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The Incredible Foresight of ETTORE MAJORANA Haim Harari Erice, August 31, 2006. Neutrino Masses, Leptogenesis and Beyond. b -Decay. e -. A 1 A 2 + e -. b -Decay. e -. e -. e -. e -. N 1 N 2 + e -. e -. e -. e -. e -. b -Decay. Missing Energy Missing Momentum . - PowerPoint PPT Presentation
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Neutrino Masses, Leptogenesis and Beyond
The Incredible Foresight of ETTORE MAJORANA
Haim HarariErice, August 31, 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 & Gentlemen”
-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) < few eV
TheoryNo good reason for massless Simple argument for very light . is the 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
eThe schizophrenic
pp
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 12eV 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 12eV 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 12eV 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”
MixingMixingAngles(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
03
6
9
12
15
18
21
24
27
30
PeVTeV
GeVMeVkeVeV
meVeVneV
PlanckGUT
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 Eigenstates
GenerationEigenstates
APPEARANCEDISAPPEARANCE
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 ee 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°Kper cm3: 400
110 e
110
110
If m(e ) + m() + m(~ O(few e)
ClosedOpenflat
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