1 / 11

making fake TT clusters

making fake TT clusters. Creating Fake TT clusters Goal: simulate TT clusters with different stero angles planes. Method: parametrization of the X-error at TT-X1 and TT-X2 vs true momentum. assume it is the Y-error (ms+velo) . create (x,y) hit at TT1:

linda-hicks
Download Presentation

making fake TT clusters

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. making fake TT clusters • Creating Fake TT clusters • Goal: simulate TT clusters with different stero angles planes. • Method: • parametrization of the X-error at TT-X1 and TT-X2 vs true momentum. • assume it is the Y-error (ms+velo) . • create (x,y) hit at TT1: • propagate the L1Track3d to TT1-X (straight line) • use the x-measured value at TT1-X • smear the Y coordinate. • Create (u,v) for TT-X´and TT-V´ • update the state of the track using (x,y) simulated (new straight line parameters) • Create (x,y) hit at TT2, as above... Summary: [For L1] if we want to improve the momentum resolution (and reboustness) we can: increase the B strength (Bdl 2xf043) improve TT slope resolution (high energy) large lever arm smaller pitch What is the effect of the stereo angles of TT? create fake TT clusters for different stereo angles (instead of generate new DDB) Use: DaVinci v6r0 field 044 (week one) Jose A. Hernando, 31/03/02, weekly trigger meeting

  2. making fake TT clusters :: parameterization of errors mm mm mm Sigma deflection at TT-X1 Deflection at TT-X1 mm 1/GeV 1/GeV 1/GeV • X- Deflection vs 1/pp at TT-X1 TT-X2 • Propagation : (p_mc > 2.5 GeV) • Velo-TT1 straight line • TT1- update straight line • TT1-TT2 • The error are (ms+velo resol+TT) • Obtain: error X(Y) vs momentum • at TTX1 and TTX2 mm mm Sigma deflection at TT-X2 Deflection at TT-X2 1/GeV 1/GeV

  3. making fake TT clusters :: original clusters mm True MC TT Clusters TT1[X(0),V(-5 deg)] TT2[U(5 deg),X(0)] U-deflection: distance perpendicular to strips) between true MC clusters and extrapollated hit (stragiht line). (projection and vs momentum) The track (straight line) is updated after each measurement RMS: X1 2.6 mm X2 0.8 mm V1 0.01 mm U2 0.014 mm 1/MeV mm mm 1/MeV mm

  4. making fake TT clusters :: theta = 90 degrees mm Fake TT Clusters TT1[X(90),V(-5 deg)] TT2[U(5 deg),X(90)] U-deflection (per to strips) (projection and vs momentum) The track (straight line) is updated after each measurement Now X meas Y!! U,V meas X! On X planes we see the error (ms+velo) On YV, we see the error +deflection mm mm mm

  5. making fake TT clusters :: density distributions Fake TT Clusters TT1[X(0),V(-5 deg)] TT2[U(5 deg),X(0)] U-distribution vs the distance perperdicular to the strips form the hit to the extrapollated point (using straight line and updating it at TT1) For: MC clusters associated to MCParticle. (signal) For: any clusters. (signal+background) mm mm mm mm

  6. making fake TT clusters :: eff and purity X(0) Fake TT Clusters TT1[X(0),V(-5 deg)] TT2[U(5 deg),X(0)] Efficiency and purity vs distance to the extrapolated point (using straight line). Effciency fraction of all clusters Associated with the track (fraction S vs distance) Purity: # of good clusters divide by # of total clusters a given distance to the extrapolation of the trak. S/(S+B) vs distance

  7. Making fake TT clusters :: eff vs purity Fake TT Clusters TT1[X(0),V(-5 deg)] TT2[U(5 deg),X(0)] Efficiency vs Purity (for the different planes) V1-U2 almost perfect! X1-X2 we see the deflection+error effect 95% efficiency 58% purity X1 85% purity X2

  8. making fake TT clusters – eff vs purity X(0,5,10,90) X(0) X(5) X(90) X(10)

  9. making fake TT clusters :: purity at 68,95% efficiency vs theta Purity at ~68% and 95% efficiency vs theta angle (X rotation) Purity is almost a flat distribution between –5 and 15 degrees. At large angles purity of X and (U,V) inverted. But the average purity is the same. X1 : 95% eff, 58% pur, 1.7 clusters X2 : 95% eff, 83% pur, 1.2 clusters ~68 % efficiency 95 % efficiency

  10. making fake TT clusters :: effect on momentum resolution Momentum resolution: toy MC with field 043! using Kalman Filter. fast degradation of sigma_x vs theta. (factor [1(1 plane),0.7 (2 planes)]) pitch: 200 um (1 X plane) sigma = 57 um (2 X planes) sigma = 41 um pitch: 50 um (1 X plane) sigma = 15 um Small gain at high energies (were we are more sensible to Pt mistakes) Large gain at high energies for small Pitch (better slope determination) [center TT part with 50 um pitch? How bad will be the aligment for L1?]

  11. making fake TT clusters :: and more? • It seems that there is no gain in changing the stereo angles. • Still they are things that can be done: • We can “update” the state using a “helix” model instead of a “straight line” model, and the window in X2 will be reduced. • That will equivalent to have a simplified filter part of the Kalman for Velo-TT . It can be helpfull for pattern recognition and a measurement of momentum!. We can stimate its cost in time. • We can compute the number of combinations instead of the purity (following all the possible candidates from TT1 to TT2) (almost there!) • We can go to Brunell and get the MC (x,y) hits at TT and generate the (u,v) hits, instead of using the fake TT clusters method. • I will like to concentrate: • polishing some plots for the L1, B-field note (due this week). • starting studying possible improvements of L1.

More Related