Post on 01-Jul-2018
Vivek Sharma University of California at San
Diego
CP Violation in B Decays
Vulcano Workshop 2006
2
• The universe is now matter dominated: where has all the primordial anti-matter gone?– Anti-proton/proton ratio ~10-4 in cosmic rays; no
evidence for annihilation photons from intergalactic clouds
• Sakharov conditions (1967) for generation of cosmological asymmetry: – Baryon number violation, e.g., proton decay– Thermal non-equilibrium– Violation of C, CP discrete symmetries
• CP Violation seen in Particle decays• What, if any, is the connection between CP violation
in the cosmos and the CPV in subatomic systems ?
From Cosmos To Quarks !
3
CP Violation In Subatomic Systems• CP Violation first discovered in the Kaon system• Kaon system has been the playground of CPV model-building
(and model-killing ) since discovery (1964)• Kobayashi & Maskawa’s proposition (1973) of CPV in the
context of the complex weak couplings of 3 generations of quarks consistent with observed CPV in the Kaon system (postdiction!)
• But hadronic uncertainties in the Kaon system makes clean interpretation of CPV in terms of SM or New Physics difficult
• B mesons are the “new” & theoretically clean laboratory for investigation of CP Violation within SM & Beyond Standard Model
• Two dedicated experimental efforts:– PEP-II Collider & BaBar detector in California– KEK-B Collider & Belle detector in Japan
4
Asymmetric Energy e+ e- Colliders: B Factories
BaBar@PEP-II
Belle @KEK-b
350 fb-1 500 fb-1
− +×9 GeV 3.1 GeV e e
5
Belle and Babar Detectors
e
e+
b
b
(4 )Sϒ
0B0B
Enough energy to barely produce 2 B mesons, nothing else!
B mesons are entangled Need for Asymm energy collisions
6
CP Violation Studies at Asymmetric Energy Colliders
7
Inter Quark Couplings: CKM Matrix≠ ⇒Mass Eigenstates Weak Eigenstates Quark Mixing
Cabibbo-Kobayashi-Maskawa (CKM) MatrixUnitary matrix described
for 3 generations of quarks by 3 rotation
angles and 1 non-trivial phase
⎡ ⎤⎢ ⎥=⎢ ⎥⎢ ⎥⎣ ⎦
us ubud
csCKM cbcd
ts tbtd
V V VV V V V
V V V
W
c
bgVcb
W
u
bgVub
Flavor changes through mixed couplings to
quarks
KM Conjecture: The phase of CKM matrix is source of CPV
8
CKM Matrix: Phenomenology
Wolfenstein parameterization: Observed experimental hierarchy
( )
( )
λ λ λ ρ η
λ λ λ
λ ρ η λ
⎡ ⎤− −⎢ ⎥
≈ − −⎢ ⎥⎢ ⎥− − −⎣ ⎦
2 3
2 2
3 2
1 / 21 / 2
1 1CKM
A iV A
A i A
⎡ ⎤⎢ ⎥=⎢ ⎥⎢ ⎥⎣ ⎦
us ubud
csCKM cbcd
ts tbtd
V V VV V V V
V V V
CKM Phase: changessign under CP
2x2 submatrix: u,d,s,c quarks only
λ ~ 0.22sinθC
Cabibbo angle3x3 matrix: 3 quark generations
2 1~λ
3 2~λ2
3 1~λ3
λ
λ
1
1
1
ub
td
-i
-iâ
ã|
|
|V e
|V e
⎛ ⎞⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠
ckm phase
9
The Unitarity Triangle For B System
2
1
3
*arg *
*arg *
*arg *
⎡ ⎤⎢ ⎥= ≡ −⎢ ⎥⎢ ⎥⎣ ⎦
⎡ ⎤⎢ ⎥= ≡ −⎢ ⎥⎢ ⎥⎣ ⎦
⎡ ⎤⎢ ⎥= ≡ −⎢ ⎥⎢ ⎥⎣ ⎦
V Vtd tbV Vud ub
V Vcd cbV Vtd tb
V Vud ubV Vcd cb
φ
α
φb
φ
Angles of Unitarity Triangle† * *1 0= → + + =ud cd cb tbV V V V V VtdV *ubV
Specific forms of CP Violation in B decay provide clean information about the angles of the UT triangle
Same triangle also defined by length of its sides (from CP conservingB decay processes such as b u l nu ) Overconstrained triangle
2 6J A λ η≈
10
CP Violation As Quantum Interference
CPV due to interference of meson decay amplitudes
ϕ dΓ → ≠Γ →
≠ ≠stwk
( ) ( )f or 0 and 0
B f B f
Analogous to a two-slit quantum interference experiment!
