Flavor Violating Higgs Decays Joachim Kopp Galileo Galilei - PowerPoint PPT Presentation

Flavor Violating Higgs Decays Joachim Kopp Galileo Galilei Institute November 26, 2012 Based on work done in collaboration with Roni Harnik and Jure Zupan arXiv:1209.1397 Joachim Kopp Flavor Violating Higgs Decays 1

Outline Flavor mixing in the Higgs sector 1 Couplings to leptons 2 Couplings to quarks 3 Flavor-violating Higgs decays at the LHC 4 Summary 5 Joachim Kopp Flavor Violating Higgs Decays 2

Flavor Mixing in the Higgs Sector

Motivation Scenario 1: Several sources of EW symmetry breaking If fermion masses have more than one origin, they do not need to be aligned with the Yukawa couplings Simplest example: Type III 2-Higgs-Doublet Model R H ( 1 ) − Y ( 2 ) R H ( 2 ) + h . c . L Y ⊃ − Y ( 1 ) L i e j ¯ ¯ L i e j ij ij ij ¯ L f j e i L e i R − Y eff f i → − m i ¯ − R h + couplings to heavier Higgs bosons + h . c . (h = Lightest neutral Higgs boson, m h ∼ 125 GeV) Assume heavy Higgs boson are decoupled. see for instance Davidson Greiner, arXiv:1001.0434 Joachim Kopp Flavor Violating Higgs Decays 4

Motivation (2) Scenario 2: Extra Higgs couplings Assume existence of heavy new particles, which induce effective operators of the form λ ′ Λ 2 (¯ ij f i L f j R ) H ( H † H ) + h . c . + · · · , ∆ L Y = − → after EWSB, new (but misaligned) contributions to mass matrices and Yukawa couplings Effective Lagrangian is again ij ¯ L f j e i L e i R − Y eff f i L Y ⊃ − m i ¯ R h + h . c . see for instance Giudice Lebedev, arXiv:0804.1753 Joachim Kopp Flavor Violating Higgs Decays 5

Effective Yukawa Lagrangfian Effective Yukawa Lagrangian R ) h a + h . c . + · · · L Y = − m i ¯ ij (¯ L f j f i L f i R − Y a f i Previously studied by many authors: Bjorken Weinberg, PRL 38 (1977) 622 McWilliams Li, Nucl. Phys. B 179 (1981) 62 Shanker, Nucl. Phys. B 206 (1982) 253 Barr Zee, PRL 65 (1990) 21 Babu Nandi, hep-ph/9907213 Diaz-Cruz Toscano, hep-ph/9910233 Han Marfatia, hep-ph/0008141 Kanemura Ota Tsumura, hep-ph/0505191 Blanke Buras Duling Gori Weiler, arXiv:0809.1073 Casagrande Goertz Haisch Neubert Pfoh, arXiv:0807.4937 Giudice Lebedev, arXiv:0804.1753 Aguilar-Saavedra, arXiv:0904.2387 Albrecht Blanke Buras Duling Gemmler, arXiv:0903.2415 Buras Duling Gori, arXiv:0905.2318 Azatov Toharia Zhu, arXiv:0906.1990 Agashe Contino, arXiv:0906.1542 Davidson Greiner, arXiv:1001.0434 Goudelis Lebedev Park, arXiv:1111.1715 Blankenburg Ellis Isidori, arXiv:1202.5704 Arhrib Cheng Kong, arXiv:1208.4669 McKeen Pospelov Ritz, arXiv:1208.4597 . . . Joachim Kopp Flavor Violating Higgs Decays 6

Effective Yukawa Lagrangfian Effective Yukawa Lagrangian R ) h a + h . c . + · · · L Y = − m i ¯ ij (¯ L f j f i L f i R − Y a f i New in this talk: Comprehensive list of up-to-date constraints (including subdominant ones) Omit approximations where feasible First LHC limits Strategy for future LHC searches Joachim Kopp Flavor Violating Higgs Decays 6

