CP Violation and CKM Angles
Status and Prospects
Klaus Honscheid
Ohio State University
C2CR 2007
Two asymmetric-energy
factories
The Two AsymmetricBEnergy
B Factories
PEP-II at SLAC
9 GeV (e-)  3.1 GeV (e+)
peak luminosity:
1.21034cm-2s-1
13 countries,
57 institutes,
~400 collaborators
Belle
BaBar
KEKB at KEK
11 nations,
77 institutes,
~600 persons
8 GeV (e-)  3.5 GeV (e+)
peak luminosity:
1.71034cm-2s-1
K. Honscheid, Ohio State University, C2CR 2007
Experimental Landscape (early 2007)
1200
Total Integrated Luminosity (fb-1)
# of B decays recorded
1000
Belle
1.3
710Billion
fb-1
Tevatron > 2.4 fb-1
BaBar
0.8
400Billion
fb-1
800
600
400
CLEO II.5
CLEO II
200
0
1990
1992
1994
1996
1998
2000
2002
2004
2006
K. Honscheid, Ohio State University, C2CR 2007
CP Violation in the Standard Model
CP Operator:
CP(
g
q
coupling
q’
J
) =
g*
q
q’
J
Mirror
To incorporate CP violation
g ≠ g*
(coupling has to be complex)
K. Honscheid, Ohio State University, C2CR 2007
CP Violation in the SM: The CKM Matrix
The CKM matrix Vij is unitary with 4
independent fundamental parameters
Unitarity constraint from 1st and 3rd
columns: i V*i3Vi1=0
d
s
b
u
Vud
Vus
Vub
c
Vcd
Vcs
Vcb
t
Vtd
Vts
Vtb
CKM phases
(in Wolfenstein convention)
a = p-g-b
g ~ arg[Vub*]
b ~ arg[Vtd*]
1 2
-iγ 


A  3   - i  
 1- 
2


1

-
1 - 2
A 2 


2
 A3 1 -  - i-i β - A2

1




 1

 1
e

1 e 

1 1 
1 1 
K. Honscheid, Ohio State University, C2CR 2007
Interfering Amplitudes in Bo  Kp Decays
Tree decay
B0
K-p+
A1 = a 1
eif1
eid1
+
B0
K+p-
B
A2 = a2 eif eid
2
A1 = a 1
Vus*
g
0 b
d
Vub
s
u
u
d
K-
p
2
e-if1
A  Vus*Vub
eid1
+
A2 = a2 e-if eid
2
2
Penguin decay
B
b
0 u,c,t
g
d
s
u
u
d
K-
p
A  Vts*Vtb
Interference(A1+A2)2≠ (A1+A2)2
|A|2 – |A|2
G(B) – G(B)
~ 2 sin(f1 - f2) sin(d1 - d2)
Asymmetry =
=
2 + |A|2 = 0
|A|
G(B) + G(B)
K. Honscheid, Ohio State University, C2CR 2007
CP Violation in Bo  Kp Decays
227 x 106 B0 Mesons
227 x 106 B0 Mesons
Count B0K+p- Decays
Count B0K-p+ Decays
Is N(B0K+p- ) equal to N(B0K-p+ )?




Br B  f - Br  B  f
BABAR
A  K=p  = 910
n  B CP
Br B  f  Br  B  f
n  B  K p  = 696
0

-
0
-



background
subtracted
K. Honscheid, Ohio State University, C2CR 2007
Mixing Induced CP violation
Golden mode B0J/yKs:CP eigenstate, high rate, theoretically clean
No weak phase
ei0
B0
Two Vtd vertices e-i2b
e-i2b
J/yKs
B0
e-i0
+
Two Amplitudes
Interference
ACP ~ sin2b
K. Honscheid, Ohio State University, C2CR 2007
A Complication: Quantum Coherence
We need to know the flavor of the B at a reference t=0
and measure the difference in decay time Dt
t =0
B0
At t=0 we
know this
meson is B0
Flavor Tagging
Time Dependence
Dz = Dt gbc
B0
rec
yK s
(4S)
bg =0.56
B0
The two mesons oscillate
coherently : at any given
time, if one is a B0 the
other is necessarily a B0
tag
W
l - (e-, m -)
In this example, the tagside meson decays first.
It decays semi-leptonically
and the charge of the
lepton gives the flavour of
the tag-side meson :
l -= B0
l  = B 0.
Kaon tags also used.
B0
-
l-
l
b
d
Dt picoseconds
later, the B 0 (or
perhaps its now
a B 0) decays.
Time dependent asymmetry ACP = SCPsin(DmDt) - CCPcos(DmDt)
SCP = -fCP sin2b (fCP= ±1), CCP “direct” CP
violationOhio
= 0State
forUniversity,
J/yK C2CR 2007
K. Honscheid,
CP Violation in
B0J/yK
PRL 98, 031802 (2007)
s
BaBar preliminary, hep-ex/0607107
Belle preliminary, hep-ex/0608039
B0J/yKL
B0J/yKS
Dt for B0 tag  B0J/yK
Dt for B0 tag  B0J/yK
Background
Dt asymmetry
J/yKL is fCP= +1
J/yKS is fCP= -1
B0 tags
B0 tags
Belle
Belle
Preliminary
B0
tags
B0 tags
Preliminary
Dt oscillation
Period = B mixing Dm
Amplitude = D sin2b
(Dilution D due to mistags;
measured experimentally)
K. Honscheid, Ohio State University, C2CR 2007
Sin(2b) World Average
Heavy Flavors Averaging Group
E.Barberio et al., hep-ex/0603003
Statistics limited
Consistent with zero: no
evidence for NP in tree decay
o
b = 21.2 ± 1.0o
Extracting b from sin2b has ambiguities;
removed by J/yK*, D*D*KS and Dp0//'/w analyses
K. Honscheid, Ohio State University, C2CR 2007
Is “b” Universal?
News Flash
Can use 3 different categories of B0 decays to measure b:
hep/ex 0702031
b) b  cc d charm
(and charmonium )
a) b  cc s
(charmoniu m)
c) Penguin - dominated
b  dd s, b  ss s
b
s
s
B0
d
s
d

