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Second Look at TT in Trigger. S. Blusk July 1, 2009. D x 1/p z , B∙dl. Geant hit study No noise No secondary int. Does include MS and other physics proceses. First set of plots are Bs DsK MC at L = 2x10 32 cm -2 s -1. P<5 GeV , D X, D Y from projected VELO track vs Charge.
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Second Look at TTin Trigger S. Blusk July 1, 2009
Dx 1/pz, B∙dl • Geant hit study • No noise • No secondary int. • Does include MSand other physicsproceses
First set of plots are BsDsK MC at L = 2x1032 cm-2 s-1
P<5 GeV, DX, DY from projectedVELO track vs Charge True MC hits ‘All’ MC hits DX with |DY|<10 mm DY with |DX|<40 mm
5<P<20 GeV, DX, DY from projectedVELO track vs Charge True MC hits ‘All’ MC hits DX with |DY|<10 mm DY with |DX|<40 mm
P>20 GeV, DX, DY from projectedVELO track vs Charge True MC hits ‘All’ MC hits DX with |DY|<10 mm DY with |DX|<40 mm
Momentum “Calibration” Look at DX vs Pz foreach of the four T-stations Fit to: |Dx| = p0 + p1/Pz
Check of Calibration Average Per Track Per TT Hit Dp vs ptrue Dp/ptrue vs ptrue sp/p ~ 25%, but high-side tail. Overestimate of momentum due,due to MS --> When hit moves closer to VELOextrapolation, momentum increases Dp/ptrue
vs Momentum (true) vs pT(true) P, Pt distributions pT(est)>1.0 GeV p(est)>10 GeV pT(est)>1.0 p(est)>10 GeV pT(est)>1.0 p(est)>10 GeV 4 hits in tight window
MinBias – DX, DY distributions at 2e32 at 2e33 ‘S/B’ under DY peak ~ 20 ~ 8 NB: DX after cut on |DY|<10 mm
Summary • ‘Quick’ Momentum estimate using TT ~40% resolution • Can reject low momentum tracks with relatively high efficiency • Could clearly benefit from larger B∙dl in region from VELO to TT • Improve sp/p highly desirable to have sharper turn-on • Eliminate gaps, good Y resolution desirable • Increase in background at high lumi. • Would need an algorithm to reject outliers • All hits should give “consistent” momentum determination – could remove hits that give large difference wrt average.