Couplings to Leptons

Low-energy constraints on LFV in the Higgs sector h µ µ − e − Y ∗ µµ P L + Y µµ P R τ τ Y ∗ eµ P L + Y µe P R µ µ τ h µ Y ∗ Y ∗ µτ P L + Y τµ P R τµ P L + Y µτ P R Y ∗ τµ P L + Y µτ P R h µ γ g − 2, EDMs τ → 3 µ , µ ee , etc. Y ∗ eµ P L + Y µe P R µ + e + µ µ τ h γ, Z h M – ¯ M oscillations t t τ τ τ µ Y ∗ ττ P L + Y ττ P R Y ∗ τµ P L + Y µτ P R γ γ µ Y ∗ µe P L + Y eµ P R e µ µ τ µ τ µ h h γ, Z h γ, Z W W W W N N γ γ µ – e conversion τ → µγ , µ → e γ , etc. Joachim Kopp Flavor Violating Higgs Decays 8

Constraints on h → µ e 10 1 � g � g � 2 � 10 0 2 � Μ � 3e � e e � f o E r M � M I D 10 � 1 m M � Y Μ e e Y e Μ E 10 � 2 D � M e � 0 f � Y Μ e � o 10 � 3 r � Y Μ e R e � Y e Μ Y Μ e BR � h �Μ e � � 0.99 � Y e Μ 10 � 4 � m e � Μ � e conv. � m Μ 0 � 10 � 5 v 2 Μ � e Γ 10 � 6 10 � 4 10 � 9 10 � 8 10 � 7 10 � 6 10 � 5 10 � 3 10 � 2 10 � 1 0.5 10 � 7 10 � 7 10 � 6 10 � 5 10 � 4 10 � 3 10 � 2 10 � 1 10 0 10 1 � Y e Μ � Assumption here: see also: Blankenburg Ellis Isidori, arXiv:1202.5704 Diagonal Yukawa coupling unchanged Goudelis Lebedev Park, arXiv:1111.1715 from their SM values. Joachim Kopp Flavor Violating Higgs Decays 9

Constraints on h → τµ and h → τ e 0 � � M Μ Τ Τ � e ΜΜ 10 0 Y Μ D 10 0 Τ � 3 Μ Μ E Y Τ � � � m � g g I � � 2 � � Μ 2 � 2 � Μ � e � 10 � 1 f e 2 o g r � � � g 10 � 1 I E m � D � M Y Τ e Y 10 � 2 e � Y ΤΜ � � Y Τ e � e Τ � � 0 BR � h � Τ e � � 0.99 BR � h � ΤΜ � � 0.99 10 � 2 � � Y Y 10 � 3 Τ � ΜΓ Τ e Τ E Y Μ Y D e Μ M Τ � Τ � e Γ Τ � � � m m e � e m Μ m 10 � 4 R e Τ � � Τ � Y v 10 � 3 v 2 2 10 � 6 10 � 2 10 � 2 10 � 5 Τ 10 � 3 10 � 1 10 � 3 10 � 1 e Y 0.75 e 0.5 0.5 Τ � � 10 � 5 0 10 � 3 10 � 2 10 0 10 � 5 10 � 4 10 � 3 10 � 2 10 0 10 � 1 10 � 1 � Y ΜΤ � � Y e Τ � Substantial flavor violation ( BR ( h → τµ, τ e ) ∼ 0 . 01) perfectly viable. Assumption here: see also: Blankenburg Ellis Isidori, arXiv:1202.5704 Diagonal Yukawa coupling unchanged Goudelis Lebedev Park, arXiv:1111.1715 Davidson Greiner, arXiv:1001.0434 from their SM values. Joachim Kopp Flavor Violating Higgs Decays 10

Couplings to Quarks

Constraints on Higgs couplings to light quarks Tight constraints from neutral meson oscillations b d c u Y ∗ bd P L + Y db P R Y ∗ ct P L + Y tc P R Y ∗ tu P L + Y ut P R h h t t h Y ∗ bd P L + Y db P R u Y ∗ tu P L + Y ut P R Y ∗ ct P L + Y tc P R c ¯ ¯ ¯ ¯ d b Joachim Kopp Flavor Violating Higgs Decays 12

