Neutrino Masses, Leptogenesis and Beyond The Incredible Foresight of ETTORE MAJORANA Haim Harari Erice, September 1, 2006

neutrino from an anti-neutrino? n may be its own antiparticle ! The Foresight Can you tell a neutrino from an anti-neutrino? MAJORANA n may be its own antiparticle !

Is n Massless or Very Light ? “Direct” experiments m (ne) < few eV Theory No good reason for massless n. Simple argument for very light n. n is the only “chargeless” particle. All quarks and leptons  “Dirac Mass” n  also “Majorana Mass”

Is n Massless or Very Light ? m L M1 ~ O(L) M2 ~ O(m2/L) “See-Saw” L m n Majorana Mass Gell-Mann, Ramond, Slansky, Yanagida

Mikheyev-Smirnov-Wolfenstein Solar Neutrinos The sun emits 1038 n per second. 1029 go to direction earth. Per 100 ton detector - 40 hits per month Homestake n + Cl37  e + A37 400 ton C2Cl4 Mikheyev-Smirnov-Wolfenstein

Kamiokande Super - Kamiokande n + n e + p 50,000 ton/clean water

GALLEX n + Ga71 e + Ge71 30 ton

GALLEX n + Ga71 e + Ge71 SNO 30 ton 1000 ton D2O (+2 ton Salt) 10,000 phototubes ne + d e + p + p (charged Current) nx + d nx + p + n (Neutral Current) nx + e nx + e (Elastic Scattering) Count total n – flux and ne - flux

m(nm) ~ 8 meV q12 Large Solar Model is Right! Neutrinos Oscillate Neutrinos have Mass m(nm) ~ 8 meV q12 Large

Kamland – Japan R R R R KAM L ~ 180 km E ~ O (MeV) Probe: ∆m2<<eV2

Cosmic Radiation p p m e ne nm nm atmosphere earth m (nt) ~ 50 meV Energetic protons arrive p Pions created in atmosphere In p-decay: N(nm) N(ne) atmosphere p = 2 m e = 1.2 !!! KAMIOKANDE: N(nm) N(ne) m (nt) ~ 50 meV ne nm nm earth

The Universe m(nt) ~ 50 meV m(nm) ~ 8 meV m(ne) ~ smaller 70% Dark Energy 25% Dark Matter 4% H, He 0.5% Heavy Nuclei 0.5% Neutrinos m(nt) ~ 50 meV m(nm) ~ 8 meV m(ne) ~ smaller Large angles! Also K2K, MINOS, others

( ) ( ) ( ) ( ) ( ) ( ) u d c s t b “The Standard Model” ne e nm m nt Generation 1st 2nd 3rd Q u c t 2/3 d s b Quarks -1/3 ne? nm? nt? e m t Leptons -1 -6 -5 -4 -2 -3 -1 -0 1 2 3 4 5 6 7 8 9 10 11 12 meV eV MeV keV GeV TeV ( ) ( ) ( ) u d c s t b “The Standard Model” ( ne e ) ( nm m ) ( nt t )

( ) ( ) ( ) ( ) ( ) ( ) u d c s t b “The Standard Model” ne e nm m nt Generation 1st 2nd 3rd Q u c t 2/3 d s b Quarks -1/3 nm nt ne? e m t Leptons -1 -6 -5 -4 -2 -3 -1 -0 1 2 3 4 5 6 7 8 9 10 11 12 meV eV MeV keV GeV TeV ( ) ( ) ( ) u d c s t b “The Standard Model” ( ne e ) ( nm m ) ( nt t )

WHEN AND HOW DID IT HAPPEN? Why are we here? B-Violation (also L-Violation) CP-Violation Non-equilibrium (also no “wash-out”) Sakharov-1967 B-Violation (and L-Violation) p-decay GUT scale or higher Not seen (but SN87A!) n-oscillations and mass CP-Violation KM phase for quarks (requires 3 generations) CP-violation in leptons (requires 2 generations) WHEN AND HOW DID IT HAPPEN?

