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Alpha decay
Beta decay
Henri Bequerel
Pierre and Marie Curie
n
electron
W. Pauli
-NEUTRINO“ I invented a new
Particle, which
Will never be
Seen! “
electron
Dear Radioactive Ladies and Gentlemen !
1956: discovery of the neutrino
Savannah river reactor
(Fred Reines – Clyde Cowan)
e  p  n  e



e e   
n-capture by cadmium
Fermi interaction
f
Enrico Fermi
G  1 . 16637  10
5
GeV
2
beta decay
n  p  e


electron
p
n
antineutrino
direct interaction ~ four fermions
Parity
x
 x
 


 y   y
z
 z
 


conserved in strong and
electromagnetic interactions
C. N. Yang
T. D. Lee
Experiment
Columbia University
Chien-Shiung
Wu
lefthanded fermion
S= - 1/2
righthanded fermion
S = + 1/2
weak interactions
current-current interaction
weak currents => lefthanded
j  ( x )   (1   5 ) 
L int  G F j  j

Feynman / Gell-Mann
Marshak / Sudarshan
R. Marshak
G. Sudarshan
maximal breaking
of
parity
weak bosons
high mass
mass generation ?
electromagnetism
electroweak gauge theory
gauge group
SU(2) x U(1)
 e 
doublet 


e 
 L
 
 e R  singlet
 
doublet
 e 
  
e
 L
 
 eR 
 
singlet
=> neutrinos massless
W
W

3
3
,W ,W

 B
 B    , Z 
Z => neutral current
Gargamelle
bubble chamber
1975 =>
three different neutrinos
 e 
 
e
 
 






 






Standard - Theory
III
II
I
???
weak
bosons
???
proton-antiproton
collider
SPS
protons
antiproton s
1984
Discovery of weak bosons
The first Z-boson, decaying into
an electron and a positron
Carlo Rubbia
LEP
Masses
of
weak bosons
??????????
Mexican
hat potential
rotation symmetry
symmetry of rotation broken
(spontaneous symmetry breaking)
spontaneous
symmetry
breaking
field theory
 0
2
massive
massless
scalar
gauge
boson

2
0
massive
gauge
boson
Erwin Schrödinger - 1952
Peter Higgs - 1964
Kibble Guralnik Hagen Englert Brout
Discovery
of
„Higgs“-particle
???
L3
Alice
ATLAS
I
LHCb
CMS
H
M(H) = 125,36 ±0,37(stat.) ±0,18 (syst.) GeV
H   
H W

W

H  Z Z
one W or Z must be virtual,
since M(H) < 2 M(W,Z)
flavor mixing
quarks
d  u W

u
d
s
  hyperon
83

  p  e e
(uds) (uud)
s  u
d  u W
s  u W
d u W



d   cos  c  d  sin  c  s
 c : Cabibbo
angle
1963
Nicola Cabibbo
weak
current :
d cos 
c
 s sin  c   1   5 u  h . c .
neutral
current
d


1


d

5
s

1   s
d

1   5 s
:
5
 h .c .
strangeness changing term not
observed in the experiments
(decay of K-mesons) !!!
1970
GIM – mechanism
( Glashow, Iliopoulos, Maiani )
c: charmed quark
III
II
I
 d    V ud
   
 s    V cd
V us   d
 
V cs   s
 cos  c
 
  sin  c
sin  c   d 
  
cos  c   s 



m uc
 0
  
a

m ds
 0
   
a

a

b

a


b
SU(2,L) x U(1)
SU(2,L) x sU(2,R) x U(1)
 0
 
a

a    mu
  
b  0
tan 2 u 
u 
mu
mc
2 mumc
mc  mu
0 

mc 
md
mu
 0 . 21
ms
 0 . 07
mc
13
c 
md
ms
e
i
mu
mc
o
mu
mc
md / ms
    90
0
III
II
I
6 leptons – 6 quarks
 e

 e


 

 
u

d
3 doublets
c
s
t 

b 
d 
s
flavor
d
b 
mixing
s
b
weak transitions
 d    V ud
  
 s     V cd
 b   V
   td
V us
V cs
V ts
V ub   d 
 
V cb   s 



V tb   b 
observed CKM – matrix
(no phasees)
 d    0 . 975
  
 s     0 . 226
 b    0 . 009
  
0 . 226
0 . 973
0 . 041
0 . 004   d 
 
0 . 042   s 



1  b 
1

V  0

 0
0
c 23
 s 23
0   c13
0 s13  e
 
s 23   0
1
0

i

c 23    s13  e 0
c13
 i
angles :  12 ,  23 ,  13
phase : 
  c12 s12 0 
 



s
c
0
12
12
 

  0
0
1



New parametrization:
 i
 cu su 0  e

 
V   su cu 0   0


 0 0 1   0

0  cd  sd 0 
 

c s   sd cd 0


 s c   0 0 1 
0
 0
 
A

 0

A
C
B

0 

B


D
 0
 
A

 0

0 

B


D
A
C
B

tan  u 
mu
tan  d 
md
mc
ms
 0
 
A


 0
A
C
B

0 

B

D 
tan  d 
md
ms
 d  13 . 0  0 . 4
o
 d  13 . 0  0 . 4
o
Exp : 11 . 7  2 . 6
o
o
tan  u 
mu
mc
 u  5 .0  0 .7
o
o
 u  5 .0  0 .7
o
Exp : 5 . 4  1 . 1
o
o
o
 V ud V us V ub 


V   V cu V cs V cb 
 V V V 
 tu ts tb 
 : 86
0
 95
0
mu
mc
md / ms
    90
0
    90
0
flavor mixing
Leptons
6 leptons
 e

e



 

 
massive neutrinos
 1


 e
2

3


 
 1

flavor

e
2


3
mixing




 V1 e

V   V1 
 V
 1
V2e
V2 
V 2
V3 e 

V3  

V 3 
e

e
Neutrino
oscillations
32   sun  35
o
37   at  40
o
 m 21  7 . 54
 0 . 26
. 0 . 22
m
 0 . 06
 010
2
2
32
 2 . 43
o
o
 10
5
 10
3
eV
2
eV
2
 e i

P   0
 0

 cos  l

U   sin  l

 0
sin  l
cos  l
0
 i
0 e
 
0  0

1   0
 l  reactor  angle
0
cos 
 sin 
0
e
i
0
0   cos  
 
sin    sin  

cos    0
   at
0

0
1 
 sin  
cos  
0
    sun
0

0

1 
 0
 
A

 0

A
 0
 
A


 0
A
C
B

0 

B

D 
C
B

0 

B


D
   arcsin
 l  arcsin
m1
m1  m 2
me
me  m
observation
32   sun  35
o
o
 m 1 / m 2  0 . 39 ... 0 . 49
m
2
21
m
2
32
 7 . 5  10
5
 2 . 4  10
3
m 1 / m 2  0 . 44
:
eV
2
eV
2
neutrino masses
( eV )
m 1  0 . 003
m 2  0 . 012
m 3  0 . 048
3
0.05 eV
2
0.01 eV
1
0.003
0.012
0.048
???????????????
neutrino masses
very small
???????????????
D    R L    L R 
M   R L 

e
e


Neutrinoless
Double Beta decay
0 130
1/ 2
T
(
Te )  1 . 8  10
24
years
Majorana neutrino mass:
< 0.23 eV
Beyond
Standard
Theory
??????????
? Grand Unification ?
? Gravity ?
? Supersymmetry ?
? String Theory ?
?…………………?
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