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

A 1  A 2 + e - e-e-  -Decay

N 1  N 2 + e - e-e- e-e- e-e- e-e-  -Decay

N 1  N 2 + e - e-e- e-e- e-e- e-e- Missing Energy Missing Momentum  -Decay

N 1  N 2 + e - + e-e- e-e- e-e- e-e- “Dear Radioactive Ladies & Gentleman”  -Decay

n  p + e - + n p n p e-e- e-e- e-e- e-e- e-e-  -Decay

d  u + e - + n p n p e-e- e-e- e-e- e-e- e-e- e-e- d

The Elusive Neutrino No Electric Charge No Strong Interactions Spin = ½ Only Weak Interactions Small or Zero Mass If reach earth - one will hit something somewhere. With one thousand tons of water, and every second since the big bang - 1 EVENT !!! Pauli: “I have done a terrible thing!”

Creating Nuclei n p + e - + p n + e + + Creation of stars Creation of heavy elements Energy of the sun Energy of stars Exploding stars: supernova The only way to convert a proton into a neutron or vice versa – involves the neutrino!  n e - + p  p e + + n (Can you tell from ?)

The SUN 4p He 4 + 2e Energy Other Processes

Neutrino Observed Reines - Cowan Big Problem: DETECTING Huge Problem: ELIMINATING BACKGROUND Reactor n + p e + + n e + + e - 2  n + Z Z ’ + 

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

Is Massless or Very Light ? “Direct” experiments m ( e ) < 10 eV Theory No good reason for massless  Simple argument for very light. is only “chargeless” particle. All quarks and leptons  “Dirac Mass”  also “Majorana Mass”

Is Massless or Very Light ?  m “See-Saw” M 1 ~ O(  ) M 2 ~ O(m 2 /  0m m  Majorana Mass Gell-Mann, Ramond, Slansky, Yanagida

Theorists predicted a new meson with a certain mass. A particle was found soon after, having the right mass. A second particle, very slightly heavier, was found soon after. The second particle turned out to be the predicted meson. The first particle turned out to be an unexplained heavy lepton, identical to the electron in all its properties, except its mass.

Theorists predicted a new meson with a certain mass. A particle was found soon after, having the right mass. A second particle, very slightly heavier, was found soon after. The second particle turned out to be the predicted meson. The first particle turned out to be an unexplained heavy lepton, identical to the electron in all its properties, except its mass. Yukawa  ~100MeV Anderson-Neddermeyer ~100MeV Powell   m (e) = 0.51 MeV m (  ) = 106 MeV

Theorists predicted a new meson with a certain mass. A particle was found soon after, having the right mass. A second particle, very slightly heavier, was found soon after. The second particle turned out to be the predicted meson. The first particle turned out to be an unexplained heavy lepton, identical to the electron in all its properties, except its mass. m(e) = 0.51 MeV m(  ) = 106 MeV GIMD ~2000GeV Perl ~1800MeV SLAC-LBL D  m(  ) = 1782 MeV

One or Two Neutrinos     e The schizophrenic  p p p P  Detector Brookhaven 1962  Is the “partner” of  the same as the “usual”, which comes with e ?  +  + +

 eV meVeVMeVkeVGeVTeV udud e () () 0 e 2/3 -1/3 d u 1 st Generation Q e ? Leptons Quarks

 eV meVeVMeVkeVGeVTeV udud e () () 0 e 2/3 -1/3 d u 1 st Generation Q  s c 2 nd cscs  () () 1970 GIM: “CHARM” e ?  ? Leptons Quarks

 eV meVeVMeVkeVGeVTeV udud e () () e ? 0 e 2/3 -1/3 d u 1 st Generation Q  s c 2 nd cscs  () () “The Standard Model” tbtb  () ()  b t 3 rd Quarks Leptons  ?  ?

udud () cscs () tbtb () “Mass Eigenstates” “Weak Eigenstates” Mixing Angles (small) Cabibbo

Is Massless or Very Light ?  m “See-Saw” M 1 ~ O(  ) M 2 ~ O(m 2 /  0m m  Majorana Mass Gell-Mann, Ramond, Slansky, Yanagida

PeV TeV GeV MeV keV eV meV  eV neV Planck GUT S.M.  t b c  s u d e   e

P i  j = Sin 2 2  ij Sin 2 (1.27  m 2 ij ) Km GeV LELE · eV 2 - Oscillations An Identity Crisis Reactor e Accelerator  Sun e    e   Mass Eigenstates Generation Eigenstates APPEARANCE DISAPPEARANCE

Three Mixing Angles e  12   23 e  13 - Oscillations P i  j = Sin 2 2  ij Sin 2 (1.27  m 2 ij ) Km GeV LELE · eV 2 LELE  m 2 << 1 P ~ 0  m 2 >> 1 P= ½ Sin 2 2  ij LELE  m 2 ~ O(1) probe  m LELE