21 2( ) wk sti iB f A A e eϕ dΓ → = +
std1A
2Awkϕ+
Γ(B
f ) wkϕ−
ϕ d−Γ → = +2
1 2( ) wk sti iB f A A e eΓ(B f )
1AB f
ϕ d2
wk sti iA e e
11
Direct CP Violation in B0 K
λ= +2 iSM amplitude e T P
( ) : sinKA
TP
•Loop diagrams from New Physics (e.g. SUSY) can modify SM asymmetry contributing to the Penguin (P) amplitude
• Measurement is a simple “Counting Experiment”
Classic example of Quantum Interference
12
Direct CP Violation in B0K+
( )( )
0
0
9
696
10
n B K
n B K π
π−
+ −
+
=
→ =
→
Bkgd symmetric!
696 910 0.133696 910
A −= =−
+
0.133 0.030 0.009KA =− ± ±
4.2, syst. includedBaBar
LARGE CP Violation !unlike Kaon system
13
B0 Mesons Oscillate, Lead To CP Violation
0 0B Bƒ
Involves Vtd = | Vtd |eib
Oscillation via spontaneous 2nd order weak transitionSensitive to new particle of BSM (H+ etc)
Event with 2 B0
(instead of B0 B0)
ARGUS
14
0Bϕfi
CPA eCPf
0B2iq e
pb−=
ϕ− fiCPA e
CPV Due To Interference of B Mixing & Decay
CPV through interference between mixing and decay amplitudes
22I m1 | |
CP
CP
CP
ff
f
Sλ
λ=
+
2
21 | |1 | |
CP
CP
CP
ff
f
Cλλ
−=
+CP
CP
CP
ff
f
Aqëp A
= ⋅
Time-dependent asymmetry
Γ → −Γ →= = Δ − ΔΓ → +Γ →
0 0
0 0( ( ) ) ( ( ) )( ) sin cos( ( ) ) ( ( ) ) CP CPCP
CP CPphys physf d d
CP CPphys physf f
B t f B t fA t mt mt
B t f B tS C
f
15
0Bϕfi
CPA eψ= 0 CPf K
0B2iq e
pb−=
ϕ− fiCPA e
Case Of Single Decay Amplitude CPV through
interference between mixing and decay amplitudes
Directly related to CKM angles for single decay
amplitude
0=I mCPfλ=
For the simple case shown with single decay mechanism
22I m1 | |
CP
CP
CP
ff
f
Sλ
λ=
+
2
21 | |1 | |
CP
CP
CP
ff
f
Cλλ
−=
+CP
CP
CP
ff
f
Aqëp A
= ⋅
0 0
0 0( ( ) ) ( ( ) )( ) sin( ( ) ) ( ( ) )CP CP
CP CPphys physf f d
CP CPphys phys
B t f B t fA t S mt
B t f B t fΓ → −Γ →
= = ΔΓ → +Γ →
Time-dependent asymmetry
16
SM Predicts Large CPV in B ψK0
CP Eigenstate: ηCP = -1: Ks
ηCP = -1: KL
0
0 0
0 0 /( ( ) ) ( ( ) ) ( ) sin( ( ) ) ( ( ) )CP S
CP CPphys physf dJ K
CP CPphys phys
B t f B t fA t S mt
B t f B t f ψ
Γ → −Γ →= = ΔΓ → +Γ →
Quark subproce
ss
B0 mixing
K0 mixing
0
* * **
* * */I m I m I mCPS
cstbcs cb td cd tdfJ K
cs cscb tb td cd td
V V V V VV VV V V V V V Vψ
λ η⎧ ⎫
=− × × =⎨ ⎬⎩ ⎭
Amplitude of CP asymmetry
b=sin2
~0.7 instead of 2x10-3 in Kaons!
