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37th International Conference on High Energy Physics July 7, 2014 Valencia, Spain

Tests of the Electroweak Interactions at Hadron Colliders. 37th International Conference on High Energy Physics July 7, 2014 Valencia, Spain Jeffrey Berryhill ( Fermilab ) On behalf of ATLAS, CDF, CMS, DØ, and LHCb collaborations. Outline. W Physics W mass W asymmetry and PDFs

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37th International Conference on High Energy Physics July 7, 2014 Valencia, Spain

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  1. Tests of the Electroweak Interactions at Hadron Colliders 37th International Conference on High Energy Physics July 7, 2014 Valencia, Spain Jeffrey Berryhill (Fermilab) On behalf of ATLAS, CDF, CMS, DØ, and LHCb collaborations

  2. Outline • W Physics • W mass • W asymmetry and PDFs • Z and Drell-Yan Physics • Cross sections • Sin2qeff & prospects • Diboson Physics and Triple Gauge Couplings • Dimension 6 gauge boson effective field theory (EFT) • Diboson cross sections • Triple gauge couplings • Observation of electroweak Z+2 jets • Tribosons, VBS, and Quartic Gauge Couplings • Dimension 8 gauge boson EFT • Triboson production and vector boson scattering results • VBS prospects for 13 TeV Links for complete set of results: CMS public electroweak results ATLAS public electroweak results CDF public electroweak results D0 public electroweak results LHCb public electroweak results V+jets studies: See C. Roda QCD summary

  3. State of the Electroweak Theory: Precision Frontier Radiative corrections to precision EWK measurements of W, Z sensitive to Mt, MH SM-like Higgs discovery at ~126 GeV is compatible with global EWK data at 1.3 sigma (p = 0.18) Indirect constraints are now superior to precise direct W, Z measurements (MW, sin2qeff) Can W,Z experiment catch up? http://project-gfitter.web.cern.ch/project-gfitter/

  4. State of the Electroweak Theory: Energy Frontier The successful LHC Run 1 is now providing TeV-scale tests of single and multiple electroweak boson production Mass of DY pairs up to 1500 GeV PLB 725 (2013) 223 CMS-PAS-SMP-12-006 Z PT in WZ up to 400 GeV ATLAS-CONF-2013-020 Mass of ZZ Up to 900 GeV

  5. W Physics

  6. Status of Tevatron W mass PRD 89 (2014) 072003 PRL 108 (2012) 151803 • CDF and DØ have world’s most precise measurements based on 20% and 50% of their data → 1.1M and 1.7M Ws, resp. • MT is the most sensitive single variable, lepton PT and MET used also • Precision lepton response (0.01%) and recoil models (1%) built up from Z dileptons, Z mass reproduced to 6X LEP precision • MW precision: • CDF 19 MeV, • DØ 23 MeV, • LEP2 33 MeV CDF W muons PRL 108 (2012) 151804 PRD 89 (2014) 012005 DØ W electrons

  7. Status of Tevatron W mass PRL 108 (2012) 151803 PRD 89 (2014) 072003 • CDF and DØ have world’s most precise measurements based on 20% and 50% of their data → 1.1M and 1.7M Ws, resp. • MT is the most sensitive single variable, lepton PT and MET used also • Precision lepton response (0.01%) and recoil models (1%) built up from Z dileptons, Z mass reproduced to 6X LEP precision • MW precision: • CDF 19 MeV, • DØ 23 MeV, • LEP2 33 MeV • 2012 world average: 15 MeV

  8. Prospects for Tevatron W mass arxiv:1310.6708 projected • Largest single uncertainties are stat. and PDF syst. • 2X PDF improvement and incremental improvement elsewhere results in 9 MeV projected final Tevatron precision • <10 MeV precision is well motivated to further confront indirect precision (11 MeV)

  9. Prospects for LHC W mass Phys.Rev.D83: 113008,2011 • The LHC has excellent detectors and semi-infinite statistics and thus has a good a priori prospect for a <10-MeV measurement • Biggest three obstacles to surmount: • PDFs: sea quarks play a much stronger role than the Tevatron. Need at least 2X better PDFs. • Momentum scale • Recoil model/MET arxiv:1310.6708

  10. W charge asymmetry arXiv:1312.6283 • At 7 TeV, ~4M W muon candidates produced per /fb • Differential W charge asymmetry precisely probes u/d ratio vs. x • Recent CMS measurement can precisely extract a clean W asymmetry using ~20 million W candidates! Mu- Mu+

