Lecture VIII: Cosmic Frontier Connections M.J. Ramsey-Musolf U Mass Amherst http://www.physics.umass.edu/acfi/ ACFI NLDBD School 10/31-11/3 2017 � 1
Lecture VIII Goals • Provide some background on leptogenesis in the broader context of baryogenesis • Discuss some implications of 0 νββ -decay searches for leptogenesis • Provide some background on cosmological probes of neutrino mass** • Invite questions ! ** Disclaimer: not my primary area of expertise 2
Lecture VIII Outline I. Origin of Matter: Leptogenesis II. Neutrino Mass from Cosmology 3
I. Origin of Matter: Leptogenesis 4
Symmetries & Cosmic History EW Symmetry Breaking: Higgs Standard Model Universe 10 -35 s 10 -11 s 10 -5 s ~ 1 m 380k yr QCD: q+g ! QCD: n+p ! Astro: stars, n,p… nuclei galaxies,..
Symmetries & Cosmic History EW Symmetry Breaking: Higgs BSM Physics? Standard Model Universe 10 -35 s 10 -11 s 10 -5 s ~ 1 m 380k yr QCD: q+g ! QCD: n+p ! Astro: stars, n,p… nuclei galaxies,..
The Origin of Matter Cosmic Energy Budget Dark Matter 27 % Baryons Baryons 5 % 68 % Dark Energy Explaining the origin, identity, and relative fractions of the cosmic energy budget is one of the most compelling motivations for physics beyond the Standard Model
The Origin of Matter Cosmic Energy Budget Dark Matter 27 % Baryons Baryons 5 % 68 % Dark Energy Explaining the origin, identity, and relative fractions of the cosmic energy budget is one of the most compelling motivations for physics beyond the Standard Model
Cosmic Baryon Asymmetry Y B = n B s = (8 . 59 ± 0 . 11) ⇥ 10 − 11 Cosmic Microwave Bcknd: Big Bang Nucleosynthesis: Shape of anisotropies Light element abundances depends on Y B depend on Y B
Symmetries & Cosmic History EW Symmetry Breaking: Higgs BSM Physics? Standard Model Universe How did we go from nothing to something ? 10 -35 s 10 -11 s 10 -5 s ~ 1 m 380k yr QCD: q+g ! QCD: n+p ! Astro: stars, n,p… nuclei galaxies,..
Ingredients for Baryogenesis • B violation (sphalerons) • C & CP violation • Out-of-equilibrium or CPT violation
Ingredients for Baryogenesis Standard Model BSM ✔ ✔ • B violation (sphalerons) ✖ • C & CP violation ✔ • Out-of-equilibrium or ✖ ✔ CPT violation
Ingredients for Baryogenesis Scenarios: leptogenesis, EW baryogenesis, Afflek- Dine, asymmetric DM, cold baryogenesis, post- sphaleron baryogenesis… Standard Model BSM ✔ ✔ • B violation (sphalerons) ✖ • C & CP violation ✔ • Out-of-equilibrium or ✖ ✔ CPT violation
Symmetries & Cosmic History EW Symmetry Breaking: Higgs Baryogenesis: When? CPV? SUSY? Neutrinos? Standard Model Universe ? 10 -35 s 10 -11 s 10 -5 s ~ 1 m 380k yr QCD: q+g ! QCD: n+p ! Astro: stars, n,p… nuclei galaxies,..
Symmetries & Cosmic History EW Symmetry Breaking: Higgs Baryogenesis: When? CPV? SUSY? Neutrinos? Standard Model Universe ? EW Baryogenesis: Leptogenesis: testable w/ EDMs + look for ingred’s colliders w/ ν s: DBD, ν osc 10 -35 s 10 -11 s 10 -5 s ~ 1 m 380k yr QCD: q+g ! QCD: n+p ! Astro: stars, n,p… nuclei galaxies,..
