SM and BSM Higgs Measurements and Searches at ATLAS
Transcripción
SM and BSM Higgs Measurements and Searches at ATLAS
SM and BSM Higgs Measurements and Searches at ATLAS Elliot Lipeles University of Pennsylvania Search 2013 Outline Diboson Channels ~ Established signals •Couplings •Spin-Parity •Differential Distributions The Search for Direct Evidence of Fermion Couplings • H ! ⌧ ⌧, H ! bb, H ! µµ • ttH production with H ! Higgs Beyond the Standard Model • Heavy Higgs in H ! W W • Flavor Changing Neutral Currents in Top Decay • Higgs to Invisible Elliot Lipeles Search 2013 2 The 2011 and 2012 Datasets Data used in analysis: -1 7 TeV 2011 5fb • -1 •2012 20fb 8 TeV Elliot Lipeles Search 2013 3 σ(pp → H+X) [pb] 102 mH =125 GeV pp → H( NN LO +NN LL 10 pp → 1 pp pp → → pp ZH ttH → (N NL O O -1 10 +N LO (NNL OQ CD + NLO (N NL O QC D (N L QC D QC D +N LO QC D) EW ) g t ggF H t t qqH W H s= 8 TeV LHC HIGGS XS WG 2012 Higgs Production Summary +N EW ) LO g EW) Large QCD Uncertainties Sensitive to new physics in the loop EW ) 10-2 80 100 200 300 400 1000 MH [GeV] H q ttH VH W, Z q Access to top coupling Elliot Lipeles VBF (vector boson fusion) W, Z Usually tagged w/ W/Z decay Small QCD Uncertainties to leptons (inc. neutrinos) Distinctive forward jet tags Search 2013 4 Higgs Decay Summary mH =125 GeV Observed: WW, ZZ, and Searches: bb, ⌧ ⌧ , Z , and µµ Each decay probes a different Higgs (Yukawa) coupling Elliot Lipeles Search 2013 5 Diboson Channels ~ Established signals Elliot Lipeles Search 2013 6 A “Higgs” Boson has been Observed Higgs: Understanding what have we found Production Mechanisms Decay Channels Kinematic Measurements Elliot Lipeles Coupling Constants Combined Fit(s) Properties/ Quantum Numbers Search 2013 7 H! is high background, but resonance allows background to be determined from sideband H! Signal/Background ~ 1/30 Systematic is largely from the cross-section theory uncertainty Signal strength relative to SM: Elliot Lipeles Search 2013 8 H! by Production Channel Diphoton sample divided into exclusive subsets for different production mechanisms 80-90% leptonic WH and ZH remainder ttH 1.9% of Sig 3.4% of Sig 95% of Sig 50% hadronic WH and ZH remainder ggF 54(76)%VBF for loose(tight) remainder ggF 75-95% ggF depending on category Most categories not very pure in one production mode ATLAS-CONF-2013-012 Elliot Lipeles Search 2013 9 H! by Production Channel Diphoton sample divided into Result is yieldexclusive in eachsubsets category for different production mechanisms 80-90% leptonic WH and ZH remainder ttH 1.9% of Sig 3.4% of Sig 95% of Sig 50% hadronic WH and ZH remainder ggF 54(76)%VBF for loose(tight) remainder ggF 75-95% ggF depending on category Most categories not very pure in one production mode ATLAS-CONF-2013-012 Elliot Lipeles Search 2013 9 by Production Channel H! H q W, Z q W, Z Involved the WWH and ZZH couplings in SM g t H t t ATLAS-CONF-2013-012 Elliot Lipeles g Involved the ttH coupling in SM Search 2013 10 H! differential cross-sections ATLAS now has preliminary differential distributions Procedure • For each range of make an m plot pT • Fit plot for yields using similar parameterized backgrounds • “Unfold” the distribution to get a particle level result Elliot Lipeles Search 2013 11 H! differential cross-sections ATLAS now has preliminary differential distributions Elliot Lipeles Search 2013 12 H ! ZZ H ! ZZ ! ```` is very low background Signal/Background ~1.5 Main Issue is getting the highest efficiency without letting this get out of control Acceptance: 