Search for Higgs beyond the Standard Model with the ATLAS Detector - PowerPoint PPT Presentation

Search for Higgs beyond the Standard Model with the ATLAS Detector Nikolina Ilic Radboud University May 9, 2018

Outline • Introduction • Beyond Standard Model Higgs theories • Results for recently published channels • Conclusion 2

Introduction The Higgs boson was discovered in 2012 Need to extend SM to address issues like hierarchy problem, quantum gravity, baryon asymmetry, dark matter/energy, neutrino masses Look for BSM physics by • Looking for deviations from the SM in Higgs properties measurements • Directly searching for beyond SM objects – Additional Higgs bosons decaying to SM particles – SM Higgs decays to BSM states (eg. invisible decays) 3

Introduction ATLAS Detector ~100 mil ch 4

Beyond Standard Model Higgs Theories SM Higgs Additional Higgs Bosons Additional Field doublet Neutral CP Even EWS: Additional EW Singlet Model SM one scaler EW singlet 5

Beyond Standard Model Higgs Theories SM Higgs Additional Higgs Bosons Additional Field doublet Neutral CP Even EWS: Additional EW Singlet Model SM one scaler EW singlet Neutral Charged CP Even CP Odd 2HDM: Two Higgs Doublet Model SM another Higgs doublet 6

Beyond Standard Model Higgs Theories SM Higgs Additional Higgs Bosons Additional Field doublet Neutral CP Even EWS: Additional EW Singlet Model SM one scaler EW singlet Neutral Charged CP Even CP Odd 2HDM: Two Higgs Doublet Model SM another Higgs doublet Neutral CP Even CP Odd 2HDM + Singlet (complex) Model + 2HDM SM doublet & singlet Higgses 7

Beyond Standard Model Higgs Theories SM Higgs Additional Higgs Bosons Additional Field doublet Neutral CP Even EWS: Additional EW Singlet Model SM one scaler EW singlet Neutral Charged CP Even CP Odd 2HDM: Two Higgs Doublet Model SM another Higgs doublet Neutral h, CP Even CP Odd 2HDM + Singlet (complex) Model + 2HDM Neutr SM doublet & singlet Higgses Neutr is Char Double Charged Higgs Triplet Model + 2HDM H ± ± SM triplet Higgses 8

Beyond Standard Model Higgs Theories EWS significantly constrained by Run 1 Higgs measurements al, eaking 2HDM: two Higgs doublets Φ 1 and Φ 2 7 parameters: 𝑛 ℎ , 𝑛 𝐼 , 𝑛 𝐵 , 𝑛 𝐼 ± , 𝑛 12 , 𝑢𝑏𝑜𝛾 , 𝛽 Ratio of VEV of Φ 1 and Φ 2 h & H mixing angle • Models motivated by bounds on FCNC – Type I : fermions couple to Φ 2 – Type II : up type quarks couple to Φ 2 , down-type quarks & charged leptons couple to Φ 1 . Eg: MSSM • Run 1 SM Higgs results give big constraints on 2HDM. Data prefers alignment limit: cos(𝛾 − 𝛽) = 0 9

Beyond Standard Model Higgs Theories Minimal Supersymmetric SM (MSSM) • Simplest extension of SM that includes SUSY • Beyond tree level more than 2 parameters affect Higgs sector, benchmarks defined: ± • 𝑛 ℎ,𝑛𝑝𝑒 : 𝑛 ℎ is close to 125 GeV • hMSSM : measured value of 𝑛 ℎ 𝑢𝑏𝑜𝛾 can be used to predict other masses • In Run 1 excluded many regions of parameter space 𝑛 𝐵 [GeV] for 1≤ tan 10