  11. W charge asymmetry arXiv:1312.6283 • At 7 TeV, ~4M W muon candidates produced per /fb • Differential W charge asymmetry precisely probes u/d ratio vs. x • Asymmetry measured to 0.1% absolute per bin • Has obvious constraining power for all PDF families

  12. W charge asymmetry PRD 88 (2013) 091102 • Tevatron has only exploited a fraction of their data until recently. • DØ muon rapidity asymmetry also has clear constraining power • DØ W rapidity asymmetry uses electron and MET to estimate W rapidity directly PRL 112 (2014) 151803

  13. W charge asymmetry NEW for ICHEP14 • LHCb has unique access to high rapidity leptons • (2 < h < 4.5) • New observed 1/fb W asymmetry constrains PDFs at lower x • In agreement with CMS/ATLAS in overlap region (2-2.4)

  14. W charge asymmetry arXiv:1312.6283 d-valence improvement • CMS W asymmetry is combined with HERA DIS to exhibit valence PDF improvement • Tevatron W asymmetry strongly constrains NNPDF2.3 Tevatron vs. NNPDF2.3

  15. Z and Drell-Yan

  16. Drell-Yan Cross Section at LHC (7 TeV) JHEP 12 (2013) 030 • Cross section vs. dilepton mass measured at 7 TeV, from 15-1500 GeV in mass. • 1M events/fb/experiment at 7 TeV! • ee, mumu in agreement with each other and with the Standard Model

  17. Drell-Yan Cross Section at LHC (7 TeV) • NNLO QCD corrections are important at low mass (mostly boosted events) • NLO EWK corrections and photon-induced production relevant at high masses. Photon PDF is needed for accurate predictions. JHEP 12 (2013) 030 JHEP 06 (2014) 112 FEWZ 3 NNLO QCD + NLO EWK + ggl+l- PLB 725 (2013) 223

  18. Drell-Yan Cross Section at LHC (8 TeV) CMS-PAS-SMP-14-003 NEW for ICHEP14 • Cross section vs. dilepton mass now measured at 8 TeV, from 15-2000 GeV in mass. • Differential double ratios (1/sZ)(ds/dm)8TeV/ (1/sZ)(ds/dm)7TeV • measured for the first time

  19. Z production properties at LHC CMS-PAS-SMP-13-013 • Z PT and rapidity can now be precisely sampled and compared with predictions • Now measured at 7 (ATLAS) and 8 TeV(CMS) doubly differentially

  20. Z production properties at LHC • Diverse (dis)agreement with predictions observed in low PT (resummation) and high PT (NNLO+) arxiv:1406.3660 PLB 720 (2013) 32

  21. Z production properties at LHC • PDFs and UE models can improve upon tuning to this data arxiv:1406.3660 • ATLAS has a new tune for PYTHIA8 and PYTHIA8+POWHEG • “AZ” and “AZNLO” • which flattens disagreement at the percent level at low PT up to 100 GeV PT • High PT Z data could potentially constrain the gluon PDF

  22. Weak mixing angle at hadron colliders • In the dilepton CM, lepton angle with respect to axis of quark momentum is sensitive to interference effects: vector with axial-vector Z couplings, Z with photon, or Z with new physics V-A int. ~ sin2qeff -1/4 Suppression of odd cosq* term due to dilution at 7 TeV LHC • This relation is (un)diluted in (pp) pp collisions, where reconstructed cos q* axis is (strongly) weakly correlated with real quark axis.

  23. Weak mixing angle at LHC ATLAS-CONF-2013-043 • Select central dilepton pairs, and also central-forward electrons with full 7 TeV dataset • Raw AFB = Count forward/backward abundance in CS frame • AFB in good agreement with PYTHIA * PHOZPR NNLO K-factor (MSTWNNLO2008) • 1.8s lower angle than LEP+SLD average backward forward ATLAS 5/fb LEP + SLD

  24. Weak mixing angle at Tevatron DØ note 6426-CONF • Low dilution makes raw AFB visibly apparent • ~10/fb analyzed by D0 (CDF) for ee (mumu) • Much lower PDF and energy scale systematics than realized at LHC • 3X less precise than LEP+SLD • With CDF 9/fb ee, expect • Tevatron ≈ LEP ≈ SLD! Raw AFB LEP + SLD

  25. Prospects for weak mixing angle at LHC • Need a 6X better measurement to achieve world-average precision • Statistical error hits this target with ~20/fb @ 13-14 TeV • PDF uncertainty is biggest concern, needs >5-10X improvement over pre-LHC PDFs! • Lepton energy scale must also improve >5X • Gfitter: Next 2X in world direct precision (1.6E-4) will match indirect precision (1.0E-4) http://project-gfitter.web.cern.ch/project-gfitter/

