Tracking/Vertexing/BeamSpot/b-tag Results from First Collisions (TRK )

Transcription

1 Tracking/Vertexing/BeamSpot/b-tag Results from First Collisions (TRK-1-1) Yanyan Gao, Fermilab on behalf of Tracking-Btagging POGs 3 March 21 / CERN CMS General Weekly Meeting: GWM8

2 Contributors and Acknowledgement TRK-1-1 summarizes 1 analyses performed with Dec9 data by many people in Tracking/B-tagging POGs and Tracker DPG. List of the Contributors W. Adam, J. Bendavid, J. Bernardini, P. Bortignon, G. Bruno, K. Burkett, G. Cerati, S. Chauhan, T. Dorigo, B. Drell, F. Fiori, M. Galanti, Y. Gao, A. Giammanco, M. Gouzevitch, G. Hanson, G.-Y. Jeng, H. Liu, B. Mangano, M. Margoni, N. Marinelli, F. Palla, L. Perrozzi, G. Petrucciani, F. Ptohos, L. Quertenmont, A. Raspereza, A. Rizzi, F. Simonetto, G. Sguazzoni, C. Saout, L. Spiegel, K. Stenson, K. Ulmer, L. Uplegger, A. Venturi, J.-R. Vlimant, F. Yumiceva We would like to thank the ARC memembers James Alexander, Vyacheslav Krutelyov, Michele Pioppi for their help and support Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 2

3 Introduction and Documentation TRK-1-1 demonstrates tracking works in collision based on basic tracking/vertexing variables primary vertex resolution and beam spot reconstruction K S, Λ, φ, Ξ ±, and K (892) reconstruction K S and Λ lifetime measurements photon conversion and nuclear interaction reconstructions initial study of b-tagging observables Supporting Analysis Notes Tracking and Vertexing Results from First Collsisons: AN 21/55 de/dx measurement: AN 21/2 φ KK analysis: AN 21/35 Photon conversions: AN 21/39 Photon conversions (CTVMFT-based):AN 21/49 Material Budget estimate from photon conversions: AN 21/4 Dedicated Twiki: Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 3

4 Approval Talks 1. Tracking/Vertexing/BeamSpot/b-tag Results from First Collisions 2. K S, Λ,K ±, Ξ ±, φ resonances + de/dx applications 3. Conversions and Nuclear Interactions Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 4

5 Outline /MC Samples and Event Selections Tracking Reconstruction Primary Vertex Reconstruction and Resolution BeamSpot Reconstruction b-tag Related Variables Conclusion Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 5

6 /MC Samples and Event Selections /MC samples : /MinimumBias/BeamCommissioning9-BSCNOBEAMHALO-Dec19thSkim 336p3 v1/ 9Gev MC: /MinBias/Summer9-STARTUP3X V8K 9GeV-v1/ 236GeV MC: /MinBias/Summer9-STARTUP3X V8L 236GeV-v1/ Common Baseline Event Selections (Not strict) 1. Trigger: BPTX/BSC/No BeamHalo { & (4 41) &!(36-39)} 2. Run/Lumi: Select Tracker on and PhysicsDeclared Bit 3. Primary Vertex: At least 1 real primary vertex Primary vertex ndof>= 3 (equivalent to ntracks>= 4) Primary vertex z < 15 cm Primary vertex (x pvtx x bs ) 2 + (y pvtx y bs ) 2 < 2 cm 4. Fraction of highpurity tracks >.2 if ntracks>= 1 Selection efficiency on BSCNOBEAMHALO skim 85%, 26K events left Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 6

7 Basic Tracking Distributions

8 Basic Tracking Distributions (1/3) Study fundamental kinematic quantities of reconstructed track ntracks, Track η, Normalized χ 2, nhits, p T, φ, d xy and d z Addtional track selection to reject low p T fake tracks Select HighPurity Tracks dz significance: d z /σ < 1 (σ = σd 2 z + σz 2 pvtx) σp T /p T < 1% Selection variable distributions (NOT IN PAS) dz significance w.r.t. pvtx dz/σdz >1 dz/σdz < Track η σpt/pt<.1 σpt/pt> Track pt (GeV) The peak at η is mainly due to the loopers in the tracker Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 8