Constraints on Higgs couplings to light quarks Tight constraints from neutral meson oscillations Work in Effective Field Theory: b R d L ) 2 + ˜ b L d R ) 2 + C db 2 (¯ 2 (¯ 4 (¯ b L d R )(¯ H eff = C db C db b R d L ) + . . . Wilson coefficients constrained in UTfit (Bona et al.), arXiv:0707.0636 see also Blankenburg Ellis Isidori, arXiv:1202.5704 Technique Coupling Constraint | Y uc | 2 , | Y cu | 2 < 5 . 0 × 10 − 9 D 0 oscillations < 7 . 5 × 10 − 10 | Y uc Y cu | | Y db | 2 , | Y bd | 2 < 2 . 3 × 10 − 8 B 0 d oscillations < 3 . 3 × 10 − 9 | Y db Y bd | | Y sb | 2 , | Y bs | 2 < 1 . 8 × 10 − 6 B 0 s oscillations < 2 . 5 × 10 − 7 | Y sb Y bs | ℜ ( Y 2 ds ) , ℜ ( Y 2 [ − 5 . 9 . . . 5 . 6 ] × 10 − 10 sd ) ℑ ( Y 2 ds ) , ℑ ( Y 2 [ − 2 . 9 . . . 1 . 6 ] × 10 − 12 sd ) K 0 oscillations [ − 5 . 6 . . . 5 . 6 ] × 10 − 11 ℜ ( Y ∗ ds Y sd ) [ − 1 . 4 . . . 2 . 8 ] × 10 − 13 ℑ ( Y ∗ ds Y sd ) Joachim Kopp Flavor Violating Higgs Decays 12

Couplings involving top quarks Constraints from Single top production 0.5 10 1 BR � h � t � q � h 10 � 1 BR � t � hq � t t q single top bound on � Y ut � , � Y tu � 0.5 single top bound on � Y ct � , � Y tc � t � Y tq � � q � c, u � Y ∗ tt P L + Y tt P R Y ∗ tq P L + Y qt P R 10 � 2 10 0 t � hq lim it � Craig et al. � 10 � 1 10 � 3 g 10 � 2 CDF 0812.3400, DØ 1006.3575 10 � 4 ATLAS 1203.0529 10 � 1 10 � 3 t → hq 10 � 5 Craig et al. 1207.6794 10 � 4 based on CMS multilepton search 10 � 2 1204.5341 10 � 2 10 � 1 10 0 10 1 Not sensitive � Y qt � � q � c, u � t → Zq CMS 1208.0957 Joachim Kopp Flavor Violating Higgs Decays 13

Flavor-Violating Higgs Decays at the Large Hadron Collider

h → τµ and h → τ e at the LHC Basic idea: based on ATLAS, arXiv:1206.5971 25 h → τℓ has the same final state ATLAS 4.7 fb � 1 as h → ττ ℓ 20 ATLAS MC (but is enhanced by 1 / BR ( τ → ℓ ) ) Events � 10 GeV ATLAS data � � Recast h → ττ search 15 5 � H � Τ � Τ � here: ATLAS, arXiv:1206.5971 5 � H � Τ � Μ 10 We consider only 2-lepton 2 � � Y ΤΜ 2 � 1 � 2 � m Τ � � Y ΜΤ v final states 5 Use VBF cuts � � � � (much lower BG than gg fusion) � � 0 0 100 200 300 400 see however ΤΤ collinear mass m ΤΤ � GeV � Davidson Verdier, arXiv:1211.1248 Joachim Kopp Flavor Violating Higgs Decays 15

h → τµ and h → τ e at the LHC Most important cuts based on ATLAS, arXiv:1206.5971 25 2 forward jets ( p T , j 1 > 40 GeV, ATLAS 4.7 fb � 1 p T , j 2 > 25 GeV, | ∆ η | > 3 . 0, 20 m inv j 1 , j 2 > 350 GeV) ATLAS MC Events � 10 GeV ATLAS data no hard jet activity in between � � 15 5 � H � Τ � Τ � no b tags 5 � H � Τ � Μ 2 opposite sign leptons ℓ 1 , ℓ 2 with 10 2 � � Y ΤΜ 2 � 1 � 2 � m Τ � � Y ΜΤ v p T ,ℓ � 10–20 GeV (depending on 5 flavors) � τ momentum fraction x carried by � � � � � 0 ℓ 1 , ℓ 2 satisfies 0 . 1 < x 1 , 2 < 1 . 0 0 100 200 300 400 ΤΤ collinear mass m ΤΤ � GeV � (computed in collinear approximation) 30 GeV < m ℓℓ < 75 (100) GeV for same (opposite) flavor leptons / E T > 20 (40) GeV for same (opposite) flavor leptons Joachim Kopp Flavor Violating Higgs Decays 15