39% 4µ , 26% 2e2µ/2µ2e ,19% 4e Elliot Lipeles Separate VBF and VH categories added Search 2013 13 Mass from H ! and H ! ZZ Some tension between mass determinations and ZZ Main systematics on mass Photon energy scale (from Z ! ee data) Material modeling (validated with conversions) Main systematics on ZZ mass Electron energy scale Muon momentum scale (both validated with J/ data) Mass combined including systematic correlations Many detailed cross-checks have been performed Consistency is at the 2.5 sigma level Elliot Lipeles Search 2013 14 H ! WW H ! W W ! `⌫`⌫ is intermediate background, but there is no mass peak We must model all backgrounds in detail Selection is complex and its effect on signal has to be modeled Use approximate mass variable mT Signal/Background ~ 1/8 Elliot Lipeles H to WW relies heavily on theory Search 2013 15 Review of H to WW Analysis WW suppression using spin correlations Roughly at rest W ! W ! H ! Spin=0 Spins have to add to zero Elliot Lipeles W products back-to-back For each W spins add to one Search 2013 16 Review of H to WW Analysis WW suppression using spin correlations Roughly at rest W H ! Spin=0 W ! ! Spins have to add to zero Elliot Lipeles W products back-to-back e + ⌫ µ ⌫¯ For each W spins add to one Search 2013 16 Review of H to WW Analysis WW suppression using spin correlations Roughly at rest W H ! Spin=0 ConsequencesW ! ! W products back-to-back e + ⌫ µ For each W ¯directions Small angle ll between charged-lepton ⌫ spins add to have Small invariant Spins mass m ll of the two charged-leptons one to add to zero Elliot Lipeles Search 2013 16 Review of H to WW Analysis WW suppression using spin correlations Consequences of spin correlations Small invariant mass mll of the two charged-leptons Elliot Lipeles Small angle ll between charged-lepton directions Search 2013 17 Modeling of the WW background Focusing on 0-jet •Jet requirements adds a dependence on the modeling of QCD jet emission •Signal to background ratio means need to model WW at the 20% * 1/8 = 2.5% level to not be dominated by this uncertainty Signal Region Control Region Uncertainty on •We are claiming1.6% ratio of signal/ modeling! Use control regions control is ~ 1.6% Elliot Lipeles Search 2013 18 H ! W W sources of uncertainty From the ATLAS H to WW conference note µ ⌘ observed / SM ATLAS-CONF-2013-030 Main systematics are theory uncertainties Uncertainty is 50% statistical and 50% systematics Elliot Lipeles Search 2013 19 Modeling of the WW background Uncertainty on ratio of signal/control is ~ 1.6% WW cross-section uncertainty ~ 6% using NLO Example for 10 < mll < 30 GeV Source Vary factorization and renormalization scales Uncertainty PDFs 1.5% Underlying Event and Parton Shower Models 0.2% “Modeling” 1.2% •Choice of Generator Elliot Lipeles 0.9% Search 2013 20 H ! W W Categorization plots 0-jet (mostly ggF) Analysis bins: •0-jet (ggF), 1-jet(ggF), 2-jet(VBF) •Same-flavor, opposite-flavor •2011, 2012 Elliot Lipeles 2-jet (mostly VBF) Finding H to WW might show the way to finding BSM under the SM Search 2013 21 H ! W W VBF event Elliot Lipeles Search 2013 22 Spin Elliot Lipeles Search 2013 23 Spin H! A spin-1 resonance cannot decay to two photons so spin-1 is excluded Photon spins are not observed Spin-2 with initial state of gg or q q̄ will have different decay kinematics ⇤ cos ✓ is the angle of photons relative to beam direction with a correction for the boost of the system Selection modified to reduce m ⇤ Elliot Lipeles cos ✓ correlation Search 2013 24 H! Spin Background