9 Basic Tracking Distributions (2/3) ntrack and η disagreement is due to imperfect D6T MC tuning This is also seen from underlying event studies (see PAS QCD-1-1 and backup slides) Number of Events CMS Preliminary s=9gev Monte Carlo / CMS Preliminary s=9gev Monte Carlo Track Pseudorapidity and the MC in general agree in the shape of all other variables. / CMS Preliminary s=9gev Monte Carlo Normalized χ CMS Preliminary s=9gev Monte Carlo Number of Valid Hits Per Track Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 9

10 Basic Tracking Distributions (3/3) Track p T and φ The dip at φ 1.2 is due to inactive modules affecting mainly low-p T tracks with few layers /.2 GeV/c 6 1 CMS Preliminary s=9gev Monte Carlo (GeV/c) p T / CMS Preliminary s=9gev Monte Carlo Track Azimuthal Angle Track impact parameters dxy and dz w.r.t. primary vertex /.5 cm CMS Preliminary s=9gev Monte Carlo /.1 cm CMS Preliminary s=9gev Monte Carlo Track dxy corrected by pvtx (cm) Track dz corrected by pvtx (cm) Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 1

11 Primary Vertex Reconstruction and Resolution

12 Primary Vertex Reconstruction Primary vertex efficiency ǫ 95% on BSCNOBEAMHALO skim Primary vertex 2D distributions Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 12

13 Primary Vertex Resolution (1/3) Primary vertex resolutions depend on ntracks used and their < p T > -driven two-vertex method to measure primary vertex resolution 1. Split tracks into two independent sets 2. Run PrimaryVertexProducer (offlineprimaryvertices) on each trackset 3. Compare the two fitted vertex positions and calculate - Resolution: σ of the gaussian fit to x 1 x Pull: σ of the gaussian fit to x 1 x 2 σx 2 1 +σx 2 2 Twiki: Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 13

14 Primary Vertex Resolution (2/3) Primary vertex resolution vs ntracks used in the pvtx Primary Vertex Resolution X (µm) CMS Preliminary, s=9gev Primary Vertex Resolution Y (µm) CMS Preliminary, s=9gev Primary Vertex Resolution Z (µm) CMS Preliminary, s=9gev Fitted pulls vs ntracks from the primary vertex distributions Primary Vertex Pull X CMS Preliminary, s=9gev Primary Vertex Pull Y CMS Preliminary, s=9gev Primary Vertex Pull Z CMS Preliminary, s=9gev Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 14

15 Primary Vertex Resolution (3/3) Primary vertex resolution vs ntracks for different average p T Primary Vertex Resolution X (µm) CMS Preliminary, s = 9 GeV <.4 GeV. GeV < P T <.8 GeV.4 GeV < P T < 1.2 GeV.8 GeV < P T Primary Vertex Resolution Y (µm) CMS Preliminary, s = 9 GeV <.4 GeV. GeV < P T <.8 GeV.4 GeV < P T < 1.2 GeV.8 GeV < P T Primary Vertex Resolution Z (µm) CMS Preliminary, s = 9 GeV <.4 GeV. GeV < P T <.8 GeV.4 GeV < P T < 1.2 GeV.8 GeV < P T Fitted pulls vs ntracks for different average p T Primary Vertex Pull X CMS Preliminary, s = 9 GeV <.4 GeV. GeV < P T <.8 GeV.4 GeV < P T < 1.2 GeV.8 GeV < P T Primary Vertex Pull Y CMS Preliminary, s = 9 GeV <.4 GeV. GeV < P T <.8 GeV.4 GeV < P T < 1.2 GeV.8 GeV < P T Primary Vertex Pull Z CMS Preliminary, s = 9 GeV <.4 GeV. GeV < P T <.8 GeV.4 GeV < P T < 1.2 GeV.8 GeV < P T Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 15

