LPT-Orsay CLFV and Neutrino Mass Models LPT Orsay ☞ Neutrino data calls for New Physics ☞ Which BSM? Neutrino mass models ☞ BSM (with m ν ): impact on LFV observables CLFV 2019, Fukuoka, 17-20 June 2019 Asmaa Abada
☞ Facts: ν change flavours after propagating a finite distance sol ≃ 7 . 6 × 10 − 5 eV 2 ∆ m 2 Solar SNO, BOREXino, Super-Kamiokande, sin 2 θ sol ≃ 0 . 30 ν e → ν µ,τ GALLEX/GNO, SAGE, Homestake, Kamiokande Atmospheric IMB, MAcro, Soudan-2, ν µ → ν τ Kamiokande, Super-Kamiokande atm ≃ 2 . 4 × 10 − 3 eV 2 ∆ m 2 LBL Accelerator sin 2 θ atm ≃ 0 . 50 ν µ disappearance K2K, T2K, MINOS LBL Accelerator ν µ → ν τ Opera LBL Accelerator T2K, MINOS ∆ m 2 ν µ → ν e atm Daya Bay, RENO sin 2 θ Chooz ≃ 0 . 023 LBL Reactor Double Chooz ν e disappearance ¯ SBL Accelerator LSND, MiniBooNE ∆ m 2 ≃ 1eV 2 (?) ν µ (¯ ν µ ) → ν e (¯ ν e ) ++ Solar: GALLEX, SAGE++ sin 2 θ ≃ 0 . 1 (?) SBL Reactor Bugey, ILL, Rovno,... ν e disappearance ¯
✠ ☞ ✞ ♠ ❉ ❪ ✞ ✌ ✸ ✟ ❉ ♠ ✞ ✞ ✟ ✥ ✸ ✲ ✡ ✸ ❞ ❈ ✏ ❉ ♠ ✞ ✞ ☛ ✥ ✡ ✲ ❪ ✞ ✌ ☞ ✠ Lepton mixing & neutrino data: current status ◆ ✒ ✓✔ ✕ ✖ ✗ ✘ ✙ ✚ ✘ ✛ ✜ ✢ ✁ � ✽ ✁ � ✻ ❍ ❍ ✁ � ☎ ✁ � ✁ ✑ ✁ � ✁ ✑ ✁ � ☎ ✞ ☎ ✑ ✁ � ✻ ⇒ ⇒ ⇒ ✑ ✁ � ✽ ✄ ✻ ✵ ✝ ✆ ✁ ✼ ✵ ❍ ❍ ✍ ✽ ✵ ✾ ✵ ✵ ✵ � ✄ ✵ � ☎ ✵ � ✂ ✵ � ✻ ✵ � ✼ ✷ s✆ ✝ q ✷ ✎ ◮ “Precision era” for neutrino physics ✽ ✼ � ✂ ◮ Only three oscillation parameters unknown... ❍ ❍ ✼ θ 23 octant; δ CP ; ν -mass ordering ✻ � ✂ ✵ � ✁ ✵ � ✁ ✂ ✵ � ✄ ✵ � ✄ ✂ ✵ � ☎ ✵ � ✵ ✍ ✂ ✵ � ✵ ✁ ✵ � ✵ ✁ ✂ ✵ � ✵ ✄ sin 2 θ 23 = 0 . 58 (preference: sin 2 θ 23 = 0 . 58 sin 2 θ 23 = 0 . 58 (b.f) 2 nd octant; δ CP = 217 ✷ ✷ δ CP = 217 δ CP = 217 (b.f);) s✆ ✝ q s✆ ✝ q ✶ ✷ ✶✎ ◮ Exciting experimental road ahead!
