Recent Results on Top Physics at CMS Jasmin Gruschke (KIT) on behalf of the CMS Collaboration Moriond/QCD: Rencontres de Moriond on QCD and High Energy Interactions March 2 th -29 th 211 Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 1 / 25
The Top Story on Cross Sections and Properties hps://twiki.cern.ch/twiki/bin/view/cmspublic/physicsresultstop t t Cross Section Measurement in the Lepton+Jets Channels w/o b-tagging (TOP-2) t t Cross Section Measurement in the Lepton+Jets Channels with b-tagging (TOP-3) t t Cross Section Measurement in the Dilepton Channels (TOP-5) Combination of t t Cross Section Measurements and Comparison with Theory Predictions (TOP1-1) Single Top Quark Cross Section Measurement (TOP-8) Top Quark Mass Measurement in the Dilepton Channels (TOP-6) Charge Asymmetry Measurement (TOP-) The m(t t) Spectrum and Searches for New Physics (TOP-7) All presented results are obtained from the full 2 pp dataset: L = (36 ± 1) pb 1 Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 2 / 25
CMS-PAS TOP-2 t t Cross Section in the Lepton+Jets Channels w/o b-tagging (CMS-PAS TOP-2) Binned Likelihood Template Fit to E T and M3 (inv. mass of three jets with highest vectorial summed p T ) distributions e+jets channel µ+jets channel Combined measurement in both channels Special Features: Data-driven lepton selection and trigger efficiencies Data-driven QCD template Events 7 6 5 4 3 2 36 pb at s = 7 TeV e+jets, N jets Data Single-Top W lν + - Z/γ* l l QCD/γ+jets event fraction event fraction.25.2.15.1.5 e+jets Channel: CMS Simulation at s = 7 TeV.3 e+jets, N =3 jets Single-Top W lν + - Z/γ* l l QCD/γ+jets 2 4 6 8 12 14 16 E T [GeV] CMS Simulation at s = 7 TeV.25 e+jets, N 4 jets.2.15.1.5 Single-Top W lν + - Z/γ* l l QCD/γ+jets 2 3 4 5 6 7 M3 [GeV] 1 1 2 3 4 Jet Multiplicity Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 3 / 25
CMS-PAS TOP-2 t t Cross Section in the Lepton+Jets Channels w/o b-tagging (CMS-PAS TOP-2) µ+jets Channel: Events / 25 GeV Events / 5 GeV 16 14 12 8 6 4 2 12 36 pb at s = 7 TeV µ+jets, N = 3 jets Data Single-Top W lν + - Z/γ* l l QCD 2 4 6 8 12 14 16 18 E [GeV] T 8 6 4 2 36 pb at s = 7 TeV µ+jets, N 4 jets Data Single-Top W lν + - Z/γ* l l QCD 2 3 4 5 6 M3 [GeV] fit β 3.5 3 2.5 2 1.5 1.5 Combined Measurement: 95% confidence belt 68% confidence belt fit β =1..5 1 1.5 2 2.5 3 in β β t t = σobs t t σ theory t t JES uncertainty is the dominating source of systematic uncertainties Differential cross section measurement in the backup! Combined Measurement: σ t t = 173 +39 32 (stat. + syst.) ± 7 (lumi.) pb Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 4 / 25
CMS-PAS TOP-3 t t Cross Section in the Lepton+Jets Channels with b-tagging (CMS-PAS TOP-3) Binned Likelihood Fit to the secondary vertex mass in the e+jets, µ+jets channel, and in the combination of both channels Data µ+jets channel: T op S ingle Top Wbx Wc x W+LF Jets Z + J ets QC D Combined Measurement: σ t t = 15 ± 9 (stat.) ± 17 (syst.) ± 6 (lumi.) pb Profiling: most important systematics included as parameters, thus their impact reduced µ-in-jet and neural net analyses as well as a counting experiment (e+jets channel) can be found in the backup! Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 5 / 25