16 BeamSpot Reconstruction

17 BeamSpot Reconstruction Exploit d -φ correlation to fit BeamSpot (CMS Note 27/21) d (φ, z) = x sin φ + dx dz sin φ z y cos φ dy dz cos φ z d -φ for a displaced beamspot when (,) (left) and fitted BS are used (right) for a single run Beamwidth measured in 9(236)GeV σ x 2(12)µm, σ y 25(12)µm and σ z 4(2.8)cm Compare with results from the primary vertex distributions x (cm).125 CMS Preliminary PrimaryVertex Beam Spot y (cm).6 CMS Preliminary 29.5 PrimaryVertex Beam Spot z (cm) CMS Preliminary 29 PrimaryVertex Beam Spot (2.36 TeV) (2.36 TeV) Run (2.36 TeV) (2.36 TeV) Run (2.36 TeV) (2.36 TeV) Run Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 17

18 b-tag Related Variables

19 b-tag Related Variables Crucial at Higher s has few well-defined jets or tracks with P used in b-tag We validate the variables that are crucial for b-tag 3D impact parameter significance /MC match well, indicate data is udsg dominated Add more comments.. Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 19

20 SV Reconstruction Using All Tracks Secondary vertex reco. tested on all tracks and we reconstruct K S Inclusive secondary vertex finder works well on two-track vertices Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 2

21 SV Reconstruction Using Tracks in Jets ntracks (Left) and normalized χ 2 for vertices in jets Secondary vertex reconstruction has been performed with a slightly modified version of algorithm K S veto is applied L xy < 2.5cm and M Ks M vtx >.15GeV Secondary vertex 3D decay length (left) and vertex mass (right) Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 21

22 Conclusion We have studied the reconstructed tracks in the first data and observe agreement with simulation 1. Shape of fundamental track kinematics matches well 2. Primary vertex resolution measured with data-driven method σ x,y 5µm and σ z 7µm with ntracks(pvtx) > 1 3. BeamSpot reconstructed with d -φ fitter and with primary vertices 9(236) GeV : σ x 2(12)µm, σ y 25(12)µm and σ z 4(2.8)cm 4. b-tag related variables match well between data/mc Tracking impact parameter significance indicate 29 data is udsg-dominated Inclusive secondary vertex reconstructed tested in all tracks and K S is reconstructed Secondary vertex reconstruction using tracks in jets are tested with good data/mc agreement V, γ conversion and nuclear interaction results follow next Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 22

23 Supporting Material

24 Run/Lumi Selections Run LS ranges Triggered Events Selected Events Physics Declared Bit never set end Not available in December 19 th processing end end end end end end end Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 24

25 Compare with D6T/ProQ2 MC h GeVFeb9ReReco DT6V16D ProQ2V16D h1 Entries Mean.998 RMS h2 Entries Mean.152 RMS h3 Entries Mean.1364 RMS Track Pseudorapidity Similar disagreement seen in UE analysis (PAS QCD-1-1) No perfect tune to account for both disagreement yet

26 Basic Tracking Distributions In Pre-Approval (12/2) This version does not have the d z signifance and σp T /p T cut η peak is removed by d z signficance cut Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 26

27 Basic Tracking Distributions Normalized by nevents The excess in the tracks are not localized in any specific region Per Event / CMS Preliminary s=9gev Monte Carlo Track Pseudorapidity Per Event / CMS Preliminary s=9gev Monte Carlo Normalized χ 2 Per Event CMS Preliminary s=9gev Monte Carlo Number of Valid Hits Per Track Per Event / CMS Preliminary s=9gev Monte Carlo Track Azimuthal Angle Per Event /.5 cm 1.6 CMS Preliminary s=9gev Monte Carlo Track dxy corrected by pvtx (cm) Per Event /.1 cm CMS Preliminary s=9gev Monte Carlo Track dz corrected by pvtx (cm) Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 27

28 BeamSpot Positions Fit Results Fitted beamspot x and y (left) and z (right) by run Fitted beamspot x and y (left) and z (right) by fill Yanyan Gao, Fermilab Tracking/Vertexing/BeamSpot/b-tag Results from the First Collisions March 3, 21 Page 28