LHC Selected Physics Eckhard Elsen Director Research and Computing Results from LHC Run 1 and Run 2 ILC Advisory Committee, Dec 6, 2017, MEXT, Tokyo, Japan 1
LHC and its injector chain used for physics LHC Run 1 @ 7-8 TeV ongoing Run 2 @ 13 TeV Run 3 starting 2021 @ 14 TeV Injectors supporting additional programme Fixed target programme ISOLDE (isotopes) n-tof 75% of all p Antiproton Decelerator (AD) programme 2
!!! CERN-Council-S/106 Original: English 7 May 2013 ORGANISATION EUROPEENNE POUR LA RECHERCHE NUCLEAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH!! Action to be taken Voting Procedure executing the ongoing European Strategy!!! For Approval EUROPEAN STRATEGY SESSION OF COUNCIL 16 th Session - 30 May 2013 European Commission Berlaymont Building - Brussels Simple Majority of Member States represented and voting for Particle Physics The European Strategy for Particle Physics Update 2013 Having finalised its text by consensus at its Session of 22 March 2013, the Council is now invited to formally adopt the Update of the European Strategy for Particle Physics set out in this document.! released in 2013 3
LHC as #1 tool 4
LHC Integrated Luminosity Run 2 (2015-2018) Luminosity of 2017 exceeded 50 fb, a new record also allowed for special runs at 5 TeV LHC is very well understood and meticulously maintained to reach optimum availability. 5
Event Pile-Up and Luminosity Levelling at LHC Peak L ~ 2 10 34 cm -2 s ATLAS and CMS prefer L 1.5 10 34 cm -2 s and longer fills (slow beam burn-off) Initially separate the *Thanks Max. to IT lumi for With loan separation of machines! beams transversely and slowly increase overlap levelling Levelling leads to cleaner events and only small degradation of integrated luminosity 6
Run 1 and Run 2 Luminosities 95 fb have been J. Wenninger produced in Run 2 so far 2018 will add to this 123 fb produced since start of LHC Expect to reach 300 fb for Runs 1-3; before 2024 7
LHC schedule HL-LHC High Luminosity Phase of LHC LS2 (2019-2020): Substantial upgrades LS3 for (2024-2026): LHC Injectors Upgrade (LIU) ALICE and LHCb; HL-LHC installation Civil engineering for HL-LHC equipment preparatory P1,P5 upgrades for end of original LHC First 11 T dipoles P7; cryogenics in P4ATLAS and CMS including Phase upgrade of LHC experiments civil construction Schedule driven by radiation damage to inner triplet (eol: 2023) Phase-2 upgrade of ATLAS and CMS 8
Run 1 Highlight Discovery of Higgs Particle only fundamental scalar particle of Standard Model couples to all massive particles portal to new physics Initial observation Large Japanese Events / 2.5 GeV 35 Data 30 25 20 15 10 5 ATLAS H ZZ* 4l s = 7 TeV: Ldt = 4.5 fb s = 8 TeV: Ldt = 20.3 fb Signal (m H Background ZZ* Background Z+jets, t t Systematic uncertainty = 124.5 GeV µ = 1.66) 0 80 90 100 110 120 130 140 150 160 170 m 4l Run 1 result 4l [GeV] contribution to machine and ATLAS detector for F Englert and P Higgs 9
H ττ at LHC Higgs boson couples to mass among leptons the decay to τ-leptons is preferred (τ-lepton, BR=6.3%) τ-detection challenging τhτh, eτh, µτh- modes used Observation of Higgs particle coupling to leptons 4.9 σ from 13 TeV data 10
H bb from ATLAS Higgs boson couples to mass preferential decay to heaviest quark allowed (b-quark, BR=58%) overwhelming background from light quarks Use associate production with W or Z Higgs particle coupling to quarks 3.6 σ 11
and H bb from CMS Higgs boson couples to 35.9 fb (13 TeV) mass; b-quark preferred overwhelming background from light quarks S/(S+B) weighted entries 200 150 100 50 CMS pp VH, H bb Data VH(bb) (µ=1.2) VZ(bb) MC uncertainty Use associate production with W or Z with leptonic decay signature 0 50 0 50 100 150 200 250 [GeV] M jj 3.8 σ when combining with 7+8 TeV syst. limited 12
Inclusive boosted H bb with pt,higgs > 450 GeV, the b-jets fuse, into a single jet containing displaced vertices use jet-substructure and vertex tagging Z bb @ 5.1 σ H bb @ 1.5 σ b b Promising technique; requires more statistics 13
H fermions H τ τ H b b Using τ τ h h eτ h μτ h eμ Evidence for VH(bb): 3.6 when 4.9 σ 3.5 σ 14
Direct Measurement of tth coupling Identifikation of top and Higgs tt with 1 or 2 leptons λ t = 2m t ν t Higgs in WW, ττ and ZZ tҧ ATLAS-CONF-2017-77 ATLAS-CONF-2017-77 15