Vivek Sharma , UCSD 17
+e-e
B0 J/ψ Ks
z
Ä zÄt âã c≈< >
Brec
Btag( )4sΥ
b(4S) = 0.55
zΔ-∂
0sK
+∂
+ì-ì
Coherent BB pair
B0
B0
distinguishB0 Vs B0
Steps in Time-Dependent CPV Measurement
18
Effect of Mis-measurements On Δt Distribution
00tag BB = 00
tag BB =00tag BB = 00
tag BB =
CP PDF
perfect flavor tagging & time
resolutionrealistic
mis-tagging & finite time resolution
( )( )| |/
, ( ) 1 sin2 (1 2 )sin4t
CP CPef t tw m
τη βτ
−Δ
±
⎧ ⎫⎪ ⎪⎨ ⎬⎪ ⎪⎩ ⎭
− Δ Δ ℜΔ = ⊗m~ 1 ps 170 m
~ 6 ps 1000 m2
Δ ⇔
⇔
t
ixt
19
B Charmonium Data Samples
CP sample NTAG purity ηCP
J/ψ KS (KS→π+π-) 2751 96%
J/ψ KS (KS→π0π0) 653 88%
ψ(2S) KS (KS→π+π-) 485 87%
χc1 KS (KS→π+π-) 194 85%
ηc KS (KS→π+π-) 287 74%
Total for ηCP=-1 4370 92%
J/ψ K*0(K*0→ KSπ0) 572 77% +
J/ψ KL 2788 56% +
Total 7730 78%
MES [GeV]MES [GeV]
ΔE [MeV]
BABAR
(227 ) M BB
(ηCP = +1)
4370 events 572 events
2788 events
20
Sin(2b) Result From B Charmonium K0 Modes (2004)
sin2β = 0.722 ± 0.040 (stat) ± 0.023 (syst)
(cc) KS modes (CP = 1)
(PRL 89, 201802 (2002): sin(2β) = 0.741 ± 0.067 ± 0.034)
J/ψ KL mode (CP = +1)
(227 ) M BB
hep-ex/0408127
background
022b⇒ ;
21
ρ +
ρ−
Angle α From B0 ρ+ρ-
( )* *
* *
sin(2 2 2 ) sin 2
tb td ud ub
tb td ud ub
V V V VB V V V V
ππ
λ π π
λ π β γ α
+ − ⎛ ⎞⎛ ⎞→ = ⎜ ⎟⎜ ⎟
⎝ ⎠⎝ ⎠⇒ = − − =Im
Neglecting Penguin diagram (P)
2ie b− 2− ie
PT
22
Angle α From B0 ρ+ρ-
tags0B
tags0B
09.018.003.0
024.033.0 008.0 014.0
±±−=
±−= +−
ρρ
ρρ
C
S( )15
9105o
α +−=
World Average:
23
Direct CPV In BDK Decay Angle
0K + − iV eub
Constraint on
in the ρ,η plane
oo 1959WA ±=
measurements datalimited (~ 2.4)
24
The Unitarity Triangle Defined By CPV Measurements
159105 , , 59 19 degrees
First time that all angles 21.7 1.3
measured + +α
α b b+
− = ±= = ±⇒ ;
Precise Portrait of UT Triangle
from CPV Measurements
25
UT With CPV & CP Conserving Measurements
Incredible consistency between measurements !
Paradigm shift !SM/CKM Picture Describes observed CPV
Look for NP as correction to the CKM picture
26
Searching For New Physics by Comparing Pattern of CP Violation
in Penguin Decays of B Mesons
27
Tree
b
dd
W +cbV∗
csV
c /J ψ
s0K
c
Penguin
b s
, ,u c t, ,g Z
tb tsV V∗
s
dd
s φ
0K
3 New Physics
Comparing CP Asymmetries : Penguins Vs Tree
In SM both decays dominated by a single amplitude with no
additional weak phase
New physics coupling to Penguin decays can add additional amplitudes withdifferent CPV phases
ψb b⇒
→ =⇒ S
Asymmetry must be same[B K ] [penguin]sin2 sin2
Measured CPV
b bψ⇒⇒
→ ≠S
Asymmetries can be very differesinsi 2n2
nt[B K ] [pengu in]eff
CPV
28
New Physics ?