Results for all published channels ~36 fb -1 (up to 2017) 𝐼 ±± → 𝑚𝑚 ZV → llqq / νν qq 13.2-15.4 fb -1 (2015+2016) WV→ lvqq 𝐼 ± → τν Neutral X->Z γ Charged 𝐼 ± → tb 3.2 fb -1 (2015) Heavy WW → lν l ν Higgs Light 𝐼 ± → cs 5-20.3fb -1 (RUN 1) Higgs to ZZ → 4l VBF 𝐼 ± → WZ bosons VV→ 2j Legend A → Z/ Wh (w h→bb ) H → γγ +MET H → 4 γ H → bb+MET H → WH hZ → INV ( lep) Higgs H → Z ( 𝑚𝑚 )+MET exotic Neutral A/H/h → ττ VBF h → INV with Higgs to A/H/h → tt hV → INV (had) MET fermions H → γ+ MET H→ INV (1 jet) h (125) → aa → 4 ℓ hh → 4b Higgs to Neutral hh → WWγγ h(125) → aa → 2j2 𝛿 Rare h(125) → φ / 𝜍 γ light Higgs to hh → bbγγ decays/ h(125) → aa → 4b h(Z) → J/ψγ res. di-Higgs LVF hh → bbττ h → τμ / τe / eμ H/h → aa → μμττ

Results for all published channels ~36 fb -1 (up to 2017) 𝐼 ±± → 𝑚𝑚 ZV → llqq / νν qq 13.2-15.4 fb -1 (2015+2016) WV→ lvqq 𝐼 ± → τν Neutral X->Z γ Charged 𝐼 ± → tb 3.2 fb -1 (2015) Heavy WW → lν l ν Higgs Light 𝐼 ± → cs 5-20.3fb -1 (RUN 1) Higgs to ZZ → 4l VBF 𝐼 ± → WZ bosons VV→ 2j Legend A → Z/ Wh (w h→bb ) H → γγ +MET H → 4 γ Will focus on H → bb+MET H → WH newer results hZ → INV ( lep) Higgs H → Z ( 𝑚𝑚 )+MET Updates on these exotic Neutral A/H/h → ττ VBF h → INV with Higgs to + new channels A/H/h → tt hV → INV (had) MET fermions coming soon H → γ+ MET H→ INV (1 jet) h (125) → aa → 4 ℓ hh → 4b Higgs to Neutral hh → WWγγ h(125) → aa → 2j2 𝛿 Rare h(125) → φ / 𝜍 γ light Higgs to hh → bbγγ decays/ h(125) → aa → 4b h(Z) → J/ψγ res. di-Higgs LVF hh → bbττ h → τμ / τe / eμ H/h → aa → μμττ

Results for all published channels 𝐼 ±± → 𝑚𝑚 ZV → llqq / νν qq WV→ lvqq 𝐼 ± → τν Neutral X->Z γ Charged 𝐼 ± → tb Heavy WW → lν l ν Higgs Light 𝐼 ± → cs Higgs to ZZ → 4l VBF 𝐼 ± → WZ bosons VV→ 2j A → Z/ Wh (w h→bb ) H → γγ +MET H → 4 γ H → bb+MET H → WH hZ → INV ( lep) Higgs H → Z ( 𝑚𝑚 )+MET exotic Neutral A/H/h → ττ VBF h → INV with Higgs to A/H/h → tt hV → INV (had) MET fermions H → γ+ MET H→ INV (1 jet) hh → 4b Neutral hh → WWγγ Rare h(125) → φγ Higgs to hh → bbγγ decays/ h(Z) → J/ψγ di-Higgs LVF hh → bbττ h → τμ / τe / eμ

Neutral Heavy ZV → llqq / νν qq Why these channels? Higgs to bosons WV→ lvqq X->Z γ 14 • Is unitarisation of WW scattering at high energy ensured ONLY by SM Higgs? • Prominent decay is to W/Z in many BSM models SM

Neutral Heavy ZV → llqq / νν qq Why these channels? Higgs to bosons WV→ lvqq X->Z γ 15 • Is unitarisation of WW scattering at high energy ensured ONLY by SM Higgs? • Prominent decay is to W/Z in many BSM models SM BSM