  26. Triple Gauge Couplings

  27. Effective Field Theory and Boson Interactions UNBROKEN • For generic new physics effects descended from some high energy scale L, explore operator product expansion with Wilson coefficients c_i • Before EWSB, 5 gauge boson interaction terms respect gauge invariance (3 CP even + 2 CP odd) BROKEN • After EWSB, induces trilinear VVV’, VV’H, and quartic interactions with correlated coefficients. • At dim 6, expect WWg, WWZ interactions with 3 CP-even parameters (g1,k, l) • Manifested as high mass/momentum production tails

  28. PRD 87, 112003 (2013) WZ and Wg Production CMS-PAS-SMP-12-006 • LHC has thousands of high purity trilepton WZ candidates, tens of thousands of Wg • Photon and lepton fakes are the predominant background • No evidence of new physics in high PT tails WZ trileptons, Z PT Wg, g PT inclusive exclusive 0-jet

  29. JHEP 10 (2013) 164 Zg Production PRD 89 (2014) 092005 PRD 87 (2013) 112003 Zg llg g PT • Thousands of dilepton-photon events at 7 TeV agree with SM • MET-photon channel: Higher BR and low background at high PT gives superior (dim 8) TGC constraint ZgMET+g g PT

  30. 32 ZZ Production ATLAS-CONF-2013-020 arxiv:1406.0113 ZZ  4l ZZ mass • ~300 ZZ to 4-lepton candidates observed at 8 TeV/experiment with SM rate and shapes • ~200 ZZ to 2l2v candidates observed at 8 TeV, give best (dim 8) TGC constraint ZZ  2l2v Z PT

  31. PRD 87 (2013) 112001 EPJC 73 (2013) 2610 WW Production (7 TeV) EPJC 73 (2013) 2283 ATLAS-CONF-2012-157 WW leading lepton PT, 7 TeV WW leading lepton PT, 7 TeV • Thousands of candidates in dilepton channel • Leading lepton PT shows no anomalous contribution • Significant diboson signal in semileptonic channel • Higher BR and low background at high PT gives superior TGC constraint W dijet mass, 7 TeV W dijet PT, 7 TeV

  32. Charged aTGCs: World Summary • Best single LHC 7 TeV measurements equal LEP2 or Tevatron combinations • Semileptonic WW gives the best information on k and l, leptonic WW and WZ better for g. • LHC 8 TeV will provide 2-3X better constraints, eclipsing LEP2 • Higgs-VV’ couplings also compete here! • Probing L ≈ 200-500 GeV • for c ≈ 1

  33. PLB 721 (2013) 190  WW Production (8 TeV) NEW for ICHEP14 ATLAS-CONF-2014-033 • Kinematic shapes agree with prediction, but cross section excess observed at 20% level in CMS and ATLAS • ~5000 emu ATLAS candidates with 20/fb! • Systematics from jet veto acceptance, background methods • Not yet reporting: CMS lvlv 20/fb, • WWlvjj 20/fb • Theory calculation being actively studied (jet vetoes, NNLO) leading lepton PT, 8 TeV WW scaled by 1.2 emu dilepton mass, 8 TeV WW scaled by 1.2 CMS 69.9±2.8 (stat.)±5.6 (syst.)±3.1 (lum.) pb (1.8s) ATLAS 71.4±1.2 (stat.)±5.0 (syst.)±2.2 (lum.) pb (2.1s) MCFM 58.7±3.0 (syst.) pb =qq,qg 53.2 MCFM NLO +gg 1.4 MCFM LO +HWW 4.1 NNLO+NNLL Higher order/other≈ +3-4pb?

  34. JHEP 04 (2014) 031 Electroweak Z + 2 jet production JHEP 10 (2013) 062 CMS 8 TeV to be submitted • VBF Z one of 3 (interfering) • EWK Z + 2 jet amplitudes • Unique laboratory for studying rapidity gaps and VBF jet dynamics • Require dijet “VBF topology”: • large dijet mass (250-1000 GeV) • large dijetDy (or rapidity gap) • and other kinematic information to separate from QCD Z+ 2 jet • CMS observed a 2.6s signal in the 7 TeV data after a BDT selection

