Physics of Anti-matter
Lecture 6
N. Tuning
Niels Tuning (1)
Plan
1) Mon 3 Feb:
Anti-matter + SM
2) Wed 5 Feb:
CKM matrix + Unitarity Triangle
3) Mon 10 Feb:
Mixing + Master eqs. + B0J/ψKs
4) Wed 12 Feb:
CP violation in B(s) decays (I)
5) Mon 17 Feb:
CP violation in B(s) decays (II)
6) Wed 19 Feb:
CP violation in K decays + Overview
7) Mon 24 Feb:
Mini-project (MSc. V. Syropoulos)

Wed 26 Feb:
Exam

Final Mark: 2/3*Exam + 1/6*Homework + 1/6*Mini project

In March: 7 Lectures on Flavour Physics by prof.dr. R. Fleischer
Niels Tuning (2)
L SM
 LYuk
L Kinetic
Recap
 L Kinetic  L Higgs  LYukawa


 I

d
I
I
 Yij (uL , d L )i  0  d Rj  ...
 
W
g I   I
g I   I

uLi W d Li 
d Li W uLi  ...
2
2
dI
Diagonalize Yukawa matrix Yij
– Mass terms
– Quarks rotate
– Off diagonal terms in charged current couplings
W
uI
u
 LMass 
LCKM
d,s,b
 d , s, b 
L
 md




ms
 d 
 
 s 
mb   b  R
dI 
 I
 s   VCKM
 bI 
 
 u , c, t 
L
 mu




mc
d 
 
s
b
 
 u
 
  c   ...
mt   t  R
g
g


5

ui W Vij 1    d j 
d j WVij* 1   5  ui  ...
2
2
L SM
 LCKM  L Higgs  L Mass
Niels Tuning (4)
Why bother with all this?
• CKM matrix has origin in
L
Yukawa
 Intricately related to quark massed…
• Both quark masses and CKM elements show intriguing
hierarchy
• There is a whole industry of theorist trying to postdict
the CKM matrix based on arguments on the mass
matrix in
L
Yukawa…
Niels Tuning (5)
CKM-matrix: where are the phases?
• Possibility 1: simply 3 ‘rotations’, and put phase on smallest:
• Possibility 2: parameterize according to magnitude, in O(λ):
W
u
d,s,b
Niels Tuning (6)
This was theory, now comes experiment
• We already saw how the moduli |Vij| are determined
• Now we will work towards the measurement of the
imaginary part
– Parameter: η
– Equivalent: angles α, β, γ .
• To measure this, we need the formalism of neutral
meson oscillations…
Niels Tuning (7)
Meson Decays
• Formalism of meson oscillations:
P 0 (t )
• Subsequent: decay
P0 f
P0P0 f
Interference
(‘direct’) Decay
Interference
Classification of CP Violating effects
1. CP violation in decay
2. CP violation in mixing
3. CP violation in interference
Niels Tuning (9)
Classification of CP Violating effects
1. CP violation in decay
Example:
B 0  K  
B 0  K  
2. CP violation in mixing
Example:
3. CP violation in interference
Example:
ACP (t ) 
B0→J/ψKs
N B0  f  N B0  f
N B0  f  N B0  f
 sin( 2 ) sin( mt )
Niels Tuning (10)
Remember!
Necessary ingredients for CP violation:
1) Two (interfering) amplitudes
2) Phase difference between amplitudes
– one CP conserving phase (‘strong’ phase)
– one CP violating phase (‘weak’ phase)
Niels Tuning (11)
Remember!
Niels Tuning (12)
CKM Angle measurements from Bd,u decays
bu
• Sources of phases in Bd,u amplitudes*
Amplitude
Rel. Magnitude
Weak phase
bc
Dominant
0
bu
Suppressed
γ
td (x2, mixing)
Time dependent
2β
*In Wolfenstein phase convention.
 1 1 e-iγ 