CMS-PAS TOP-5 t t Cross Section in the Dilepton Channels (CMS-PAS TOP-5) Event counting with dedicated data-driven techniques for the estimation of background contributions in the e + e, the µ + µ, and the e ± µ channels ee,µµ, and eµ ee,µµ, and eµ More supporting Tables/Figures can be found in the backup! σ t t = 168 ± 18 (stat.) ± 14 (syst.) ± 7 (lumi.) pb Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 6 / 25
CMS-PAS TOP1-1 Combination of t t Cross Section Measurements and Comparison with Theory Predictions (CMS-PAS TOP1-1), s=7 TeV 5.8 15 CMS combined (prel.) 158 ± ± 15 ± 6 TOP1-1 (unc. ± cor. ± lum.) (36 pb ) 17 CMS l+jets+btag (prel.) 15 ± 9 ± ± 6 17 TOP-3 (36 pb ) 14 CMS dilepton (prel.) 168 ± 18 ± 14 ± 7 TOP-5 (36 pb ) NLO QCD 36 CMS l+jets (prel.) 173 ± 14 ± 29 ± 7 TOP-2 (36 pb ).25 5 15 2 25 3 Top Pair Production Cross Section [pb] Approx. NNLO QCD value ± stat. ± (luminosity) syst. ± lum. error 15 ATLAS combined (prel.) 18 ± 9 ± 15 ± 6 ATLAS-CONF-211-4 (35 pb ) Theory: Langenfeld, Moch, Uwer, Phys. Rev. D8 (29) 549 MSTW28(N)NLO PDF, scale PDF(9% C.L.) unc. Top Pair Production Cross Section [pb] 2 CMS combined (36 pb ) ATLAS combined (35 pb ) CDF D Approx. NNLO QCD (pp) scale unc. NLO QCD (pp) Approx. NNLO QCD (pp) scale unc. Langenfeld, Moch, Uwer, Phys. Rev. D8 (29) 549 MSTW 28 NNLO PDF 1 2 3 4 5 6 7 8 s [TeV] σ NLO t t (MCFM) = 158 +23 24 pb app. NNLO σ (HATHOR) t t = 164 +11 13 pb app. NNLO σ (Kidonakis) t t = 163 +11 pb σ CMS t t = (158 ± 19) pb Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 7 / 25
CMS-PAS TOP-8 Single Top Quark Cross Section Measurement (CMS-PAS TOP-8) Two complementary analyses (only 36 pb 1!!): A 2D template fit to cos(θlj ) and η lj (characteristic for EWK production of single top quarks) and a multivariate technique (BDT) Combined: e+jets & µ+jets Combination of both analyses:, 36 pb, s = 7 TeV Events 45 4 35 3 25 2 15 5.5 1 1.5 2 2.5 3 3.5 4 4.5 5 η lj data t channel s channel tw Wbb Wcc Wc W+light jets Z+jets VV QCD σ 4FS t = (59.1 +3. 4. ) pb σ 5FS t = (62.3 +2.3 2.4 ) pb Both analyses yield a significance > 3σ Combination of both analyses: σ t = 83.6 ± 29.8 (stat. + syst.) ± 3.3 (lumi.) pb Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 8 / 25
CMS-PAS TOP-6 Top Quark Mass Measurement in the Dilepton Channels (CMS-PAS TOP-6) Two analysis techniques based on template fits: fully kinematic analysis (left) and analytical matrix weighting technique (AMWT, right) The shaded area corresponds to the background-only shapes; PIPs show the LLH as functions of m top Combination of both analyses: m top = 175.5 ± 4.6 (stat.) ± 4.6 (syst.) GeV/c 2 Combination takes into account full study of statistical uncertainties Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 9 / 25
CMS-PAS TOP- t t Charge Asymmetry Measurement (CMS-PAS TOP-) events At the Tevatron: Deviation > 3σ from SM predicted A FB 5% At the LHC: Initial state symmetric (pp collider!) charge asymmetry (visible in η t η t ) Expected asymmetry is small A C =.13(11) [Ferrario, Rodrigo, et. al.], however, BSM like a Z or an axigluon could show up 5 Expect L = 1 fb 1 necessary to compete with Tevatron data 1 36 pb at s = 7 TeV e+jets, µ+jets single top rec A C =.18±.34 Z+jets W+jets QCD (reconstructed) t η t η 4 2 2.4.2 η 1/σ dσ/d( η ).4.2 1 36 pb at s = 7 TeV unfolded result LO MadGraph NLO prediction 4 2 2 η η 4 t t 4 4 2 2 4 η η (generated) t t 4 2 2 4 η η t t A C =.6 ±.134 (stat.) ±.26 (syst.) Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 / 25
