Probing New Physics of Cubic Higgs Interaction

Transcription

1 Probing New Physics of Cubic Higgs Interaction Jing Ren University of Toronto ACFI Workhop September 19, 2015 Based on H.J. He (Tsinghua), JR, W. Yao (LBNL),

2 Outline Motivation New physics v.s. Higgs self-interactions Strong first order electroweak phase transition (SFOEWPT) Higgs non-minimal gravitational interaction Probing new cubic Higgs interactions on hadron collider Effective theory with dim=6 operators Higgs pair production on hadron collider 1

3 Higgs Discovery We now have the 125GeV SM-like Higgs with LHC Run1 ATLAS and CMS Collaborations RRL 114, (2015) But no convincing evidence from new physics search 2

4 Higgs Discovery We now have the 125GeV SM-like Higgs with LHC Run1 ATLAS and CMS Collaborations RRL 114, (2015) But no convincing evidence from new physics search Higgs as the window for new physics QM gravity Higgs Selfcoupling 2 Inflation Baryon Asymm etry

5 Less Known Higgs Potential SM Higgs potential EWSB: μ 2, λ fixed by v = 246GeV, M h = 125GeV EWPT: far from first order, (~cross-over) Self-couplings: λ 3 = 3M h 2 /v, λ 4 = 3M h 2 /v 2 Higgs self-couplings measurement Dihiggs production to probe λ 3 ~ 50% accuracy on HL-LHC ~ 27% accuracy on ~ 35% accuracy on CEPC5 (careful!) TriHiggs production to probe λ 4 : much more challenging Higgs self-interactions as the window to new physics 3 V H = μ 2 H H + λ(h H) 2 [Snomass Higgs Working Group Report, arxiv: ] [arxiv: ] [McCullough, arxiv: ] [See Jianming Qian s talk] [Plehn, Rauch, PRD 72 (2005) ]

6 New Physics v.s. Higgs Self- Interactions

7 Strong first order EWPT (SFOEWPT) Case 3: Correlation between SFOEWPT and cubic Higgs coupling Quantum Non-renormalizable Singlet >20% can be both >0 & <0 [See M. Perelstein s talk] [See C. Wagner s talk] [See P. Winslow s talk] 5

8 Strong first order EWPT (SFOEWPT) Case 3: Correlation between SFOEWPT and cubic Higgs coupling Quantum Non-renormalizable Singlet >20% can be both >0 & <0 [See M. Perelstein s talk] [See C. Wagner s talk] Resonance dihiggs production [See P. Winslow s talk] 5 [See C. Chen s talk]

9 Higgs non-minimal gravitational interaction Case 3: Joint effective action for SM and GR: 6

10 Higgs non-minimal gravitational interaction Case 3: Joint effective action for SM and GR: L Einstein frame transformation Ω 2 = 1 + 2ξ hh H 2 M Pl ΔL 6 = 3λ Λ2 ( μ H H) ξ1 Λ2 λ H H 3 +, Λ ξ1 = M Pl ξ2 ξ h Λ ξ2 = M Pl ξ h, if ξ h 1 6

11 Higgs non-minimal gravitational interaction Case 3: Joint effective action for SM and GR: L Einstein frame transformation Ω 2 = 1 + 2ξ hh H 2 M Pl ΔL 6 = 3λ Λ2 ( μ H H) ξ1 Λ2 λ H H 3 +, Λ ξ1 = M Pl ξ2 ξ h Λ ξ2 = M Pl ξ h, if ξ h 1 Higgs rescaling induced by graviton-higgs kinetic mixing 6v 2 2 O 0.1 ξ h (LHC bound) Λ UV Λ ξ1 (Unitarity bound) Λ ξ1 New derivative Higgs self-couplings: h μ h μ h Higgs inflation: extreme flat potential at large field Slow roll: n s 1 2/N, r s 12/N 2 6 V(h) [Bezrukov, Shaposhnikov, Phys.Lett. B 659 (2008) 703]

12 Probing New Cubic Higgs Interactions

13 EFT: Dim=6 Operators Dim=6 operators for Higgs self-interactions: [Corbett, Eboli, Gonzalez-Fraile, Gonzalez-Garcia, Phys. Rev. D 87, (2013)] 8

14 EFT: Dim=6 Operators Dim=6 operators for Higgs self-interactions: [Corbett, Eboli, Gonzalez-Fraile, Gonzalez-Garcia, Phys. Rev. D 87, (2013)] Violate custodial symmetry, negligible for collider study 8

15 EFT: Dim=6 Operators Dim=6 operators for Higgs self-interactions: [Corbett, Eboli, Gonzalez-Fraile, Gonzalez-Garcia, Phys. Rev. D 87, (2013)] Violate custodial symmetry, negligible for collider study Eliminated by EOM 8

16 EFT: Dim=6 Operators Dim=6 operators for Higgs self-interactions: [Corbett, Eboli, Gonzalez-Fraile, Gonzalez-Garcia, Phys. Rev. D 87, (2013)] Violate custodial symmetry, negligible for collider study Eliminated by EOM The 2d Parameter Space: (x 2, x 3 ) Higgs-SM couplings rescaled by ζ = (1 + x 2 ) 1/2 Effective cutoff Cubic Higgs coupling λ 3 8

