OVERVIEW OF SM/QCD PHYSICS AT ATLAS.

Transcription

1 OVERVIEW OF SM/QCD PHYSICS A. James Robinson on behalf of the Collaboration HEPMAD 6, Antananarivo, Madagascar 8th October 6

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3 he Large Hadron Collider LHCb p p ALICE CMS

4 he detector > General purpose detector - study proton collisions or heavy ions > Full cylindrical coverage around the interaction point J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page /

5 Proton-proton collisions at ] otal Integrated Luminosity [fb Online Luminosity LHC Delivered Recorded otal Delivered:.9 fb otal Recorded: 9.5 fb s = ev /4 8/5 5/6 /7 /8 7/9 5/ Day in 6 > Average number of interactions per event: 4 (5) (6) 7/6 calibration /.] Delivered Luminosity [pb > 4 million events per second > Use multi-level trigger system to reduce to O() Online, s= ev Ldt=.4 fb J.E.M. Robinson Overview of SM/QCD Physics Mean at Number 4//6 of Interactions Page per / Crossing 5: <µ> =.7 6: <µ> =. otal: <µ> =.4 7/6 calibration

6 Standard Model overview > Matter consists of quarks and leptons > Interactions between them occur via force carrying gauge bosons > Most recently Higgs boson discovered in by and CMS Collaborations; Hugely successful but unable to explain some phenomena J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 4/

7 Particle detection with J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 5/

8 Particle detection with Jet: (collimated particles from quark/gluon) energy deposits in both calorimeter systems J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 5/

9 Particle detection with Photon: energy clusters in EM calorimeter without matching track J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 5/

10 Particle detection with Electron: energy clusters in EM calorimeter with matching ID track J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 5/

11 Particle detection with Muon: matching tracks in the ID and muon tracker J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 5/

12 Particle detection with au: narrow jet with matching tracks J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 5/

13 Particle detection with ME: (missing transverse energy) p required to balance all observed objects J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 5/

14 Cross section and luminosity > Cross section quantifies probability that colliding particles will interact > Units of area analogous to classical geometric cross section > L int = N/σ is a measure of the amount of data collected J.E.M. Robinson Overview of SM/QCD Physics at 4//6 Page 6/

15 Introduction to the Standard Model

16 he importance of QCD J.E.M. Robinson Introduction to the Standard Model 4//6 Page 7/

17 he importance of QCD Hard-scatter J.E.M. Robinson Introduction to the Standard Model 4//6 Page 7/

18 he importance of QCD Hadronisation modelling Hard-scatter J.E.M. Robinson Introduction to the Standard Model 4//6 Page 7/

19 he importance of QCD Hadronisation modelling Hard-scatter Beam-remnants, primordial k J.E.M. Robinson Introduction to the Standard Model 4//6 Page 7/

20 he importance of QCD Hadronisation modelling Parton-shower (initial- and final-state radiation) Hard-scatter Beam-remnants, primordial k J.E.M. Robinson Introduction to the Standard Model 4//6 Page 7/

21 he importance of QCD Hadronisation modelling Parton-shower (initial- and final-state radiation) Hard-scatter Beam-remnants, primordial k Multiple-parton interactions, underlying event J.E.M. Robinson Introduction to the Standard Model 4//6 Page 7/

22 he importance of QCD Hadronisation modelling Parton-shower (initial- and final-state radiation) Hard-scatter Beam-remnants, primordial k Multiple-parton interactions, underlying event QCD (strong interaction) involved at many scales in each event J.E.M. Robinson Introduction to the Standard Model 4//6 Page 7/

23 Why make Standard Model measurements? > Accurate QCD predictions are crucial: Multiple different scales in the same event topology est predictions in unprobed phase space and kinematic regimes Understanding of dominant backgrounds for BSM searches > Constraints on models Inputs for parton distribution functions (PDFs) Information for further tuning of tools such as MC generators > Measure fundamental SM parameters: New measurements can improve on current precision Sensitivity to SM processes that have not yet been observed Need to understand the SM before extending knowledge beyond it J.E.M. Robinson Introduction to the Standard Model 4//6 Page 8/

24 Different aspects of the Standard Model Personal choice of what to show: full list of results here > Soft QCD inelastic cross section, elastic/total cross section, low p minimum bias, underlying event > PDF constraints inclusive jet, multijet, W/Z cross sections and ratios, high-mass Drell-Yan and prompt photon > Constraints on perturbative QCD Z+jets, DPI in 4-jet events, b b cross section, charged particles inside jets, Zϕ, W angular distributions > Electroweak sector diboson cross sections, Z+photons > op physics Covered in Kevin s talk J.E.M. Robinson Introduction to the Standard Model 4//6 Page 9/

25 Soft QCD

26 Inelastic pp cross section at ev arxiv:66.65 > Non-perturbative QCD cannot be calculated > rigger with scintillating counters > Select events with ξ > M X /s > 6 dn events dn MBS n events Data Pythia8 SS Pythia8 DL, ε =.6 Pythia8 DL, ε =.85 Pythia8 DL, EPOS LHC =. ε MBR QGSJE-II [mb] σ inel (MBS) (ALFA) OEM ALICE LHCb Auger pp (non-lhc) pp Pythia 8 EPOS LHC QGSJE-II MC/data.5 ev, 6. µb Inclusive selection LHC region n MBS 4 s [GeV] > Constrain extrapolation using previous measurements at 7 ev J.E.M. Robinson Soft QCD 4//6 Page /