2 2 CMS-PAS TOP-7 The m(t t) Spectrum and Searches for New Physics (CMS-PAS TOP-7) Search for massive neutral bosons decaying into a t t pair (e+jets and µ+jets channel); background and LLH treatment similar to TOP-3 Events / 5 GeV/c Events / 5 GeV/c 5 4 3 2 12 8 6 4 2 3 jets; 1 b-tag 36 pb at s = 7 TeV e+µ, = 3 jets, 1 b-tags Data QCD + - Z/γ* l l Vbb+X Vc(c)+X W lν Single-Top (+ light jets) (+ light jets) Z'.5 TeV (5 pb) Z'.75 TeV (5 pb) Z' 1 TeV (5 pb) Z' 1.25 TeV (5 pb) 4 6 8 12 14 16 18 2 m [GeV/c ] 36 pb at s = 7 TeV e+µ, 4 jets 4 jets Data QCD + - Z/γ* l l Vbb+X Vc(c)+X W lν Single-Top (+ light jets) (+ light jets) Z'.5 TeV (5 pb) Z'.75 TeV (5 pb) Z' 1 TeV (5 pb) Z' 1.25 TeV (5 pb) 4 6 8 12 14 16 18 2 m [GeV/c ] No significant signal observed upper limits on the production cross section aafo the boson mass: BR(Z' ) [pb] Upper Limit σ Z' 8 7 36 pb at s = 7 TeV 6 5 4 3 2 Observed (95% CL) Expected (95% CL) ± 1σ Expected ± 2σ Expected.4.6.8 1 1.2 1.4 1.6 1.8 2 2 [TeV/c ] m Z' Complementary analysis in the backup! Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 11 / 25
Conclusions Conclusion and Outlook We have started to scrutinise the Standard Model on the top quark sector We re even becoming competitive with the Tevatron experiments Measurement of: σ t t in the Lepton+Jets (e and µ) channels with and w/o b-tagging σ t t in the Dilepton channels (ee, eµ, and eµ) σ t t as the combination of the upper two results σ t single top quark production in the Lepton+Jets (e and µ) channels the top quark mass in the Dilepton Channels the charge asymmetry A C the m t t spectrum and searches for massive neutral bosons decaying into t t Until now, no major surprises. But we just started...... who knows what might be out there! Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 12 / 25
Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 13 / 25
Additional Information on TOP-2 Cross section results for the e+jets and for the µ+jets channels, and for the combined measurement. e+jets Channel: µ+jets Channel: Combined Measurement: Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 14 / 25
Additional Information on TOP-2 σ ( µ+jets ) [ pb ] Data/MC CMS preliminary 36 pb at s = 7 TeV 4 3 2 Data W lν Single-Top signal 1 1 1.5 1 2 3 4 1.5 1 2 3 4 1.5 1 2 3 4 N jets (p >3GeV) T σ ( µ+jets ) [ pb ] Data/MC CMS preliminary 36 pb at s = 7 TeV 4 3 2 1.5 Data W lν Single-Top signal 1 2 3 4 N jets (p >3GeV) T Cross section for the production of an isolated muon in association with additional hard jets: as function of inclusive (left) and exclusive (right) jet multiplicity Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 15 / 25
Additional Information on TOP-3 Cross section results for the e+jets and for the µ+jets channels, and for the combined measurement. e+jets Channel: µ+jets Channel: Combined Measurement: Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 16 / 25
Additional Information on TOP-3 Jet multiplicity in muon channel with at least one muon-in-jet. The measured cross section is σ t t = 163 ± 21 (stat.) ± 35 (syst.) ± 7 (lumi.) pb Fit result of neural net analysis. The measured cross section is σ t t = 151 ± 15 (stat.) +35 28 (syst.) ± 6 (lumi.) pb b-tag multiplicity in the electron channel. The measured cross section is σ t t = 169 ± 13 (stat.) +39 32 (syst.) ± 7 (lumi.) pb Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 17 / 25