Standard Model
ψ bb → ≠S
experimentally observe[B K ] [pesin2 nguisin2 n]
then ... eff
If
29
Naïve Ranking Of Penguin Modes by SM “pollution”B
ronz
eG
old
Supe
rGol
d
b
dgt
0B
d
ss
s
W − 2~tb tsV V λ∗∝
0K
0', fη
0K
b
dgt
d
ss
s
W −
0B
2~tb tsV V λ∗∝
b
dgt
0B
d
ds
d
W −
2~tb tsV V λ∗∝0 0, , ρ ω
0K
2( )~ 5%λΟ
−~ 5 10%
2( / )~ 20%λ λΟ
λ λΟ +2( (1 / ))qqf
b
dgu
0B
d
ss
W −λ∗ −∝ 4~ i
ub us uV V R e
λ∗ −∝ 4~ iub us uV V R e
W −bd
0B
d
uu η 's 0K
0Ks
λ∗ −∝ 4~ iub us uV V R e
W −bd
0B
d
uu 0 0, , ρ ω
s 0K
Decay amplitude of interest SM PollutionNaive (dimensional) uncertainties on sin2b
Note that within QCD Factorization these uncertainties turn out to be much smaller !
ϕ ϕ
30
Golden Penguin Mode : B0 ϕ K0
• Modes with KS and KL
are both reconstructed
0 0LB Kφ→0 0
SB K K Kφ + − + −→ →
114 ± 12 signal events 98 ± 18 signal events
full backgroundcontinuum bkg
(Opposite CP)
0K
b
dgt
d
ss
s
W −
[ ],
CPK Kφ + −
hep-ex/0502019 BaBar: 222M BB
31
CP analysis of ‘golden penguin mode’ B0 ϕ K0
0tagB
0tagB
0tagB
0tagB
S(ϕKS) = +0.29 ± 0.31(stat) S(ϕKL) = -1.05 ± 0.51(stat)
0
0
0.07 0.040.50 0.25
0.00 0.23 0.05K
K
S
Cφ
φ
+−=+
±+
±
±=
Combined fit result Standard Model Prediction
S(ϕK0) = sin2b = 0.69 ± 0.03
C(ϕK0) = 1-|λ| = 00.8
0 0LB Kφ→0 0
SB K K Kφ + − + −→ → (Opposite CP)
ηϕK0
BaBar
φη =+× ± ±0 0.44 0.27 0.: 05f K
Belle S
32
Golden penguin mode: B0 η’K0
• Large statistics mode
• Reconstruct many modes η’ η + –, ρ0 η , + –0
– KS + – ,00
B0 η’KS
819 ± 38 signal events (Ks mode)
440 ± 54 signal events (KL mode)
η −′→ ×0 0 6BR( ) ~ 65.2 10B K
η −′→ ×0 0 6recBR( ) ~ 14.9 10SB K
hep-ex/0502017,0507087
B0 η’K0
η
η
′
′
=+
=−
± ±
± ±
0
0
0.36 0.03
0.16
0.13
0.09 0.02K
K
S
C
sin2b [cc] @ 2.7
ηϕK0BaBar
η’KS
33
Taken individually, eachdecay mode in reasonable agreement with SM
but (almost) all measurementsare lower than sin2b from ccs
Naïve b s penguin average sin2beff = 0.50± 0.06
Compared to Tree:sin2beff = 0.69± 0.03
Theory models predict SM pollution to increase sin2beff !!
Bottom line
34
Theory Predictions, Accounting For subdominant SM Amplitudes
2-body:Beneke, PLB 620 (2005) 143
b bΔ = − sin2 sin2 ef f
3-body:Cheng, Chua & Soni,
hep-ph/0506268
Calculations within framework
of QCD factorization
greblu
y =e = 1
full s
ig ae
mrang
±
sin2beff > 0.69 larger discrepency !
