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Neutrino Masses, Leptogenesis and Beyond
The Incredible Foresight of ETTORE MAJORANA
Haim HarariErice, August 2006
A1 A2 + e-
e-
-Decay
N1 N2 + e-
e-
e-
e-
e-
-Decay
N1 N2 + e-
e-
e-
e-
e-
Missing EnergyMissing Momentum
-Decay
N1 N2 + e- +
e-
e-
e-
e-
“Dear RadioactiveLadies & Gentleman”
-Decay
n p + e- +
np
np
e-
e-
e-
e-
e-
-Decay
-Decay
d u + e- +
np
np
e-
e-
e-
e-
e-
e-
d
The Elusive Neutrino
No Electric ChargeNo Strong InteractionsSpin = ½Only Weak InteractionsSmall or Zero Mass
1016
If 1016 reach earth - one will hit something somewhere.
With one thousand tons of water, and 1016 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 starsCreation of heavy elementsEnergy of the sunEnergy of starsExploding 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 He4 + 2e+ + 2 + Energy
Other Processes
1957 - 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
TheoryNo 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”
M1 ~ O()
M2 ~ O(m2/
0 mm
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
GIM D ~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 ?
+ + +
-6 -5 -4 -2-3 -1 -0 1 2 3 4 5 6 7 8 9 10 11 12
eV meV eV MeVkeV GeV TeV
ud
ee
( )
( )
0
-1e
2/3
-1/3du
1stGeneration Q
e?
Leptons
Quarks
-6 -5 -4 -2-3 -1 -0 1 2 3 4 5 6 7 8 9 10 11 12
eV meV eV MeVkeV GeV TeV
ud
ee
( )
( )
0
-1e
2/3
-1/3du
1stGeneration Q
sc
2nd
cs
( )
( )1970 GIM: “CHARM”
e? ?
Leptons
Quarks
-6 -5 -4 -2-3 -1 -0 1 2 3 4 5 6 7 8 9 10 11 12
eV meV eV MeVkeV GeV TeV
ud
ee
( )
( )
e? 0
-1e
2/3
-1/3du
1stGeneration Q
sc
2nd
cs
( )
( )“The Standard Model”
tb
( )
( )
bt
3rd
Quarks
Leptons
? ?
ud( ) c
s( ) tb( )
“Mass Eigenstates”
“Weak Eigenstates”Mixing
MixingAngles(small)
Cabibbo
Is Massless or Very Light ?
m
“See-Saw”
M1 ~ O()
M2 ~ O(m2/
0 mm
Majorana Mass
Gell-Mann, Ramond, Slansky, Yanagida
-12
-9
-6
-3
0
3
6
9
12
15
18
21
24
27
30
PeVTeV
GeVMeV
keV
eV
meV
eV
neV
Planck
GUT
S.M.
tbc su de
e
Pij = Sin 2 2ij Sin 2 (1.27 m2ij)
KmGeV
LE
· eV2
- Oscillations
An Identity CrisisReactor e
Accelerator
Sun e
e
Mass
EigenstatesGenerationEigenstates
APPEARANCE
DISAPPEARANCE
Three Mixing Angles
e 12 23
e 13
- Oscillations
Pij = Sin 2 2ij Sin 2 (1.27 m2ij)
KmGeV
LE
· eV2
LE m2 << 1 P ~ 0
m2 >> 1 P= ½ Sin2 2ijLE
m2 ~ O(1) probe mLE
Reactors:
Accelerators:
E L Probe m2
MeV
GeV
m
km
eV>~
eV>~
If mj >> mi m2ij ~ mj
2
All experiments were :
e e
e x
x
- Oscillations
Hence: limits only on 12
Allowed Excluded
m2 eV2
1000
100
10
1
0.1
Sin2 2
Cosmological Dark Matter
The universe is
95% is Dark matter or Dark EnergyWhat is the Dark Matter? Cosmic Background
Radiation: 2.7°K
per cm3: 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 1990 - 98
No events
cannot account for most
of the dark matter in the universe!
Cosmological Dark Matter
Accelerator x
400 ton C2Cl4
Cle + A37
Homestake
Solar Neutrinos
The sun emits 1038 per second.
1029 go to direction earth.