27 otal and elastic pp cross sections at 8 ev PLB (6) 58 > Detect small-angle elastic scatters with ALFA detector > Measure in terms of momentum transfer t = [ (θ x ) + (θ y ) ] p ] [mb/gev /dt dσ el data Elastic fit s=8 ev, 5µb σ [mb] > σ tot = 4π Im [ f el ( t )] 5 5 OEM Lower energy Lower energy Cosmic rays pp pp COMPEE HPRR ln(s) +.4 ln (s) (Fit-data)/data otal error Statistical t [GeV ] (b) 5 σ tot σ el (a) 4 s [GeV] J.E.M. Robinson Soft QCD 4//6 Page /

28 rack-based minimum bias at ev PLB (6) 758, EPJC 76 (6) 5 > Charged particle distributions test non-perturbative models / dn ch ev dn /N ev MC / Data n ch, p > 5 MeV, η <.8 τ > ps s = ev Data PYHIA 8 A PYHIA 8 Monash EPOS LHC QGSJE II n ch > Compare various generators/models η <. / dη ch dn /N ev p Data PYHIA8 A PYHIA8 Monash EPOS LHC QGSJE II-4 > MeV, n ch p p > 5 MeV, n ch > 5 MeV, n ch 4 6 τ > ps (extrapolated) s [GeV] > Agreement across range of energies J.E.M. Robinson Soft QCD 4//6 Page /

29 Underlying event ev AL-PHYS-PUB-5-9 > Any hadronic activity not associated to hard scatter > Measure in azimuthal regions wrt reference object /dη dφ> [GeV] Σ p <d MC/Data.5 ransverse region Preliminary p lead p >.5 GeV, η <.5 > GeV DAA (uncorrected) PYHIA 8 A4 HERWIG++ EE5 s = ev EPOS PYHIA 8 A PYHIA 8 Monash plead [GeV] > ransverse region has best distinguishing power J.E.M. Robinson Soft QCD 4//6 Page /

30 PDF constraints

31 Inclusive jet cross section at ev [pb/gev] dy σ/dp d anti-k t jets, R=.4 ev,. fb Systematic uncertainties NLOJE++ (C4nlo) Non-pert. corr. EW corr. Relative uncertainty of.% on the integrated luminosity not included > Compare to fixed-order NLO calculations Preliminary y <.5 ( ) y <. ( y <.5 ( y <. ( y <.5 ( y <. ( - ) -6 ) -9 ) ) 5 ) p [GeV] > Data/theory agreement within uncertainties for most PDF sets heory / data heory / data y <.5 y <. y <.5 y <.5 y <. y <.5 p [GeV] heory / data heory / data y <.. y <.5.5 y < y <.. y <.5.5 y <. -CONF-6-9 Preliminary s L dt =. fb = ev anti-k t jets, Data NLOJE++ max µ = µ = p F R Non-pert and EW corr. C4 R=.4 MMH 4 NNPDF. p [GeV] Preliminary s L dt =. fb = ev anti-k t jets, Data NLOJE++ max µ = µ = p F R Non-pert and EW corr.. HERAPDF..8 ABM n f = 5 p [GeV] p [GeV] J.E.M. Robinson PDF constraints 4//6 Page 4/ C R=.4

32 Multijet cross sections at 8 ev JHEP (5) 5 () ) [fb/gev] dσ / d(p s=8 ev, 95 pb. fb Data Pythia 8 (.6) Herwig++ (.4) MadGraph+Pythia (.) () ) [fb/gev] dσ / d(p s=8 ev, 95 pb. fb Data HEJ (.9) BlackHat/Sherpa (.) NJet/Sherpa (.) () p > GeV () p > GeV 4 4 heory/data.5.5 () p [GeV] otal experimental systematic uncertainty heory/data.5.5 () p [GeV] > NLO predictions generally describe data better than LO otal experimental systematic uncertainty NLO (scale PDF) uncertainty min /m 4j ) [fb/bin width] j dσ / d(m 9 s=8 ev, 95 pb. fb mmin j /m 4j heory/data heory/data heory/data heory/data mmin j /m 4j > m min j /m 4j probes range of scales in the event Data HEJ (.9) BlackHat/Sherpa (.) NJet/Sherpa (.) m 4j>5 GeV m 4j> GeV m 4j>5 GeV m 4j> GeV otal experimental systematic uncertainty NLO (scale PDF) uncertainty J.E.M. Robinson PDF constraints 4//6 Page 5/

33 W and Z cross sections at ev PLB 759 (6) 6 > Agreement with NNLO QCD + NLO EW > Uncertainties cancel in ratio fid /σ meas ) pred (σ ev, 8 pb - W + W luminosity experimental uncertainties experimental uncertainties ± W Z MMH4nnlo68CL NNPDF. C4nnlo ABM -epwznnlo HERAPDF.nnlo (inner uncert.: PDF only) ev, 8 pb R W + /W - = σ fid / σ fid + - W W data ± total uncertainty data ± stat. uncertainty ABM C4nnlo NNPDF. MMH4nnlo68CL -epwznnlo HERAPDF.nnlo / σ fid σ + W fid - W > W+/W- sensitive to u and d PDF differences at low x > W/Z can constrain strange-quark sea J.E.M. Robinson PDF constraints 4//6 Page 6/

