Looking for New Physics:

Precision measurement of

B meson decays

b s

Content:

CKM Matrix and Unitarity Triangle

CKM Metrology - Experimental Status

B Physics with LHCb

Ulrich Uwer

Why studying B mesons ?

2

Mesons with b-Quarks:

• Heaviest quark that forms hadronic bound

states (m~4.7 GeV).

• Must decay outside 3rd family

• All decays are CKM suppressed

• High mass: many accessible final states

• Long lifetime (~1.6 ps):

experimentally simple to identify

• Large CP violation expected

d

u

s

c

b

t

0Bcb

d

D

W

0B 0Bd t

t

b

b d

0B 0Kb st

d

Loop corrections are important:

d

CKM Matrix

3

b

s

d

VVV

VVV

VVV

tbtstd

cbcscd

ubusud

'

'

'

b

s

d

Number of

independent

parameters:

18 parameter (9 complex elements)

-5 relative quark phases (unobservable)

-9 unitarity conditions

=4 independent parameters: 3 angles + phase

Wolfenstein Parametrization

4

23

22

32

112

1

21

O

AiA

A

iA

VVV

VVV

VVV

V

tbtstd

cbcscd

ubusud

CKM

6

42423

2242

52

342

21211

4182

12

182

1

O

AiAAiA

AAiA

iA

VCKM

b

s

d

VVV

VVV

VVV

tbtstd

cbcscd

ubusud

'

'

'

b

s

dd s b

u

c

t

, A, , with = 0.22|Vub| e-i

|Vtd| e-i

4|Vts| e-i s

CKM matrix is unitary :

All 6 triangles have the same area (= JCP/2 ): a measure of CPV in the

Standard Model.

0

0

0

0

0

0

***

***

***

***

***

***

cbubcsuscdud

tbcbtscstdcd

tbubtsustdud

tstdcscdusud

tbtscbcsubus

tbtdcbcdubud

VVVVVV

VVVVVV

VVVVVV

VVVVVV

VVVVVV

VVVVVV

(ut)

(ct)

(uc)

cdcbVV *

udubVV *tdtbVV * tbubVV *

tdudVV *

tsusVV *

ubusVV *cbcsVV *

tbtsVV *

tbcbVV *

tdcdVV *

tscsVV *

usudVV *

tstdVV *cscdVV *

cbubVV *

cdudVV *

csusVV *

(db)(ut)

(sb)

(ds)(uc)

(ct)

(db)

(sb)

(ds)

Unitarity Triangles

5

Redraw “unsquashed” ’s and divide by

Unitarity Triangle

3

*

A

VV udub

Re1

3

*

A

VV tdtb

3

*

A

VV cdcb

0VVVVVV *

tbtd

*

cbcd

*

ubudIm

(db)

argVcb*Vcd

Vtb*Vtd

tan 1

1~ 21oarg

Vub*Vud

Vcb*Vcd

tan 1 ~ 70o

, 1 2 2 ,

cdcbVV *

6

7

Unitarity Triangle from B Decays

0 Re

Im

&

Sides from CP

conserving observables

ub

cb

8

Unitarity Triangle from B Decays

00 / :CPV SKJB

,, :CPV 0B

KKKDB

DKDKDKB

ss

s

,

,,,:CPV

0

*0)(0

0 Re

Im

„Golden channel“

Angles from CP

violating observables

Very rare decays several 109 B mesons necessary

The 2nd Unitarity Triangle

Re

ss

s

3

*

A

VV tbub 3

*

A

VV tdud

3

*

A

VV tsus

22

21

0VVVVVV *

tbub

*

tsus

*

tdud

Im

s argVcb*Vcs

Vtb*Vts

~ 2 ~1o

(ut)

9

~20 mrad

CKM Metrology - Experimental Status

• e+ e- B factories

• Measurement B0 B0 oscillation

• Measurement of CP Violation in B0 J/ Ks

• UnitarityTriangle

10

e+ e- B factories

GeV5810.s

pair is produced in a coherent L=1 state:00BB

BB

BBBB /

%/%

00

5050

nb.11bb

e+ e+ (4s) B B

nb~Continuum 3

1.1 million / fb-1

(e+ e+ )