Neutral Heavy ZV → llqq / νν qq Higgs to bosons WV→ lvqq X->Z γ 16 • Is unitarisation of WW scattering at high energy ensured ONLY by SM Higgs? • Prominent decay is to W/Z in many BSM models • Heavy Higgs in Narrow Width Approximation (NWA): Higgs width smaller than experimental resolution (tests EWS, 2HDM, singlet+doublet) • Other BSM models tested: Spin 1 Z’/W’ , spin 2: Kaluza-Klein graviton ( 𝐻 𝑙𝑙 ∗ ) resolved boosted • Resolved analysis at lower mass: 2 small radius jets (llqq) • Boosted analysis: when resonance mass higher than W/Z mass 2 jets merge into 1 big radius jet (llqq, νν qq, lvqq) • Discriminating variable: invariant/transverse mass

Neutral Heavy ZV → llqq / νν qq Higgs to bosons WV→ lvqq X->Z γ 17 Theories: heavy Higgs in NWA, 𝑎 ′ , 𝑋 ′ , 𝐻 𝑙𝑙 ∗ ZZ → ( 𝑚𝑚/𝜉𝜉 ) ( 𝑟𝑟 ) where 𝑚 = 𝑓, 𝜈 • ggF and VBF studied 𝑚𝑚𝑟𝑟 channel 𝑚𝑚𝑟𝑟 boosted m(J) [GeV] Excluded 𝐼 𝑕𝑕𝑔 𝜏 × 𝐶𝑆 > 1.7 pb – 1.4 fb 𝐼 𝑊𝐶𝐺 𝜏 × 𝐶𝑆 > 0.42 pb – 1.1 fb

Neutral Heavy ZV → llqq / νν qq Higgs to bosons WV→ lvqq X->Z γ 18 Theories: heavy Higgs in NWA, 𝑎 ′ , 𝑋 ′ , 𝐻 𝑙𝑙 ∗ WW → ( 𝑚𝜉 )( 𝑟𝑟 ), where 𝑚 = 𝑓, 𝜈 ZZ → ( 𝑚𝑚/𝜉𝜉 ) ( 𝑟𝑟 ) where 𝑚 = 𝑓, 𝜈 • ggF and VBF studied 𝑚𝑚𝑟𝑟 channel 𝑚𝑚𝑟𝑟 boosted m(J) [GeV] Excluded Excluded 𝐼 𝑕𝑕𝑔 𝜏 × 𝐶𝑆 > 1.7 pb – 1.4 fb 𝐼 𝐸𝑍 𝜏 × 𝐶𝑆 > 1.7 pb – 1.3 fb 𝐼 𝑊𝐶𝐺 𝜏 × 𝐶𝑆 > 0.98 pb – 2.8 fb 𝐼 𝑊𝐶𝐺 𝜏 × 𝐶𝑆 > 0.42 pb – 1.1 fb

Neutral Heavy ZV → llqq / νν qq Why this channels? Higgs to bosons WV→ lvq X->Z γ • Final state can be reconstructed with high efficiency and good invariant mass resolution,s, relatively small backgrounds • Loop is sensitive to new physics, branching ratio is expected to be different from SM for many BSM theories th (neutral/charged scaler Higgs, additional leptons coupling in loop) exchanged in the H → ell o Clean channel, we don’t expect a lot of

Neutral Heavy ZV → llqq / νν qq Higgs to bosons WV→ lvq X->Z γ The Z(→ ``)γ final state can be reconstructed c i Theories: heavy Higgs in NWA, spin 2 resonance backgr • ggF, VBF VH studied e • 6 categories defined based VBF production, high/low momenta leptons • VBF is most sensitive category and uses Boosted Decision Tree A H → pr ne c add or exchanged in the H → de narr us pair Excluded ℎ 𝜏 × 𝐶𝑆 > 6.6 x SM prediction Clean channel, we don’t expect a lot of SM 𝐼 𝜏 × 𝐶𝑆 > 88 fb – 2.8 fb for 𝑛 𝐼 = .25 − 2.4 TeV e