 1 1 1 
 e-iβ 1 1 


td
• The standard techniques for the angles:
B0 mixing +
single bu decay
B0 mixing +
single bc decay
Interfere bc and bu in B± decay.
Niels Tuning (13)
Classification of CP Violating effects
1. CP violation in decay
2. CP violation in mixing
3. CP violation in interference
Niels Tuning (14)
Other ways of measuring sin2β
• Need interference of bc transition and B0 –B0 mixing
• Let’s look at other bc decays to CP eigenstates:
b
B 
d
0
b
B 
d
0
c 
D
d
c 
D
d
All these decay amplitudes have the same phase
(in the Wolfenstein parameterization)
so they (should) measure the same CP violation
c
 J  ,  2S  ,  c ,...
c
s,d 
0
K
,
K
,

 s L
d 
Niels Tuning (15)
CP in interference with BφKs
• Same as B0J/ψKs :
• Interference between B0→fCP and B0→B0→fCP
– For example: B0→J/ΨKs and B0→B0→ J/ΨKs
– For example: B0→φKs and B0→B0→ φKs
Amplitude 1
Amplitude 2
+
e-iφ
J / K
s
J / K
 q  AJ / Ks  q  AJ / K 0  p 
 
 
 
 p  B0 AJ / Ks  p  B0 AJ / K 0  q  K
s
 Vtb*Vtd  VcbVcs*  VcsVcd * 
 
 * 
* 
*
V
V
V
V
 tb td  cb cs  Vcs Vcd 
ACP (t ) 
 B  f (t )   B f (t )
 B  f (t )   B f (t )
 Im( f )sin mt
ACP (t )   sin 2 sin(mt )
Niels Tuning (16)
CP in interference with BφKs: what is different??
• Same as B0J/ψKs :
• Interference between B0→fCP and B0→B0→fCP
– For example: B0→J/ΨKs and B0→B0→ J/ΨKs
– For example: B0→φKs and B0→B0→ φKs
Amplitude 1
Amplitude 2
+
e-iφ
ACP (t ) 
 B  f (t )   B f (t )
 B  f (t )   B f (t )
 Im( f )sin mt
ACP (t )   sin 2 sin(mt )
Niels Tuning (17)
Penguin diagrams
Nucl. Phys. B131:285 1977
Niels Tuning (18)
Penguins??
The original penguin:
A real penguin:
Our penguin:
Niels Tuning (19)
Funny
Flying Penguin
Dead Penguin
Super Penguin:
Penguin T-shirt:
Niels Tuning (20)
The “b-s penguin”
B0J/ψKS
Asymmetry
in SM
B0φKS

“Penguin” diagram: ΔB=1
… unless there is new physics!
s
b
μ
μ
• New particles (also heavy) can show up in loops:
– Can affect the branching ratio
– And can introduce additional phase and affect the asymmetry
Niels Tuning (21)
Hint for new physics??
d
d
B
b
s
c
c
•
Ks
d
B
J/ψ
sin2βbccs = 0.68 ± 0.03
sin2β
d
?
b
~~
g,b,…?
•
t
s
s
s
Ks
φ
sin2βpeng = 0.52 ± 0.05
sin2βpeng
S.T’Jampens, CKM fitter, Beauty2006
Niels Tuning (22)
Next… Something completely different? No, just K
1. CP violation in decay
2. CP violation in mixing
3. CP violation in interference
Kaons…
• Different notation: confusing!
K1, K2, KL, KS, K+, K-, K0
• Smaller CP violating effects
 But historically important!

