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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 - PowerPoint PPT Presentation
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SEDWG April 22, 2023 R. Kelley
Comparing Vertex from Z μμ to the Remaining
Tracks
April 22, 2023
Ryan Kelley
SEDWG April 22, 2023 R. Kelley2
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
SEDWG April 22, 2023 R. Kelley
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
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SEDWG April 22, 2023 R. Kelley
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
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SEDWG April 22, 2023 R. Kelley
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
5
SEDWG April 22, 2023 R. Kelley
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.
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SEDWG April 22, 2023 R. Kelley
Validity of the Fits
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χ2/dof of the Fits
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SEDWG April 22, 2023 R. Kelley
χ2/dof of the Fits (zoom)
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# d.o.f of Fits
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χ2 prob of Fits
11
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# Tracks Used
12
SEDWG April 22, 2023 R. Kelley
Track Weights Used
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# Tracks Used vs # d.o.f
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SEDWG April 22, 2023 R. Kelley
# Tracks Used vs # d.o.f
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SEDWG April 22, 2023 R. Kelley
# Tracks Used vs # d.o.f
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SEDWG April 22, 2023 R. Kelley
# Tracks Used vs # d.o.f
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SEDWG April 22, 2023 R. Kelley
# Tracks Used vs # d.o.f
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SEDWG April 22, 2023 R. Kelley
# Tracks Used vs # d.o.f
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SEDWG April 22, 2023 R. Kelley
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
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SEDWG April 22, 2023 R. Kelley
Validity and # d.o.f of vertex from Z candidates
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χ2/dof and χ2 prob. of vertex from Z candidates
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Delta = Track - Z
• Used attribute (vx, vy, vz) to calculate
– Δvx = vxtracks – vx
z
– Δvy = vytracks – vy
z
– Δvz = vztracks – vz
z
• Showing AVF results
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SEDWG April 22, 2023 R. Kelley
Δvx
24
• Δvx = vxtracks – vx
z
• no pT on Tracks
SEDWG April 22, 2023 R. Kelley
Δvx
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• Δvx = vxtracks – vx
z
• pT > 500 MeV on Tracks
SEDWG April 22, 2023 R. Kelley
Δvx
26
• Δvx = vxtracks – vx
z
• pT > 1.0 GeV on Tracks
SEDWG April 22, 2023 R. Kelley
Δvx
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• Δvx = vxtracks – vx
z
SEDWG April 22, 2023 R. Kelley
Δvx
28
• Δvx = vxtracks – vx
z
SEDWG April 22, 2023 R. Kelley
Δvx
29
• Δvx = vxtracks – vx
z
SEDWG April 22, 2023 R. Kelley
Δvy
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• Δvy = vytracks – vy
z
• no pT on Tracks
SEDWG April 22, 2023 R. Kelley
Δvy
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• Δvy = vytracks – vy
z
• pT > 500 MeV on Tracks
SEDWG April 22, 2023 R. Kelley
Δvy
32
• Δvy = vytracks – vy
z
• pT > 1.0 GeV on Tracks
SEDWG April 22, 2023 R. Kelley
Δvy
33
• Δvy = vytracks – vy
z
SEDWG April 22, 2023 R. Kelley
Δvy
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• Δvy = vytracks – vy
z
SEDWG April 22, 2023 R. Kelley
Δvy
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• Δvy = vytracks – vy
z
SEDWG April 22, 2023 R. Kelley
Δvz
36
• Δvz = vztracks - vz
z
• no pT on Tracks
SEDWG April 22, 2023 R. Kelley
Δvz
37
• Δvz = vztracks - vz
z
• pT > 500 MeV on Tracks
SEDWG April 22, 2023 R. Kelley
Δvz
38
• Δvz = vztracks - vz
z
• pT > 1.0 GeV on Tracks
SEDWG April 22, 2023 R. Kelley
Δvz
39
• Δvz = vztracks – vz