from sideband data The data are fit for signal and background yields for spin-0 and spin-2 The ratio of the best fit likelihoods is used as a test statistic to set limits Only 8 TeV data are used at this point Elliot Lipeles Search 2013 25 H! Spin Background from sideband data The data are fit for signal and background yields for spin-0 and spin-2 The ratio of the best fit likelihoods is used as a test statistic to set limits Spin-2 produced by gluon is excluded at 99% CL Only 8 TeV datafusion are used at this point Elliot Lipeles Search 2013 25 H ! ZZ Spin Considered Jp: 0+, 0-, 1+,1-,2+ Full kinematics measured = 5 angles Decay products sensitive to Z spins BDT trained to distinguish different spin states Elliot Lipeles Search 2013 26 H ! ZZ Spin Considered Jp: 0+, 0-, 1+,1-,2+ Full kinematics measured = 5 angles Decay products sensitive to Z spins BDT trained to distinguish different spin states 0- is excluded at the 97.8% CL Elliot Lipeles Search 2013 26 H ! W W Spin Discriminating variables: spin-2 looks more like background Elliot Lipeles Search 2013 27 H ! W W Spin 2d binned fit BDT0 vs BDT2 BDT separating non-Higgs from spin-0 BDT separating non-Higgs from spin-1 Elliot Lipeles Test statistic likelihood ratio of spin-0 over spin-2 2-d BDT remapped to 1-d Fit with Spin-0 Fit with Spin-2 Exclusion of 2+ varies from 99% for 100% q q̄ to 95% for 100% gg production Search 2013 28 Spin Combination Spin results from WW, ZZ, and combined Jp=2+ excluded at 99.9% CL independent of fqq̄ Elliot Lipeles Search 2013 29 Grand Combination We combine all the inputs just discussed into global likelihood fit Includes correlations of systematics! Two sets of results: •Using preliminary results from Moriond including bb̄ and ⌧ ⌧ •Published results using only , W W , and ZZ Elliot Lipeles Preliminary Results with ggF VBF VH ttH X WW X ZZ X ⌧⌧ X X X X X bb̄ X X X X X X Published Results with ggF VBF VH ttH X X WW X X ZZ X X X X X Search 2013 30 Inclusion of uncertainties Each analysis has a table like this....only more complicated •In order to correctly fit all the data you need to include these correlations Elliot Lipeles Search 2013 31 Evidence of VBF production 3.3𝞂 evidence of VBF production Important because if you’ve only seen ggF then all measurements are proportional to gg total Recall we measure things like this gg Elliot Lipeles ⇥B = gg ⇥ total Search 2013 32 Coupling Interpretation Several different models depending on assumptions: •New particles in loops? •BSM contributions to total width (invisible decays, other decays to BSM)? V f or g g f f V V t H t t g Both combined in Elliot Lipeles Search 2013 33 Relationship between measurements and coupling An individual measurement looks like this gg ⇥B = gg ⇥ total We include this in our fitting ⇥B gg,SM ⇥ B gg = ,SM 2 2 g 2 H where we define total Elliot Lipeles / 2 H Search 2013 34 Example Fit: change couplings to SM Many combinations of assumptions you can make Assume only SM particles, but give fermions one scale factor and bosons another Elliot Lipeles Search 2013 35 Example Fit 2: add BSM in loops Keep SM couplings fixed, but add BSM in loops Only decays to SM particles Include invisible or other BSM BRinvisible or non-SM < 0.6 at 95% CL Elliot Lipeles Search 2013 36 Scaling to 13 TeV LHC Plans to Run at 13-14 TeV for the next ~15 years Have •2015-2016 13 TeV, 100 fb-1 •2018-2020 13(?) TeV, 300 fb-1 •2011 7 TeV 5 fb-1 -1 -1 2022-202(?) 