Constraints on BSM physics through the Higgs couplings J er emie - PowerPoint PPT Presentation

Constraints on BSM physics through the Higgs couplings J´ er´ emie Quevillon LPT Orsay Frontiers of Fondamental Physics 2014, Marseille, 17 July 2014 LPT Orsay J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 1 / 28

The Brout-Englert-Higgs mecanism Crucial problem in particle physics: how to generate particle masses in an SU (2) × U (1) gauge invariant way? � φ + � Take an SU(2)-doublet of scalar fields Φ = , Y Φ = +1, φ 0 with a Lagrangian invariant under SU (2) L × U (1) Y : L S = ( D µ Φ) † D µ Φ − V (Φ), � 2 , ′ Y V (Φ) = µ 2 Φ † Φ + λ � Φ † Φ D µ = ∂ µ − igT a W a µ − ig 2 B µ W a T a are the SU(2) generators & µ are the SU(2) gauge bosons Y is the hypercharge & B µ is the U(1) gauge boson µ 2 > 0: 4 scalar particles & µ 2 < 0: Φ gets a V.E.V. � 0 � � − µ 2 � 0 | Φ | 0 � = with v = = 246 GeV v V( � ) V( � ) √ λ 2 � � 0 ⇒ Φ( x ) = v + H ( x ) √ 2 � � > > 0 0 ⇒ three d.o.f. for M W ± and M Z 2 2 + v � > 0 � < 0 Fermion masses: L Yuk = − f e (¯ e , ¯ ν ) L Φ e R + ... ⇒ one residual scalar boson= the Higgs ( M H = 2 λ v 2 ) [Higgs (1964); Brout, Englert (1964); Hagen,Kibble,Guralnik (1964)] J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 2 / 28

The Higgs boson couplings After EWSB, the Higgs boson couples to fermions, gauge bosons and itself as: g Hff = m f v × ( − i ) g HHH = 3 M 2 H × ( − i ) v g HVV = 2 M 2 V × ( ig µν ) v g HHHH = 3 M 2 v 2 × ( − i ) H g HHVV = 2 M 2 V v 2 × ( ig µν ) g Hff ∝ m f : Higgs couples mostly to top and bottom quarks fermion ggH and γγ H couplings arise at one-loop level − → Since v is known, the only free parameter in the SM is M H (or λ ) J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 3 / 28

The 4th of July 2012: discovery of a new 125 GeV boson Events / 2 GeV ATLAS -1 -1 CMS s = 7 TeV, L = 5.1 fb s = 8 TeV, L = 5.3 fb Data 3500 S/(S+B) Weighted Events / 1.5 GeV Sig+Bkg Fit (m =126.5 GeV) 3000 H Events / 1.5 GeV Bkg (4th order polynomial) Unweighted 2500 1500 2000 1500 1500 ∫ 1000 -1 s =7 TeV, Ldt=4.8fb 1000 → γ γ ∫ H -1 500 s =8 TeV, Ldt=5.9fb 1000 Events - Bkg 200 120 130 100 110 120 130 140 150 160 m (GeV) 100 γ γ 0 -100 -200 Data 500 100 110 120 130 140 150 160 S+B Fit m [GeV] γ γ B Fit Component 1 σ (stat.) ± σ ATLAS Prelim. Total uncertainty 2 ( sys inc. ) ± σ σ theory ± σ µ m = 125.5 GeV 1 on 0 H σ (theory) 110 120 130 140 150 → γ γ + 0.23 m (GeV) H - 0.22 0.24 γ γ + µ 0.33 = 1.57 + - 0.18 -1 -1 + 0.17 s = 7 TeV, L ≤ 5.1 fb s = 8 TeV, L ≤ 19.6 fb - 0.28 0.12 - + 0.35 Combined → → H ZZ* 4l 0.32 - CMS Preliminary m = 125.7 GeV µ = 0.80 ± 0.14 + 0.20 H µ + 0.40 - 0.13 = 1.44 H → bb (VH tag) p = 0.94 + 0.17 0.35 - - 0.10 SM + 0.21 H → WW* → l ν l ν - 0.21 H → bb (ttH tag) 0.24 + µ 0.32 0.19 = 1.00 + - + 0.16 0.29 H → γ γ (untagged) - - 0.08 Combined + 0.14 - 0.14 H → γ γ , ZZ*, WW* H → γ γ (VBF tag) 0.16 + 0.21 µ = 1.35 + - 0.14 0.13 + - 0.20 0.11 H → γ γ (VH tag) - ± 0.5 → W,Z H b b H → WW (0/1 jet) ± 0.4 µ + 0.7 = 0.2 0.6 <0.1 H → WW (VBF tag) - → τ τ + 0.3 H (8 TeV data only) - 0.3 H → WW (VH tag) + 0.4 0.5 µ = 1.4 + - 0.3 0.2 + - 0.4 0.1 - H → τ τ (0/1 jet) Combined + 0.24 - 0.24 H → b b , τ τ + 0.27 H → τ τ (VBF tag) 0.36 µ = 1.09 + - 0.21 0.08 + - 0.32 - 0.04 H → τ τ (VH tag) + 0.12 Combined 0.12 - H → ZZ (0/1 jet) + 0.14 µ + 0.18 - 0.11 = 1.30 0.10 + 0.17 H → ZZ (2 jets) - - 0.08 -0.5 0 0.5 1 1.5 2 ∫ -1 -4 -2 0 2 4 s = 7 TeV Ldt = 4.6-4.8 fb Best fit / µ σ σ Signal strength ( ) ∫ s = 8 TeV Ldt = 20.3 fb -1 SM J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 4 / 28

