Physics Highlights from the ATLAS Experiment Karl Jakobs For the ATLAS Collaboration ICHEP 2020, Prague / Virtual Conference 10 Years at the Energy Frontier 2010 CERNMarch/April 2020 cerncourier.com COURIERReporting on international high-energy physics Fabiola Gianotti 0 ICHEP 2010, Paris ATLAS 2011 - 2012 Obs. -1 s = 7 TeV: ∫Ldt = 4.6-4.8 fb Exp. Local p s = 8 TeV: ∫Ldt = 5.8-5.9 fb-1 ±1 σ LARGE HADRON COLLIDER 1 0σ 10-1 1σ 10-2 2σ 10 YEARS AT THE -3 10 3σ 10-4 4σ ENERGY FRONTIER 10-5 10-6 5 10-7 σ 2012 10-8 -9 10 6σ -10 107 10 Data 2012 ATLAS 106 Z/γ* -11 Z’ → ee 10 Events Top quark 5 -1 10 L dt = 20.3 fb Dijet & W+Jets ∫ Diboson 110 115 120 125 130 135 140 145 150 4 10 s = 8 TeV Z’ SSM (1.5 TeV) Z’ SSM (2.5 TeV) m [GeV] 103 H 102 10 1 10-1 1.4 1.2 1 0.8 0.6 0.08 0.1 0.2 0.3 0.4 0.5 1 2 3 4 Data/Expected mee [TeV] ~~ ~ 0 gg production; g→ q q χ∼ 1 ATLAS SUSY 2014 1400 Observed limit (±1 σtheory) [GeV] 0 1 ∼ Expected limit (±1 σ ) χ -1 exp m L dt = 20.3 fb , s=8 TeV 1200 ∫ Observed limit (4.7 fb-1, 7 TeV) 0 leptons, 2-6 jets Expected limit (4.7 fb-1, 7 TeV) 1000 800 600 400 200 0 400 600 800 1000 1200 1400 m~g [GeV] 2016 MICE reports muon cooling Protons target cardiac arrhythmia Exploring the Einstein Telescope 2018 K. Jakobs, ATLAS Experiment, ICHEP 2020 ICHEP 2018, Seoul 2 LHC Run 2 (2015 – 2018) pp In Run 2 (2015 – 2018): Delivered: 156 fb-1 Recorded: 147 fb-1 (Data taking efficiency 94.2%) Good for Physics: 139 fb-1 (Efficiency 94.6%, à high data quality) • 94 public results (51 papers) with complete Run-2 pp dataset, 139 fb-1 https://twiki.cern.ch/twiki/bin/view/AtlasPublic/ResultswithData2018 • 10 public results ( 2 papers) incl. the 2018 Heavy Ion data, 1.7 nb-1 https://twiki.cern.ch/twiki/bin/view/AtlasPublic/HeavyIonsPublicResults • 35 ICHEP 2020 Conference contributions https://atlas.cern/updates/atlas-news/summary-ichep-2020 K. Jakobs, ATLAS Experiment, ICHEP 2020 3 Higgs Boson Physics H à ZZ* à4ℓ H à γγ H à WW* à eν µν arXiv:2004.03969 ATLAS-CONF-2020-026 (VBF) ATLAS-CONF-2020-045 6 180 ATLAS Preliminary 10 Data 3000 Data ATLAS Preliminary Data Uncertainty ATLAS Higgs (125 GeV) -1 -1 s = 13 TeV, 139 fb s = 13 TeV, 139 fb H H H ZZ* 4l VBF ggF 160 → → Z(Z*) Background 5 H → WW * → eνµν s = 13 TeV, 139 fb-1 m = 125.09 GeV 10 tXX, VVV 2500 H Other H tt/Wt 140 Z+jets, tt Signal + Background WW Z /γ* All categories Events / bin 