11

0000

212

1BBBBBB

Asymmetric B factories

PEP-II @ SLAC

Energy: 9.0 GeV e- + 3.1 GeV e+

Max. currents: e+ / e- ~ 3.2 / 2.3 A

Design luminosity : 3 x 1033 cm-2s-1

Peak luminosity : 1.207 x 1034 cm-2 s-1

B mesons: rate ~ 13 Hz, 470 M BB

KEK-B @ KEK

Energy: 8.0 GeV e- +3.5 GeV e+

Design luminosity : 1 x 1034 cm-2s-1

Peak luminosity : 1.71 x 1034 cm-2 s-1

B mesons: rate ~ 19 Hz, 780 M BB

12

Asymmetric beam energy

GeV3.5

e e B mesons at rest

decay length z 0

GeV9

e e

GeV3.5

GeV1.3

Boost = 0.56 (BABAR) tcz

GeV58.10ECMS 50% / 50%

Symmetric:

Asymmetric:

decay length

z 250 m

13

14

15

16

Mixing Phenomenology

)(

)(

)(

)(

tB

tBi

tB

tB

dt

di

0

0

0

0

2M

Mass eigenstates:

0B0B

HHH

LLL

mBqBpB

mBqBpB

,

,

with

with

00

00

ttim

LHLH

LHLH eeBtB

,,)()( ,,

2

1

0

Flavor eigenstates: )()( HLHL BBq

BBBp

B2

1

2

1 00

complex coefficients

No mass

eigenstates

Mixing of neutral mesons

mteeeBBPBBPttt HLHL

cos24

1)()(

2/0000

mteeeq

pBBP

mteeep

qBBP

ttt

ttt

HLHL

HLHL

cos24

1)(

cos24

1)(

2/

2

00

2/

2

00

CPT

LH mmm

17

B0-B0 Mixing

0

0,2

0,4

0,6

0,8

1

1,2

0 2 4 6 8 10

)cos1(2

1)(

00mteBBP

t

mteBBPt

cos12

1)(

00

-1,5

-1

-0,5

0

0,5

1

1,5

0 1 2 3 4 5 6 7 8 9 10B

t

)()(

)()(

0000

0000

BBPBBP

BBPBBP

Bt /

LH mmm

) (mit ΓΓΓ LH

mOscillation

Frequency

18

Steps of oscillation measurement

K

B Mass & Vertex Reconstruction

Start / Stop

Tagging Quality: Q = 30.5%

B-flavor Tagging & Vertex Reconstruction

t measurement

SigB

tagB

)4( s

mz 250

0B

D

19

perfect

tagging & t resolution

realistic

tagging & t resolution

unmixed

mixed

B0 Oscillation

mixed

unmixed

20

Negative t:

Signal B decays before tagging B

mttBNtBN

tBNtBNtA

mixedunmixed

mixedunmixedmix cos~

)()()()(

)()()()()(

B0 Oscillation

-1ps.. 00505070dm

dmT 2

(World average, PDG 20098)