34 High-mass Drell-Yan ev JHEP 8 (6) 9 > Off-shell measurements dominated by coupling to γ (sensitive to new physics) [pb/gev] dσ dm ll s = 8 ev,. fb MMH4 with 68% CL (PDF + α s ) + scale + PI unc. Data Sys. uncertainty otal uncertainty w/o luminosity uncer. > PI process (γγ ll) significant at large m ll > Sensitivity to PI corrections x γ(x,q ). 4 Q = GeV NNPDF.qed 68% CL NNPDF.qed + high mass DY data.8 MRS4qed, current quark mass MRS4qed, constituent quark mass C4qed 68% CL.6 heory/data heory/data.5 MMH4 w/o PI corrections.95. MMH4.9 6 HERAPDF. C4 ABM NNPDF. [GeV] m ll m ll [GeV].4. Parton momentum fraction x > Data significantly constrains photon PDF J.E.M. Robinson PDF constraints 4//6 Page 7/

35 Inclusive isolated prompt photon cross section at 8 ev JHEP 6 (6) 5 > Experimental uncertainty generally smaller than the theoretical one -5 > Improved phase-space -6-7 Data -8 coverage and precision -9 s = 8 ev,. fb compared to previous 4 measurements γ [GeV] Systematic Unc γ [GeV] E Statistical Unc [pb/gev] γ dσ / de γ [GeV] E η γ <.6 (x ) -.6 η γ <.7 (x ) η γ <.8 (x ) -6.8 η γ <.7 (x ) NLO: JEPHOX C E γ 88nb η <.6 γ 5pb η <.6 γ 4.6fb η <.7 γ.fb η <.6 J.E.M. Robinson PDF constraints 4//6 Page 8/

36 Constraints on perturbative QCD

37 Z+jets cross sections at ev -CONF-6-46 > BLACKHA (fixed-order NLO) good for distributions sensitive to single jet > ALPGEN and MADGRAPH CKKW (LO ME+PS) model too hard a jet spectrum > SHERPA and MADGRAPH FxFx (NLO ME+PS) improve this > Recent N jetti (NNLO) describes jet p and H well [pb] jet dσ/d y Pred./Data Pred./Data Pred./Data Preliminary ev,.6 fb anti-k t jets, R =.4 jet jet p > GeV, y <.5 + Z/γ *( l l ) + jet Data Z + jet N NNLO jetti BLACKHA + SHERPA SHERPA. ALPGEN + PY6 MG5_aMC+ PY8 CKKWL MG5_aMC+ PY8 FxFx jet y (leading jet) jet y (leading jet) J.E.M. Robinson Constraints on perturbative QCD 4//6 Page 9/

38 DPI in 4-jet events at 7 ev (to JHEP) arxiv: Entries/.5 Fit/Data > Extract complete-dps and semi-dps components with neural network 5 4 s = 7 ev, 7 pb. ξ sdps < ξ ξ sdps cdps ξ + ξ sdps cdps Experiment (energy, final state, year) ( s = 7 ev, 4 jets, 6) CDF ( s =.8 ev, 4 jets, 99) UA ( s = 6 GeV, 4 jets, 99) AFS ( s = 6 GeV, 4 jets, 986) DØ ( s =.96 ev, γ+ jets, 6) DØ ( s =.96 ev, γ+ jets, 4) DØ ( s =.96 ev, γ+ b/c + jets, 4) DØ ( s =.96 ev, γ+ jets, ) CDF ( s =.8 ev, γ+ jets, 997) ( s = 8 ev, Z + J/ψ, 5) CMS ( s = 7 ev, W + jets, 4) ( s = 7 ev, W + jets, ) DØ ( s =.96 ev, J/ψ + Υ, 6) LHCb ( s = 7&8 ev, Υ(S)D,+, 5) DØ ( s =.96 ev, J/ψ + J/ψ, 4) LHCb ( s = 7 ev, J/ψΛ + c, ) LHCb ( s = 7 ev, J/ψD + s, ) LHCb ( s = 7 ev, J/ψD +, ) LHCb ( s = 7 ev, J/ψD, ) [mb] σ eff > Compatible with model of σ eff as process-independent J.E.M. Robinson Constraints on perturbative QCD 4//6 Page /

39 Charged particle multiplicity in jets at 7 ev EPJC 76(6) (6) - forward - n charged > Dijet topology: p /p <.5 > Ghost matching associates tracks to jets central charged n - s = 8 ev, L =. fb int track p >.5 GeV Data (with stat. uncertainty) Data stat. syst. uncert. Pythia 8.75 AU C Pythia 8.86 A4 NNPDF. Herwig++.7. EE5 CEQ6L 5 5 Jet p [GeV] charged n Data/Model s = 8 ev track p > GeV jet η <. L dt =. fb Data Data (with stat. uncertainty) stat. syst. uncert. Herwig++.6. EE CEQ6L Herwig++.7. EE5 CEQ6L Pythia 8.75 AU C Pythia 8.86 A4 NNPDF. Pythia 8.86 Monash NNPDF. Pythia 6.48 P CEQ6L Pythia 6.48 P RadHi Pythia 6.48 P RadLo Jet p [GeV] > Input for MC tuning J.E.M. Robinson Constraints on perturbative QCD 4//6 Page /

40 σ b b cross section at 7 ev arxiv:67.84 ± χ P > Extract b b with template fit P POWHEG+PYHIA 6 MC@NLO+HERWIG 6 σ P SHERPA.4 > Flavour creation dominates over gluon splitting at R π > Modelling is worst for low b-jet p J.E.M. Robinson Constraints on perturbative QCD 4//6 Page /