4 Uncertainty 2000 10 Mis-Id Other VV 120 ln(1+S/B) weighted sum 1500 S = Inclusive 3 Events/2.5 GeV 10 100 1000 Sum of Weights / GeV 102 80 500 60 10 100 40 mγγ [GeV] 1 50 20 0 1.4 Cont. Bkg. 1.2 0 − −50 80 90 100 110 120 130 140 150 160 170 110 120 130 140 150 160 1 Data / Pred. 0.8 Data mγγ [GeV] m4l [GeV] 0.6 4 3 σ = 53.5 ± 4.9 (stat) ± 2.1 (syst) pb σ BRγγ = 127 ± 7 (stat) ± 7 (syst) fb 2 σ = 55.7 ± 2.8 pb σ BR = 116 ± 5 fb Bkg.) / Bkg. 1 SM SM γγ − 0 Top CR Z+jets CR [0,0.25] [0.25,0.59][0.59,0.73][0.73,0.83][0.83,0.89][0.89,0.93][0.93,1.00] (Tot. CRs DNN output in SR Large Run-2 dataset allows for more detailed measurements +0.17 VBF BR = 0.85 ± 0.10 (stat) (syst) pb σ WW - 0.13 - Differential cross sections VBF σ SM BRWW = 0.81 ± 0.02 pb - Search for rarer decay modes Obs. (exp.) significance: 7.0σ (6.2σ) K. Jakobs, ATLAS Experiment, ICHEP 2020 4 (i) Decays into Fermions: Run-2 results on VH, H à bb Resolved analysis (standard) Vector bosons at high pT (boosted topology) arXiv:2007.02873 arXiv:2007.02873 CERN-EP-2020-093 Resolved analysis Signal strength: µ = σobs / σSM +0.12 +0.14 µVH(bb) = 1.02 - 0.11 (stat) - 0.13 (syst) Good agreement between measurements and SM predictions Obs. (exp.) significance: 6.7σ (6.7σ) significance (ZH): 5.3σ (5.1σ) Boosted analysis: measurement at high pT à increased sensitivity to BSM physics K. Jakobs, ATLAS Experiment, ICHEP 2020 5 (ii) Decays into 2nd Generation Fermions? • Important milestone: test of Yukawa sector H à µµ decays offer the most promising path to 2nd gen arXiv:2007.07830 • However: BR (H à µµ) ~ 2.2 10-4, and huge background from Drell-Yan production of µ pairs • Optimised analysis: - Exploit topological and kinematic differences between different Higgs production modes and the background - Use of multivariate techniques à Classify events in 20 mutually exclusive categories Best fit signal strength: µ = 1.2 ± 0.6 Obs. (exp.) significance: 2.0σ (1.7σ) Run 3 and beyond essential to increase sensitivity K. Jakobs, ATLAS Experiment, ICHEP 2020 6 (iii) Search for rare and invisible decays qqH à qq inv. (VBF) H à Zγ ATLAS-CONF-2020-008 arXiv:2005.05382 Limit on BR (H à inv.): < 0.13 (95% CL) Background-only hypothesis: p-value of 1.3% (2.2σ) Best fit signal strength: µ = 2.0 ± 0.9 (stat) +0.4 (syst) Zγ - 0.3 (exp. µZγ = 1.0 ± 0.8 ± 0.3 for a SM Higgs) Run 3 and beyond essential to