Baryogenesis Scenarios 10 12 Standard thermal lepto Energy Scale (GeV) 10 9 Affleck Dine Electroweak, resonant lepto, 10 2 WIMPY baryo, ARS lepto… 10 -1 Post-sphaleron, cold… 16
What Questions Does It Address ? Is the neutrino its own antiparticle ? • Why is there more matter than antimatter ? • Why are neutrino masses so small? • ν = ν “See saw mechanism” “Leptogenesis” Heavy neutrino decays in early universe generate baryon asym New heavy neutrino-like particle = its own anti-particle 17
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe • Majorana neutrinos can decay to particles and antiparticles • Rates can be slightly different (CP violation) Γ ( N ! ` H ) 6 = Γ ( N ! ¯ ` H ∗ ) ( • Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons 18
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe • Majorana neutrinos can decay to particles and antiparticles • Rates can be slightly different (CP violation) Γ ( N ! ` H ) 6 = Γ ( N ! ¯ ` H ∗ ) ( • Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons 19
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe _ l l N R N R h h + H * H ` H ∗ ) = | h | 2 Γ N ⌘ Γ ( N R ! ` H ) + Γ ( N R ! ¯ 8 ⇡ M N Hubble rate T 2 H ( T ) ⇠ 1 . 66 g ∗ M P 20
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe Simple estimation Γ N < H(T=M N ) ~ 0.8 Γ N (z) / Γ N Γ N ( z ) = K 1 ( z ) 0.6 K 2 ( z ) Γ N 0.4 0.2 z = M N / T 2 4 6 8 10 21
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe Γ N < H(T=M N ) Simple estimation ~ � ✓ ◆ ✓ m 1 ≈ m ∗ m 1 ⇡ m 2 D M N m ∗ = 8 π ∗ (1 . 66 g ∗ ) v 2 ~ few x 10 -3 eV M P 22
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe Washout processes _ l l N R H H * Δ L = 2 23
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe Complete calculation: Boltzmann equations Non-Eq: T < m N Eq: T > m N di Bari ‘12 24
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe • Majorana neutrinos can decay to particles and antiparticles • Rates can be slightly different (CP violation) Γ ( N ! ` H ) 6 = Γ ( N ! ¯ ` H ∗ ) ( • Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons 25
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe • Majorana neutrinos can decay to particles and antiparticles • Rates can be slightly different (CP violation) Γ ( N ! ` H ) 6 = Γ ( N ! ¯ ` H ∗ ) ( • Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons 26
Neutrinos and the Origin of Matter CPV Asymmetry Tree-level CPV One-loop “absoprtive part” X 27 Buchmuller, Peccei, Yanagida ‘05
Neutrinos and the Origin of Matter CPV Asymmetry Tree-level CPV One-loop “absoprtive part” X CPV phases but not same as φ PMNS 28 Buchmuller, Peccei, Yanagida ‘05
Neutrinos and the Origin of Matter Putting pieces together: B-L asymmetry Buchmuller, Peccei, Yanagida ‘05 29
Neutrinos and the Origin of Matter • Heavy neutrinos decay out of equilibrium in early universe • Majorana neutrinos can decay to particles and antiparticles • Rates can be slightly different (CP violation) Γ ( N ! ` H ) 6 = Γ ( N ! ¯ ` H ∗ ) ( • Resulting excess of leptons over anti-leptons partially converted into excess of quarks over anti-quarks by Standard Model sphalerons 30
Electroweak Sphalerons A λ Sphaleron Configuration 31
Electroweak Sphalerons A λ Sphaleron Anomaly Δ (B+L) / N F Configuration 32
Electroweak Sphalerons A λ Sphaleron Anomaly Δ (B+L) / N F Configuration 33 EW sphalerons convert B-L asymmetry to Y B
Davidson-Ibarra Bound 3 M N 1 m ν 3 | ✏ 1 | < ∼ h H 0 i 2 8 ⇡ M N1 > 10 9 GeV ~ 34 Davidson, Ibarra ‘02
TeV Scale LNV ? L mass = y ¯ L mass = y ¯ L ˜ L c HH T L + h . c . H ν R + h . c . Λ Dirac Majorana TeV LNV Mechanism e − e − F B B O(1) for Λ ~ 1 TeV ( ) ( ) A Z , N A Z − 2, N + 2 Implications 35 33
TeV LNV & Leptogenesis 10 12 Standard thermal lepto Energy Scale (GeV) Deppisch et Fast Δ L = 2 int: erase L 10 3 al ‘14, ‘15 10 2 10 -1 36
TeV LNV & Leptogenesis 10 12 Standard thermal lepto Energy Scale (GeV) Deppisch et Fast Δ L = 2 int: erase L 10 3 al ‘14, ‘15 Electroweak, resonant lepto, 10 2 WIMPY baryo, ARS lepto… 10 -1 Post-sphaleron, cold… Baryogenesis alternatives 37
Low Scale “ARS” Leptogenesis 1. 3 Singlet RH neutrinos: N A , N B , N C 2. L TOT = L SM + L A + L B + L C 3. N k oscillations + CPV ! L A = 0, L A = 0, L A = 0 but / / / L TOT =0 4. Yukawa interactions: L k , H + l k in equilibrium above T EW for k=A,B but not for k=C 5. Lepton number for l A,B converted to n B by EW sphalerons 6. Conditions 4 ! M Nk can be ~ O( GeV ) 38 Akhmedov, Rubakov, Smirmov ‘98
Low Scale “ARS” Leptogenesis 39 M. Drewes
II. Neutrino Mass from Cosmology 40
ACFI Workshop 41 December 2015
νββ -Decay: Standard Mechanism 0 νβ Three active light neutrinos Effective DBD neutrino mass (eV) Inverted Normal Lightest neutrino mass (eV ) ! 42
νββ -Decay: Standard Mechanism 0 νβ Three active light neutrinos Effective DBD neutrino mass (eV) Current generation Current generation Ton Scale Inverted Normal Lightest neutrino mass (eV ) ! 43
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