13(?) TeV, 3000 fb 2012 8 TeV, 20 fb • • Signal ggF VBF ttH WH ZH qq to WW background gamma gamma bkg 14 TeV/8 TeV 2.6 2.6 4.7 2.1 2.1 2.1 2.1 In 2016, 4*2.6~10 more signal, 4*2.1~8 more background Elliot Lipeles Search 2013 37 H ! Z Search Another loop induced coupling Reconstructed in the + channel H!Z !` ` Observed limit is18.2xSM with 13.5xSM expected Elliot Lipeles Search 2013 38 Search for direct evidence of fermion couplings Elliot Lipeles Search 2013 39 H ! ⌧ ⌧ Search Problem is tau decays involve neutrinos • ⌧ ! `⌫⌫ • ⌧ ! h⌫ where h is some number of pions Large Backgrounds •Multijet QCD • Z ! ⌧⌧ Two viable signal regions: Boosted ggF VBF Make best estimate using measured constrains of tau mass and measured missing momentum Elliot Lipeles Search 2013 40 H ! ⌧ ⌧ Search Analysis divided by (tau decay) x (VBF, ggF, Boosted ggF): •lepton-lepton •lepton-hadron •hadron-hadron Two of the most sensitive categories Boosted ggF VBF Not updated since HCP (Nov 2012) Elliot Lipeles Search 2013 41 H ! ⌧ ⌧ Search Analysis divided by (tau decay) x (VBF, ggF, Boosted ggF): •lepton-lepton •lepton-hadron •hadron-hadron Two of the most sensitive categories Boosted ggF VBF Upper limit: 1.9xSM (1.2xSM expected) Significance: 1.1 sigma (1.9 sigma expected) Signal Stength/SM: µ = 0.7 ± 0.7 Not updated since HCP (Nov 2012) Elliot Lipeles Search 2013 41 H ! bb Search Extremely difficult because •b-jets are common •jet resolutions are not so great •jet distributions hard to model Highest S/B categories Abandon gluon fusion (ggF), and focus on VH production •V= W ! `⌫, Z ! `` , Z ! ⌫⌫ •Focus on high PT V systems Very Recent Update = July Elliot Lipeles Search 2013 42 H ! bb Search Highest S/B categories Fit normalizes backgrounds and exploits Analysis very complex different S/B for channels Signal regions sliced based •Extremely difficult because • 26 signal Abandon gluon fusion (ggF), and regions with m distributions jj on 0, 1, or 2 leptons, and b-jets are common focus on VH production •based V bins) V (0,1,2 leptons)x(0,1-jet)x(p T on P T Z ! ⌫⌫ Z ! `` W ! `⌫ resolutions are not so great V= , , •jet • • 27 control regions Usedistributions lower PT V to control ••jet hard to model • 26 one Focus on+ high Ptop systems T V control • eµ b-tag 1 background modeling region Elliot Lipeles Very Recent Update = July After global fit background uncertainty is ~3% Search 2013 42 H ! bb Search Even find the W Z + ZZ ! W bb̄ + Zbb̄ background was hard Sum over all channels weighted by S/B WZ+ZZ (to bb) is ~5 times the Higgs signal Elliot Lipeles Search 2013 43 H ! µµ Search If it is really the Higgs it couples to mass, so H ! µµ should be very small Limit is 9.8 times SM at mH = 125 GeV Predicted signal is under a sea of Drell-Yan Elliot Lipeles Search 2013 44 ttH production with H ! Similar to regular H ! but with either •Leptonic tag: 1e/µ + 1 b-jet •Hadronic tag: 6 jets w/ 2 b-jets Fit m Elliot Lipeles just like regular analysis Search 2013 45 Beyond the Standard Model Elliot Lipeles Search 2013 46 Heavy Higgs decaying to WW Selection similar to SM but cuts modified for high mass • pT,lep > 40 GeV, mll > 50 Ge V, ⌘ll < 1 • still fit in mT Two widths considered: Narrow and SM-like •Couplings unknown means width unknown •Interference with gg ! W W important for wider Higgs 0-jet (ggF) 2-jet (VBF) Analysis includes ggF and VBF categories like standard analysis Elliot Lipeles Search 2013 47 Heavy Higgs decaying to WW Selection similar to SM but cuts modified for high mass Limits • pT,lep > 40 GeV, mll > 50 Ge V, ⌘ll < 1 • still fit in mT Two widths considered: Narrow and SM-like •Couplings unknown means