CMS Tracking POG Performance Plots 2015

Track Reconstruction Performance

The new conditions of Run II with respect to Run I (center of mass energy and bunch spacing) call for a complete characterization of the detectors from the beginning, in order re-calibrate the whole system and verify its performances. The plots shown below focus on the performance analysis of the CMS tracking system from both direct and indirect measurements.

Beamspot reconstruction

Plot Description




CMS beam spot center coordinates for collisions at 13 TeV.Data were taken with CMS magnet at 3.8 T (black dots), 2.8 T (green dots) or 0 T (red dots). The error bars indicate the statistical uncertainty from the fit.

Vertex Finding

Plot Description

Comparison of the primary vertex resolution in Y vs pT sum of the associated tracks for four different data taking: 7 TeV (50 ns), 8 TeV (50 ns), 13 TeV (50 and 25 ns).

Muon Tag & Probe

Plot Description




Data (black dots) and simulation (light blue rectangles) tracking efficiency for muons coming from the Z decay as a function of the absolute pseudorapidity(top), the phi (center) and the number of primary vertexes(bottom) of the probe muon.
tagprobe_final.png Data (dots) and simulation (rectangles) tracking efficiency for muons as a function of the transverse momentum of the probe muon for tracks reconstructed with tracker info only in purple as well as the tracks reconstructed with tracker and muon seeded in blue and black.

Pion relative efficiency

Plot Description

The D0 -> K3π decay has a complex structure due to the interference of different intermediate states in two or three bodies that could affect the final efficiency. The previous analysis considered it as systematics uncertainty, we used a strategy to correct the final measurement.

We have to assign the proper efficiency to each event. The kinematics of a spin-0 particle decaying in a four-body final state are fully described by five invariant quantities. We choose the square of five invariant sub-mass: sij = (pi + pj)2 where pi,j is the particle momentum.

Finally we define the function F(x)=m0+m1s1+m2s2+m3s3+m4s4+m5s5, a linear combination of the sub-mass states, that well describes the efficiency.

Each event in the Nk3𝜋 final state is then weighted with the quantity 1/F.

Comparison between the value of the function F(x) bin by bin (black) and the reconstruction efficiency in Monte Carlo sample (red).




ΔM=M^{D*}-M^{D0} distributions for Kπ (top) and K3π (bottom) for data, stream ZeroBias.

The fitted shapes in blue well describe data point for both signal (solid) and background (dashed).




The ratio of tracking relative efficiencies for charged pions, as a function of the minimum D*% candidates pT threshold, is shown in three different pseudorapidity regions: barrel (top), transition (center) and endcap (bottom).
-- ValentinaMariani - 2016-03-21
Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng beam_spot_x.png r1 manage 22.2 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng beam_spot_y.png r1 manage 22.1 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng beam_spot_z.png r1 manage 26.0 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng eff_endcap.png r1 manage 15.7 K 2016-03-21 - 21:55 ValentinaMariani  
PDFpdf eff_pt_comparison.pdf r1 manage 15.5 K 2016-03-24 - 16:54 ValentinaMariani  
PNGpng eff_transition.png r1 manage 16.7 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng fit2bDATA.png r1 manage 15.6 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng fit2bMC.png r1 manage 14.4 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng fitpesato.png r1 manage 16.8 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng fun_effi.png r1 manage 20.7 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng muon_eff_eta.png r1 manage 8.3 K 2016-03-21 - 21:55 ValentinaMariani  
PNGpng muon_eff_numvert.png r1 manage 10.3 K 2016-03-21 - 21:56 ValentinaMariani  
PNGpng muon_eff_phi.png r1 manage 7.6 K 2016-03-21 - 21:56 ValentinaMariani  
PNGpng rel_eff_barrel.png r1 manage 16.1 K 2016-03-21 - 21:56 ValentinaMariani  
PNGpng tagprobe_final.png r2 r1 manage 46.4 K 2016-03-24 - 16:57 ValentinaMariani  
PNGpng vertex_reso_y.png r1 manage 32.0 K 2016-03-21 - 21:56 ValentinaMariani  
PNGpng vertex_reso_z.png r1 manage 31.7 K 2016-03-21 - 21:56 ValentinaMariani  
PNGpng vertexreso_7_8_13_TeV.png r1 manage 66.2 K 2016-03-21 - 21:56 ValentinaMariani  
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Topic revision: r5 - 2016-04-04 - MarcoRovere
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