Precision Constraints on Higgs and Z couplings Joachim Brod Seminar - PowerPoint PPT Presentation

Precision Constraints on Higgs and Z couplings Joachim Brod Seminar talk, IPPP Durham, November 20, 2014 With Ulrich Haisch, Jure Zupan – JHEP 1311 (2013) 180 [arXiv:1310.1385] With Admir Grelio, Emmanuel Stamou, Patipan Uttayarat – arXiv:1408.0792 Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 1 / 45

What do we know about the Higgs couplings? -1 -1 19.7 fb (8 TeV) + 5.1 fb (7 TeV) CMS m = 125 GeV Combined H µ = 1.00 ± 0.13 Preliminary H → bb tagged µ = 0.93 ± 0.49 H tagged → τ τ = 0.91 0.27 µ ± H → γ γ tagged µ = 1.13 ± 0.24 H WW tagged → = 0.83 0.21 µ ± H → ZZ tagged µ = 1.00 ± 0.29 0 0.5 1 1.5 2 Best fit σ / σ SM [ATLAS-CONF-2013-034] [CMS-PAS-HIG-14-009] Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 2 / 45

Outline Anomalous Higgs couplings ttH bbH ττ H Anomalous ttZ couplings Conclusion Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 3 / 45

SM EFT No BSM particles at LHC ⇒ use EFT with only SM fields [See, e.g., Buchm¨ uller et al. 1986, Grzadkowski et al. 2010] L eff = L SM + L dim.6 + . . . For instance, m t = y t v EWSB y f ( ¯ √ Q L t R H ) + h.c. − → 2 √ √ H † H 2) 3 2) 2 δ m t ∝ ( v / δ y t ∝ 3( v / EWSB Λ 2 ( ¯ Q L t R H ) + h.c. − → , Λ 2 Λ 2 If both terms are present, mass and Yukawa terms are independent Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 4 / 45

From h → γγ . . . In the SM, Yukawa coupling to fermion f is L Y = − y f ¯ √ γ f f h 2 We will look at modification h � � Y = − y f t κ f ¯ κ f ¯ L ′ √ f f + i ˜ f γ 5 f h 2 γ New contributions will modify Higgs production cross section and decay rates Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 5 / 45

. . . to electric dipole moments Attaching a light fermion line leads to EDM Indirect constraint on CP -violating Higgs γ coupling f SM “background” enters at three- and h four-loop level t Complementary to collider measurements f γ Constraints depend on additional f assumptions Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 6 / 45

Electric Dipole Moments (EDMs) – Generalities Energy Higher-dimensional T eV Higgs e ective operators Modi ed Higgs couplings GeV QCD neutron EDM nuclear EDMs of para- EDMs of atomic magnetic atoms diamagnetic and molecules atoms [Adapted from Pospelov and Ritz, hep-ph/0504231] Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 7 / 45

ACME result on electron EDM Expect order-of-magnitude improvements! Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 8 / 45

Anomalous ttH couplings Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 9 / 45

Electron EDM γ i e σ µν γ 5 e F µν L eff = − d e 2 ¯ t γ h e EDM induced via “Barr-Zee” diagrams [Weinberg 1989, Barr & Zee 1990] � � √ m 2 d e e = 16 α 2 G F m e κ e ˜ κ t f 1 t 3 (4 π ) 3 M 2 h | d e / e | < 8 . 7 × 10 − 29 cm (90% CL) [ACME 2013] with ThO molecules Constraint on ˜ κ t vanishes if Higgs does not couple to electron Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 10 / 45

Neutron EDM – EDM and CEDM i ig s q σ µν γ 5 q F µν − ˜ q σ µν T a γ 5 q G a L eff ⊃ − d q 2 ¯ d q 2 ¯ µν γ g t t γ g h h q q � � √ m 2 d q ( µ W ) = − 16 α 3 eQ q 2 G F m q κ q ˜ κ t f 1 t (4 π ) 3 M 2 h � � √ m 2 ˜ α s d q ( µ W ) = − 2 2 G F m q κ q ˜ κ t f 1 t M 2 (4 π ) 3 h Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 11 / 45

Neutron EDM – The Weinberg Operator g h t g g Here the Higgs couples only to the top quark Get bound even if light-quark couplings are zero � � √ m 2 w ( µ W ) = g s α s 2 G F κ t ˜ κ t f 3 t (4 π ) 3 M 2 4 h Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 12 / 45

Neutron EDM – RG Running Need to run from µ W ∼ M W to hadronic scale µ H ∼ 1 GeV Operators will mix: µ d d µ C ( µ ) = γ T C ( µ )   32 0 0 3   γ = α s  32 28  0   3 3 4 π 14 + 4 N f 0 − 6 3 At hadronic scale µ H need to evaluate hadronic matrix elements Use QCD sum rule techniques [Pospelov, Ritz, hep-ph/0504231] There are large O (100%) uncertainties E.g. excited states, higher terms in OPE, ambiguity in nuclear current. . . In the future, lattice might provide more reliable estimates Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 13 / 45