width unknown •Interference with gg ! W W important for wider Higgs 0-jet (ggF) 2-jet (VBF) Analysis Relative includes ggF vs ggF VBF andcross-sections are model dependent VBF categories like standard analysis Elliot Lipeles Search 2013 47 Flavor Changing Neutral Currents in Top Decay: t ! cH Reconstruct H in diphotons Two mass peaks, one from each top: •One mass is mj •Hadronic reco: 3-jets •Leptonic reco: mjl⌫ using W mass constraint 4 combinations per event Non-resonant background model is smoothed SHERPA diphotons + n-partons Elliot Lipeles Search 2013 48 Flavor Changing Neutral Currents in Top Decay: t ! cH Reconstruct H in diphotons Two mass peaks, one from each top: •One mass is mj Limit onreco: top 3-jets •Hadronic branching fraction mjl⌫ reco: •Leptonic 0.83% Observed using W mass constraint 0.53% Expected 4 combinations per event Non-resonant background model is smoothed SHERPA diphotons + n-partons Elliot Lipeles Search 2013 48 Higgs to Invisible We have also searched directly for Higgs to invisible... Z recoiling against nothing SM source of Z recoiling against nothing Elliot Lipeles BRinvisible < 0.65 (observed) at 95% CL, (0.84 expected) Search 2013 49 Higgs to Invisible Interpretation Implications for dark matter searches if DM to nucleon couplings is entirely Higgs from arXiv:1109.4398v1 [hep-ph] Based on expected sensitivity (BRinv<0.75) very close to observed Elliot Lipeles Search 2013 50 Summary There is an important interplay between theory and experiment •Experiment is an input into Theory •Theory is an input into Experiment •Some important measurements are close to being theory limited Couplings: •order 20-30% constraints on vectors, fermions just crossing the sensitivity thresholds •Interesting sensitivity to dark matter and other BSM Elliot Lipeles Spin: •various combinations of 0-, 1+,1-, and 2+ excluded Search 2013 51 WW Summary Elliot Lipeles Search 2013 52 H! Elliot Lipeles VBF BDT Search 2013 53 H! Elliot Lipeles VBF Significance Search 2013 54 H! VBF Candidate VBF Channel has a high purity, S/B ~= Elliot Lipeles Search 2013 55 Why bother with H ! W W ? Electroweak fits make it hard to mess with the ratio of HWW/HZZ couplings, can’t we just measure H ! ZZ ? WW uncertainty is smaller than ZZ µW W µZZ = = 1.01 ± 0.31 +0.5 1.7 0.4 Difference will big bigger at13 TeV, IF the theory uncertainties can be controlled Elliot Lipeles Search 2013 56 Review of H to WW Analysis Signature: two e or µ leptons and two neutrinos Gluon Fuison (ggH) typically gives 0 or 1 jets Vector Boson Fusion gives 2 or more jets Many of the lessons in H to WW will apply to other searches where the signal is under significant SM background and does not peak Elliot Lipeles Search 2013 57 Review of H to WW Analysis Just about everything in the hadron collider zoo is a background gg ! H ! W W Elliot Lipeles VBF H ! W W Search 2013 58 Review of H to WW Analysis W+jets background • qq̄ ! W ! l⌫ with an associated jet... • the jet is misidentified as a lepton • small background, but uncertainty is large • one of the largest Hard to predict theoretically, because of experimental dependence on fragmentation and uncertainties detector response Elliot Lipeles Search 2013 59 Review of H to WW Analysis Z+jets background • Different-flavor (eµ ) background mainly from Z ! ⌧ ⌧ • Tiny Background • Same-flavor ( ee & µµ ) background from ⇤ q q̄ ! Z/ ! ll with false missing momentum signature •again, a small Hard to predict ... background, but see next slide uncertainty is large Elliot Lipeles Search 