Reactors: Accelerators: EL Probe  m 2 MeV GeV m km eV > ~ > ~ If m j >> m i  m 2 ij ~ m j 2 All experiments were : e   e e x  x - Oscillations Hence: limits only on  12 AllowedExcluded  m 2 eV Sin 2 2    

Cosmological Dark Matter The universe is 95% is Dark matter or Dark Energy What is the Dark Matter? Cosmic Background Radiation: 2.7°K per cm 3 : 400  110 e 110  110  If m( e ) + m(  ) + m(    ~ O(few e ) Closed Open flat Dark matter would be Hence: Crucial to search for    oscillations at O(eV)

“CHORUS” CERN No events  cannot account for most of the dark matter in the universe! Cosmological Dark Matter   Accelerator x  

400 ton C 2 Cl 4  Cl     e + A 37 Homestake Solar Neutrinos The sun emits per second go to direction earth. Per 100 ton detector - 40 hits per month

Kamiokande Super - Kamiokande  + n e + p Kamiokande  ton/clean water

GALLEX  Ga   e + Ge ton

GALLEX  Ga   e + Ge ton SNO 1000 ton D 2 O (+2 ton Salt) 10,000 phototubes e + d  e + p + p (charged Current) x + d  x + p + n (Neutral Current) x + e  x + e (Elastic Scattering) Count total – flux and e - flux

Solar Model is Right! Neutrinos Oscillate Neutrinos have Mass m(  ) ~ 8 meV  12 Large

L ~ 180 km E ~ O (MeV) Probe: ∆m 2 <<eV 2 Kamland – Japan KAM R R R R

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

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

 eV meVeVMeVkeVGeVTeV udud e () () e ? 0 e 2/3 -1/3 d u 1 st Generation Q  s c 2 nd cscs  () () “The Standard Model” tbtb  () ()  b t 3 rd Quarks Leptons  ?  ?

 eV meVeVMeVkeVGeVTeV udud e () () e ? 0 e 2/3 -1/3 d u 1 st Generation Q  s c 2 nd cscs  () () “The Standard Model” tbtb  () ()  b t 3 rd Quarks Leptons  

Supernova SN87A Feb.23, :35 UT 20 Neutrinos Detected (KAM, USA) Emitted:10 57 Reached Earth10 28 Reached Detectors10 17 Detected 20 A few hours later: Seen by telescope

Why are we here? Sakharov-1967 B-Violation (also L-Violation) CP-Violation Non-equilibrium (also no “wash-out”) B-Violation (and L-Violation) p-decay GUT scale or higher Not seen (but SN87A!) -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?

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

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

QUARKS and LEPTONS Note: ↔ is possible udud dudu e - e + The universe is made of Neutrino oscillations  m( ) ≠ 0, very small  m( ) ~ m2Mm2M Seesaw mechanism: 0 m m M L=0 AT BIG BANG BUT  L ≠ 0 PROCESSES ARE ABUNDANT ! L=0 AT BIG BANG BUT  L ≠ 0 PROCESSES ARE ABUNDANT ! ≠ 0, - mixing, heavy neutrino with mass M Hence:  is a Majorana neutrino

LEPTOGENESIS The particle, which is its own antiparticle, is responsible for having more particles than antiparticles in the universe ERGO SUM NEUTRINO At Big Bang : B = L = 0. COGITO Majorana:  L≠0 and  (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

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

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

Rishons HH+Seiberg T V T V / / Buchmann+Schmid Anomaly cancellation: N H = N C = N G = 3 SU(3) H Singlets QSU(3) H C NN3(B-L) T V “Matter” e + u d TTT TTV TVV VVV (+1) (+ 2 / 3 ) (+ 1 / 3 ) (0) color “Antimatter” VVV VVT VTT TTT d u e - (0) (- 1 / 3 ) (- 2 / 3 ) (-1) color e - TTT p TTT(TT)(VV)(VV) e + TTT p TTT(TT)(VV)(VV)

Rishons HH+Seiberg T V T V / / SU(3) H Singlets QSU(3) H C NN3(B-L) T V “Matter” e + u d TTT TTV TVV VVV (+1) (+ 2 / 3 ) (+ 1 / 3 ) (0) color “Antimatter” VVV VVT VTT TTT d u e - (0) (- 1 / 3 ) (- 2 / 3 ) (-1) color TO BREAK B-L WE NEED TO BREAK N Simplest J=0, Q=0, SU(3) H – singlet, SU(3) C – singlet IS : BREAKS L, HENCE CREATES B ≠0 ERGO SUM V

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

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