ATLAS and CMS prospects for Higgs measurements and

ATLAS and CMS prospects for Higgs measurements and searches at the high luminosity LHC Rainer Mankel (DESY) on behalf of the ATLAS and CMS collaborations 6 th International Conference on New Frontiers in Physics Kolymbari (Greece) 21 August 2017

Outline HL-LHC and detector upgrades H(125) precision measurements in di-boson channels Pair-production of Higgs bosons Direct searches for physics beyond the SM 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 2

Related talks Ø Marcello Bindi: "Future Prospects (ATLAS)" Thursday 24 -August Ø Kerstin Hoepfner: "Overview talk on upgrades, future plans and prospects of the CMS experiment at the future HL-LHC" Thursday 24 -August Ø Stewart Patrick Swift: "Tracking and Vertexing with the ATLAS Inner Detector in the LHC Run 2 and Beyond" Monday 28 -August 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 3

The Higgs boson – as of Summer 2017 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 4

What we know (spotlight) l l l Higgs boson: prime research object to understand the origin of masses in particle physics; potential portal to New Physics Mass known to ~0. 2%, prominent couplings measured down to the ~10 -20% level Recent highlight: l decays to fermions directly established (observation of H , evidence for H bb) ATLAS-CONF-2017 -041 JHEP 08 (2016) 045 ar. Xiv: 1708. 00373 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 5

What we need to know l Accurate measurement of Higgs couplings, down to the level of few percents l deviations from SM would reveal New Physics example: additional particles in loop processes (gluon fusion, di-photon decay) Does the Higgs boson couple to itself, as predicted by SM? l measure trilinear Higgs coupling Higgs pair production shape of Higgs potential (fingerprint of Higgs boson) Is the Higgs boson just one member of an extended Higgs sector? search for additional Higgs bosons l Are there heavy resonances decaying to Higgs bosons? Need much better access to these rare processes and decays High luminosity LHC (HL-LHC) X 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 6

The HL-LHC and the detector upgrades 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 7

The HL-LHC today 13 l 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 8

ATLAS Phase 2 upgrade in a nutshell l Upgrade trigger & data acquisition system l l l based on FPGA technology high rate capability L 1 track trigger l Upgrade electronics for tile and LAr calorimeters l New inner muon barrel trigger chambers (MDT) Optional: l l 21 August 2017 l forward muon tagger timing detectors R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 9

CMS Phase 2 upgrade Upgrade trigger l l L 1 track trigger extended L 1 latency improved rate capability in a nutshell l New High Granularity Calorimeter endcaps using silicon sensors; 3 D shower imaging l Upgrade in barrel calorimeters l l electronics cooling of photodetectors 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 10

Strategy for projections (ATLAS) l Chosen scenario 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 11

Strategy for projections (CMS) l l Extrapolation of analyses performed at 13 Te. V on 2015 (2. 3 -2. 7 fb-1) or 2016 datasets (12. 9 fb-1) Evolvement of systematic + theoretical uncertainties: several scenarios l l assumptions made on how systematic & theoretical uncertainties will develop detector upgrades designed to (at least) compensate degradations due to high pileup Systematic & theoretical uncertainties High-PU + detector improvements S 1 constant no S 1+ constant yes S 2 scaled no S 2+ scaled yes -- no Stat. only 21 August 2017 Description All systematic uncertainties are kept constant. Theoretical uncertainty ½, experimental systematic uncertainty 1/ L until detector -driven lower limit is reached. R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 12

H(125) properties in bosonic decay channels 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 13

Higgs couplings ATL-PHYS-PUB-2014 -016 l Reduced couplings hashed areas: increase of estimated error due to theory systematic uncertainties 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 14

H CMS PAS FTR-16 -002 l Projections performed from analysis performed on 2016 dataset (12. 9 fb-1) l l production modes: gluon fusion, VBF, tt. H the 3000 fb-1 scenarios take degradations of photon+vertex identification due to pileup conditions into account In S 2 and S 2+ scenarios, experimental uncertainty ultimately dominated by luminosity measurement 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 15

H : precision timing CMS PAS FTR-16 -002 l Precision timing for calorimeter clusters and/or tracks can improve the vertex association for photons from Higgs decay l l effective if photons are well separated in rapidity (~50% of events) corresponds to a 5 x pileup suppression for such candidates Three variants of the S 2+ scenario have been studied significant impact on Higgs signal shape (mass resolution) significant impact on (fiducial) cross section uncertainty 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 16

H ZZ* 4 ℓ (inclusive) CMS PAS FTR-16 -002 l l Very clean, low backgrounds expect huge benefit from high luminosity Projection of 2016 data analysis (12. 9 fb-1) to 300 and 3000 fb-1. sub-leading production modes are dominated by statistical component theory uncertainties are crucial 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 17

H ZZ* 4 ℓ (VBF) ATL-PHYS-PUB-2016 -008 l l Vector boson fusion of Higgs bosons provides very clean signatures Initial selection: l l l Z 2 jets with m(jj) > 130 Ge. V 4 leptons consistent with H ZZ* Test benefit from extension of tracker acceptance use of track information to reject forward pileup jets l Results for pileup 200 presented for: l l gg. F H(4ℓ)+2 j statistical uncertainty only stat + systematic uncertainty from QCD scale Significant improvement with tracker acceptance / Tracker Scenario VBF H(4ℓ) 21 August 2017 Z Signal unc. R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) w/syst. Significance stat only w/syst. stat only 0. 182 0. 152 7. 2 10. 2 0. 192 0. 157 6. 9 9. 5 0. 208 0. 165 6. 2 8. 6 18

H WW* e (VBF) ATLAS-TDR-025 l ATL-PHYS-PUB-2016 -018 Reference Middle Low 21 August 2017 excluding VBF + gg. F prod. theor. uncertainties R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 19