increase sensitivity K. Jakobs, ATLAS Experiment, ICHEP 2020 Dark Matter interpretation (Higgs portal models) 7 Combined Measurements of Higgs Boson production and decays Channels included in the combination: (ii) Production Cross Sections (assume SM branching ratios) ATLAS-CONF-2020-027 ATLAS Preliminary Total Stat. Syst. SM s = 13 TeV, 24.5 - 139 fb-1 m = 125.09 GeV, |y | < 2.5 H H p = 86% SM Total Stat. Syst. ggF 1.00 ± 0.07 ( ± 0.05 , ± 0.05 ) + 0.18 + 0.12 VBF 1.15 − 0.17 ( ± 0.13 , − 0.10 ) + 0.23 + 0.17 + 0.15 WH 1.20 − 0.21 ( − 0.16 , − 0.14 ) + 0.22 + 0.15 ZH 0.98 − 0.21 ( ± 0.16 , − 0.13 ) ttH+tH 1.10 + 0.21 ( + 0.16 , + 0.14 ) (i) Global signal strength − 0.20 − 0.15 − 0.13 Describing a common scaling of the expected Higgs boson 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 yields in all processes (σ x BR) (SM: µ = 1.0) Cross-section normalized to SM value All major production processes observed µ = 1.06 ± 0.07 (significance > 5σ ) +0.05 First observation of WH production: 6.3σ (5.2σ exp) [ ± 0.04 (stat) ± 0.03 (exp) - 0.04 (sig.th) ± 0.02 (bkg.th) ] K. Jakobs, ATLAS Experiment, ICHEP 2020 8 (iii) Measurements of simplified template cross-sections (STXS) ATLAS-CONF-2020-027 ATLAS - Partition phase space into a set of non-overlapping regions Preliminary Total Stat. Syst. -1 s = 13 TeV, 139 fb +0.14 +0.12 +0.07 B γγ /B ZZ* 1.07 ( , ) - Defined in terms of kinematics of the Higgs boson, associated jets, m = 125.09 GeV, |y | < 2.5 −0.12 −0.11 −0.06 H H p = 95% B /B +0.57 +0.48 +0.30 SM bb ZZ* 0.77 −0.28 ( −0.25, −0.12) W and Z bosons Total Stat. Syst. SM 0 0.5 1 1.5 2 à Match experimental selections, avoid large theory uncertainties, Total Stat. Syst. H +0.22 +0.19 +0.10 0-jet, p < 10 GeV 0.82 ( , ) sensitive to deviations from SM T −0.20 −0.18 −0.09 0-jet, 10 ≤ pH < 200 GeV +0.15 +0.13 +0.08 T 1.12 −0.14 ( −0.12, −0.07) 1-jet, pH < 60 GeV +0.31 +0.28 T 0.61 −0.30 ( −0.27, ±0.13) 1-jet, 60 ≤ pH < 120 GeV +0.31 +0.28 +0.13 T 1.31 −0.29 ( −0.27, −0.10) gg H + bbH¯ 1-jet, 120 ≤ pH < 200 GeV +0.45 +0.42 +0.15 ! T 0.72 −0.41 ( −0.40, −0.09) H H gg→H × B ZZ* ≥ 2-jet, m jj < 350 GeV, p < 120 GeV 0.30 ±0.45 ( ±0.42, ±0.16) 0-jet,pT < 10 GeV T = 0 jets ≥ 2-jet, m < 350 GeV, 120 ≤ pH < 200 GeV +0.46 +0.41 +0.21 jj T 0.67 −0.44 ( −0.39, −0.19) 0-jet, 10 pH < 200 GeV EW qq0 Hqq0 T ! H +0.83 +0.73 +0.39 ≥ 2-jet, m jj ≥ 350 GeV, p < 