35
What Are s-Penguins Telling Us ?
This could be one of the greatest discoveries of the century, depending, of course, on how far down it goes…
2.4
discrepancy
36
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
Jan-03Jul-03 Jan-04Jul-04 Jan-05Jul-05 Jan-06Jul-06 Jan-07Jul-07 Jan-08Jul-08 Jan-09Jul-09
Error on sine amplitude
Need More Data To Understand The Puzzle
K*
4 discovery region if non-SM physics is 0.19 effect
2004=240 fb-1
2008=1.0 ab-1
Individual modes reach
4-5 sigma level
Projections are statistical errors only; but systematic errors at few percent
level
Luminosity expectation
s:
20082004
=( ) 0.19S
f0KS
KS0
φKS
η’KS
KKKS
37
0
200
400
600
800
1000
1200
Jul-99Jul-00Jul-01Jul-02Jul-03Jul-04Jul-05Jul-06Jul-07Jul-08
Projected Data Sample GrowthIn
tegr
ated
Lum
inos
ity
[fb-
1 ]
12
17
20
Lpeak = 9x1033
o PEP-II: IR-2 vacuum, 2xrf stations, BPM work, feedback systems
o BABAR: LST installation
4-month down for LCLS, PEP-II &
BABAR
Double from 2004 to 2006
ICHEP06
Double again from 2006 to
2008 ICHEP08
Expect each experiment to accumulate 1000 fb-1 by 2008
38
Summary & Prospects• CP Violation in B decays systematically studied at
BaBar & Belle. A Comprehensive profile emerging• Standard Model picture (3 generation CKM matrix) of
CP Violation consistent will all observations– SM CPV too weak to explain cosmic CPV
• New Physics (in loops) can still contribute to observed CPV but is unlikely to be the dominant source
• CPV violation in the (rare) Penguin Decays appears lower than SM predictions (> 2.4)– more data needed to reveal true nature of discrepancy– B-factories expect to triple data sets by 2008
• Super B-factories after then…
Backup Slides
40
B Meson: Special Laboratory for CPV Investigations• Large Mass : MB=5.279 GeV/c2
• “Large” lifetime: • Large mixing• Large rate for penguin decays
Long B lifetime
Exclusive B decays
B0 B0 oscillations
Observation of BK*
41
Direct CPV in s-Penguins ?
No sign of direct CPV !
42
Compare sin2b with “sin2b” from CPV in Penguin decays of B0
Both decays dominated by single weak phase
b s
, ,u c t, ,g Z
tb tsV V∗
Penguin:
s
dd
s
Tree:
b
dd
W +cbV∗
csV
φ
0K
c /J ψ
s0K
New Physics? 3
bψ ψ ψ
λ η η∗
−∗
→
⎛ ⎞⎛ ⎞ ⎛ ⎞= ⋅ ⋅ =⎜ ⎟⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠⎝ ⎠
0 0 0, , ,
2/ / /
S L S L S L
icb csJ K J K J K
cb csB K
b ccs
V Vq q ep V V p
c
bφ φ φλ η η
∗−
∗
→
⎛ ⎞⎛ ⎞ ⎛ ⎞= ⋅ ⋅⎜ ⎟⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠⎝ ⎠
0 0 0, , ,
2
~S L S L S L
itb tsK K K
tb tsB K
b sss
V Vq q ep V V p
?[charmonium]sin2 [ -penguin]sin2 sb b=
0
-i2
In SM interference between B mixing and dominant b sss (b suu)
[penguin amplitudes have no CKM phase]Loop d
givesiagram
the same CPs sensitive
V (due to e ) as in to high virtual mass
b ccs scales
b
⇒ → →
→⇒
NPcouλincαnbρininneωηαetηαt αψcαuedeviαtionenitivetone
ϕρo exectedωηψi
"ic
n2 "b
Must be if one amplitude dominates
43
Compare sin2b with “sin2b” from CPV in Penguin decays of B0
Both decays dominated by single weak phase
b s
, ,u c t, ,g Z
tb tsV V∗
Penguin:
s
dd
s
Tree:
b
dd
W +cbV∗
csV
φ
0K
c /J ψ
s0K
New Physics? 3
bψ ψ ψ
λ η η∗
−∗
→
⎛ ⎞⎛ ⎞ ⎛ ⎞= ⋅ ⋅ =⎜ ⎟⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠⎝ ⎠
0 0 0, , ,
2/ / /
S L S L S L
icb csJ K J K J K
cb csB K
b ccs
V Vq q ep V V p
c
bφ φ φλ η η
∗−
∗
→
⎛ ⎞⎛ ⎞ ⎛ ⎞= ⋅ ⋅⎜ ⎟⎜ ⎟ ⎜ ⎟⎝ ⎠ ⎝ ⎠⎝ ⎠
0 0 0, , ,
2
~S L S L S L
itb tsK K K
tb tsB K
b sss
V Vq q ep V V p
?[charmonium]sin2 [ -penguin]sin2 sb b=
0
-i2
In SM interference between B mixing and dominant b sss (b suu)
[penguin amplitudes have no CKM phase]Loop d
givesiagram
the same CPs sensitive
V (due to e ) as in to high virtual mass
b ccs scales
b
⇒ → →
→⇒
NPcouλincαnbρininneωηαetηαt αψcαuedeviαtionenitivetone
ϕρo exectedωηψi
"ic
n2 "b
Must be if one amplitude dominates
44
Rules out Superweak model
Establishes CPV not just due
to phase of B Mixing
But hadronic uncertaintiespreclude determination ofCKM angle challenge to theory
Combined significance >> 6
Direct CP Violation in B0 K : Belle (386M BB)
Belle
45
46
An Optimist’s Global CKM fit ? : 2008 (1 fb-1 each)
( ) 6.5%ubV = ( ) 5%sm Δ = (sin 2 ) 0.019 b = o( ) 8 α = o( ) 10 =
95% contours
?
47
CP Violation • CP violation can be observed by comparing decay rates
of particles and antiparticles
• The difference in decay rates arises from a different interference term for the matter vs. antimatter process. Analogy to double-slit experiment:
1A
2A
1A
2A
CP Viola io( t) n) (Γ → ≠Γ → ⇒α ϕ α ϕ
source1A
2AClassical double-slit experiment:Relative phase variation due to different path lengths: interference pattern in space
48
CP Violation Is a Quantum Phenomenon
• CPV is due to Quantum interference between > two amplitudes
• Phases of QM amplitudes is the key • Need to consider two types of phases
– CP-conserving phases: don’t change sign under CP (Sometimes called strong phases since they can arise from strong, final-state interactions)
– CP-violating phases: these do change sign under CP transformation
(originate in the Weak interaction sector)
49
Definition of CP Asymmetry
To extract the CP-violating phase from an observed CP asymmetry, we need to know the value of the CP-conserving phase difference
2 2
1 2 1 2 1 22 2 22
1 2 1 2 1 2 1 2
2 sin( )sin( )cos( )cos( )
A A A AAsymmetry
A A A AA A
d d φ φd d φ φ
− − −= =
+ + − −+
B system: extraordinary laboratory for quantum interference experiments: many final states, multiple “paths” Lots of channels for CP Violation
50
The CKM matrix & its mysterious pattern
212
2
3
3
2 412
2
1 ( )1 ( )
(1 ) 1
0.97 0.23 0.004 0.23 0.97 0.04 (magnitudes only)
0.004 0.04 1
ud us ub
cd cs cb
td ts tb
V V V A iV V V A OV V V A i A
λ
λ
λλλ ρ η
λ λη
λρ λ
⎛ ⎞− −⎛ ⎞ ⎜ ⎟⎜ ⎟= − − +⎜ ⎟⎜ ⎟⎜ ⎟ ⎜ ⎟− − −⎝ ⎠ ⎝ ⎠⎛ ⎞⎜ ⎟−⎜ ⎟⎜ ⎟−⎝ ⎠
;
• The SM offers no explanation for this numerical pattern.• But SM framework is highly predictive:
Unitarity triangle: (Col 1)(Col 3)* =0 etc. Only 4 independent parameters: A, λρη One independent CP-violating phase parameter
(Wolfenstein parametrization)
51
Impressionist’s View of The CKM matrix
â
-i
-i
ã1 11 1 1
1 1
e
e
⎛ ⎞⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠
u
d
t
c
bs
λ
λ
λ
λ3
λ2
λ2
Largest phases in the WolfensteinparametrizationMagnitudes of CKM elements
Note: all terms in the inner product between columns 1 and 3 are of order λ3. This produces a unitarity triangle of roughly equal sides.