Higgs couples to massive particles Standard Model predictions for Higgs branchings v V m κ V 1 ATLAS and CMS LHC Run 1 W Z t Decay mode Branching fraction [%] H! bb 57.5 ± 1.9 H! WW 21.6 ± 0.9 H! gg 8.56 ± 0.86 H! tt 6.30 ± 0.36 H! cc 2.90 ± 0.35 H! ZZ 2.67 ± 0.11 H! gg 0.228 ± 0.011 H! Zg 0.155 ± 0.014 H! µµ 0.022 ± 0.001 or v F m κ F 1 10 2 10 3 10 µ τ b ATLAS+CMS SM Higgs boson [M, ε] fit Invisible Higgs decays 68% CL experimentally not accessible at LHC 4 10 95% CL 1 10 1 10 10 Particle mass [GeV] 2 16
W and Z production cross section at 7 TeV Improvements over 2010 measurement 100x statistics over previous result luminosity determination 3.5% 1.8% better understanding of the triggers and the lepton reconstruction reduced systematics before Large impact on PDFs: strange quarks at high x not suppressed after 17
Measuring Standard Model Cross Sections 18
W mass measurement W mass 7 TeV, 4.6fb 20 MW = 80370 ± 19 MeV ±7 statistics ±11 systematic ±14 modelling Electroweak sector consistency 2 ATLAS measurement is consistent with SM predictions ATLAS measurement has similar precision to the current best measurement 19
Top Mass Measurement 23 ATLAS Preliminary m top summary - September 2017, L int = 35 pb - 20.3 fb l+jets* 169.3 ± 6.3 ( 4.0 ± 4.9 ) ATLAS-CONF-2011-033 = 35 pb Eur. Phys. J. C72 (2012) 2046 l+jets 174.5 ± 2.4 ( 0.6 ± 0.4 ± 2.3 ) = 1.04 fb ATLAS-CONF-2012-030 = 2.05 fb Eur. Phys. J. C75 (2015) 158 all jets* 174.9 ± 4.3 ( 2.1 ± 3.8 ) all jets 175.1 ± 1.8 ( 1.4 ± 1.2 ) single top* 172.2 ± 2.1 2.0 ) ATLAS-CONF-2014-055 ( 0.7 ± =20.3 fb Eur. Phys. J. C75 (2015) 330 l+jets 172.3 ± 1.3 ( 0.2 ± 0.2 ± 0.7 ± 1.0 ) = 4.7 fb Eur. Phys. J. C75 (2015) 330 dilepton 173.8 ± 1.4 ( 0.5 ± 1.3 ) = 4.7 fb Phys. Lett. B761 (2016) 350 dilepton 173.0 ± 0.8 ( 0.4 ± 0.7 ) = 20.2 fb all jets 173.7 ± 1.2 1.0 ) arxiv:1702.07546 = 20.2 fb ( 0.6 ± l+jets* ATLAS-CONF-2017-071 = 20.2 fb 172.1 ± 0.9 ( 0.1 ± 0.1 ± 0.3 ± 0.8 ) = 4.6 fb m top ± tot. (stat. ± JSF ± bjsf ± syst.) 1 σ (tt) l+jets σ (tt) dilepton =4.6-20.3 fb JHEP 10 (2015) 121 2.3 Differential σ(tt+1-jet) 173.7 ± =4.6 fb 2.1 Differential σ(tt) dilepton (8 dist.) ATLAS-CONF-2017-044 173.2 ± 1.6 ATLAS Comb. September 2017* 172.51 ± World Comb. Mar. 2014 (arxiv:1403.4427) 173.34 ± Tevatron Comb. Jul. 2014 (arxiv:1407.2682) 174.34 ± ATLAS-CONF-2011-054, L =35 pb int Eur. Phys. J. C74 (2014) 3109 0.50 0.76 0.64 =20.2 fb ATLAS-CONF-2017-071 160 165 170 175 180 185 190 [GeV] 166.4 172.9 ± ± 7.8 7.3 2.5 2.6 World Comb. ± 1 σ stat. uncertainty stat. JSF bjsf uncertainty total uncertainty *Preliminary, Input to ATLAS comb. m top 20
HL-LHC schedule LS2 (2019-2020): LHC Injectors Upgrade (LIU) Civil engineering for HL-LHC equipment P1,P5 First 11 T dipoles P7; cryogenics in P4 Phase upgrade of LHC experiments LS3 (2024-2026): HL-LHC installation Phase-2 upgrade of ATLAS and CMS Schedule driven by radiation damage to inner triplet (eol: 2023) 21
Impact of HL-LHC precise measurement of Higgs couplings deviations may be at the few %-level access to second generation couplings H μμ 20-30% larger discovery potential (8 TeV) precision measurements Full prospects of HL-LHC will be presented in a Physics Book end 2018 22
LHC ultimate prospects for Higgs measurements 3 ab goal of the High Luminosity Upgrade (HL-LHC) provides the ultimate precision for Higgs coupling measurements, including H μμ Current presentation of Upgrades TDR to detectors will maintain the detector capabilities of Run 1 despite of a pile-up of 200 Hope for similar Japanese contribution as in phase 1 Nonetheless the Higgs Branching ratios cannot be determined in a model independent fashion (invisible Higgs decays) complementarity of e + e - colliders 23
Prospects for Measurements of Higgs Coupling Standard Model Effective Field Theory formalism (EFT) assumes that scale of new physics is relatively heavy LHC: 3 or 4 ab ILC: 2 ab @ 250 GeV ILC: 0.4 ab @ 350 GeV ILC: 4 ab @ 500 GeV Precision of Higgs boson couplings [%] 12 10 8 6 4 2 g(hww) g(hzz) LHC 3000 fb LHC 3000 fb LHC 3000 fb ILC 500 GeV, 4000 fb 11% (ATLAS: ATL-PHYS-PUB-2014-016 (2014), Model Dependent ILC 250 GeV, 2000 fb ILC 250 GeV, 2000 fb g(hcc) g(hτ τ ) g(hgg) g(hbb) 350 GeV, 200 fb (Model Independent EFT fit) (Model Independent EFT fit) 14% g(htt) g(hµµ) g(hγ Z) κ fit) g(hγ γ ) 0 24