K0
Possible contribution from
BD+Dgolden mode
J /yK
New
Physics
(NP):
new
0

0
S
=
-1.12
±
0.37
±
0.09
*  heavy
particles
fK
,K
K -C)
K Sin, the loop
0
0
0
D
D
,
D
D
A
=
0.91
±
0.23
±
0.06
(=
y ( 2 S ) K ,  K , K
0
S
S
c1
S
c
S
J /yK L0
J /yK *0 ( K *0  K S0p 0 )
0
0
0
0
0 0
See
the
following
talk

K
K
K
,

K
,
K
S 0) S
Sp ,
J /yp , D
D to be closeS to
(expected
by Tom Browder
0
wK S , f 0 (980) K S0
0
*
*-
K. Honscheid, Ohio State University, C2CR 2007
Let’s try this for the next angle:
a
Access to a from the interference of a b→u decay (g) with B0B0 mixing (b)
Tree decay
B0B0 mixing
b
B
0
d
Vtb*
Vtd*
t
t
Vud*
g
d
B
0
b
Vtb
Vtd
q / p  Vtb*Vtd / VtbVtd*
B
Penguin decay
Vub
0 b
d
p-
d
u
u
d
p

B
b
0 u,c,t
d
 =e
i 2a
Inc. penguin contribution
T  P e  ig eid
T  P e -ig eid
C  sin d
App (Dt ) = Spp sin( Dmd Dt ) - Cpp cos(Dmd Dt )
T = "tree" amplitude
p
S = 1 - C 2 sin( 2a eff )
S = sin( 2a )
C =0
NB :
p-
A  Vtd*Vtb
A  Vud* Vub
q A
=
= e -i 2 b e -i 2g = ei 2a
p A
Time-dep. asymmetry :
g
d
u
u
d
How can we
obtain α
from αeff ?
P = "penguin" amplitude
K. Honscheid, Ohio State University, C2CR 2007
How to estimate |a-aeff| : Isospin analysis
Use SU(2) to relate decay rates of different hh final states (h  {p,})
Need to measure several related B.F.s
Α  - = A( B 0  p p - )
~ Α = A( B 0  p p - )
Α = A( B  p p )
0


0
Α 00 = A( B 0  p 0p 0 )
~ 00
Α = A( B 0  p 0p 0 )
Limiting factor in analysis
Gronau, London : PRL65, 3381 (1990)
K. Honscheid, Ohio State University, C2CR 2007
Measuring a in B  pp
hep-ex/0608035
+ - p ±p0
hep-ex/0607106
p 0 p0
pp
1464±65
Np p 0 = 572  53
Np 0p 0 = 140  25
BRp p 0 = (5.12  0.47  0.29) 10-6
BRp 0p 0 = (1.48  0.26  0.12)  10-6
Ap p 0 = -0.019  0.088  0.014
Cp 0p 0 = -0.33  0.36  0.08
Da
|Da|<41°@90% C.L.
Sp+p- = -0.61 ± 0.1 ± 0.04
Ap+p- (=-C) = 0.55 ± 0.08 ± 0.05
BRp+p- = (5.1±0.2±0.2) x 10-6
K. Honscheid, Ohio State University, C2CR 2007
Sometimes you have to be lucky
hep-ex/0607092
hep-ex/0607097
hep-ex/0607098
•B   is almost completely polarized
B0  -
B  0
B0  00
98-32
31  22
615±57
f L,    - = 0.977  0.024-0.015
0.013
390±49
BR   0 = (16.8  2.2  2.3) 10-6
 0.05
S
 - = -0.19  0.21- 0.07
BR   = (23.5  2.2  4.1) 10-6 f L ,   = 0.905  0.042-0.023
0.027
C   - = -0.07  0.15  0.06 A = -0.12  0.13  0.10
 