z
SEDWG April 22, 2023 R. Kelley
Δvz
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• Δvz = vztracks - vz
z
• pT > 500 MeV on Tracks
SEDWG April 22, 2023 R. Kelley
Δvz
41
• Δvz = vztracks - vz
z
• no pT on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution = Track - Gen
• Used attribute (vx, vy, vz) to calculate
– Res vx = vxtracks – vx
gen
– Res vy = vytracks – vy
gen
– Res vz = vztracks – vz
gen
• Showing AVF results
42
SEDWG April 22, 2023 R. Kelley
Resolution vxTracks
43
• Res vx = vxtracks - vx
gen
• no pT on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vxTracks
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• Res vx = vxtracks - vx
gen
• pT > 500 MeV on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vxTracks
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• Res vx = vxtracks - vx
gen
• pT > 1 GeV on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vxTracks
46
• Res vx = vxtracks – vx
gen
SEDWG April 22, 2023 R. Kelley
Resolution vxTracks
47
• Res vx = vxtracks – vx
gen
SEDWG April 22, 2023 R. Kelley
Resolution vxTracks
48
• Res vx = vxtracks – vx
gen
SEDWG April 22, 2023 R. Kelley
Resolution vytracks
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• Res vy = vytracks - vy
gen
• no pT on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vytracks
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• Res vy = vytracks - vy
gen
• pT > 500 MeV on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vytracks
51
• Res vy = vytracks - vy
gen
• pT > 1.0 GeV on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vytracks
52
• Res vy = vytracks – vy
gen
SEDWG April 22, 2023 R. Kelley
Resolution vytracks
53
• Res vy = vytracks – vy
gen
SEDWG April 22, 2023 R. Kelley
Resolution vytracks
54
• Res vy = vytracks – vy
gen
SEDWG April 22, 2023 R. Kelley
Resolution vztracks
55
• Res vz = vztracks - vz
gen
• no pT on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vztracks
56
• Res vz = vztracks - vz
gen
• pT > 500 MeV on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vztracks
57
• Res vz = vztracks - vz
gen
• pT > 1.0 GeV on Tracks
SEDWG April 22, 2023 R. Kelley
Resolution vztracks
58
• Res vz = vztracks – vz
gen
SEDWG April 22, 2023 R. Kelley
Resolution vztracks
59
• Res vz = vztracks – vz
gen
SEDWG April 22, 2023 R. Kelley
Resolution vztracks
60
• Res vz = vztracks – vz
gen
SEDWG April 22, 2023 R. Kelley
Resolution = Z - Gen
• Used attribute (vx, vy, vz) to calculate
– Res vx = vxZ – vx
gen
– Res vy = vyZ – vy
gen
– Res vz = vzZ – vz
gen
• Showing AVF results
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SEDWG April 22, 2023 R. Kelley
Resolution vxZ
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• Res vx = vxZ – vx
gen
SEDWG April 22, 2023 R. Kelley
Resolution vyZ
63
• Res vy = vyZ - vy
gen
• μ = 0.06 μm, σ = 12 μm
SEDWG April 22, 2023 R. Kelley
Resolution vzZ
64
• Res vz = vzZ – vz
gen
SEDWG April 22, 2023 R. Kelley
Back Up
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SEDWG April 22, 2023 R. Kelley
Definitions
• PCA– Point of Closest
approach (x0,y0,z0)
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SEDWG April 22, 2023 R. Kelley67
vx
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vy
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vz
SEDWG April 22, 2023 R. Kelley
vxz and vy
z
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vzz
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Calculation of Weights
• Used sum of two Gaussians (core + wide)
72
• Mean
• Standard Deviation• √variance
SEDWG April 22, 2023 R. Kelley
μ Variables: pT
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μ Variables: η
74
What causes this bump?
SEDWG April 22, 2023 R. Kelley
μ Variables: Φ
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μ Variables: x0 and y0
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μ Variables: z0
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μ Variables: d0
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μ Variables: # hits and χ2
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SEDWG April 22, 2023 R. Kelley
Number of Z’s per Event
80