41 Z/γ ϕ η at ev EPJC 76(5) (6) -6 /σ dσ/dφ* ϕ = tan ( ) π ϕ sin ( θη ) > Only depends on angles between leptons η Channel Combined Pull [σ] s = 8 ev,. fb 46 GeV m ll < 66 GeV, y <.4 ll ee-channel µµ-channel Combined Statistical uncertainty otal uncertainty χ /NDF = 54 / 6 - φ* η > Correlated with p Z /M ll cos ( θη ) ( ) = tanh η + η Monte Carlo / Data /σ dσ/dφ* η GeV m ll < 66 GeV, y <.4 ll - 66 GeV m ll < 6 GeV, y <.4 ll - 6 GeV m ll < 5 GeV, y <.4 ll - Data - statistical uncertainty Data - total uncertainty S HERPA POWHEGPYHIA (AU) POWHEGPYHIA (AZNLO) POWHEGHERWIG s = 8 ev,. fb φ* η φ* φ* > Best agreement at low mass J.E.M. Robinson Constraints on perturbative QCD 4//6 Page / η η

42 W-boson angular distributions at 8 ev arxiv: dσ/d( R) [fb] Pred./Data Pred./Data 8 6 s = 8 ev,. fb Data ALPGEN+PYHIA6 W+jets Leading Jet p > 5 GeV PYHIA8 W+j & jj+weak shower 4 SHERPA+OpenLoops W+j & W+jj W + jet N NNLO jetti R(µ, closest jet) > W µν plus at least one jet > NLO QCD+EW prediction from SHERPA +OPENLOOPS > NNLO calculation of W+ jet from N jetti implications for processes with real W emission J.E.M. Robinson Constraints on perturbative QCD 4//6 Page 4/

43 Electroweak physics

44 WW cross section at ev -CONF-6-9 > Measurement in the eµ decay channel Preliminary s = ev,.6 fb Events / 5 GeV 5 5 Preliminary s = ev,.6 fb WW e ± νµ ± ν, SR Data SM (sys stat) WW op Quark Drell Yan W+jets Diboson nnnlo+h calculation (fixed order acceptance) nnnlo+h calculation (MC acceptance) WW e ± ν µ ν Fiducial cross section ± Data / SM Leading lepton p > Suppress top background with b-jet veto [GeV] Data 59 ± ± 5 ± fb stat. stat.+syst.+lumi WW [fb] σ fid > Good agreement with NNLO theoretical prediction J.E.M. Robinson Electroweak physics 4//6 Page 5/

45 WZ cross sections at ev PLB 76 (6) ; -CONF-6-4 [fb] fid. σ Ratio to Powheg 5 4 Data Powheg+Pythia Sherpa ± W Z l νll s = ev,. fb > Final states with three e/µ > Fiducial cross sections differential in p and mass combined fid. theory σ ± / σ ± W Z W Z 4 N jets J.E.M. Robinson Electroweak physics 4//6 Page 6/ eee µee eµµ µµµ.6 ±. ±.8 ±.9 ±.4 ± Preliminary s = ev,. fb ± W Z > Small excess wrt. NLO POWHEG +PYHIA Data Powheg+Pythia C

46 ZZ cross section at ev PRL 6, 8 (6) > ZZ 4l gives a clean signal (stats dominated) pp ZZ 4l Fiducial 4e eµ 4µ Combined s = ev,. fb Measurement ot. uncertainty Stat. uncertainty α s prediction ± σ ± σ heory: PLB 75 (5) 47 C NNLO σ data /σ theory [pb] tot σ ZZ LHC Data 5 ( s= ev) ZZ llll (m 666 GeV). fb ll LHC Data ( s=8 ev) CMS ZZ llll (m 666 GeV) 9.6 fb ll LHC Data ( s=7 ev) ZZ ll(ll/νν) (m 666 GeV) 4.6 fb ll CMS ZZ llll (m 6 GeV) 5. fb ll evatron Data ( s=.96 ev) CDF ZZ ll(ll/νν) (on-shell) 9.7 fb D ZZ ll(ll/νν) (m 6 GeV) 8.6 fb ll MCFM, C4 NLO ZZ (pp) ZZ (pp) s [ev] > Fiducial and total cross sections agree well with NLO prediction from MCFM J.E.M. Robinson Electroweak physics 4//6 Page 7/

47 γ Zγ and Zγγ production at 8 ev PRD 9, (6) > Z ll (including neutrinos) > ISR/FSR plus triple/quartic couplings [fb/gev] γ) - l + - l + dσ(pp l dm l heory Data s = 8 ev,. fb N jets + - l l γ channel Data Sherpa (C) MCFM (C) NNLO (MMH4) m + - l l γ [GeV] ] -4 [ev 4 f M/Λ Allowed ννγγ, µµγγ and eeγγ channels Data observed MC expected ± σ ± σ Unitarity bounds s=8 ev,. fb [ev] Λ FF > Limits on BSM form-factors of anomalous couplings > No deviations from SM expectations seen J.E.M. Robinson Electroweak physics 4//6 Page 8/