Concepts same as in B-system, so you have a chance to understand…
Niels Tuning (24)
Neutral kaons – 60 years of history
1947 : First K0 observation in cloud chamber (“V particle”)
1955 : Introduction of Strangeness (Gell-Mann & Nishijima)
K0,K0 are two distinct particles (Gell-Mann & Pais)
… the θ0 must be considered as a "particle mixture" exhibiting two
distinct lifetimes, that each lifetime is associated with a different set of
decay modes, and that no more than half of all θ0's undergo the familiar
decay into two pions.
1956 : Parity violation observation of long lived KL (BNL Cosmotron)
1960 : m = mL-mS measured from regeneration
1964 : Discovery of CP violation (Cronin & Fitch)
1970 : Suppression of FCNC, KL - GIM mechanism/charm hypothesis
1972 : 6-quark model; CP violation explained in SM (Kobayashi & Maskawa)
1992-2000 : K0,K0 time evolution, decays, asymmetries (CPLear)
1999-2003 : Direct CP violation measured: e’/e ≠ 0 (KTeV and NA48)
From G.Capon
Niels Tuning (25)
Intermezzo: CP eigenvalue
• Remember:
– P2 = 1 (x  -x  x)
– C2 = 1 (ψ ψ  ψ )
–  CP2 =1
• CP | f > =  | f >
• Knowing this we can evaluate the effect of CP on the K0
CP|K0> = -1| K0>
CP| K0> = -1|K0 >
• CP eigenstates:
|KS> = p| K0> +q|K0>
|KL> = p| K0> - q|K0>
( S(K)=0  L(ππ)=0 )
|Ks> (CP=+1) →  
|KL> (CP=-1) →   
(CP= (-1)(-1)(-1)l=0
=+1)
(CP = (-1)(-1)(-1)(-1)l=0 = -1)
Niels Tuning (26)
Decays of neutral kaons
• Neutral kaons is the lightest strange particle  it must
decay through the weak interaction
• If weak force conserves CP then
– decay products of K1 can only be a CP=+1 state, i.e.
|K1> (CP=+1)
→
(CP= (-1)(-1)(-1)l=0
=+1)
( S(K)=0  L(ππ)=0 )
– decay products of K2 can only be a CP=-1 state, i.e.
|K2> (CP=-1)
→
(CP = (-1)(-1)(-1)(-1)l=0 = -1)
• You can use neutral kaons to precisely test that the
weak force preserves CP (or not)
– If you (somehow) have a pure CP=-1 K2 state and you observe it
decaying into 2 pions (with CP=+1) then you know that the weak
decay violates CP…
Niels Tuning (27)
Designing a CP violation experiment
• How do you obtain a pure ‘beam’ of K2 particles?
– It turns out that you can do that through clever use of kinematics
• Exploit that decay of K into two pions is much faster
than decay of K into three pions
– Related to fact that energy of pions are large in 2-body decay
–
t1 = 0.89 x 10-10 sec
–
t2 = 5.2 x 10-8 sec (~600 times larger!)
• Beam of neutral Kaons automatically becomes beam of
|K2> as all |K1> decay very early on…
K1 decay early (into )
Pure K2 beam after a while!
(all decaying into πππ) !
Initial
K0
beam
Niels Tuning (28)
The Cronin & Fitch experiment
Essential idea: Look for (CP violating)
K2   decays 20 meters away from
K0 production point
Decay of K2 into 3 pions
Incoming K2 beam
If you detect two of the three pions
of a K2   decay they will generally
not point along the beam line
Niels Tuning (29)
The Cronin & Fitch experiment
Essential idea: Look for K2   decays
20 meters away from K0 production point
Decay pions
Incoming K2 beam
If K2 decays into two pions instead of
three both the reconstructed direction
should be exactly along the beamline
(conservation of momentum in K2   decay)
Niels Tuning (30)
The Cronin & Fitch experiment
Essential idea: Look for K2   decays
20 meters away from K0 production point
Decay pions
Incoming K2 beam
Result: an excess of events at Q=0 degrees!
• CP violation, because K2 (CP=-1)
changed into K1 (CP=+1)
K2   decays
(CP Violation!)
K2   decays
Note scale: 99.99% of K  decays
are left of plot boundary
Niels Tuning (31)
Nobel Prize 1980
"for the discovery of violations of
fundamental symmetry principles
in the decay of neutral K mesons"
The discovery emphasizes, once again, that even
almost self evident principles in science cannot be
regarded fully valid until they have been critically
examined in precise experiments.
James Watson Cronin
1/2 of the prize
University of Chicago
Chicago, IL, USA
b. 1931
Val Logsdon Fitch
1/2 of the prize
Princeton University
Princeton, NJ, USA
b. 1923
Niels Tuning (32)
Cronin & Fitch – Discovery of CP violation
• Conclusion: weak decay violates CP (as well as C and P)
– But effect is tiny! (~0.05%)
– Maximal (100%) violation of P symmetry easily follows from absence
of right-handed neutrino, but how would you construct a physics law
that violates a symmetry just a tiny little bit?
• Results also provides us with
convention-free definition of
matter vs anti-matter.
– If there is no CP violation, the K2 decays
in equal amounts to
+ e- ne (a)
- e+ ne (b)
– Just like CPV introduces K2  ππ decays,
it also introduces a slight asymmetry in
the above decays (b) happens more often than (a)
– “Positive charge is the charged carried by the lepton preferentially
produced in the decay of the long-lived neutral K meson”
Niels Tuning (33)
Intermezzo: Regeneration
• Different cross section for σ(p K0) than σ(pK0)
o
Elastic scattering:
same
o
Charge exchange :
same
o
Hyperon production: more for
K2 
1
2
K
0
K0