00dd BB

21

Observation of CP violation

1AfB

iieeA CP

2

fB

)cos(2 21

22

21

2

CPAA

AAA

CP

1AfB

iieeA CP

2

fB

)cos(2 21

22

21

2

CPAA

AAA

22

Observation of CP violating phase Interference effect of 2 amplitudes

CP-Violation through mixing and decay

23

CPf0B

0B

)sin( βsin~)( mtet t 21)sin( βsin~)( mtet t 21

CP

CPf0B

0B

)sin( βsin))(())((

))(())(()( mt

tfBtfB

tfBtfBtACP 2

00

00

2ieie

ie

2ie

CP Violation in B0 J/ Ks

i

cdcb

cdcb

tdtb

tdtb

cdcs

cdcs

cscb

cscb

tdtb

tdtb eVV

VV

VV

VV

VV

VV

VV

VV

VV

VV

A

A

p

q 2

*

*

*

*

*

*

*

*

*

*

CP

b

d b

dB0 mixing

pq /

b

d

ccs

d

W+

B0 decay

*

cscbVVA

K0 mixings

d s

d

KK pq /

iep

q 2~

i

tdtd eVV no direct CPV, no CPV in mixing

Sa

me

fo

r a

ll ccK

0ch

an

ne

ls

Beside Vtd all other CKM elements are real

1CP

β)sin(2)Im(

1

CP

CP

24

Account for direct CP Violation

tmtme

tfB

tmtme

tfB

d

CP

dCP

CP

CP

t

CP

d

CP

dCP

CP

CP

t

CP

B

B

cos2

1sinIm

2

1

1))((

cos2

1sinIm

2

1

1))((

22

2

/

0

22

2

/

0

0

0

25

...))(())((

))(())(()(

CPCP

CPCPCP

ftBftB

ftBftBtA

00

00

CP Asymmetry in B0 J/ Ks

)sin(1

)(2)cos(

1

1

)()(

)()()(

22

2

mtmt

fBfB

fBfBtA

f

f

f

f

CPCP

CPCPCP

f

ff

A

A

p

q 2sin)( ff

Direct CP violation CP violation through

interference

0B

CP Asymmetry if no direct CPV

27

tmftBftB

ftBftBtA d

CPCP

CPCPCP sinsin

))(())((

))(())(()( 2

00

00

tmetfB

tmetfB

d

t

CP

d

t

CP

B

B

sinsin))((

sinsin))((

/

/

21

21

0

0

0

0

Steps of the CP measurement

K

B Meson & Vertex Reconstruction0

SK

/J

Start /StopB-flavor Tagging &

Vertex Reconstruction

t measurement

CPB

tagB

)4( s

mz 250

0B

Now: CP eigenstate

28

29

Decay B0 Ks

B0 D*+ -fast

D0 +soft

K- +

Ks

+ - + -

B0

e+ e- (4S) B B

BABAR Experiment (SLAC, USA, 1999-2008)

at t=0: BCP = B0

BCP

Btag

CP Violation in B0 Ks

30

7%

0120028068702 ...sin

mtACP sinsin~ 2

PRD 79, 072009 (2009)

BELLE experiment

(KEK, Japan, 1999-2010)

0170031064202 ...sin

PRL 79, 031802 (2007)

535 Mio. B B

BB-rate: 13 Hz

BB – events: 470 Mio. 6750 B0 / B0 Ks

B0B0

Trigonometrie

31

oo 90021 .. %).(..sin 53023067202

With BABAR/BELLE difficult:o19

2473

o44

2489 .

.World average.

http://ckmfitter.in2p3.fr/

Experimental Status

Constraints

only from loops

Within uncertainties loop-processes well described by SM.

New Physics effects only appear corrections to leading SM terms.

32

Flavor Violation beyond the SM

33

220)( NP

W

SMBSM

c

m

cXqb AA

Effects of New Physics*) at = O( EW) on B decays can be treated in a

low-energy “effective theory” approach (similar to Fermi-theory).

New Physics in flavor changing amplitudes:

“CKM”

factors

Loop-factors

In most general case NP has generic flavor structure!

*) electroweak

b su, c,

tb sX

Y

Experiments tell us that NP around the EW scale should be MFV.

B Physics with LHCb

34

Contents:

• B production at the LHC

• B event signature

• Detector properties

• Key measurements

b s= Looking for corrections to corrections

and other future B experiments

35

B Production at the LHC

pp collisions at s = 7, 10, 14 TeV

Correlated forward production of bb

B , B0, Bs, Bc, b …

L ~ 2 x 1032 cm-2 s-1 (tuned at LHCb)

• ~ 1012 bb events / year (2 fb-1)

• 50 kHz bb-events in LHCb

Charged particle multiplicity ~30 / unit of rapidity

inel ~ ( 0.89, 0.95, 1 ) 100 mb

bb ~ ( 0.44, 0.67, 1) 500 b

bb Production

bb

pp

b

b

1x 2xp

p

b

b

B Physics & LHCb Detector

LHCb:

• Forward, single arm spectrometer, 1.9 < < 4.9

(bb pairs correlated, mainly forward)

• Excellent vertexing and particle ID (K/ separation)

• “high” pT triggers, including purely hadronic modes,

very flexible

• Luminosity tuneable by adjusting beam focus:

run at L ~ 2 1032 cm–2s–1 n 0.5

100 b

230 b

36

Rate of multiple interactions (MHz)

Luminosity x1032 cm-2 s-1

b Hadron

Typical Event

37

Bs

-

K-

+

-

-

+

K-

K-

Simulíertes Ereignis

2 m

• Decay length L typical ~ 7 mm

• Decay products with p ~ 1–100 GeV

• K/ Separation

• Trigger on “low pt” particles (similar to backgr)

B factory versus Hadron Maschines

38

LHC / Tevatron = “b” (not only B) factory:

B0, B+, Bs, Bc, b-baryons ~ 40 : 40 : 10 : 0.1 : 10 %

PEP-II, KEK-B TeVatron LHC

prod 1 nb ~100 b ~500 b

typ. rate 10 Hz ~50 kHz 100…1000 kHz

purity ~1/4 bb/ inel 0.2% bb/ inel 0.6%

pile-up 0 1.7 0.5-20

B content

B boost small, ~0.56 large, decay vertices are displaced

event structure pair alone many particles non-associated to

prod. vertex Not reconstructed reconstructed with many tracks

tagging/mixing coherent incoherent flavour tagging dilution

bb

B B 50% , B0B0

50% B 40% , B0 40% , Bs 10% , Bc 1% , b baryons 10%

BBSee )(4 TeV2sXbbpp TeV14sXbbpp

Vertex Reconstruction

Bs Ds(K K )

K-

+

K+

50 m

150 m

440 m

mm7L

Proper time resolution

ss DB0

~ 40 fs

ctL

39

Lp

Mct B

mL 160

fsct 36

CDF: ~100 fs

(momentum uncertainty

negligible)

40

Trigger

Calorimeter

Muon system

Pile-up system

Level-0 Hardware: (4 s)

“High pT“ , e, h, signatures

1.1, 2.8, 3.6, 2.6 GeV

40 MHz 1 MHz

PC Farm:

Higher Level

Trigger

Readout2 KHz

Disk

B events look

very much like

minimum bias

Rather modest pt values only modest rate reduction

41

Higher Level SoftwareTrigger

Storage (event size ~ 35 KB)

1. Confirmation of trigger signature

using tracking information (1 ms/track)

+ track impact parameter information

~ 30 KHz

2. Global event reconstruction:

inclusive & exclusive selections

Higher Level Trigger (Software)

Computing Fram ~ 10000 CPUs

~ 30 KHz

w/r to “offline” selection tot 1…3%

42

B meson key measurements at the LHC

LHCb – Key Measurements

43

sB sB

0B 0K

sd,B

Bs mixing phase s b s penguins

ACP (Bs J/ )Bd K*

Bd K*

Very rare FCNC proc.

Bd,s

CKM angle B

0D

ubV

KB DK

Bs – Mixing: Amplitude and Phase

44

Access to the 2nd

Unitarity TriangleRe

ss

s

3

*

A

VV tbub 3

*

A

VV tdud

3

*

A

VV tsus

22

21

0VVVVVV *

tbub

*

tsus

*

tdud

Im

s argVcb*Vcs

Vtb*Vts

~ 2 ~1o

(ut)

Bs Mixing Phenomenology

0

0

22221212

12121111

0

0

0

0

22

22

s

s

s

s

s

s

B

B

im

im

im

im

B

B

B

B

dt

di

**

H

Bd Bs

m=mH-mL 0.5 ps-1 17.8 ps-1

= H- L O(0.01)· d O(0.1)· s (*)

s,d22 )arg( tdtbVV ststbVV 22 )arg(

0sB

0sB

b

s

s

bt

t

tsVtbV

tsVtbV

In SM

small:

0.04

45

Bs Mixing Measurement

46

Bs Ds- +

Bs Ds+ -

tmtBNtBN

tBNtBNtA s

mixedunmixed

mixedunmixedmix cos~

)()()()(

)()()()()(

Bs

PV+

Ds-

-

K-

K+

B flavor tagging B

Problem w/ neutral B’s

(no coherence)

Signal B

(flavor specific decay)

Necessary Tool: B Flavor Tagging

Tag Tag (%) w (%)eff (%)

Muon 6 32 0.8

Electron 3 32 0.4

Kaonopp 15 36 1.3

Vertex Charge 44 42 1.1

Frag. kaon (Bs) 26 35 2.4

Combined B0 (decay dependent:

Combined Bs trigger + select.)

4.2

6.2

B0

Bs D

K-

b

b

s

u

s

u

Bs

+

Signal B (same side tagging)

Tagging B (opposite tagging)

• lepton

• kaon

• Vertex charge

• Fragmentation kaon near Bs

Dilution

form

oscillation

if B0

Mistag rate

Dilution D=(1-2w)

