Electroweak scale neutrinos and Higgses Alfredo Aranda Facultad de - PowerPoint PPT Presentation

Electroweak scale neutrinos and Higgses Alfredo Aranda Facultad de Ciencias - Universidad de Colima Dual CP Institute of High Energy Physics XIII Mexican School of Particles and Fields - 2008 Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 1 / 33

Outline Standard Model 1 Particle Content Gauge Structure The missing ingredient Beyond the Standard Model 2 Experimental Evidence Pseudo-experimental evidence Theoretical evidence Going beyond Minimal model 3 Electroweak scale additions The Model Model with Higgs triplets 4 Additional field content Virtues Conclusions 5 Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 2 / 33

Standard Model Particle Content Particle Content Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 3 / 33

Standard Model Gauge Structure Gauge Structure. interactions 1 SU(3) C × SU(2) W × U(1) Y 2 8 gluon fields for the Strong interaction. 3 3 gauge fields for the Weak interaction. 4 1 gauge field for the Electromagnetic interaction. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 4 / 33

Standard Model Gauge Structure Gauge Structure. interactions 1 SU(3) C × SU(2) W × U(1) Y 2 8 gluon fields for the Strong interaction. 3 3 gauge fields for the Weak interaction. 4 1 gauge field for the Electromagnetic interaction. � u � c � t � ν e � ν µ � ν τ � � � � � � e − d s b µ − τ − L L L L L L e R µ R τ R u R d R c R s R t R b R Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 4 / 33

Standard Model The missing ingredient Higgs - The missing ingredient. Massive force carriers! 1 Principle of Gauge Symmetry → Massless Gauge bosons. 2 Massive Gauge bosons → inconsistent theory! 3 Solution: Spontaneous Symmetry Breaking - Higgs Mechanism Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 5 / 33

Standard Model The missing ingredient Higgs - The missing ingredient. Massive force carriers! 1 Principle of Gauge Symmetry → Massless Gauge bosons. 2 Massive Gauge bosons → inconsistent theory! 3 Solution: Spontaneous Symmetry Breaking - Higgs Mechanism SM predicts the existence of a new particle, the Higgs. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 5 / 33

Standard Model The missing ingredient Higgs - The missing ingredient. Massive force carriers! 1 Principle of Gauge Symmetry → Massless Gauge bosons. 2 Massive Gauge bosons → inconsistent theory! 3 Solution: Spontaneous Symmetry Breaking - Higgs Mechanism Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 5 / 33

Beyond the Standard Model Experimental Evidence Why go beyond the Standard Model? Experimental Evidence 1 Neutrinos are MASSIVE. 2 Baryon Asymmetry - A mystery. 3 Dark Matter 4 Dark Energy Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 6 / 33

Beyond the Standard Model Experimental Evidence Why go beyond the Standard Model? Experimental Evidence 1 Neutrinos are MASSIVE. 2 Baryon Asymmetry - A mystery. 3 Dark Matter 4 Dark Energy Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 6 / 33

Beyond the Standard Model Experimental Evidence Why go beyond the Standard Model? Experimental Evidence 1 Spectrum of fermion masses. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 7 / 33

Beyond the Standard Model Experimental Evidence Why go beyond the Standard Model? Experimental Evidence 1 Spectrum of fermion masses. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 7 / 33

Beyond the Standard Model Pseudo-experimental evidence Why go beyond the Standard Model? Pseudo-experimental Evidence 1 Gauge coupling unification. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 8 / 33

Beyond the Standard Model Pseudo-experimental evidence Why go beyond the Standard Model? Pseudo-experimental Evidence 1 Gauge coupling unification. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 8 / 33

Beyond the Standard Model Pseudo-experimental evidence Why go beyond the Standard Model? Pseudo-experimental Evidence 1 Gauge Hierarchy problem. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 9 / 33

Beyond the Standard Model Pseudo-experimental evidence Why go beyond the Standard Model? Pseudo-experimental Evidence 1 Gauge Hierarchy problem. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 9 / 33

