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