Additional Information on TOP-5 Additional distributions N jets distribution in the ee, µµ, eµ, and for the combination of all channels N b tags distribution in the ee, µµ, eµ, and for the combination of all channels Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 18 / 25
Additional Information on TOP-5 Distribution of the b-tagging discriminator in events with at least two jets and passing full analysis selection criteria prior to applying a b-tagging requirement compared to signal and background expectations from simulation. A jet is b-tagged if the value of the discriminator is above 1.7. The distributions are for events in e + e, µ + µ, e ± µ, and all final states combined. Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 19 / 25
Additional Information on TOP1-1 Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 2 / 25
Additional Information on TOP1-1, 9.8 s=7 TeV value ± stat. ± syst. ± lum. error (luminosity) CMS combined (prel.) 158 ± ± ± 6 15 15 TOP1-1 (unc. ± cor. ± lum.) (36 pb ) CMS l+jets+btag (prel.) 15 ± 9 ± ± 6 17 17 TOP-3 (36 pb ) CMS dilepton (prel.) 168 ± 18 ± ± 7 14 14 TOP-5 (36 pb ) CMS l+jets (prel.) 173 ± 14 ± ± 7 36 29 TOP-2 (36 pb ) ATLAS combined (prel.) 18 ± 9 ± ± 6 15 15 ATLAS-CONF-211-4 (35 pb ) NLO QCD Approx. NNLO QCD 21 ATLAS l+jets+btag (prel.) 186 ± ± ± 6 2 ATLAS-CONF-211-35 (35 pb ) 18 ATLAS dilepton (prel.) 173 ± 22 ± 16 ± 8 ATLAS-CONF-211-34 (35 pb ) 2 ATLAS l+jets (prel.) 171 ± 17 ± 17 ± 6 ATLAS-CONF-211-23 (35 pb ) ATLAS dilepton+btag (prel.) 171 ± 22 ± ± 7 21 16 ATLAS-CONF-211-34 (35 pb ) Theory: Langenfeld, Moch, Uwer, Phys. Rev. D8 (29) 549 MSTW28(N)NLO PDF, scale PDF(9% C.L.) unc..25 5 15 2 25 3 Top Pair Production Cross Section [pb] Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 21 / 25
Additional Information on TOP-8 7.8, s=7 TeV, L=35.9 pb 5.9 2D, µ channel 4.1 ± 5.9 2D, e channel 73.1 154.2 ± 73.1 4.4 BDT, µ channel 89.8 ± 4.4 BDT, e channel 37.8 59.2 ± 37.8 2D, e+ µ channel 48.1 124.2 ± 48.1 BDT, e+ µ channel CMS combination NLO - 4FS SM Prediction NLO - 5FS 29.5 78.7 ± 29.5 3. 83.6 ± 3. Expected and observed significances -5 5 15 2 Single Top t-channel Production Cross Section [pb] Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 22 / 25
Additional Information on TOP-6 Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 23 / 25
Additional Information on TOP- Reconstruction of the t t system: events 3 2 1 36 pb at s = 7 TeV e+jets, µ+jets data single top Z+jets W+jets QCD Covariance matrix: bin 1.241.11.7.31.7. bin 2..48.27.4.22.3 bin 3.7.27.87.27.34.13 bin 4.32.4.26.177.43.53 bin 5.6.23.35.43.68.3 bin 6.1.3.13.52.2.64 1.2.4.6.8 1 Ψ bin 1 bin 2 bin 3 bin 4 bin 5 bin 6 Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 24 / 25
Additional Information on TOP-7 e+jets channel (2 tags): Complementary to the analysis presented above: Data-driven techniques in order to reduce systematic uncertainties (mainly modelling) Alternative isolation requirements (less sensitive to the boost of the top quark but also less effective for background rejection) Alternative b-tagging algorithm µ+jets channel (2 tags): Jasmin.Gruschke@cern.ch (KIT) Top Physics @ CMS: Recent Results Moriond/QCD March, 29th 211 25 / 25