48 Conclusions

49 Standard Model measurements at Standard Model Production Cross Section Measurements Status: August 6 pp t t p> GeV Ldt [fb ] Reference 8 5 arxiv: Nucl. Phys. B, (4) Jets R=.4.<p< ev 4.5 JHEP, 5 (5) Dijets R=.4.<mjj< 5 ev 4.5 JHEP 5, 59 (4) p>5 GeV γ. arxiv: [hep-ex] 4.6 PRD 89, 54 (4) W.8 PLB 759 (6) 6.5 PRD 85, 74 () Z. -CONF PRD 85, 74 (). arxiv: [hep-ex]. EPJC 74: 9 (4) 4.6 EPJC 74: 9 (4). -CONF-5-79 tt chan. -CONF-4-7 heory 4.6 PRD 9, 6 (4). -CONF-6-9 WW LHC pp s = 7 ev. CERN-EP-686 γγ PRD 87, () JHEP, 86 () Data. -CONF-6-65 stat Wt stat syst. JHEP, 64 (6) LHC pp s = 8 ev. PLB 76, 459 (). arxiv:66.47 [hep-ex] WZ. PRD 9, 94 (6) Data 4.6 EPJC 7, 7 () stat. PRL 6, 8 (6) ZZ stat syst. -CONF-- LHC pp s = ev 4.6 JHEP, 8 () ts chan. PLB 756, 8-46 (6) Data Wγ 4.6 PRD 87, () arxiv:47.68 [hep-ph] PRD 9, (6). arxiv:47.68 [hep-ph] stat stat syst Zγ 4.6 PRD 87, () arxiv:47.68 [hep-ph] t tw. -CONF-6-. JHEP, 7 (5) t tz. -CONF-6-. JHEP, 7 (5) t tγ Preliminary 4.6 PRD 9, 77 (5) ZjjEWK Wγγ. JHEP 4, (4) Run, s = 7, 8, ev. PRD 9, (6). PRL 5, 8 (5) W ± W ± jjewk. PRL, 48 (4) WZjjEWK. PRD 9, 94 (6) σ [pb] data/theory Agreement with predictions over 5 orders of magnitude! J.E.M. Robinson Conclusions 4//6 Page 9/

50 Summary > Numerous SM measurements performed by (only a selection shown here) > Uncertainties and correlations propagated throughout > data provide constraints on PDF and theoretical models > No significant discrepancies from SM seen More measurements to come! J.E.M. Robinson Conclusions 4//6 Page /

51 Backup

52 coordinates > uses a right-handed coordinate system > he origin is at the nominal interaction point and the z-axis along the beam pipe > he x-axis points from the IP to the centre of the LHC ring, and the y-axis points upward. > Cylindrical coordinates (r, ϕ) are used in the transverse plane, ϕ being the azimuthal angle around the beam pipe > he pseudorapidity is defined in terms of the polar angle θ as η = ln tan (θ/). J.E.M. Robinson Backup 4//6 Page /

53 Detector performance Detector component Resolution η coverage racking σ p /p.5%p % η < ±.5 EM calorimeters σ E /E % E.7% η < ±. Hadronic calorimeters barrel and end-cap σ E /E 5% E % η < ±.7 forward σ E /E % E %. < η < 4.9 Muon spectrometer σ p /p % at p = ev η < ±.7 NB. Energy and transverse momentum in GeV J.E.M. Robinson Backup 4//6 Page /

54 Jet calibration in Jet reconstruction jet constituents jets Simulated particles racks Calorimeter clusters (EM scale) Local cluster weighting Jet finding Jet finding Jet finding Calorimeter clusters (LCW scale) Jet finding Particle jets (aka truth jets) rack jets Calorimeter jets (EM scale) Calorimeter jets (LCW scale) Jet: collimated flow of particles originating from a quark or a gluon Jet calibration Calibrates clusters based on cluster properties related to shower development Calorimeter jets (EM or LCW scale) Pile-up offset correction Origin correction Energy &! calibration Residual in situ calibration Calorimeter jets (EM+JES or LCW+JES scale) Corrects for the energy offset introduced by pile-up. Depends on µ and NPV. Derived from MC. Changes the jet direction to point to the primary vertex. Does not affect the energy. Calibrates the jet energy and pseudorapidity to the particle jet scale. Derived from MC. Residual calibration derived using in situ measurements. Derived in data and MC. Applied only to data. Dag Gillberg, Carleton Jet calibration schemes J.E.M. Robinson Backup 4//6-9-5 Page / 6

55 Data correction to particle level > Measurements corrected back to particle level using a matrix-based method transfer matrix relating particle level to reconstructed observable determine shape uncertainty in-situ: exploits data/reco MC (perform for several unfolding methods; choose most precise) > Full propagation of uncertainties and correlations: statistical uncertainty (data and MC) using pseudo-experiments (bootstrap method tracks correlations with other measurements) systematic uncertainties using nuisance parameters (asymmetric uncertainties taken into account) J.E.M. Robinson Backup 4//6 Page 4/

56 Inelastic pp cross section at ev arxiv:66.65 R SS Data 5 Pythia8 SS Pythia8 DL, ε=.85 Pythia8 DL, ε=.6 Pythia8 DL, ε=. Pythia8 MBR EPOS LHC QGSJE-II s= ev, L=6. µb f D > σ fid ( ξ > 6 ) = N N bkg ϵ trig L f ξ> 6 ϵ sel > Diffractive fraction impacts f ξ> 6 J.E.M. Robinson Backup 4//6 Page 5/

57 otal and elastic pp cross sections at 8 ev PLB (6) 58 x(7 m) C-Side [mm] ] - [GeV dn/dt s=8 ev, 5 µb x(7 m) A-side [mm] s=8 ev, 5 µb (a) Data arm t [GeV ] (b) Antigolden background DPE background σ tot = 6π( hc) Acceptance Relative error Relative error dσ el +ρ dt t= Arm Arm Simulation s=8 ev Arm otal Statistical -t [GeV ] Arm otal Statistical -t [GeV ] t [GeV ] J.E.M. Robinson Backup 4//6 Page 6/