K0  p  K  n
K0 n  K  p
K0 !
K 0  p  0   
K 0  p  0  K 0  K 
strong interactions:
must conserve strangeness
leave little free energy – unlikely!
• What happens when KL-beam hits a wall ??
• Then admixture changes…: |KL> = p| K0> - q|K0>
 Regeneration of KS !
• Could fake CP violation due to KS→π+π-…
Niels Tuning (34)
KS and KL
Usual (historical) notation in kaon physics:
KS 
KL 
K  e K
1 e
2
K  e K
1 e
2
,
K S  t   e iS t K S ,
.
K L  t   e  iLt K L .
Modern notation used in B physics:
KS  p K 0  q K 0 ,
p  1  e 
KL  p K 0  q K 0 .
q  1  e 


2
1 e
2
1 e
2
2
,
.
Regardless of notation:
KL and KS are
not orthogonal:
2
KS KL
e e
2e
p



1
2
2
q
1 e
1 e
Niels Tuning (35)
Three ways to break CP; e.g. in K0→ π+π  K      A    g  (t )   g  (t ) 

0

2
1


0
 
  K      A    g  (t )  g  (t ) 



K   
0

0

 K  


 A
2
 A
2



 g t  2  

 

2
1
 g t  


CP violation in decay:
Af
  
2
2
g   t   2   g   t  g   t   

2
g t  
2
2
q A  

p A  
2
 
2
  


g  t  g  t  



1
Af
q
CP violation in mixing:
1
p
 q Af 
CP violation in interference mixing/decay:  f   
0
 p Af 


Niels Tuning (36)
Classification of CP Violating effects
1. CP violation in decay
2. CP violation in mixing
3. CP violation in interference
Niels Tuning (37)
Time evolution
  t 1   2  t

S
L

e
e

1



  K 0       


 1  
 1  
t 
 2e  
 cos  m  t    
 sin  m  t   

 1  
  1  
 

0
 K    

  t 1   2  t

S
L

e
e

1 




 1  
 1  
t 
 2e  
 cos  m  t    
 sin  m  t   

 1  
  1  
 
2
  K 0       N eS t   eLt  2et  cos  m  t    




2
 K      N eS t   eLt  2et  cos  m  t    


0
 
   K L
1 
pA  qA

  
1 
pA  qA   K S
   ei

Niels Tuning (38)
B-system
BB 
0
AT  t  
0
2. CP violation in mixing
 
N   t   N   t 
N   t   N   t 

X
K-system
I en   t   I en   t  1  q p
AT  t  

 4e
4
I en   t   I en   t  1  q p
4
1 q p
4
1 q p
4
CPLEAR, Phys.Rep. 374(2003) 165-270
BaBar, (2002)
CPLear (2003)
AT  t    6.6  1.6 10 3
 q p  0.9967  0.0008  1
B-system
BB 
0
AT  t  
0
2. CP violation in mixing
 