At Big Bang: B=0 , L=0 (also B-L=0) Why are we here? At Big Bang: B=0 , L=0 (also B-L=0) We need to create a nonzero B (also B-L?) “Leptogenesis” (other theories: GUT, electroweak) : If we could create a nonzero L and then trade B for L, we could create a positive B. IT IS NOT ENOUGH TO TRADE B for L WE MUST ALSO CREATE B-L

(qiqjqk) (qiqjqk) (qiqjqk) (ℓiℓjℓk) B and L violation in the standard model (but no B-L) (qiqjqk) (qiqjqk) (qiqjqk) (ℓiℓjℓk) “instanton” terms: i,j,k = generations “SPHALERON”: Connecting degenerate ground states L and B can change (together) each by 3 UNITS (for Ng = 3) B – L is conserved (and must be nonzero) B + L is violated e.g. D(B + L) = 6 is allowed THE STANDARD MODEL CREATES (together) B AND L

Neutrino oscillations  m(n) ≠ 0, very small The universe is made of QUARKS and LEPTONS Note: ↔ n is possible u d n e- d u e+ n Neutrino oscillations  m(n) ≠ 0, very small  m(n) ~ m2 M Seesaw mechanism: 0 m m M L=0 AT BIG BANG BUT DL ≠ 0 PROCESSES ARE ABUNDANT ! <nn> ≠ 0, n-n mixing, heavy neutrino with mass M Hence: n is a Majorana neutrino

NEUTRINO COGITO ERGO SUM LEPTOGENESIS At Big Bang: B = L = 0. Majorana: DL≠0 and D(B-L)≠0 are allowed. Hence, the universe has L≠0 and B-L≠ 0 . LEADING TO B≠0 !!! (Elaborate quantitative estimates). e.g. Buchmueller-Peccei-Yanagida The particle, which is its own antiparticle, is responsible for having more particles than antiparticles in the universe NEUTRINO COGITO ERGO SUM

Perhaps it all happens at the subparticle level !? Warning And in 2056 – for Majorana’s 150th birthday . Perhaps it all happens at the subparticle level !? Warning No evidence for subquarks and subleptons. No reasonable dynamical theory

The Quark - Lepton Connection Why q and ℓ have simple charge ratios? (0, -1) ( +2/3, -1/3 ) Why p and e+ have same charge? Why SQi = 0 for q’s and ℓ’s in one generation? [ SQi = (-1) + (0) + 3(+2/3) +3(-1/3) = 0 ] Why three colors and three generations? PREONS? TOY MODELS?

Rishons HH+Seiberg Anomaly cancellation: NH = NC = NG = 3 n SU(3)H Q SU(3) H C N 3(B-L) T V T V + 1/3 3 1 -1 T V 3 - 1/3 -1 1 “Matter” e+ u d n TTT TTV TVV VVV (+1) (+2/3) (+1/3) (0) 1 3 color “Antimatter” VVV VVT VTT TTT n d u e- (0) (- 1/3) (- 2/3) (-1) 1 3 color SU(3)H Singlets e+ TTT p TTT(TT)(VV)(VV) e- TTT p TTT(TT)(VV)(VV) Anomaly cancellation: NH = NC = NG = 3 Buchmann+Schmid

<VVVVVV>≠0 ERGO SUM HH+Seiberg Rishons Q SU(3) H C N 3(B-L) T V T V + 1/3 3 1 -1 T V 3 - 1/3 -1 1 “Matter” e+ u d n TTT TTV TVV VVV (+1) (+2/3) (+1/3) (0) 1 3 color “Antimatter” VVV VVT VTT TTT n d u e- (0) (- 1/3) (- 2/3) (-1) 1 3 color SU(3)H Singlets TO BREAK B-L WE NEED TO BREAK N Simplest J=0, Q=0, SU(3)H – singlet, SU(3)C – singlet IS <VVVVVV> : BREAKS L, HENCE CREATES B V <VVVVVV>≠0 ERGO SUM

n in Nucleosynthesis  - Less Double -Decay n - Decays Measuring Masses and Angles Clues for Theory “Beyond the Standard Model” Neutrino Astronomy UHE Cosmic Neutrinos Dark Matter Z nn n in Nucleosynthesis  - Less Double -Decay n - Decays n - Magnetic Moments Heavy n Sterile n

Neutrino Masses, Leptogenesis and Beyond ETTORE MAJORANA WAS NO FOOL WAS BRILLIANT !!!