Effective Tagging Power

eff= TagD2

47

LH

Cb

-Pub

-20

09

-029

Effect of mistags on mixing

))(())((

))(())(()(

tBNtBN

tBNtBNtA

)()()21())(())((

))(())(()21(

))(()1)()(())(()1)()((

))(()1)()(())(()1)()((

))(())((

))(())(()(

tADtAtBNtBN

tBNtBN

tBNtBNtBNtBN

tBNtBNtBNtBN

tBNtBN

tBNtBNtAmeas

)(),( BNBN

)21(D

Observed asymmetry w/ wrong tag fraction

Observed number of events of given flavor

Tagging “dilution”: =50% D=0

no measurement possible

BtB )( 0

Dilution

(1-2 )

Sensitivity and Tagging Power

Statistical error of asymmetry

)()( BNBNNTotal event number fixed

)()(

)()(

BNBN

BNBNA

Statistical error calculated according binominal distribution (A or notA):

2/12)1(1

AN

A

Tagging efficiency: NNN

2/12))(1(1

measmeas AN

A

Wrong tag fraction: ADAmeas

We are interested in A and

therefore also in the error of A measAD

A1 ND

Astat2

1~

= effective tagging power

qqN

q

N

Nq

pNNqN

qNN

B

B

B

)(

)(

,

11

1

Effective Tagging Power

2DNNeff

%

%

Finite Proper Time Resolution

)(tP),,(/t

t ttGe

ct

Dilution:2

2

ctsmD

ctexp~

Affects the observed asymmetry: Aobs = Dct A

Statistical Significance of Mixing Asymmetry

53

2exp

2)(

22

1

2ct

tag

stat

m

S

BS

DSA

Background:

shape and level

from side-bands

Sstat

1~

With background:

Only signal:

2

1

1

S

BS

Sstat ~

Statistical significance including all tagging/resolution/background:

Bs Mixing

LHCb expects 80k Bs Ds events in 1 yr

Bs Ds

2 fb-1 (1 yr) of data

ms=20 ps-1

Bs changes its flavor about ~9 times until it

decays: need an excellent proper time

resolution to resolve the mixing

(LHCb ~40 fs)

Observation of Bs mixing is basis for time

dependent CP asymmetry measurements.

54

CDF:

ps

ps..)( -1

syststat

100

070100

ct

sm-1ps.)( 0060sstat m

Bs Mixing at Tevatron

55

CDF

-1ps)syst.(.)stat.(.. 0701007717sm

tmDA scos:Fit

CP Violation in Bs J/

56

A

ieA ~sie

2

CPJ )/(sB

sB

))(/())(/(

))(/())(/()(

tJBtJB

tJBtJBtA

CPsCPs

CPsCPsCP

/)B(B ss JProblem: is not a pure CP state

)/sinh(cos)/cosh(

)sin()sin(

222

2

tt

mt

sf

sf

Bs J/

Vector mesons w/ JPC=1--

J/ is admixture of CP states:

L = 0,2 CP = + 1

L = 1 CP = - 1

Angular analysis to separate CP +/-1 states:

Decompose decay amplitudes in term of

linear polarizations.

LCP )1(

Bs J/

KK

58

Transversity Basis

• Decompose decay amplitudes in term of linear polarization,

when J/ and are:

–A0: longitudinally polarized (CP-even)

–A┴: transversely polarized and ┴ to each other (CP-odd)

–A||: transversely polarized and ║ to each other (CP-even)

• 3 angles , ϕ, ψ describe directions of final decay products

J/ → , →K+K

Angular Distributions

Angular and proper time distribution

CP=+1

CP= -1

Experimental Status (Tevatron)

61

EPS 2009

# Bs (CDF) ~ 3200 (2.8 fb-1)

WNew

PhysicssB sB A.Lenz, U.Nierste

))Im()Re(( qqSMNPSM iAA

LHCb Prospects for s

#Evts (2fb-1) B/S tag(%)

117k 2.0 6.2

MC Studie für 50 pb-1

A. Bien

20

10

20

11

63

CKM Angle

IndirectDirect

measurement

• A lot of pioneering work

from B factories

• No significant constraint

from direct

measurements yet

64

from B DK tree decays

i

ubub eVV ||Tree decays:

0

0

( )

( )Bi i

B

A B D K

A B D Kr e e

fD

fD

Principle of the “ in trees” measurement:

Cabibbo favored and suppressed decay amplitudes of

the B- (B+) can interfere in case that the D0 and D0

decay into the same final state fD.

Several methods are proposed and have

already been explored at the B factories.

65

from B DK Tree Decays

GLW (Gronau,London,Wyler) method:

fD is a CP eigenstate, fD= K+K-, + -

ADS (Atwood,Dunietz,Soni) method:

Common flavour state fD=(K+ –)Note: D0→K+ – doubly Cabibbo suppr.