200 GeV 1.61 ( , ) H T −0.76 −0.69 −0.32 pT < 200 GeV 200 ≤ pH < 300 GeV +0.40 +0.37 +0.15 H T 1.19 −0.36 ( −0.33, −0.12) 1-jet,pT < 60 GeV 1-jet 300 ≤ pH < 450 GeV +0.56 +0.52 +0.20 = 1 jet T 0.39 −0.49 ( −0.46, −0.16) 1-jet, 60 pH < 120 GeV T pH ≥ 450 GeV +1.44 +1.33 +0.55 2 jets T 1.76 ( , ) ≥ −1.12 −1.05 −0.40 1-jet, 120 pH < 200 GeV T 2-jet,mjj < 350 GeV, VH topo +0.99 +0.95 2 jets ≥ ≤ 1-jet ≥ 1.00 −0.89 ( −0.84, ±0.29) +1.66 +1.54 +0.62 2-jet,m < 350 GeV, VH veto ≥ 2-jet, m jj < 350 GeV, VH veto 2.29 ( , ) ≥ jj −1.52 −1.45 −0.47 +0.83 +0.79 +0.24 2-jet,m < 350 GeV,pH < 120 GeV ≥ 2-jet, m jj < 350 GeV, VH topo 0.65 ( , ) mjj < 350 GeV ≥ jj T −0.73 −0.69 −0.21 qq→Hqq × B ZZ* H +0.64 +0.59 +0.26 ≥ 2-jet, 350 ≤ m jj < 700 GeV, p < 200 GeV 0.81 ( , ) H mjj 350 GeV T −0.56 −0.52 −0.21 2-jet,mjj < 350 GeV, 120 pT < 200 GeV ≥ ≥ H +0.34 +0.29 +0.19 ≥ 2-jet, m jj ≥ 700 GeV, p < 200 GeV 1.16 ( , ) H T −0.29 −0.26 −0.14 2-jet,mjj 350 GeV,pT 200 GeV 2-jet,m 350 GeV,pH < 200 GeV ≥ ≥ ≥ H +0.44 +0.41 +0.18 ≥ jj ≥ T ≥ 2-jet, m ≥ 350 GeV, p ≥ 200 GeV jj T 1.20 −0.37 ( −0.34, −0.14) H pT < 200 GeV 200 pH < 300 GeV T pV < 75 GeV +1.18 +1.16 +0.22 T 2.46 −1.02 ( −1.02, −0.13) H H 2-jet, 350 mjj < 700 GeV,p < 200 GeV V +1.01 +0.99 +0.20 300 pT < 450 GeV T 75 ≤ p < 150 GeV ≥ T 1.70 −0.82 ( −0.81, −0.12) qq→Hl ν × B ZZ* V +0.93 +0.83 +0.42 H H 150 ≤ p < 250 GeV 1.46 ( , ) p 450 GeV 2-jet,mjj 700 GeV,pT < 200 GeV T −0.72 −0.65 −0.32 T ≥ ≥ ≥ pV ≥ 250 GeV +0.79 +0.71 +0.34 T 1.28 −0.56 ( −0.52, −0.21) V(lep)H pV < 150 GeV +0.74 +0.54 +0.50 T 0.19 −0.82 ( −0.57, −0.59) H`⌫,pW < 75 GeV V +0.77 +0.70 +0.32 T gg/qq→Hll × B ZZ* 150 ≤ p < 250 GeV 1.30 ( , ) t¯tH T −0.56 −0.52 −0.21 pV ≥ 250 GeV +0.91 +0.81 +0.41 W T 1.41 ( , ) H`⌫, 75 pT < 150 GeV −0.63 −0.59 −0.23 qq0 H`⌫ H ! pT < 60 GeV W H`⌫, 150 pT < 250 GeV pH < 60 GeV +0.77 +0.76 +0.13 H T 0.72 ( , ) 60 pT < 120 GeV −0.64 −0.64 −0.08 H +0.51 +0.51 +0.08 W 60 ≤ p < 120 GeV 0.66 ( , ) H`⌫,pT 250 GeV T −0.43 −0.43 −0.05 ≥ H t Ht × B 120 p < 200 GeV ZZ* H +0.60 +0.59 +0.14 T 120 ≤ p < 200 GeV T 1.00 −0.51 ( −0.50, −0.10) H +0.53 +0.52 +0.10 Z H p ≥ 200 GeV H``,pT < 150 GeV p 200 GeV T 0.86 ( , ) T ≥ −0.45 −0.45 −0.06 pp H`` ! Z H``, 150 pT < 250 GeV tH × B +3.31 +3.23 +0.71 ZZ* 1.71 −2.52 ( −2.44, −0.63) H``,pZ 250 GeV tH T ≥ −6 −4 −2 02468 Figure 8: Definition of the STXS measurement regions used in this note.