11
1
1
52
Machine Performance Exceeds Design (x3)
96% efficiency over the entire history of
BABARBABAR, Run 5
Peak luminosity(cm-2 s-1)
1.0025 x 1034
Best shift 247.2 pb-1
Best day 710.5 pb-1
Best week 4.464 fb-1
Best month 17.036 fb-1
BABAR logged
343 fb-1
KEK-B operation even more spectacular !
53
0Bϕfi
CPA eCPf
0B2iq e
pb−=
ϕ− fiCPA e
CP violation in the B system
CPV through interference between mixing and decay amplitudes
Directly related to CKM angles for single decay
amplitude
22I m1 | |
CP
CP
CP
ff
f
Sλ
λ=
+
2
21 | |1 | |
CP
CP
CP
ff
f
Cλλ
−=
+CP
CP
CP
ff
f
Aqëp A
= ⋅
Time-dependent asymmetry0 0
0 0( ( ) ) ( ( ) )( ) sin cos( ( ) ) ( ( ) )CP CP CP
CP CPphys physf f d f d
CP CPphys phys
B t f B t fA t S mt C mt
B t f B t fΓ → −Γ →
= = Δ − ΔΓ → +Γ →
54
0Bϕfi
CPA eCPf
0B2iq e
pb−=
ϕ− fiCPA e
CP violation in the B system
CPV through interference between mixing and decay amplitudes
Directly related to CKM angles for single decay
amplitude
0=I mCPfλ=
For simple case shown with single decay mechanism
22I m1 | |
CP
CP
CP
ff
f
Sλ
λ=
+
2
21 | |1 | |
CP
CP
CP
ff
f
Cλλ
−=
+CP
CP
CP
ff
f
Aqëp A
= ⋅
0 0
0 0( ( ) ) ( ( ) )( ) sin( ( ) ) ( ( ) )CP CP
CP CPphys physf f d
CP CPphys phys
B t f B t fA t S mt
B t f B t fΓ → −Γ →
= = ΔΓ → +Γ →
Time-dependent asymmetry
55
The Unitarity Triangle Defined By CPV Measurements
159105 , , 59 19 degrees
First time that all angles 21.7 1.3
measured + +α
α b b+
− = ±= = ±⇒ ;
New B Factory milestone: Comparable UT precision
from CPV in B decays alone
56
A fundamental cosmological question• The universe is now matter dominated: where has all the
anti-matter gone?– Anti-proton/proton ratio ~10-4 in cosmic rays; no
evidence for annihilation photons from intergalactic clouds
• Cosmological generation of asymmetry: Sakharov conditions (1967)– Baryon number violation, e.g., proton decay– Thermal non-equilibrium– Violation of CP discrete symmetry
Broken Phase:Massive quarks,
W, Z bosonsUnbroken Phase:Massless quarks
Transition to broken electroweak symmetry provides these
conditionsConnection between CPV in cosmos & subatomic particles ?
57
Direct CP Violation in B0 K : BaBar
B0K+
B0K+
BABAR
1606 510.133 0.030 0.009
K
K
nA
= ±=− ± ±
( )( )
0
0
9
696
10
n B K
n B K π
π−
+ −
+
=
→ =
→
4.2 effect (syst. included)
similar results from Belle
58
• New physics at the electroweak scale generically introduces many new large flavor-violating or CP-violating couplings to quarks
• Quantum loop diagrams can attract couplings to heavy new particles of BSM physics
• Theory robust : capable of discriminating between SM and New Physics in special cases
CP Violation & Sensitivity To New Physics
0 0 OscillationB Bƒ " " DecaysPenguin