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Comparing Vertex from Z μμ to the Remaining Tracks. August 21, 2014 Ryan Kelley. Introduction. Compare vertex of the Z μμ Idea is to take the μ’s from the Z μ from primary interaction point used two μ tracks to form a vertex u sing KalmanVertexFitter
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Comparing Vertex from Z μμ to the Remaining Tracks August 21, 2014 Ryan Kelley
Introduction • Compare vertex of the Z μμ • Idea is to take the μ’s from the Z • μ from primary interaction point • used two μ tracks to form a vertex • using KalmanVertexFitter • used remaining tracks with pT > (1.0, 0.5, 0) or |p| > (0.5,1.0, 2.0) to form another vertex • using KalmanVertexFitter • using TrimmedVertexFitter • using AdaptiveVertexFitter • compare the difference in X,Y,Z positions
Selection • Used SEDWG PAT configuration 2_2_10 • Datasets: • /Zmumu/Summer08_IDEAL_V11_redigi_v2/GEN-SIM-RECO • 20K Events • Selection • μ's • pT > 10.0 GeV • GlobalMuonPromptTight (recommended by μ I.D. note) • χ2/dof < 10 • |d0| < 2 mm (designed to reject decays in flight and punch through) • nHits from track ≥ 11 • Z Candidates • Created Z’s from μ+μ- (from above mu’s) • mZ – 4ΓZ < mμ+μ- < mZ + 4ΓZ
Several Fitting Option oob • The fitters now available are • The KalmanVertexFitter: the simple least-squares algorithm (uses all the tracks with a weight of 1) • The AdaptiveVertexFitter: iterative re-weighted KalmanFitter? which down-weights tracks according to their distance to the vertex • The TrimmedVertexFitter: conventional robust version of the Kalman fitter, which removes tracks incompatible with the vertex • The GaussianSumFitter: fitter using the non-Gaussian distributions of measurement errors • The AdaptiveGsfVertexFitter: a combination of the adaptive fitter and the Gaussian-sum fitter • The GSF fitters are designed for objects that use GSF error calculations (e.g. Electrons) • wouldn’t work for tracker Tracks (from the μ’s and general tracks) • https://twiki.cern.ch/twiki/bin/view/CMS/SWGuideVertexFitting
Vertex formed from Tracks • Used all tracks not from the Z candidates’ μ’s with • pT > 1.0 GeV • pT > 500 MeV • |p| > 500 MeV • |p| > 1.0 GeV • |p| > 2.0 MeV • no pT cut
Convergence of the Fits • Only looked at the first three types • GSF fitting primarily for electrons • KVF and AVF w.r.t BeamSpot (TVF not implemented in CMSSW) • Log scale • The TVF rejects tracks when they’re killing the fit more invalid.
Vertex formed from Z’s • Used the two tracks not from the Z candidates’ μ’s with • Used KalmanVertexFitter since only two tracks and we want the weight always =1
Delta = Track - Z • Used attribute (vx, vy, vz) to calculate • Δvx = vxtracks – vxz • Δvy = vytracks – vyz • Δvz = vztracks – vzz • Showing AVF results
Δvx • Δvx = vxtracks – vxz • no pT on Tracks
Δvx • Δvx = vxtracks – vxz • pT > 500 MeV on Tracks
Δvx • Δvx = vxtracks – vxz • pT > 1.0 GeV on Tracks
Δvx • Δvx = vxtracks – vxz
Δvx • Δvx = vxtracks – vxz
Δvx • Δvx = vxtracks – vxz
Δvy • Δvy = vytracks – vyz • no pT on Tracks
Δvy • Δvy = vytracks – vyz • pT > 500 MeV on Tracks
Δvy • Δvy = vytracks – vyz • pT > 1.0 GeV on Tracks
Δvy • Δvy = vytracks – vyz
Δvy • Δvy = vytracks – vyz
Δvy • Δvy = vytracks – vyz
Δvz • Δvz = vztracks - vzz • no pT on Tracks
Δvz • Δvz = vztracks - vzz • pT > 500 MeV on Tracks
Δvz • Δvz = vztracks - vzz • pT > 1.0 GeV on Tracks
Δvz • Δvz = vztracks – vzz
Δvz • Δvz = vztracks - vzz • pT > 500 MeV on Tracks
Δvz • Δvz = vztracks - vzz • no pT on Tracks
Resolution = Track - Gen • Used attribute (vx, vy, vz) to calculate • Res vx = vxtracks – vxgen • Res vy = vytracks – vygen • Res vz = vztracks – vzgen • Showing AVF results
Resolution vxTracks • Res vx = vxtracks - vxgen • no pT on Tracks
Resolution vxTracks • Res vx = vxtracks - vxgen • pT > 500 MeV on Tracks
Resolution vxTracks • Res vx = vxtracks - vxgen • pT > 1 GeV on Tracks
Resolution vxTracks • Res vx = vxtracks – vxgen
Resolution vxTracks • Res vx = vxtracks – vxgen
Resolution vxTracks • Res vx = vxtracks – vxgen
Resolution vytracks • Res vy = vytracks - vygen • no pT on Tracks
Resolution vytracks • Res vy = vytracks - vygen • pT > 500 MeV on Tracks