with Djouadi et al. (2013) Is it a Higgs? Higgs couplings as predicted by Higgs mechanism couplings proportional to masses as expected couplings to WW , ZZ , γγ roughly as expected Is it a spin 0? state decays into γγ ⇒ not spin-1 Ellis et al. (2012) (Landau–Yang th.) is it a spin–2 like graviton? A priori no: c g � = c γ , c V ≫ 35 c γ Is it CP-even? HV µ V µ vs H ǫ µνρσ Z µν Z ρσ ⇒ d Γ( H → ZZ ∗ ) and d Γ( H → ZZ ) -1 CMS s = 7 (8) TeV, L = 5.1 (12.2) fb 3000 dM ∗ d Φ Pseudoexperiments 0+ 0- 2500 ATLAS/CMS: ∼ 3 σ for CP-even Observed 2000 1500 1000 ⇒ It is THE-A Higgs boson! 500 0 -30 -20 -10 0 10 20 30 L L -2ln( / ) - + 0 0 J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 5 / 28

Outline 1 Constraints on SUSY models through the Higgs sector 2 Constraints on Dark-Matter models through the Higgs sector J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 6 / 28

Motivations for SUSY � Λ d 4 k 1 k 2 ∼ Λ 2 + m 2 The hierarchy problem: why M H ≪ M Pl ? Λ δ m 2 H ∼ loop ln m loop ◮ The fermion 1-loop correction to the Higgs mass: λ 2 � � − Λ 2 + 6 m 2 δ (f) m 2 F F ln Λ f H ⊃ 8 π 2 mF H H ◮ The scalar 1-loop correction to the Higgs mass: s � � �� λ S − Λ 2 + (2 m 2 δ (s) m 2 S − 2 λ S v 2 ) ln Λ H ⊃ 16 π 2 mS H H ◮ SUSY theory with 2 N F = N S and with λ S = − λ 2 F ⇒ the quadratic divergences vanish (remain the logarithmic ones): ⇒ the hierarchy and naturalness problems solved λ 2 � � � � �� if m F = m S ⇒ M H is protected by SUSY δ (f+s) m 2 ( m 2 F − m 2 + 3 m 2 mS S Λ H = S ) ln F ln 4 π 2 mS mF ⇒ SUSY must be broken, m S ≫ m F SM MSSM 60 U � 1 � Y 60 U � 1 � Y 50 50 The gauge coupling unification 40 40 S U � 2 � L � 1 � 1 Α X Α X S U � 2 � L 30 30 S U � 3 � c 20 20 S U � 3 � c A dark matter candidate (relies on R-parity) 10 10 0 0 5 10 15 5 10 15 Q Q Log � � Log � � 1 GeV 1 GeV J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 7 / 28