N   t   N   t 
N   t   N   t 

K-system
X
1 q p
4
1 q p
4
( K L  e n )  ( K L  e n )
 L ( e) 
( K L  e n )  ( K L  e n )
BaBar, (2002)
NA48, (2001)
L(e) = (3.317  0.070  0.072)  10-3
Niels Tuning (40)
B-system 3.Time-dependent CP asymmetry
B0→J/ψKs
ACP (t ) 
N B0  f  N B0  f
N B0  f  N B0  f
 sin( 2 ) sin( mt )
BaBar (2002)
Niels Tuning (41)
B-system 3.Time-dependent CP asymmetry
K0→π-π+
B0→J/ψKs
ACP (t ) 
N B0  f  N B0  f
N B0  f  N B0  f
K-system
 sin( 2 ) sin( mt )
R( k 0  f , t )  R( k 0  f , t )
Af (t ) 
R ( k 0  f , t )  R( k 0  f , t )
~50/50 decay as Ks and KL
+ interference!
K0
_
K0
 rate asymmetry
BaBar (2002)
CPLear (PLB 1999)
The Quest for Direct CP Violation
Indirect CP violation in the
mixing:
e
Direct CP violation in the
decay:
e’
A fascinating 30-year long
enterprise: “Is CP violation a
peculiarity of kaons? Is it induced by
a new superweak interaction?”
Niels Tuning (43)
B system
1. Direct CP violation
K system
K0→π-π+ K0→π-π+
B0→K+π- B0→K-π+
K0→π0π0 K0→π0π0
 
Amp (k L     )

Amp (ks     )
Amp (k L   o o )
oo 
Amp (ks   o o )
Different CP violation for the two decays 
Some CP violation in the decay!
BR(K L      )
BR(Ks      )
2
 
e  e 2
 e 



1

6Re
o o
e
oo
BR(K L    )
e  2 e 2
BR(Ks   o o )
ε’≠ 0
Niels Tuning (44)
Niels Tuning (45)
Hints for new physics?
1) sin2β≠sin2β ?
d
d
B
b
~~
g,b,…?
t
s
s
s
Ks
φ
2) ACP (B0K+π-)≠ACP (B+K+π0) ?
4th generation, t’ ?
3) βs≠0.04 ?
4) P(B0s→B0s) ≠ P(B0s←B0s)
Niels Tuning (46)
Present knowledge of unitarity triangle
Niels Tuning (47)
“The” Unitarity triangle
• We can visualize the CKM-constraints in (r,) plane
Present knowledge of unitarity triangle
I) sin 2β
ACP (t ) 
N B0  f  N B0  f
N B0  f  N B0  f
 sin( 2 ) sin( mt )
I) sin 2β
ACP (t ) 
N B0  f  N B0  f
N B0  f  N B0  f
 sin( 2 ) sin( mt )
II)
KS 
KL 
ε and the unitarity triangle:
K  e K
1 e
2
K  e K
1 e
2
box diagram
CP violation in mixing
,
.
KS  p K 0  q K 0 ,
p  1  e 
KL  p K 0  q K 0 .
q  1  e 


2
1 e
2
1 e
2
2
,
.
II)
ε and the unitarity triangle:
box diagram
II)
ε and the unitarity triangle:
box diagram
Im(z2)=Im( (Rez+iImz)2)=2RezImz
II)
ε and the unitarity triangle
ρ
Niels Tuning (55)
III.) |Vub| / |Vcb|
• Measurement of Vub
– Compare decay rates of
B0  D*-l+n and B0  -l+n
– Ratio proportional to (Vub/Vcb)2
– |Vub/Vcb| = 0.090 ± 0.025
– Vub is of order sin(qc)3 [= 0.01]
2
(b  ul n l ) Vub  f (mu2 / mb2 ) 

2 
2
2 

f
(
m
/
m
(b  cl n l ) Vcb 
c
b)