= 11 …13 (2 fb-1)

= 10 (13o) ampl.model/binned fit

GGSZ (Giri,Grossman,Soffer,Zupan):

Use Dalitz decays

= 11 …13 (2 fb-1)

B( ) 0 45 90 135 180

( ) 4.6 6.1 5.7 6.0 4.3

Combined 2fb-1)

LHCb-2008-031

)(KD/D s

00

Mode Yield (2 fb-1) B/S

B D (fav.) 84k 0.6

B D (sup.) 1.6k 0.6

B D( 8.5k 1.2

B D( )K 3k 3.2

B D(Ks )K 6.8k 0.4

ADS/GLW

GGSZ

66

from Tree Sensitivity

Combination:

B D0K

B0 D0K*0

Time dependent: Bs Ds B0 D

B (o) 0 45 90 135 180

for 0.5 fb-1 (o) 8.1 10.1 9.3 9.5 7.8

for 2 fb-1 (o) 4.1 5.1 4.8 5.1 3.9

for 10 fb-1 (o) 2.0 2.7 2.4 2.6 1.9

Tree Level Processes

2o …3o reachable after 5 yr

LHCb-2008-031

CKM Metrology and LHCb

67

stat = 2…3o für L = 10 fb-1 (5 J)

(sin2 )stat 0.01

stat 4.5 ofür L = 10 fb-1

Mit LHCb Daten*) L = 10 fb-1 (5 J)

*) +Verbesserung von Gitterrechnungen.

68

and very rare decays

A.Lenz

Penguin

B Xs Challenge for any NP model

69

Constraints from observed BR on

Type II 2-Higgs Doublett Models:

Br 10-4

(Br)

Probe photon polarization:

Bs events:

From time dependent decay rates:

= amount of wrong pol. photons

Test models w/ RH currents

LHCb: 12k (2fb-1)

LHCb: ( ) 0.11

Misiak et al. PRL (2007)

70

B0 K*

Standard Model

7O109 OO

Corresponding Wilson coefficients Ci describe short-range physics.

New Physics in Wilson coefficients Ci = CiSM + Ci

NP or new operators.

Effective Theory

Operator Product Expansion

Sensitivity of Angular Observables

71

Angular observables offer a powerful test bench for any New Physics model

Observables: l, K, , m2

AFB(q2) ~ - Re C10* [ C7eff + (q2) C9

eff ]

forward-backward asymmetry:

q2

SUSY

72

B0 K* - Experimental Status

B0 K* events:

(4.4 fb-1)

LHCb expectation for 2 fb-1

~7000 events w/ B/S~0.25

~450 evts

700 events for 200 pb-1

Poor agreement with SM.

LHCb data will clarify.

BELLE arXiv:0904.07770

384 M BB

657 M BB

BABAR PR D79:031102

73

B0 K* - Prospects

100 pb-1

Example:

LHCb sensitivity for early data

(assume BELLE values for AFB)

1) Simple Counting

2) Full angular fit

s [GeV2]

2 fb-1

10 fb-1

20 GeV5.0)(s

20 GeV28.0)(s

AF

B(s

)

Very Rare Decays - Bd,s

74

Large SUSY

contributions

possible

SM: BR(Bs μ+μ-)= (3.2 0.2)x10-9

BR(Bd μ+μ-)= (1.0 0.1)x10-10

sdB ,

w/ non-universal Higgs mass (NUHM)

Constrained MSSM

Buchmüller et al., 2009

LHCb Prospects for Bs

75

2

2

~

td

ts

d

s

V

V

)(B

)(BR

BB

For ~150 pb-1 LHCb expects to

reach the final Tevatron sensitivity.

Ratio is sensitive test for MFV

MFV

SM

Experimental status: CDF 2009

BR(Bs → μ+ μ-) < 4.3 10-8 95% CL

BR(Bd → μ+ μ-) < 7.6 10-9 95% CL

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

10

CDF +D0 (8 fb-1

)

CDF (3.7fb-1

)

BR

(Bs

0->

+- )

(x10

-9)

L (fb-1)

@ 3.5 + 3.5 TeV

SM prediction

3 Evidence

5 Observation

Conclusion

76

“Imagine if Fitch and Cronin

had stopped at the 1%

level, how much physics

would have been missed”

A.Soni