58 rack-based minimum bias at ev PLB (6) 758, EPJC 76 (6) 5 Observables measured > Charged particles with a mean lifetime τ > ps > N ev dn ch dη, πp N ev d N ch dη dp, N ev dn ev dn ch, p vs.n ch Monte Carlo predictions in order of agreement to data EPOS: parton-based Gribov-Regge theory (QCD-inspired EF) Pythia: separation into non-diffractive and diffractive (involving colour-singlet) QGSJE-II: Reggeon field theory with semi-hard pomerons J.E.M. Robinson Backup 4//6 Page 7/

59 Underlying event ev AL-PHYS-PUB-5-9 /dη d φ > [GeV] Σ p <d MC/Data MC/Data p >.5 GeV, η <.5 DAA (uncorrected) PYHIA 8 A4 HERWIG++ EE5 lead p lead p > 5 GeV > GeV Preliminary s = ev EPOS PYHIA 8 A PYHIA 8 Monash toward transverse away lead p lead p > 5 GeV > GeV φ φ [rad] > Use tracks with p >.5 GeV and η <.5 > None of the models are very discrepant from data, building confidence in MPI energy extrapolation model J.E.M. Robinson Backup 4//6 Page 8/

60 Inclusive jet cross section at ev -CONF-6-9 > Jet reconstruction with anti-k t R =.4 > Double differential cross sections as a function of jet p and y > he NLO pqcd predictions calculated with NLOJE interfaced to APPLGRID > Renormalisation and factorisation scale uncertainties > Appropriate PDF uncertainties depending on which set is used Systematic Uncertainty (relative to nominal) JES + JER JES JER. < y <.5 Preliminary p [GeV] Systematic Uncertainty (relative to nominal) JES + JER JES JER.5 < y <. Preliminary.6 p [GeV] J.E.M. Robinson Backup 4//6 Page 9/

61 Multijet cross sections at 8 ev JHEP (5) 5 > At least four anti-k t R =.4 jets with y <.8 and p > 64 GeV > No explicit subtraction of DPI (expected to be %) > HEJ, NJE/SHERPA and BLACKHA/SHERPA describe leading jets > As well as these, MADGRAPH +PYHIA describes variables sensitive to wide-angle gluon radiation > HEJ performs worst for rapidity measurements at low p J.E.M. Robinson Backup 4//6 Page /

62 ± ± W and Z cross sections at ev PLB 759 (6) 6 Entries / GeV 5 5 W eν ev, 8 pb Data MC Stat. Syst. Unc. W eν Multijet + - Z e e W τν Entries / GeV 5 Data MC Stat. Syst. Unc. - 4 Z µ + µ Diboson - Z τ + τ op quarks + - Z µ µ ev, 8 pb 5 Other backgrounds Data / Pred m [GeV] Data / Pred m µµ [GeV] µν / σ W.5 ev, 8 pb 68% CL ellipse area ev, 8 pb R = σ fid / σ fid W/Z ± W Z eν R W = σ W.95 Data R W PDG average R Z PDG average Standard Model data ± data ± total uncertainty stat. uncertainty ABM C4nnlo NNPDF. MMH4nnlo68CL -epwznnlo HERAPDF.nnlo R Z = σ - Z e / σ + Z µ + - e µ σ fid / σz fid ± W J.E.M. Robinson Backup 4//6 Page /

63 High-mass Drell-Yan ev JHEP 8 (6) 9 Entries Data/Exp. 4 Data s = 8 ev,. fb Z/γ* tt & Wt m ee > GeV Multijet & W+Jets Diboson Photon induced heory/data s = 8 ev,. fb MMH4 with 68% CL (PDF + α s ) + scale + PI unc. MMH4 w/o PI corrections 6 GeV < m < 5 GeV. ll.9 5 GeV < m < GeV. ll.9 heory/data..9. HERAPDF. C4 ABM NNPDF..9 6 GeV < m ll 5 GeV < m ll < 5 GeV Data Sys. uncertainty otal uncertainty w/o luminosity uncer. < GeV y ll e E [GeV] GeV < m < GeV. ll. GeV < m ll < GeV y ll Entries 4 Data s = 8 ev,. fb Z/γ* tt & Wt m µ > GeV Diboson Multijet & W+Jets Photon induced.9 GeV < m ll < 5 GeV GeV < m ll < 5 GeV y ll Data/Exp µ p [GeV] GeV < m ll < 5 GeV y ll GeV < m ll < 5 GeV y ll y ll J.E.M. Robinson Backup 4//6 Page /

64 Inclusive isolated prompt photon cross section at 8 ev JHEP 6 (6) 5 > Photons with E γ > 5 GeV and η γ <.7 (except crack region) > PEER (NLO+NNNLL) predictions agree much better than JEPHOX (NLO) Systematic Unc. Systematic Unc η γ <.6 γ E [GeV].56 η γ <.8 γ E [GeV] Systematic Unc. Systematic Unc η γ <.7 γ E [GeV].8 η γ <.7 γ E [GeV] s = 8 ev,. fb Data Lumi Uncert. Systematic Unc.: Combined Energy Scale Admixture R bkg heory / Data heory / Data.5.4. η γ < γ E [GeV] η γ < γ E [GeV] heory / Data heory / Data η γ < γ E [GeV] η γ < γ E [GeV] s = 8 ev,. fb Data η γ <.6.6 η γ <.7.56 η γ <.8.8 η γ <.7 Lumi Uncert. NLO: JEPHOX C LO: PYHIA SHERPA heory / Data heory / Data.5.4. η γ < γ E [GeV] η γ < γ E [GeV] heory / Data heory / Data η γ < γ E [GeV] η γ < γ E [GeV] s = 8 ev,. fb Data η γ <.6.6 η γ <.7.56 η γ <.8.8 η γ <.7 Lumi Uncert. NLO: PEER C JEPHOX C J.E.M. Robinson Backup 4//6 Page /