IV.) Δmd and Δms
• Δm depends on Vtd
• Vts constraints hadronic uncertainties
ms mBs f BBs

md mBd f BBd Vtd
2
Bs
2
Bd
Vts
2
2

Vts
mBs 2

mBd
Vtd
2
2
Present knowledge of unitarity triangle
Niels Tuning (58)
Hints for new physics?
1) sin2β≠sin2β ?
d
d
B
b
~~
g,b,…?
t
s
s
s
Ks
φ
2) ACP (B0K+π-)≠ACP (B+K+π0) ?
4th generation, t’ ?
3) βs≠0.04 ?
4) P(B0s→B0s) ≠ P(B0s←B0s)
Niels Tuning (59)
More hints for new physics?
5)
εK ?
 Treatment of errors…
 Input from Lattice QCD BK
 Strong dependence on Vcb
Niels Tuning (60)
More hints for new physics?
6) Vub: 2.9σ ??
BR(B+→τυ)=1.68 ± 0.31 10-4
Predicted: 0.764± 0.087 10-4
(If fBd off, then BBd needs to be off too,
to make Δmd agree)
?
|Vub| avg from semi-lep
|Vub| from fit
From:
H.Lacker, and A.Buras,
Beauty2011, Amsterdam
|Vub| from B→τν
Niels Tuning (61)
A.Buras, Beauty2011:
Niels Tuning (62)
A.Buras, Beauty2011:
Niels Tuning (63)
Standard Model: 25 free parameters
Elementary particle masses (MeV):
me 
0.51099890
m  105.658357
mt  1777.0
mn < 0.000003
e
mn < 0.19

mn < 18.2
t
mu 
3
mc 
1200
mt  174000
md 
7
ms  120
mb  4300
Electro-weak interaction:
e(0)
mW
mZ
mHH
 1/137.036
 80.42 GeV
 91.188 GeV
>114.3
GeV
CMS
Strong interaction:
s(mZ) 0.117
quark mixing (4)
u’
d’ =
s’
Vijq
u
d
s
neutrino mixing (4)
ne
n =
nt
Vijl
n1
n2
n3
LHCb
Niels Tuning (64)
The CKM matrix
• Couplings of the
charged current:
• Wolfenstein
parametrization:
• Magnitude:
 Vud

 Vcd
V
 td
 d '   Vud
  
 s '    Vcd
 b'  V
   td
 d
 
s 
 b 
 L
Vus Vub  d 
 
Vcs Vcb  s 

Vts Vtb 
 b 

2
1


2


2


1
2
 3
2
 A 1  r  i   A


W
b
gVub
u

A 3  r  i  
 d 
 
A 2
 s 
 b 
1
  L


• Complex phases:
Vus Vub   0.9738  0.0002 0.227  0.001 0.00396  0.00009 
 

Vcs Vcb    0.227  0.001 0.9730  0.0002 0.0422  0.0005 
Vts Vtb   0.0081  0.0005 0.0416  0.0005 0.99910  0.00004 
 1 1 e-iγ 


 1 1 1 
 e-iβ 1 1 


Niels Tuning (65)
The CKM matrix
• Couplings of the
charged current:
1)  LYuk
2)  LW 
• Wolfenstein
parametrization
• Magnitude:
 Vud

 Vcd
V
 td
3) LW



 I

d
I
I
 Yij (uL , d L )i  0  d Rj  Yiju ...  Yijl ...
 
g

uLiI
  d LI i W
2
d 

g
2
 u , c , t L VCKM   s 
b
 L
  W
• Complex phases:
Vus Vub   0.9738  0.0002 0.227  0.001 0.00396  0.00009 
 

Vcs Vcb    0.227  0.001 0.9730  0.0002 0.0422  0.0005 
Vts Vtb   0.0081  0.0005 0.0416  0.0005 0.99910  0.00004 
 1 1 e-iγ 


 1 1 1 
 e-iβ 1 1 


Niels Tuning (66)
The CKM matrix
• Couplings of the
charged current:
• Wolfenstein
parametrization:
• Magnitude:
 Vud