  35. JHEP 04 (2014) 031 Electroweak Z + 2 jet production JHEP 10 (2013) 062 CMS 8 TeV to be submitted • >5 s evidence has been reported by both experiments at 8 TeV, • first published by ATLAS. Cross sections are consistent with SM predictions. sEWK = 226 ± 44 fb sVBFNLO = 239 fb • After reweighting QCD Z+2 jets in sidebands, jet dynamics well-modeled in and around search regions sEWK = 10.7 ± 2.1 fb sPOWHEG = 9.4 fb

  36. JHEP 04 (2014) 031 Electroweak Z + 2 jet production JHEP 10 (2013) 062 CMS 8 TeV to be submitted • Now a laboratory for studying generator behavior in VBF/VBS context! • TGC limits obtained from ATLAS less stringent than diboson

  37. ATLAS Diboson Summary

  38. CMS Diboson Summary

  39. Quartic Gauge Couplings

  40. Effective Field Theory Revisited • SM has 4 quartic interactions (QGCs): WWWW, WWZZ, WWgg, and WWZg • Dim 6 OPE has QGC correlated with TGCdibosons dominate their constraints • 19 new quartic terms become relevant at Dim 8. Neutral 4 boson vertices can be non-zero (ZZZZ, ZZZg, ZZgg, Zggg). • Manifested as triboson or vector-boson scattering phenomena SM Quartic interactions

  41. WW QGC via two-photon production JHEP 1307 (2013) 116 Two photon production of WW (s, t, and u channel) • First search for photon-photon scattering production of WW • WWgg quartic gauge coupling one of the amplitudes • Two em events observed with no UE present • First quartic gauge coupling limits at LHC; WWgg limit two orders better than LEP or Tevatron!

  42. Triboson search in WWg and WZg arxiv:1404.4619 • Studied in lv+jj+g final state for best aQGC sensitivity • Photon PT exhibits no anomalous high PT tail • Cross section UL on SM triboson rate is 3.4XSM (<241 fb) • First limits ever on several aQGCs

  43. arxiv:1405.6241 W±W± scattering at LHC CMS-PAS-SMP-13-015 NEW for ICHEP14 • SM electroweak symmetry breaking with Higgs essential to preservevector boson scattering cross section unitarity • Same-sign WW vector boson scattering production provides attractive S/B at LHC • Anomalous differential cross sections would indicate extended Higgs sector (e.g. George-Machacek H++), new particles, or (giant) anomalous QGCs

  44. arxiv:1405.6241 W±W± scattering at LHC CMS-PAS-SMP-13-015 • The 8 TeV data have been searched by both CMS and ATLAS for same-sign WW+2 jets ATLAS: 500 GeVdijet mass and 2.4 rapidity gap define signal rich VBS region ATLAS: Good agreement with SM expectation in signal and control regions. Background mainly from real multilepton sources.

  45. arxiv:1405.6241 W±W± scattering at LHC CMS-PAS-SMP-13-015 • Cross section in VBS region is SM-like with 3.6 s • significance (2.8 expected) • first evidence for vector boson scattering! • Limits obtained on aQGCs in a unitarizedmodel, • L ≈ 650 GeV for c ≈ 1

  46. arxiv:1405.6241 W±W± scattering at LHC CMS-PAS-SMP-13-015 • CMS: 500 GeVdijet mass and 2.5 dijet rapidity gap, with top veto, Z veto, and dilepton mass > 50 GeV • Most remaining background is fake/non-prompt leptons • Observed events agree with SM predictions 2.0s excess from VBS (3.1 expected) 4.0+2.4−2.0 (stat) +1.1−1.0 (syst) fb VBFNLO: 5.8 ± 1.2 fb

  47. arxiv:1405.6241 W±W± scattering at LHC CMS-PAS-SMP-13-015 • aQGC limits obtained in non-unitarized scheme from dilepton mass spectrum H++sBR limits as low as 20 fb obtained from George-Machacek model

  48. VV scattering: future prospects Snowmass study to understand VBS potential of Run2+ Select 3 lepton or same-sign dilepton events with “VBF dijet” (dijet mass > 1 TeV) Several modes expected to be observed with < 300/fb 5 sigma anomalous dim 8 production at the 1 TeV scale possible in Phase 1 ATLAS-PHYS-PUB-2013-006

  49. Summary • W and Z physics at Tevatron+LHC now providing precision tests of PDFs and NNLO QCD + NLO EWK calculations, in preparation for further constraining the precision electroweak sector. • The LHC is now the leading laboratory for exploring the gauge boson self-interactions. • The vector boson scattering era is upon us! Now poised to directly test electroweak symmetry breaking. Joaquin Sorolla, Valencia, 1863-1923

  50. Backups

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