2013 60 Challenges in predicting missing energy distributions We make multiple cuts to suppress Z/ ⇤ ! `` and Z ! ⌧ ⌧ Missing Transverse “Energy” miss ~ ET = X p~T calorimeter Missing Transverse Energy Relative ⇢ miss |E | miss,rel T ET ⌘ miss |ET | sin if if ⇡/2 < ⇡/2 miss ~ where is the angle between ET and the nearest lepton or jet miss,rel ET Elliot Lipeles is less sensitive to mismeasurements of leptons and jets Search 2013 61 Challenges in predicting missing energy distributions: Pile-up •You should think great H ! W W ⇤ ! `⌫`⌫ has miss ET and Z/ ! `` doesn’t, so we are done •But it’s difficult to measure hadronic energies precisely •There is still too much left after a reasonable cut for the same-flavor so we have to use the soft recoil system and calibrate it with data •Made much worse by pile-up: Elliot Lipeles Search 2013 62 Challenges in predicting missing energy distributions: Pile-up Pile-up is hard to model: Soft QCD These properties are very hard to model Models are tuned directly to data, but we still find modeling issues which grow with pile-up Elliot Lipeles Search 2013 63 Challenges in predicting missing energy distributions: Underlying Event Underlying event is due to a variety of soft QCD effects •To use simulation, total amount of energy needs to be simulated in data •Simulation is tuned to data, but the modeling is limited Elliot Lipeles Search 2013 64 Review of H to WW Analysis Top and Single top Looks just like WW but with more jets Single Top Diagrams Elliot Lipeles Search 2013 65 Review of H to WW Analysis Jet Counting Strategy: •Divide analysis into 0-jet, 1-jet, and 2+-jets. •“controls” top background, but leads to many of the uncertainties Most of the sensitivity is from 0-jets Use b-jet “tagging” to suppress top bkg in1-jet Elliot Lipeles Specialize the 2+-jets to looking for the VBF signature Search 2013 66 Review of H to WW Analysis WW background •WW is considered “irreducible” •It can be partially suppressed using the effect of spin correlations on the angles because the leptons q q̄ ! W W Gets contributions from both •It can also be gg ! W W and suppressed using gg ! W W will become more important kinematics at 13 TeV Elliot Lipeles Search 2013 67 Review of H to WW Analysis WW suppression using spin correlations Roughly at rest W ! W ! H ! Spin=0 Spins have to add to zero Elliot Lipeles W products back-to-back For each W spins add to one Search 2013 68 Review of H to WW Analysis WW suppression using spin correlations Roughly at rest W H ! Spin=0 W ! ! Spins have to add to zero Elliot Lipeles W products back-to-back e + ⌫ µ ⌫¯ For each W spins add to one Search 2013 68 Review of H to WW Analysis WW suppression using spin correlations Roughly at rest W H ! Spin=0 ! W products back-to-back e + ⌫ µ ! W For each W between charged-lepton directions Consequences Small angle ll ⌫ ¯ spins add to Small invariant Spins mass m of the two charged-leptons ll have one to add to zero Elliot Lipeles Search 2013 68 Review of H to WW Analysis WW suppression using spin correlations Consequences of spin correlations Small invariant mass mll of the two charged-leptons Elliot Lipeles Small angle ll between charged-lepton directions Search 2013 69 Review of H to WW Analysis WW suppression approximate mass calculation This obeys the right basic kinematics mT < mH But width of distribution for both signal and background is broad Elliot Lipeles Search 2013 70 Review of H to WW Analysis Diboson Backgrounds • qq̄ ! W Z/ ⇤ ! lll⌫ with a lost lepton ⇤ q q̄ ! Z ! ll⌫⌫ is • also a small background •These are generally modeled with simulation ⇤ ⇤ •There is special case W where the is nearly massless that is difficult to predict Elliot Lipeles Search 2013 71 Modeling of the WW background Focusing on 0-jet •Jet requirements adds a dependence on the modeling of QCD jet emission •Signal to background ratio means need to model WW at the 20% * 1/8 = 2.5% level to not be dominated by this uncertainty Signal Region Control Region Uncertainty on •We are claiming1.6% ratio of signal/ modeling! Use control regions control is ~ 1.6% Elliot Lipeles Search 2013 72 Modeling of the WW background Uncertainty on ratio of signal/control is ~ 1.6% WW cross-section uncertainty ~ 6% using NLO Example for 10 < mll < 30 GeV Source Vary factorization and renormalization scales Uncertainty PDFs 1.5% Underlying Event and Parton Shower Models 0.2% 0.9% “Modeling” •Choice of Generator •Different Generators make difference 1.2% approximations: zero width, massless bquarks.... Elliot Lipeles Search 2013 73 Modeling of the WW background Why vary the factorization and renormalization scales? • An all orders calculation wouldn’t depend on these scales, so any dependence is a rough estimate of the uncalculated terms From Michelangelo Mangano’s slides Elliot Lipeles Search 2013 74 Example: ggH signal •This is actually the single largest systematic uncertainty on µ ⌘ observed / SM •I.e the denominator from theory is bigger than all the experimental errors, but not yet the statistical uncertainty •We determine the uncertainty from renormalization and scale variation Elliot Lipeles Search 2013 75 Modeling the ggH Signal Acceptance Next two slides from Stewart-Tackmann,(arXiv:1107.2117 [hep-ph]) lots of strong interactions • gg ! H is full of gluons •Jet cuts make it significantly harder to calculate acceptance. •Adding a jet cut adds a new scale into the problem Inclusive cross-section Cross-section requiring a jet pT > 30 GeV 1-jet cross-section looks schematically like this where Elliot Lipeles Search 2013 76 Modeling the ggH Signal Acceptance Then 0-jet looks like this: Cancelation between terms with L and without at roughly the experimental cut Suggested procedure to fix this gives large uncertainty introduced due to jet cuts Elliot Lipeles Search 2013 77 VBF analysis in a slide The process Veto jets between the tagging jets in Y Properties Keep Elliot Lipeles Keep Search 2013 78 Modeling the VBF Backgrounds ggF+2 jets 43% uncertainty from QCD scale and PDFs WW+2jets 42% uncertainty from QCD scale and PDFs Elliot Lipeles ttbar +2jets 15% uncertainty for extrapolation from control region Search 2013 79 H ! W W VBF event Elliot Lipeles Search 2013 80 WW Spin Elliot Lipeles Search 2013 81 H ! W W Spin Discriminating variables: spin-2 looks more like background Elliot Lipeles Search 2013 82 H ! W W Spin 2d binned fit BDT0 vs BDT2 BDT separating non-Higgs from spin-0 BDT separating non-Higgs from spin-1 Elliot Lipeles Test statistic likelihood ratio of spin-0 over spin-2 Fit with Spin-0 Fit with Spin-1 Exclusion of 2+ varies from 99% for 100% q q̄ to 95% for 100% ggproduction Search 2013 83 H ! W W Spin Variables Elliot Lipeles Search 2013 84 Spin Combination Spin results from WW, ZZ, and combined Jp=2+ excluded at 99.9% CL independent of Elliot Lipeles fqq̄ Search 2013 85 Gamma Gamma VBF Elliot Lipeles Search 2013 86 H! Elliot Lipeles VBF BDT Search 2013 87 H! Elliot Lipeles VBF Significance Search 2013 88 H! VBF Candidate VBF Channel has a high purity, S/B ~= Elliot Lipeles Search 2013 89