The Minimal Supersymmetric Standard Model Defined by 4 assumptions : (a) Minimal gauge group: the MSSM is based on the group SU ( 3 ) C × SU ( 2 ) L × U ( 1 ) Y , i.e. the SM gauge symmetry. (b) Minimal particle content: gauge bosons + spin 1/2 SUSY partners : ˆ G a , ˆ W a , ˆ B (vector superfileds) quarks and leptons + squarks and sleptons: ˆ Q , ˆ U R , ˆ D R , ˆ L , ˆ E R . (3 gen. of chiral superfields) 2 Higgs doublets + spin 1/2 SUSY partners: ˆ H 1 , ˆ H 2 (c) Minimal Yukawa interactions and R–parity conservation: a discrete symmetry called R –parity is imposed (enforce lepton and baryon number conservation) R p = ( − 1) 2 s +3 B + L ; R p = ± 1 for SM/SUSY particule (d) Minimal set of soft SUSY–breaking terms: � � W a ˜ G a ˜ • Mass for gauginos: −L gino = 1 M 1 ˜ B ˜ � 3 a =1 ˜ � 8 a =1 ˜ B + M 2 W a + M 3 G a + h . c . 2 Q † L † u R i | 2 + m 2 d R i | 2 + m 2 i = gen m 2 ˜ i ˜ Q i + m 2 ˜ i ˜ L i + m 2 d i | ˜ ℓ i | ˜ ℓ R i | 2 • Mass for sfermions: −L sf = � u i | ˜ ˜ ˜ ˜ ˜ ˜ Q i L i H 2 H † H 1 H † • Mass and bilinear for the Higgs: −L Higgs = m 2 2 H 2 + m 2 1 H 1 + B µ ( H 2 · H 1 + h . c . ) � � R i H 2 · ˜ ij ˜ R i H 1 · ˜ ij ˜ R i H 1 · ˜ A u ij Y u u ∗ Q j + A d ij Y d d ∗ Q j + A l ij Y ℓ ℓ ∗ • Trilinear: −L tril . = � ij ˜ L j + h . c . i , j = gen 105 parameters (SSB) + 19 (SM) ⇒ phenomenological analysis complicated Only 22 for the pMSSM: τ R , A τ , A b , A t , tan β, m 2 H 1 , m 2 M 1 , M 2 , M 3 , m ˜ q , m ˜ u R , m ˜ d R , A u , A d , A e , m ˜ l , m ˜ e R , m ˜ Q , m ˜ t R , m ˜ b R , m ˜ L , m ˜ H 2 J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 8 / 28

The Higgs sector of the MSSM � H 0 H + � � � 1 2 One needs 2 complex scalar doublets: H 1 = and H 2 = H − H 0 2 1 give masses to respectively d and u fermions in SUSY invariant way cancel the chiral anomalies After EWSB: 3 d.o.f. to make W ± L , Z L ⇒ 5 physical states left out: h , H , A , H ± At tree-level only 2 free parameters tan β, M A : tan 2 α = tan 2 β M 2 A + M 2 � � � h , H = 1 Z ) 2 − 4 M 2 Z cos 2 2 β M 2 M 2 A + M 2 ( M 2 A + M 2 A M 2 Z ∓ , Z M 2 A − M 2 2 Z M 2 H ± = M 2 A + M 2 W Important constraint on the MSSM Higgs boson masses: M h ≤ min ( M A , M Z ) · | cos 2 β | ≤ M Z , M H > max ( M A , M Z ), M H ± > M W M A ≫ M Z : decoupling regime, all Higgses heavy except h: M H ∼ M ± M h ∼ M Z | cos 2 β | ≤ M Z , H ∼ M A , α ∼ π − β ⇒ Inclusion of radiative corrections to M h are essential to explain M h ≈ 125 GeV > M Z J´ er´ emie Quevillon (LPT Orsay) Higgs Physics Beyond the Standard Model FFP 2014, Marseille, 15 July 2014 9 / 28