✆ ✠ ✝ ✞ ✟ Still undetermined m 2 m 2 ν e ν µ ◮ Oscillation data: only two squared-mass differences ν τ Undetermined mass ordering! 2 2 m 3 m 2 solar~7 × 10 − 5 eV 2 2 m 1 normal [ m ν 1 < m ν 2 ≪ m ν 3 ] atmospheric ~2 × 10 − 3 eV 2 atmospheric inverted [ m ν 3 ≪ m ν 1 � m ν 2 ] ~2 × 10 − 3 eV 2 2 m 2 solar~7 × 10 − 5 eV 2 2 2 m 1 m 3 Unknown absolute mass scale! need direct measurment ? ? 0 0 ☞ Resolving the absolute mass scale for light neutrinos - Tritium decays ( 3 H → 3 He + ν e + e − ) : m ν e � 2 . 1 m ν e � 2 . 1 m ν e � 2 . 1 eV [Troitsk] ☞ June 11 2018, the KATRIN experiment has been inaugurated! 0 ν 2 β decays ➙ Majorana nature : | m ee | � 0 . 3 - 0 ν 2 β 0 ν 2 β | m ee | � 0 . 3 | m ee | � 0 . 3 eV [GERDA, KamLAND-Zen] � - Cosmology (CMB, LSS, Ly α ) : � � i m ν i � 0 . 23 → 0 . 12 ❈✖ ❩ ✘ ✜ ✚ i m ν i � 0 . 23 → 0 . 12 i m ν i � 0 . 23 → 0 . 12 eV ❚ ✗ ❙ ✗ ❈ ✚ ❚ ✗ ✶ ▼ ✙ ●✗ K (T) ✛ ✗ ✌ ✍ ✎ ☎ ❑ ❛✏ ▲ ❆ ◆ ❉ ✲ ✑ ☛♥ ✒ ❳ ☛☞ ✶ ✄ ■ ✡ ✷ ✶ ✄ ◆ ✡ Q ✸ T ✶ ✄ m ν ✸ ✹ ✷ ☎ ✶ ✄ ✶ ✄ ✶ ✄ ✶ ✄ ✺ ✔ ✕ ✔ ✔ ✕ ✺ ✔ ♠ ✥� ❱✮ ✓ ❧ ✐ ❣ ✁✂ ❡ s ✂
☞ Indisputable: ν s are massive and mix ➙ The minimal SM is incomplete! ➙ ✞ ☎ An observational caveat that is also a theoretical one! ✝ ✆
ν � = ◮ Is ν ν mass generation mechanism � = � = the one of quarks/charged leptons ? ◮ ν mixings "add fuel to the fire": add to the fermion flavour puzzle! 1 − λ 2 / 2 1 − λ 2 / 2 1 − λ 2 / 2 Aλ 3 ( ρ − iη ) Aλ 3 ( ρ − iη ) Aλ 3 ( ρ − iη ) λ λ λ 1 − λ 2 / 2 Aλ 2 1 − λ 2 / 2 1 − λ 2 / 2 Aλ 2 Aλ 2 V CKM = , λ ∼ 0 . 2 , A ≃ 0 . 8 , ρ ≃ 0 . 1 , η ≃ 0 . 4 V CKM = V CKM = − λ , λ ∼ 0 . 2 , A ≃ 0 . 8 , ρ ≃ 0 . 1 , η ≃ 0 . 4 , λ ∼ 0 . 2 , A ≃ 0 . 8 , ρ ≃ 0 . 1 , η ≃ 0 . 4 − λ − λ Aλ 3 (1 − ρ − iη ) Aλ 3 (1 − ρ − iη ) Aλ 3 (1 − ρ − iη ) − Aλ 2 − Aλ 2 − Aλ 2 1 1 1 Quarks: small mixing angles, 1 Dirac CPV phase s 13 e − iδ s 13 e − iδ s 13 e − iδ c 13 c 12 c 13 s 12 c 13 c 12 c 13 c 12 c 13 s 12 c 13 s 12 � � � � � � e iα 1 , e iα 2 , 1 e iα 1 , e iα 2 , 1 e iα 1 , e iα 2 , 1 − c 23 s 12 − s 23 s 13 c 12 e iδ − c 23 s 12 − s 23 s 13 c 12 e iδ − c 23 s 12 − s 23 s 13 c 12 e iδ c 23 c 12 − s 23 s 13 s 12 e iδ c 23 c 12 − s 23 s 13 s 12 e iδ c 23 c 12 − s 23 s 13 s 12 e iδ U P MNS = × diag U P MNS = U P MNS = × diag × diag − s 23 c 13 − s 23 c 13 − s 23 c 13 s 23 s 12 − c 23 s 13 c 12 e iδ − s 23 c 12 − c 23 s 13 s 12 e iδ s 23 s 12 − c 23 s 13 c 12 e iδ s 23 s 12 − c 23 s 13 c 12 e iδ − s 23 c 12 − c 23 s 13 s 12 e iδ − s 23 c 12 − c 23 s 13 s 12 e iδ c 23 c 13 c 23 c 13 c 23 c 13 Leptons: 2 large mixing angles, 1 Dirac (+ 2 Majorana) CPV phase(s) ⇒ Very different mixing pattern for Leptons and Quarks ✞ ☎ Is this related to neutrino mass generation mechanism? ☞ ✝ ✆
ν ◮ Light ν ν mass scale ? ◮ ν data worsens fermion hierarchy problem! ✞ ☎ Why ν so light? ☞ ✝ ✆ ✞ ☎ and what absolute neutrino mass scale? ☞ ✝ ✆