Neutron EDM – Bounds � � � d n κ t + 5 . 1 · 10 − 2 κ t ˜ e = (1 . 0 ± 0 . 5) − 5 . 3 κ q ˜ κ t � + (22 ± 10) 1 . 8 · 10 − 2 κ t ˜ · 10 − 25 cm . κ t w ∝ κ t ˜ κ t subdominant, but involves only top Yukawa | d n / e | < 2 . 9 × 10 − 26 cm (90% CL) [Baker et al., 2006] Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 14 / 45

Constraints from gg → h gg → h generated at one loop Have effective potential α s α s h h µν G µν, a − ˜ µν � G µν, a v G a v G a V eff = − c g c g 12 π 8 π g c g , ˜ c g given in terms of loop functions h b, t κ g ≡ c g / c g , SM , ˜ κ g ≡ 3˜ c g / 2 c g , SM g σ ( gg → h ) = | κ g | 2 + | ˜ κ g | 2 = κ t 2 + 2 . 6 ˜ 2 + 0 . 11 κ t ( κ t − 1) κ t σ ( gg → h ) SM Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 15 / 45

Constraints from h → γγ h → γγ generated at one loop Have effective potential α 3 α h h v F µν F µν − ˜ v F µν � F µν V eff = − c γ c γ π 2 π γ γ c γ , ˜ c γ given in terms of loop functions h h κ γ ≡ c γ / c γ, SM , ˜ κ γ ≡ 3˜ c γ / 2 c γ, SM W b, t γ γ Γ( h → γγ ) = | κ γ | 2 + | ˜ κ γ | 2 = (1 . 28 − 0 . 28 κ t ) 2 + (0 . 43 ˜ κ t ) 2 Γ( h → γγ ) SM Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 16 / 45

LHC input CMS Preliminary -1 -1 2.0 s = 7 TeV, L ≤ 5.1 fb s = 8 TeV, L ≤ 19.6 fb g κ , κ κ g γ 1.8 1.6 1.4 Naive weighted average of ATLAS, CMS 1.2 1.0 0.8 κ g , WA = 0 . 91 ± 0 . 08 , κ γ, WA = 1 . 10 ± 0 . 11 0.6 0.4 g /γ, WA = | κ g /γ | 2 + | ˜ We set κ 2 κ g /γ | 2 0.2 0.0 0.0 0.5 1.0 1.5 2.0 κ γ [CMS-PAS-HIG-13-005] Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 17 / 45

Combined constraints on top coupling Assume SM couplings to electron and light quarks Future projection for 3000fb − 1 @ high-luminosity LHC [J. Olsen, talk at Snowmass Energy Frontier workshop] Factor 90 (300) improvement on electron (neutron) EDM [Fundamental Physics at the Energy Frontier, arXiv:1205.2671] Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 18 / 45

Combined constraints on top couplings Set couplings to electron and light quarks to zero Contribution of Weinberg operator will lead to strong constraints in the future scenario Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 19 / 45

Anomalous bbH couplings Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 20 / 45

Constraints from EDMs Contributions to EDMs suppressed by small Yukawas; g still get meaningful constraints in future scenario For electron EDM, simply replace charges and couplings b g h q For neutron EDM, extra scale m b ≪ M h important � � √ m 2 log 2 m 2 + π 2 α d q ( µ W ) ≃ − 4 eQ q N c Q 2 b b 2 G F m q κ q ˜ κ b , b M 2 M 2 (4 π ) 3 3 h h � � √ m 2 log 2 m 2 + π 2 α s ˜ b b d q ( µ W ) ≃ − 2 2 G F m q κ q ˜ κ b , (4 π ) 3 M 2 M 2 3 h h � � √ m 2 log m 2 α s + 3 b b w ( µ W ) ≃ − g s 2 G F κ b ˜ κ b . M 2 M 2 (4 π ) 3 2 h h Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 21 / 45

RGE analysis of the b -quark contribution to EDMs g ≈ 3 scale uncertainty in CEDM Wilson coefficient b Two-step matching at M h and m b : g h q Mixing into Integrate out Higgs Matching onto O q qq ¯ O q q σ µν T a q ¯ bi σ µν γ 5 T a b 4 = ¯ mb 1 = ¯ bi γ 5 b O q 6 = − i q σ µν T a γ 5 qG a gs ¯ 2 µν Joachim Brod (University of Mainz) Precision Constraints on Higgs and Z couplings 22 / 45