17 EFT: Dim=6 Operators Dim=6 operators for Higgs self-interactions: [Corbett, Eboli, Gonzalez-Fraile, Gonzalez-Garcia, Phys. Rev. D 87, (2013)] Violate custodial symmetry, negligible for collider study Eliminated by EOM The 2d Parameter Space: (x 2, x 3 ) Higgs-SM couplings rescaled by ζ = (1 + x 2 ) 1/2 Effective cutoff Cubic Higgs coupling λ 3 8 Treat r, x as two free inputs Accidental cancelation with other operators in single higgs measurement Nonlinear realization: quadratic & cubic correlation broken down

18 Dihiggs Production on Hadron Collider A. Djouadi, Phys. Rept. 457 (2008) 1 [arxiv:hep-ph/ ] Gluon fusion production h h h h h h Vector boson fusion production Top-pair associated production h Frederix, et al, Phys. Lett. B 732 (2014) 142] h h NLO cross section in unit of fb s (TeV) pp HH pp HHjj pp t thh pp WHH pp ZHH

19 Dihiggs Production on Hadron Collider gg hh pp hhjj pp tt hh (dash, solid, dot) for r = ( 1,0,1) 10

20 Kinematic r = 0 x = 1 gg hh gg hh r = 0 r = 0 pp tt hh pp hhjj (VBF) 18 11

21 Dihiggs Decay Channels HL-LHC with 3ab 1 S/ B = 1.3σ (0.26%) [ATL-PHYS-PUB ] (7.3%) (25%) (33%) WW WW (3l3υjj,2l ± 2υ4j) (4.7%) S/ B~1.5σ (3l3υjj) [Li, Li, Yan, Zhao, ] [Baur, Plehn, Rainwater, PRL 89, (2002)] Search in tthh and VBF channel, [Liu, Zhang, ] [Dolan et al,, ] 12 HXWG meeting, Michael Spannowsky,

22 Fast Simulation of Events generation: Madgraph5, Pythia 6.2, Delphes 3 Signal: include finite mt effect Background: include up to one extra parton with MLM matching Detector simulation based on ATLAS responses Use anti-kt for jets with ΔR = 0.5 b-tagging efficiency: 75%, 18.8%, and 1% for bottom, charm, and light favor jets in the central region Photon identification efficiency: roughly 80% for photons with E T > 50GeV and η < 2.5 (HL-LHC: E T > 80GeV) Jet-faking-photon background: a faking probability of f j = exp ( E T /27) as a function of jet E T in GeV, and scale the jet energy by 0.75 ± 0.12 as the photon energy 13

23 Fast Simulation of Background: bbγγ, bbh γγ, Z bb h γγ, t th γγ, jjγγ (mis-tagging b or b) Events selection 2 bjets and b photon t tγγ, bbjγ, bbjj, t tγ (jet-faking-photon) [W. Yao, arxiv: [hep-ph]] Kinematic cuts (Higgs decay angle) 14

24 Results Signal and background at pp(100tev) with L = 3ab 1 S/ B Comparison: -- S/ B = 8.4, conservative (photon identification) efficiency -- S/ B = 15.2, comparable efficiency [Azatov et al, arxiv: ] 16.5 [Bar et al, JHEP 1502 (2015) 016, arxiv: ] 15

25 Discrimination of Two Operators Utilize distribution in reconstructed M hh bins 16

26 Sensitivity on (r, x) Plane: SM dash: 3ab 1 solid: 30ab 1 r, x = (0,0) Degenerate direction around origin Exclusive analysis breaks degenerate direction 1d sensitivity: δr ~13% 4%, δx~5%(1.6%) The weakest 2d sensitivity: δr ~25% 8%, δx~10%(3%) Dihiggs measurements alone can probe both r, x to a good accuracy 17

27 Sensitivity on (r, x) Plane: SM dash: 3ab 1 solid: 30ab 1 Exclusive analysis translated as probe of the effective cutoffs Tow cases: x 2 x 3 > 0 (red), x 2 x 3 < 0 (blue) 1d sensitivity: Λ 2, Λ TeV Weakest 2d sensitivity: Λ 2, Λ TeV 18

28 Sensitivity for Generic (r, x) Sensitivity contours qualitatively different Benchmark B: non-minimal gravitational coupling. r, x = (0, 0.2) (B1), r, x = (0, 0.5) (B2), sensitivity contour and degenerate direction strongly depend on the explicit x. Benchmark C: CW potential in classical scale invariant model. r, x = (2/3, 0), similar to the SM. Benchmark B1 Benchmark B2 Benchmark C 19

29 Summary Higgs self-interactions as the window for new physics, important for big questions: EWPT, EWSB, Higgs gravitational interaction Probing new physics of Higgs self-couplings based on effective theory with dim=6 operators. For dihiggs production on hadron collider, discriminate deviation couplings from the SM one by using M hh bins. Dihiggs production alone can probe both cubic Higgs couplings to a good accuracy on 100TeV. Sensitivity qualitatively different for various benchmark points. 20

30 Thank You!

31 Perturbative Unitarity Bound [JR, Z. Z. Xianyu, H.J. He, ] Goldstone boson equivalence theorem: ξ h RH H is gauge invariant Coupled channel analysis: 2 2 scattering E 2 < 16πv 2 1 ζ ζ 4 Unitarity analysis for Higgs inflation Puzzle: go beyond cutoff for Unitarity bound depends on background field The strongest bound from π + π π 0 π 0 E < 8π 3 M Pl ξ h 21

32 Other Dim=6 Operators For different dihiggs production, some other operators contribute as well Top-pair associated production dim=6: Gluon fusion production dim=6: Vector fusion production dim=6: H HW aμν W μν a, H H D μ H (D μ H) 22

33 Higgs Mass Reconstruction When one of the reconstructed mass consistent with the Higgs mass 23