65 Z+jets cross sections at ev -CONF-6-46 ) [pb] σ(z/γ*+n jets Preliminary ev,.6 fb anti-k t jets, R =.4 jet p jet > GeV, y.5 < + Z/γ *( l l ) + jets Data BLACKHA + SHERPA SHERPA. ALPGEN + PY6 MG5_aMC+ PY8 CKKWL MG5_aMC+ PY8 FxFx [pb/gev] jet dσ/dp Preliminary ev,.6 fb anti-k t jets, R =.4 jet p jet > GeV, y.5 < + Z/γ *( l l ) + jet Data BLACKHA + SHERPA SHERPA. ALPGEN + PY6 MG5_aMC+ PY8 CKKWL MG5_aMC+ PY8 FxFx - - Pred./Data Pred./Data Pred./Data N jets N jets Pred./Data Pred./Data Pred./Data jet p [GeV] jet p [GeV] jet p [GeV] jet p [GeV] J.E.M. Robinson Backup 4//6 Page 4/

66 DPI in 4-jet events at 7 ev (to JHEP) arxiv: sdps ξ.8 SPS (AHJ) Anti-k t jets, R =.6 simulation p 4.5 GeV,,4 s = 7 ev p GeV η 4.4,,,4.. sdps ξ.8 cdps (data, overlay) Anti-k t jets, R =.6 p 4.5 GeV,,4 s = 7 ev p GeV η 4.4,,, sdps ξ.8 sdps (data, overlay) Anti-k t jets, R =.6 p 4.5 GeV,,4 s = 7 ev p GeV η 4.4,,, Entries/ GeV ξ + ξ sdps cdps p p 4 p p Data Anti-k t s jets, R =.6 p 4.5 GeV,,4 p GeV η 4.4,,,4 = 7 ev, 7 pb ξ + ξ ξ + ξ sdps cdps sdps cdps > Jets with anti-k t R =.6 > p > GeV 4 p [GeV] J.E.M. Robinson Backup 4//6 Page 5/

67 Charged particle multiplicity in jets at 7 ev EPJC 76(6) (6) - > Jets with anti-k t R =.4 > η <., p > 5 GeV dn dn track N.. s = 8 ev, L int =. fb Data Pythia 8.75 C AU Herwig++.6 CEQ6L EE 5 GeV < p < GeV GeV < p < GeV ev < p <. ev Fractions > racks with η <.5 > p > 5 MeV.5 Simulation s = 8 ev Pythia 8.75 C central forward fraction gluon - fraction gluon forward fraction gluon central fraction gluon n track 5 5 Jet p [GeV] J.E.M. Robinson Backup 4//6 Page 6/

68 b b cross section at 7 ev arxiv:67.84 Relative Systematic Uncertainty Definition Particle-level jets Detector-level jets Jet identification anti-k t with R =.4 anti-k t with R =.4 include muons and neutrinos b-jets definition b-hadron with p > 5 GeV log (p b /p l ) >.5 R (jet;b-hadron). Event selection Leading jet p > 7 GeV and η <. b-jets selection p > GeV and η <.5 b-jets separated by R >.4 otal Systematic Uncertainty Jet Angular Resolution b-agging fficiency Luminosity Jet Energy Resolution Jet Energy Scale emplate it Unfolding φ [rad] bb g g (a) flavour creation (s-channel) g g (c) gluon splitting b b b b g g g (b) flavour creation (t-channel) g g (d) flavour excitation J.E.M. Robinson Backup 4//6 Page 7/ b b b b g

69 Z/γ ϕ η at ev EPJC 76(5) (6) -6 Events / GeV [%] ll Uncertainty on /σ dσ/dp p > GeV, η <.4 Data Z ee γ γ µµ/ee multi-jet Z τ τ WW, WZ, ZZ W l t t s=8 ev,. fb m ll [GeV] ee-channel 66 GeV m ll < 6 GeV, y <.4 ll Data statistics Detector Background Model otal systematic ν + Single top s=8 ev,. fb ee-channel Particle-level definitions (reatment of final-state photon radiation) electron pairs dressed; Born muon pairs bare; dressed; Born combined Born Fiducial region Leptons p > GeV and η <.4 Lepton pairs yll <.4 Mass and rapidity regions 46GeV < mll < 66GeV yll <.8;.8 < yll <.6;.6 < yll <.4 (φ η measurements only) yll <.4 66GeV < mll < 6GeV yll <.4;.4 < yll <.8;.8 < yll <.;. < yll <.6;.6 < yll <.;. < yll <.4; yll <.4 6GeV < mll < 5GeV yll <.8;.8 < yll <.6;.6 < yll <.4 (φ η measurements only) Very-low mass regions GeV < mll < GeV GeV < mll < GeV GeV < mll < 46GeV yll <.4 } yll <.4, p ll > 45GeV, pll measurements only ll p [GeV] J.E.M. Robinson Backup 4//6 Page 8/