-


•B  00 is small
0
-6
BR 0  0 = (1.16-0.37
0.36  2.7) 10
f L,  0  0 = 0.86-0.11
0.13  0.05
0
better constraint on Da
K. Honscheid, Ohio State University, C2CR 2007
Combining all methods:
a
Other solutions
disfavoured
CL=0.683
Combined: a = [93+11-9]
Global fit without a:
aGlobal Fit = [ 98+5-19] º
K. Honscheid, Ohio State University, C2CR 2007
g = arg[Vub*]: CP violation in DK modes
GLW: Gronau, London, Wyler (2001)
ADS: Atwood, Dunietz, Soni (1997)
GGSZ: Giri, Grossman, Soffer, Zupan (2003)
E.g. B+D0 /D0K+
ei0
ei0
D0K+
D decays do not
involve Vub or Vtd: no
contribution to phase
D0/D0 CP state (GLW)
D0/D0K-p+/K+p-, CA/DCS (ADS)
D0/D0KSp+p-, Dalitz (GGSZ)
B+
V*ub vertex eig
D0K+
eig
ei0
Relative phase = e-ig
B±  DK: no time dependence; extract g from rates and CP asymmetries
but b  u amplitude is small (for example rB (DK−K.) =
0.16 ± 0.05
0.01
± 0.05 C2CR
Belle)2007
Honscheid,
Ohio ±
State
University,
The GGSZ method – an example
Look for deviations in B±D0K± plots
Map out Dalitz plot from all
D0 Ksp+p- decays
B+
BBelle
Belle
BaBar preliminary; hep-ex/0607104
Belle; Phys.Rev.D 73, 172009 (2006)
K. Honscheid, Ohio State University, C2CR 2007
Combined Result for g
Combined: g = [62+38-24 ]
Indirect (CKM) g = [59+9-4]
K. Honscheid, Ohio State University, C2CR 2007
The CKM Model has passed the experimental test
[93
+11
-9]
o
a
g
(0,0)+38 ]o
[62
-24
b
[21.2 ± 1.0]o
New Targets
Effects of TeV new physics  deviations from SM
LFV and new source of CPV
Hidden flavor symmetry and its breaking
K. Honscheid, Ohio State University, C2CR 2007
The next few years (2007 – 2010)
• LHCb is nearing completion
• Belle and BaBar
• 1 ab-1 (2006)
• 2 ab-1 (2008)
1200
ICHEP08
1000
800
600
400
200
Jul-08
Jul-07
Jul-06
Jul-05
Jul-04
Jul-03
Jul-02
Jul-01
Jul-00
Jul-99
0
• Tevatron
• 2 fb-1 (2006)
• 8 fb-1 (2009)
K. Honscheid, Ohio State University, C2CR 2007
LHCb Prospects (Some of the things they can do)
Bs Mixing phase (s) using Bs J/yf
Signal yield: 130k events per L=2fb-1 with a B/S0.1, Sensitivity s ~ 0.021
Sensitive probe of New Physics effects in the Bs mixing
s = s(SM) + s(NP) with s(SM)=-22 ~ -0.037±0.002
V. Vagnoni CKM2006
0,04
0,8
s(s)
0,6
now
0,03
pre-LHCb
LHCb at
L=2fb-1
0,02
0,4
pre-LHCb
0,2
LHCb
LHCb at
L=2fb-1 at L=10fb-1
LHCb
at L=10fb-1
0,01
0,0
0,00
2006
2008
2010
2014
year
2006
2010
2014
20
Sensitivity to g
Standard methods
Golden Mode Bs DsK
Sensitivity ~ 4.2o with 2 fb-1
2008
year
now
16
s(g) [o]
s(s)
now
12
pre-LHCb
8
4
with LHCb
with LHCb
at L=2fb-1
at L=10fb-1
0
2006
2008
2010
2014
year
K. Honscheid, Ohio State University, C2CR 2007
From B-Factories to LHCb – without new physics
Summer 2006
2014
2008*
LHCb
L=10 fb-1
s(  ) /  = 17%
s(  ) /  = 4.7%
s (  ) /  = 7 .4 %
s (  ) /  = 3 .3 %
s (  ) /  = 3. 6%
s(  ) /  = 1.8%
K. Honscheid, Ohio State University, C2CR 2007
Super B-Factory Plans at KEK and Frascati
Design Luminosity ~ 1 x 1036 /cm2/sec
Synergy with ILC
Recycle components (PEP, BaBar)
Lots of R&D needed
New Beam pipe
ILC ring
ILC FF
More RF power
Interaction Region
Crab crossing
q=30mrad.
by*=3mm
New QCS
I
P
Damping ring
Linac upgrade
KEK
L = 81035/cm2 /sec
Frascati
K. Honscheid, Ohio State University, C2CR 2007
Summary
CKM Model is now a tested theory
Great success for theorist
Great success for experimentalist
Great success for the Standard Model
a = (93+11-9)o
b = (21.2 ± 1.0)o
g = (62+38-24)o
Search for Deviations from SM and New Physics
Near Term Future Looks Promising
B Factories only half way done
Tevatron will triple data sample
LHC(b) turn on
Long Term Prospects
LHC(b) upgrades
Super B Factories (KEK, INFN)
K. Honscheid, Ohio State University, C2CR 2007