 Vcd
V
 td
• Complex phases:
Vus Vub   0.9738  0.0002 0.227  0.001 0.00396  0.00009 
 

Vcs Vcb    0.227  0.001 0.9730  0.0002 0.0422  0.0005 
Vts Vtb   0.0081  0.0005 0.0416  0.0005 0.99910  0.00004 
 1 1 e-iγ 


 1 1 1 
 e-iβ 1 1 


Remember the following:
• CP violation is discovered in the K-system
• CP violation is naturally included if there are 3 generations or more
– 3x3 unitary matrix has 1 free complex parameter
• CP violation manifests itself as a complex phase in the CKM matrix
• The CKM matrix gives the strengths and phases of the weak couplings
• CP violation is apparent in experiments/processes with 2 interfering
amplitudes with different strong and weak phase
– Often using “mixing” to get the 2nd decay process
• Flavour physics is powerful for finding new physics in loops!
– Complementary to Atlas/CMS
Niels Tuning (68)
Remember the following:
• CP violation is discovered in the K-system
• CP violation is naturally included if there are 3 generations or more
– 3x3 unitary matrix has 1 free complex parameter
• CP violation manifests itself as a complex phase in the CKM matrix
• The CKM matrix gives the strengths and phases of the weak couplings
• CP violation is apparent in experiments/processes with 2 interfering
amplitudes with different strong and weak phase
– Often using “mixing” to get the 2nd decay process
• Flavour physics is powerful for finding new physics in loops!
– Complementary to Atlas/CMS
Niels Tuning (69)
Personal impression:
• People think it is a complicated part of the Standard Model
(me too:-). Why?
1) Non-intuitive concepts?

Imaginary phase in transition amplitude, T ~ eiφ

Different bases to express quark states, d’=0.97 d + 0.22 s + 0.003 b

Oscillations (mixing) of mesons:
2) Complicated calculations?
|K0> ↔ |K0>
2
2
2
2
  B 0  f   Af  g   t    g   t   2   g   t  g   t   



2 
0
2
2
1
2
 B  f  Af  g   t   2 g   t   2     g   t  g   t   






3) Many decay modes? “Beetopaipaigamma…”
– PDG reports 347 decay modes of the B0-meson:
•
Γ1 l+ νl anything
• Γ347 ν ν γ
( 10.33 ± 0.28 ) × 10−2
<4.7 × 10−5
CL=90%
– And for one decay there are often more than one decay amplitudes…
Niels Tuning (70)
Backup
Niels Tuning (71)
SLAC: LINAC + PEPII
Linac
Ee  3.1 GeV 
   0.56, s  M  4 S 
Ee  9 GeV 
HER
LER
PEP-II accelerator schematic and tunnel view
Coherent Time Evolution at the 4S
PEP-2 (SLAC)
B-Flavor Tagging
Exclusive
B Meson
Reconstruction
Vertexing &
Time Difference
Determination
Niels Tuning (73)
LHCb: the Detector
•
High cross section
•
LHC energy
•
•
Large acceptance
•
•
pT of B-hadron
•
η of B-hadron
Large boost of b’s
Trigger
•
•
b’s produced forward
Small multiple scattering
•
•
Bs produced in large quantities
↓ Low pT
Leptons + hadrons (MUON, CALO)
Particle identification
(RICH)
 Vud

V   Vcd
V
 td
Measuring the Quark Couplings
Vus Vub 

Vcs Vcb 
Vts Vtb 
W
q
Vq’q
•
Measure the CKM triangle to unprecedented precision
•
Measure very small Branching Ratios
q’
***
***
***
VVVubub
V


V
V

V
Vtdtdtd000
V

V
V
cb
cd
tb
tbV
tb
cb
ub ud
ud
cb cd
cd
The well known triangle:
β
CP phases:
 1 1 e-iγ 


 1 1 1 
 e-iβ 1 1 


γ
γ
α
β
Niels Tuning (75)