◮ Neutrino oscillation reactor and accelerator anomalies ◮ Are there some extra fermionic gauge singlets (steriles)? 3- ν mixing scheme 3+? - ν mixing schemes ✞ ☎ Does this mean that U P MNS is incomplete? Non-Unitary? ☞ ✝ ✆ ✞ ☎ Do they play a role in the neutrino mass generation mechanism? ☞ ✝ ✆
☞ Bonus: strong Potential for CP violation! ◮ Unitarity triangle surface ∝ J lepton : J lepton CP,max ≃ 1000 × J quark CP CP J quark = 2 . 96 × 10 − 5 , J CP,max ≃ 3 . 29 × 10 − 2 CP U e 3 U ∗ e 1 U ∗ � � J ≡ Im µ 3 U µ 1 J = J max CP sin δ Unitarity Triangle (in e, µ ) Jarlskog Invariant ✞ ☎ New possibility for having BAU from Leptogenesis ? Contribution to EDMs? ☞ ✝ ✆
m ν � = 0 ⇒ New Physics Scale Standard Model ◮ ν L only and no ν R = ⇒ No Dirac mass term: L m D = m D ( ν L ν R + ν R ν L ) ⇒ No Majorana mass term: L m M = 1 2 Mν c ◮ No Higgs triplet = L ν L + h.c. Majorana field: Ψ ν = ν L + ν c Ψ ν = Ψ c ν c L ν L = ν T C = iγ 2 γ 0 L ➙ ν ➙ L Cν L , ◮ Lepton number symmetry is accidental = ⇒ Non-renormalisable operators dim 5, 6 .. ✞ ☎ SM ≡ Effective theory of a larger one valid at a scale Λ ✝ ✆ ➙ � � φ � = v δ L d =5 = c d =5 O d =5 , O d =5 = 1 �� � T � → m ν ∼ v 2 / Λ � φℓ φℓ + h.c. − Λ 2 × 10 − 3 eV 2 ⇒ Λ ∼ 10 15 GeV (near Λ GUT !) for c d =5 ∼ O (1) , m ν ∼ � � ∆ m 2 atm ∼ ✞ ☎ Depending on c d =5 (thus on NP model) ⇒ Λ ∈ [ ..., MeV , GeV , TeV , ..., GUT , ... ] ✝ ✆
◮ Lepton mixing & massive neutrinos: unique signal for NP ☞ SM has other issues that call for BSM ◮ observational problems ( ν masses & mixings): BAU and Dark Matter ◮ theoretical caveats: fine-tuning, hierarchy and flavour problems .... ☞ ν -SM = New Physics just to explain ν masses and mixings H Y ν ν L ν R + ... ➙ m ν ◮ New d.o.f, for example Right-Handed Neutrinos, H Y ν ν L ν R + ... ➙ m ν H Y ν ν L ν R + ... ➙ m ν ◮ What is the neutrino mass generation mechanism? ◮ ν ↔ ¯ ν ↔ ¯ ν ↔ ¯ ν ν ν the only particle that can have both Dirac or Majorana descriptions ◮ If ν is a Majorana particle ➙ New physics scale, LNV observables, ... ☞ ν -SM will allow for many new phenomena ◮ LFV in neutral sector. Why not in the charged sector? ℓ i → ℓ j ℓ k ℓ l , ℓ i → ℓ j γ , ... ◮ Contributions to g − 2 , Lepton EDMs ◮ Signatures of the new heavy states at colliders, ... ✞ ☎ Determination of ν -SM/BSM model requires combinations of many � = observables ☞ ✝ ✆
☞ Determination of ν -SM/BSM requires to combine � = observables: how to proceed? ◮ Inputs: - a mass generation mechanism (seesaw, radiative corrections, extra dim, ...) - and/or, extension of SM: SM + new d.o.f, or BSM (e.g. SUSY, ...) ◮ Observables (peculiar to these extensions): - Produce directly new d.o.f at LHC (if accessible) - Or/and study impact of 1. (and 1. + 2.) on e.g. cLFV observables at low- energy/high intensity (MEG, ...) and high-energy (LHC, Future colliders) ✞ ☎ ◮ Probe of New Physics: interplay of low- and high-energy observables [cLFV] ✝ ✆
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