Beyond the Standard Model Theoretical evidence Why go beyond the Standard Model? Theoretical Evidence 1 GRAVITY. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 10 / 33

Beyond the Standard Model Going beyond How do we go beyond the Standard Model? Approaches 1 Grand Unified Theories. 2 Supersymmetry. 3 Extra dimensions. 4 � ♦ � Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 11 / 33

Beyond the Standard Model Going beyond How do we go beyond the Standard Model? Approaches 1 Grand Unified Theories. 2 Supersymmetry. 3 Extra dimensions. 4 � ♦ � Paradigm: Something is happening at high (very high) energy scales. Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 11 / 33

Minimal model Electroweak scale additions Minimalistic additions Proposal 1 Any addition to the Standard Model should NOT introduce higher energy scales a . 2 Effects of additions should be testable at future accelerators: LHC/ILC a A.A, Omar Blanno and J. Lorenzo Díaz-Cruz, Physics Letters B 660, 62-66 (2008) Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 12 / 33

Minimal model Electroweak scale additions Right-handed neutrinos at the Electroweak scale The model SM particle content and gauge interactions. Existence of 3 RH neutrinos with a mass scale of EW size. Global U(1) L spontaneously (and/or explicitly) broken at the EW scale by a single complex scalar field. Higgs sector: SU(2) L doublet Higgs field Φ and a SM singlet complex scalar field η . Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 13 / 33

Minimal model The Model Neutrino and scalar sector The Lagrangian L ν H = L ν y − V , with L α N Ri Φ − 1 N c L ν y = − y α i ¯ 2 Z ij η ¯ Ri N Rj + h . c . , D Φ † Φ + λ � 2 � S η ∗ η + λ ′ ( η ∗ η ) 2 V µ 2 Φ † Φ + µ 2 = 2 � � � � η Φ † Φ + h . c . Φ † Φ ( η ∗ η ) . + κ + λ m Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 14 / 33

Minimal model The Model Breaking the symmetry � � and η = ρ + u + i σ 0 Φ = √ , (1) φ 0 + v √ 2 2 Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 15 / 33

Minimal model The Model Breaking the symmetry � � and η = ρ + u + i σ 0 Φ = √ , (1) φ 0 + v √ 2 2 Scalar masses √ λ v 2 vu ( λ m − 2 r ) � � M 2 √ S = (2) 2 λ ′ u 2 + vu ( λ m − 2 r ) 2 rv 2 1 √ σ = rv 2 M 2 √ (3) 2 Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 15 / 33

Minimal model The Model Physical states � � h � cos α φ 0 � � � − sin α H = = (4) H ρ sin α cos α Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 16 / 33

Minimal model The Model Physical states � � h � cos α φ 0 � � � − sin α H = = (4) H ρ sin α cos α Lagrangian − y α i � � ν L α N Ri ( c α h − s α H ) + h . c . L ν y ⊃ √ ¯ 2 i � � N c Z ij ¯ Ri N Rj σ + h . c . − √ 2 2 � 1 � N c Z ij ¯ Ri N Rj ( s α h + c α H ) + h . c − √ . (5) 2 2 Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 16 / 33

Minimal model The Model Neutrino masses Seesaw m D � � 0 m ν = (6) m D M M √ ( m D ) α i = y α i v / 2 Consider the third family (2 × 2 matrix) Assume m D << M M → m 1 = − m 2 D / M M and m 2 = M M Requiring m 1 ∼ O(eV) and m 2 ∼ ( 10 − 100 ) GeV leads to y τ i ≤ 10 − 6 (comparable to Yukawa coupling of the electron). Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 17 / 33

Minimal model The Model Neutrino eigenstates ν τ = cos θ ν L 1 + sin θ ν R 2 N = − sin θ ν L 1 + cos θ ν R 2 m D / m 2 ≈ 10 − ( 5 − 6 ) . p with θ = Alfredo Aranda (Colima - DCPIHEP) EW scale neutrinos and Higgses XIII-EMPC: October 6, 2008 18 / 33