Per 100 ton detector - 40 hits per month
Kamiokande Super - Kamiokande
+ n e + p
Kamiokande
ton/clean water
GALLEXGae + Ge71
30 ton
GALLEXGae + Ge71
30 ton
SNO
1000 ton D2O (+2 ton Salt) 10,000 phototubes
e + d e + p + p (charged Current)
x + dx + 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: ∆m2<<eV2
Kamland – Japan
KAM
RR
RR
= 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
-6 -5 -4 -2-3 -1 -0 1 2 3 4 5 6 7 8 9 10 11 12
eV meV eV MeVkeV GeV TeV
ud
ee
( )
( )
e? 0
-1e
2/3
-1/3du
1stGeneration Q
sc
2nd
cs
( )
( )“The Standard Model”
tb
( )
( )
bt
3rd
Quarks
Leptons
? ?
-6 -5 -4 -2-3 -1 -0 1 2 3 4 5 6 7 8 9 10 11 12
eV meV eV MeVkeV GeV TeV
ud
ee
( )
( )
e? 0
-1e
2/3
-1/3du
1stGeneration Q
sc
2nd
cs
( )
( )“The Standard Model”
tb
( )
( )
bt
3rd
Quarks
Leptons
Supernova SN87A
Feb.23, 198707:35 UT20 Neutrinos Detected(KAM, USA)
Emitted: 1057Reached Earth 1028Reached Detectors 1017Detected 20
A few hours later: Seen by telescope
Why are we here?
Sakharov-1967 B-Violation (also L-Violation)CP-ViolationNon-equilibrium (also no “wash-out”)
B-Violation (and L-Violation)
p-decayGUT scale or higherNot 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?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)
(qiqjqk) (qiqjqk) (qiqjqk) (ℓiℓjℓk)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. (B + L) = 6 is allowed
THE STANDARD MODEL CREATES (together) B AND LTHE STANDARD MODEL CREATES (together) B AND L
“instanton” terms:
QUARKS and LEPTONS
Note: ↔
is possible
ud
du
e-
e+
The universe is made of
Neutrino oscillations m() ≠ 0, very small
m() ~m2
MSeesaw mechanism: 0 mm 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 SUMERGO SUMNEUTRINONEUTRINO
At Big Bang: B = L = 0.
COGITOCOGITO
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 !?
WarningWarning
.
And in 2056 – for Majorana’s 150th birthday
Why Qi = 0 for q’s and ℓ’s in one generation?
[ Qi = (-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?PREONS? TOY MODELS?TOY MODELS?
Why p and e+ have same charge?
The Quark - Lepton Connection
Rishons HH+Seiberg
T
V
1 0 1
0 1 -1
0
0
-1-1
-1 1
T
V 0 3 3
3 3- 1/3
+ 1/33 3
0 3 3
Buchmann+Schmid
Anomaly cancellation: NH = NC = NG = 3
SU(3)H Singlets
Q SU(3) SU(3)H C
N N 3(B-L)T V
“Matter”
e+
u
d
TTT
TTV
TVV
VVV
(+1)
(+2/3)
(+1/3)
(0)
1
3
3
1
color
“Antimatter”
VVV
VVT
VTT
TTT
d
u
e-
(0)
(- 1/3)
(- 2/3)
(-1)
1
3
3
1
color
e- TTT
p TTT(TT)(VV)(VV)
e+ TTT
p TTT(TT)(VV)(VV)
Rishons
HH+Seiberg
T
V
1 0 1
0 1 -1
0
0
-1-1
-1 1
T
V 0 3 3
3 3- 1/3
+ 1/33 3
0 3 3
SU(3)H Singlets
Q SU(3) SU(3)H C
N N 3(B-L)T V
“Matter”
e+
u
d
TTT
TTV
TVV
VVV
(+1)
(+2/3)
(+1/3)
(0)
1
3
3
1
color
“Antimatter”
VVV
VVT
VTT
TTT
d
u
e-
(0)
(- 1/3)
(- 2/3)
(-1)
1
3
3
1
color
TO BREAK B-L WE NEED TO BREAK NSimplest J=0, Q=0, SU(3)H – singlet, SU(3)C – singlet
IS <VVVVVV> : BREAKS L, HENCE CREATES B
<VVVVVV>≠0 ERGO SUM<VVVVVV>≠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 MAJORANAWAS NO FOOL
WAS BRILLIANT !!!