H ZZ* 4 ℓ (differential) CMS PAS FTR-16 -002 l 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 20

Higgs pair production & trilinear coupling 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 21

HH production Measurement of Higgs self coupling is a prime goal of the experimental program l l l R. Frederix et al. , PL B 732 (2014) 142. l shape of Higgs potential Study pair production of Higgs bosons HHH vertex contribution interferes destructively with other important diagrams Dominant production mode: gluon fusion l NNLO(HH) ~ 40 fb-1 need to combine many decay channels choose at least one H bb decay (large BR) 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 22

H( )H(bb) ATL-PHYS-PUB-2017 -001 l 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 23

H(bb) ATL-PHYS-PUB-2016 -024 l l l Study based on full simulation. Run 2 detector performance, no additional pileup accounted for Resolved analysis, m 4 j as final discriminant Main background QCD multijet modeled with data-driven method 2016 analysis (10. 1 fb-1) HL-LHC projection (3000 fb-1) 500 x HH(SM) 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 24

H(bb) [cont'd] ATL-PHYS-PUB-2016 -024 l 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 25

HH sensitivity (CMS) CMS PAS FTR-16 -002 l l l Extrapolate searches made with 2. 3 -2. 7 fb-1 to 3000 fb-1 Channels studied: HH ( )(bb), (VV)(bb) Based on S 2 scenario*: experimental uncertainty 1/ L until detector-driven lower limit is reached, theoretical uncertainty ½ *for ( )(bb): S 2+ Impact of systematics differs across the channels. ( )(bb) most sensitive. 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 26

Search for Physics beyond the SM 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 27

Di-Higgs resonances CMS PAS HIG-16 -002, FTR-16 -002 l New physics could reflect in a heavy resonance decaying to HH final state: X HH l l l Projection of search from 2. 3 fb-1 to 3000 fb-1 l l motivation: warped extra dimension theory here: massive spin 0 particle (Radion) experimental uncertainty 1/ L, theoretical uncertainty ½ three mass points: m. X=300, 700, 1000 Ge. V Huge improvement compared to current sensitivity 200 ECFA 16 S 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 2 extr apola tion ( S ketch !) 28

MSSM H CMS PAS FTR-16 -002 l Search for neutral Higgs bosons of Minimal Supersymmetric SM (MSSM): h, H, A l l Projection of search from 2. 3 fb-1 to 300 and 3000 fb-1 l l production modes: gluon fusion, b-associated production Three cases considered: l l production enhanced ~tan Scenario 1: systematic uncertainties unchanged Scenario 2: experimental uncertainty 1/ L, theoretical uncertainty ½ Statistical uncertainties only gluon fusion Differences between scenarios shrink towards higher masses l background expectation is smaller 21 August 2017 300 fb-1 3000 fb-1 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) b-associated 300 fb-1 3000 fb-1 29

MSSM H (cont'd) l Interpretation in MSSM parameter space, mhmod+ scenario Huge impact of HL-LHC luminosity l large parts of MSSM parameter space can be excluded, even up to 2 Te. V of mass 2. 7 fb-1 At high masses, the analysis still remains statistics-limited 300 fb-1 3000 fb-1 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 30

Summary l Exploration of the Higgs boson is a prime motivation for the HL-LHC programme l High luminosity is key to access rare processes and decays, but also very challenging experimentally comprehensive detector upgrades for ATLAS and CMS l Detailed studies demonstrate l l impact of detector improvements substantial boost of accuracy for Higgs boson couplings and other properties access to Higgs pair production ( self coupling) greatly enhanced sensitivity to New Physics involving Higgs bosons A new era of Higgs boson research at the LHC! 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 31

Backup 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 32

ATLAS & CMS experiments l The two multi-purpose detectors at the LHC 44 m x 25 m, 7, 000 tons 21 August 2017 29 m x 15 m, 14, 000 tons R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 33

Invisible Higgs decays CMS PAS FTR-16 -002 l Invisible Higgs decay modes may be possible through l l l Invisible Higgs decays can be assessed in signatures where Higgs boson is accompanied by something visible l l here: VBF production Projection of search from 2. 3 3000 fb-1 l l decays to neutralinos (in supersymmetric models) via graviscalars (in models with extra dimensions) ECFA 16 Scenarios S 1+S 2(+) pure 1/ L scaling also shown Direct search limit for invisible decays may be pushed below 10%, based on this channel alone 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 34

tt. HH ATL-PHYS-PUB-2016 -023 l 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 35

HH (bb)(WW) (bb)(qq)(ℓ ) CMS PAS FTR-16 -002 l Based on Phase-II detector simulation (DELPHES) l l performance parameterization based on GEANT-simulation Dominant background tt + jets (SL) 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 36

21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 37

Higgs boson production mechanisms gg. F VBF VH Run 1 7 13 Sizable increase in cross sections in transition 8 13 Te. V l 8 Run 2 tt. H factors of ~2. 3 (gg. F), ~4 (tt. H) Significant improvements in theory l e. g. uncertainty of gg. F cross sections reduced to ~½ (N 3 LO) 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 38

Higgs boson decay modes l largest BR, but huge backgrounds cleanest in terms of mass resolution & backgrounds 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 39

21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 40

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Couplings vs mass l 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 42

HH 4 b l 21 August 2017 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 43

H WW* e (VBF) ATL-PHYS-PUB-2016 -018 l Tracker Scenario Theor. unc. 21 August 2017 Full Significance None Full None 0. 20 0. 14 5. 7 8. 0 0. 25 0. 20 4. 4 5. 4 0. 39 0. 30 2. 7 3. 5 R. Mankel; Higgs prospects for HL-LHC (ATLAS + CMS) 44