70 W-boson angular distributions at 8 ev arxiv: Data/MC Events /.48 Data/MC Events /. 5 s = 8 ev,. fb Data W+jets (ALPGEN.7) tt Multijets Z+jets Diboson Leading Jet p > 5 GeV s = 8 ev,. fb Data 7 W+jets (ALPGEN.7) tt 6 Multijets Z+jets Diboson R(µ, closest jet) Leading Jet p > 5 GeV φ jw > At least one jet with p > 5 GeV, exactly one muon, no b-tagged jets and no electrons Systematic Source. < R <.4 R >.4 Inclusive Scaling of dijets to data.4%.%.% Scaling of t t to data.6%.%.5% Scaling of Z + jets to data.6%.%.5% Jet energy scale 4.6% 5.8% 5.% b-tagging efficiency.7%.%.9% Data/MC disagreement for dijets.9%.6%.8% Data/MC disagreement for t t.%.4%.% Data/MC disagreement for Z + jets.6%.5%.9% Diboson background estimate.%.%.5% Unfolding dependence on prior.%.8%.% Muon momentum scale and resolution.%.%.% Muon reconstruction efficiency.4%.4%.4% Muon trigger efficiency.%.9%.9% Jet energy resolution.6%.8%.6% MC background statistical.4%.8%.% MC response statistical.7%.%.9% otal systematic (excluding luminosity) 7.6% 7.4% 7.% Luminosity.9%.%.% Data statistical.7%.6%.% J.E.M. Robinson Backup 4//6 Page 9/

71 WW cross section at ev -CONF-6-9 Selection requirement Selection value p l > 5 GeV η l η e <.47 (excluding.7 < η e <.5), η µ <.4 Lepton identification ight (electron), Medium (muon) Lepton isolation Gradient working point Number of additional leptons (p > GeV) meµ > GeV Number of jets with p >5() GeV, η <.5(4.5) Number of b-tagged jets ( p > GeV, 85% op. point) E, miss Rel > 5 GeV p miss > GeV Sources of uncertainty Relative uncertainty for σw fid W eµ Jet selection and energy scale & resolution 7.% b-tagging.% E miss and p miss.7% Electron.% Muon.4% Pile-up.9% Luminosity.% op-quark background theory.4% Drell Yan background theory.5% W +jet and multijet background.8% Other dibosons background.% Parton-shower. % PDF. % QCD scale.% MC statistics. % Data statistics.7% otal uncertainty % Events / GeV Data / SM Preliminary s = ev,.6 fb WW e ± νµ ± ν, SR Data SM (sys stat) WW op Quark Drell Yan W+jets Diboson Preliminary.6 fb ( ev) and. fb (8 ev) Data stat. stat.+syst. nnnlo+h Prediction WW e ± νµ ± ν eµ p [GeV] otal cross section ratio ( ev / 8 ev) Fiducial cross section ratio ( ev / 8 ev) Cross section ratio ( ev / 8 ev) J.E.M. Robinson Backup 4//6 Page /

72 WZ cross sections at ev PLB 76 (6) ; -CONF-6-4 Events / GeV Data / MC [fb] Z / p fid. σ Ratio to Powheg Preliminary s = ev,. fb Data ± W Z (corr. to NNLO) Misid. leptons ZZ tt+v Others ot. unc. l ll ( l, l = e or µ ) 4 pz [GeV].8 ± W Z l νll Preliminary s = ev,. fb Data Powheg+Pythia Sherpa.6 Z p [GeV] [fb] fid σ eee µee eµµ µµµ combined Relative uncertainties [%] e energy scale..... e id. efficiency µ momentum scale..... µ id. efficiency E miss and jets rigger..... Pileup Misid. leptons background ZZ background Other Irr. backgrounds Uncorrelated otal systematics Luminosity..... Statistics otal J.E.M. Robinson Backup 4//6 Page /

73 ZZ cross section at ev PRL 6, 8 (6) Z candidate mass [GeV] Leading-p,ll s = ev,. fb Data ZZ 4l +.8 Expected background: Subleading-p Z candidate mass [GeV],ll Events / GeV s = ev,. fb Data qq ZZ 4l gg ZZ 4l Prediction uncertainty +.8 Expected background: Mass of four-lepton system m 4l [GeV] J.E.M. Robinson Backup 4//6 Page /

74 Zγ and Zγγ production at 8 ev PRD 9, (6) Events / GeV γ h 4 8 Data 6 s = 8 ev,. fb Z(ee)γγ 4 Z+γj,jγ,jj Other BKG stat. syst m γγ [GeV] pp l l γ and pp ννγ s=8 ev,. fb.4 Λ FF = 4 ev Cuts l + l γ l + l γγ ν νγ ν νγγ Lepton p l > 5 GeV pl > 5 GeV - - η l <.47 η l < Boson m l + l > 4 GeV m l + l > 4 GeV > > ν pν GeV ν pν GeV Photon E γ > 5 GeV Eγ > 5 GeV Eγ > GeV Eγ > GeV η γ <.7 R(l, γ) >.7 R(l, γ) > R(γ, γ) >.4 - R(γ, γ) >.4 ɛ p h <.5 Jet p jet < 4.5 ηjet R(jet, l/γ) >. R(jet, γ) R(jet, l/γ) >. >. R(jet, γ) >. Inclusive : Njet, Exclusive : Njet = γ h, llγ and ννγ, s=8 ev,. fb CMS, ννγ, s=8 ev, 9.6 fb CMS, llγ and ννγ, s=7 ev, 5. fb CMS, llγ, s=8 ev, 9.5 fb, llγ and ννγ, s=7 ev, 4.6 fb = 95% C.L., Λ FF..4.6 Observed 95% C.L. contour Expected 95% C.L. contour Observed best-fit value.5.5 γ h Z h J.E.M. Robinson Backup 4//6 - Page / Coupling strength