-depleted (J. Bernardini): -pseudo decay lentgh in bin of pt. Jpsi and eta muons -primary vertex from beamspot (OK) -primary vertex from reconstruction event-by-event (~OK, needs some work) o Study of pseudo decay length in B->Jpsi X events(~OK) (J. Bernardini) o Upsilon events (F. Fiori) o Study of beamspot at 900 Ge. V, 7 Te. V (~200 m, 60 m) and misalignment studies (Supreet Pal Singh, F. Fiori) 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 3
Vertex Resolution function from the data using ad-hoc samples For an integrated luminosity of 200 nb-1, we would get about 0. 7 Million QCD useful combinations in the given mass range. 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 4
What we have learned. . o Vertex resolution function depends by kinetic variable as pt. Jpsi and of eta the two muons Both with | |<1. 1 RMS m Both with 1. 1<| |<2. 4 RMS m One with | |<1. 1 and the other with 1. 1<| |<2. 4 RMS m 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 5
What we have learned. . J/psi QCD 8<p. T (Ge. V)<10 J/Psi 2. 5<Mass (Ge. V)<3. 5 QCD 2009 -11 -20 Width ( m) Fraction 35 0. 52± 0. 10 33 0. 53± 0. 15 55 0. 45 52 0. 47 187 CMS B-physics Group Meeting 11, 2009 0. 03 148 0. 07 6
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What we have learned. . does not agree as expected With primary vertex reconstructed event-by-event 2009 -11 -20 resolution depends on number of tracks associated to the vertex Vertex resolution vs # of tracks c tau resolution # of tracks vs Jpsi p. T Primary Vertex resolution CMS B-physics Group Meeting 11, 2009 8
A little montecarlo toy Simulating the content in tracks of Jpsi primary vertex 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 9
B->Jpsi X Good agreement of resolution so we can use the vertexresolution function extracted by data also in B events For primary vertex event-by-event same situation than the QCD. . . 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 10
Conclusions & todo list o With beamspot good agreement QCD-Jpsi in bin of pt and eta o With primary vertex reconstructed event-byevent seems to be good, but many work to optimize the strategy o Opimize binning and fits o Analysis on Upsilon started this week (Fiori) o To be started work on misaligment and beamspot size study in the earlier run at 900 Gev and 7 Te. V (Supreet, Fiori) 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 11
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Backups 2009 -11 -20 CMS B-physics Group Meeting 11, 2009 18
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