Measurements of the angles of the Unitarity Triangle at B A B AR Measurements of the angles of the Unitarity Triangle at B A B AR PHENO06 Madison,15-18

Measurements of the angles of the Unitarity Triangle

at BABAR

Measurements of the angles of the Unitarity Triangle

at BABAR

PHENO06Madison,15-18 May 2006

PHENO06Madison,15-18 May 2006

On behalf of the BaBar CollaborationOn behalf of the BaBar Collaboration

Francesco PolciUniversita’ degli Studi di Roma “La Sapienza” & INFN Roma

Francesco PolciUniversita’ degli Studi di Roma “La Sapienza” & INFN Roma

1)1(2

1

)(2

1

23

22

32

AiA

A

iA

tbtstd

cbcscd

ubusud

CKM

VVV

VVV

VVV

V

0*** tbtdcbcdubud VVVVVVUnitarity of VCKM

Unitarity Triangle

*

*

argcbcd

ubud

VV

VV

*

*

argcbcd

tbtd

VV

VV

*

*

argubud

tbtd

VV

VV

The CKM matrix and the Unitarity TriangleThe CKM matrix and the Unitarity Triangle

The Standard Model explains the CP violation through

the matrix VCKM

1 Francesco PolciUT Angles Measurements at BaBar

2

Improving measurementImproving measurement

Francesco PolciUT Angles Measurements at BaBar

0ρρB

πaB 10

ρaB 10

BABAR [PRL95, 041805 (2005),232M BB]

Up to now the best channel

for determination is: ρρB0

68% 90%

)sin(2sin tmA effCP

Measuring in b → uud transitionsMeasuring in b → uud transitions

Penguin contribution cannot be neglected (see which is pure penguin).

That is why what we measure is eff !


)( 0 KBBr

is measured analyzing the decays: ,,0 B

• Recently a proposal of determination of penguin effect in from SU(3) related decay , which should reduce the theoretical error on (hep-ph/0604005).

• An isospin analysis allows to estimate the penguin contribution. 0B

0*KB

• The decays B are related by SU(2), thus we have isospin relations between amplitudes A+-, A+0, A00

• states can have I = 2 or 0, but gluonic penguins only contribute to I = 0 (I = ½ rule). But +0 is pure I = 2, so only tree amplitude |A+0| = |A-0|

Gronau and London, Phys. Rev. Lett. 65, 3381 (1990)

eff


The isospin analysisThe isospin analysis

~100% longitudinally polarized:New measurement of NEW

05.004.096.0)( 0 BfL

60 10)8.25.22.17()( BBr

09.014.010.0)( 0 BACP

)(230 BBM

D

9.2


New approaches: from a1? New approaches: from a1?

NEW

NEW

611

0 10)5.19.16.16())3(()( aBraBBr

Search for B0 → a1(1260)+

B0 → a1(1260)+

Interesting by itself since: - Little is known about the a1

- Can test of factorization

Signal has been observed!

– Background to – (in principle) sensitive to

)%90(@1061))3(()( 611

0 CLaBraBBr

)(218 BBM

)(218 BBM

hep-ex/0603050


Status of Status of

= (99 +12 – 9 )0 (direct measurement, HFAG)

= (91.9 ± 5.5)0 (indirect UTfit prediction from the other UT bounds)

Up to now, if we combine all world measurements (BaBar+Belle), we can determine the Standard Model solution for like this:

sssbsddb ,


Measurements of Measurements of 00 JB

00*0 KKB

0', KKKKB Lss

ss KρKB ,

sKDDB **

)( 'KB

',' 0)(B023.0040.0722.02sin

BABAR [PRL94, 161803 (2005),227M BB]

But B→J/KS is the cleanest mode!

Both theoretically:

and experimentally (large branching ratio and clean signature).

)sin(2sin)( tmtA fCP

Charmonium: Charm (and charmonium): Penguin dominated:sccb dccb

Many modes to measure :

06.026.021.0

04.030.068.0

10)17.022.094.1()( 500

C

S

JBBr

)(232 BBM

The color-suppressed tree has same weak phase as J/KS.

The b →d penguin has a different weak (and strong) phase respect to the tree.

• Penguin pollution causes deviations in the values of C and S parameters respect to J/Ks .

• Also a way for a model independent constraint on the penguin dilution within charmonium modes.


The b→d penguin pollutionThe b→d penguin pollution

UPDATE

00 JB

hep-ex/0603012

New Physics could contribute in the loop.

They are small effects, here more easily detectable since Tree is missing or negligible.

0000000

0 ),,,,,,( KKKKKfB SS

Look for sin2 ≠ 0 in many modes:

sin

sin2


The b→s penguins: sin2effThe b→s penguins: sin2eff

Theory prefers

Examples of QCD factorization:Beneke - PL B620, 143 (2005)Cheng,chua,soni - PRD72, 094003 (2005)Experimental: J/mode

Experimental: penguin modes

Complicated analysis since:– f0/ overlap, BB background– Color-suppressed tree, but sin2 expected to be

small

B0

B0

Asy

mm

etry

25.041.064.0

26.052.017.0

S

S

K

K

C

S

600 10)4.00.12.6()( KBBr 02.051.0 35.0

39.0 S

03.055.0 28.026.0

C


New results for sin2effin b→s penguinsNew results for sin2effin b→s penguins

Other searches:

: first measurement ! 00sKB

00 KB UPDATE

)%90(@1031)''( 600 CLKBBr )%90(@1025)''( 6 CLKBBr

NEW

)%90(@1014)( 60000 CLKKKBBr LSS

)(232 BBM

NEW

hep-ex/0603040

61.09.03.08.0

00*000*0 10)2.0()()( KKBBrKKBBr CLS

K%[email protected]

It is a penguin

Allows to interpret and to put a bound on its S.

sdsb

sKB 0


:other searches:other searchesSearch for 00*0 KKB

Searches for ',' 0)(B

• Can reduce theoretical uncertainty of Color Suppressed tree amplitudes for ’Ks decays in SU(3)-based analysis

[Gronau,Rosner,Zupan PLB596,107(2004)] )%90(@101.2)'( 600 CLBBr

)%90(@107.1)'( 60 CLBBr )%90(@103.1)( 600 CLBBr

Search for )( 'KB

Confirmed from Belle.

No signal for (unexpected). IKB

KB

NEW

NEW

NEW hep-ex/0603013

hep-ex/0603054

KKKDB ssoCP ),(

DKB

)2(0*aDB s

(*)(*)DDB

KDDB ss ,

0(*)0(*)0 KDB

DDB ,(*)0


Measurements of Measurements of

BABAR [PRL95, 121802 (2005),227M BB]

Best method to determination:

)( 00 sKDKDB

A

0)11132867(

If common final state to D0 and D0

( )

( )B

A b ur

A b c

_suppressedfavored

A(b→u)

A(b→c)

interference

BBCP rDKBDKB

DKBDKBA sinsin

)()(

)()(

strong phase

weak

phase Critical parameter:

2

)( 000 DD

DCP

sKD 0

(only2ambiguities)

Three methods:

D0 CP modes(GLW)

D0 to common flavor state (ADS)

D0 Dalitz (GGSZ)


from DK decays from DK decays

04.013.006.0

04.013.035.0

05.010.086.0

04.012.090.0

CP

CP

CP

CP

A

A

R

R

12.040.026.0

08.019.008.0

08.026.065.0

11.040.096.1

CP

CP

CP

CP

A

A

R

R

( ) ( ) 2 sin sin

( ) ( )CP CP

CP CPCP

CP

B BB D K B D K

B D K B D K

rAR

02( ) ( )

1 2 cos cos( )

CB B B

P PCP

CB D K B D K

B D Kr rR

4 observables (ACP+-,RCP+-) for three unknown (rB, , B):

KDCP0KDCP

0

New from BaBar: added D0 KS, KS

2

131 CP+

148 CP-


Some issues:

•B → D background

• D0CP have small BRs

• 8 ambiguities

New results for the GLW Method New results for the GLW Method

NEW

)(232 BBM

hep-ex/0512067

c0B

db

u

d

*D

h

Vcb

V*ud

d

b

c

d

0B u

*D

h0B

u,c,t

u,c,t

V*ub

Vcd

Favored SuppressedInterference and

B0 mixing

To consider tag-side CP violation, fit for:

a = 2r sin(2) cos () c= cos(2) [2r sin()+2r’sin(’)] b = 2r’ sin(2) cos (’)

Extract result from a, clep and:


sin(2) from B→D(*) sin(2) from B→D(*)

+30% theoretical error on r(Due to use of SU(3) simmetry and W-exchange neglection)

r(D) = 0.019 ± 0.004r(D*) = 0.015 ± 0.006r(D) = 0.003 ± 0.006

90% CL

68% CL

Frequentistconfidence level

Small CP asymmetry (r~0.02)!

|sin(2+)| > 0.64 (@ 68 % C.L.)|sin(2+)| > 0.42 (@ 90 % C.L.)

UPDATE

)(232 BBM

hep-ex/0602049

(*)

(*)

)/(

)/((*)0

(*)0

sD

D

cs

cdsD f

f

V

V

DBBR

DBBRr

6 sigma

5 sigma

Decays proceeding through W-exchange diagrams.

Allows a more precise estimation of the theoretical

error on r from SU(3)-related decays Ds(*)

But DsK smaller than before, so smaller rD and less sensitivity!

50 102.03.03.1 sDBBr

5*0 104.05.00.2 KDBBr s

50 104.04.05.2 KDBBr s

5*0 105.06.08.2 sDBBr

B0→Ds*and B0→ Ds* K observations. B0→Ds*and B0→ Ds* K observations.


KDDB ss**0 ,

First observations for )(230 BBM

hep-ex/0604012 NEW

0*00 KDB 0*00 KDB Vcb

Vub

5000 10)3.07.03.5()( KDBBr500*0 10)3.02.16.3()( KDBBr

CLKDBBr %[email protected])( 50*00

50*00 10)3.07.00.4()( KDBBr

r < 0.4 @90%CL

000 KDB 00*0 KDB


Charge correlation allows to tag the B0:

You can distinguish Vub from

Vcb and measure r!

But no Vub observed…

sin(2) from B0→D(*)0K(*)0 sin(2) from B0→D(*)0K(*)0

NEW

NEW

)(226 BBM

hep-ex/0604016

KDB )2460(*0

600 1019 KDBBF

KDB 00 KDB 00

600 1091588 KDBBF

)892(0*00 KDB

52

0 1019 aDBBr s


Two other approaches for Two other approaches for

)%90(@ CLUnfortunately, didn’t find b u!

- Strong phase difference accessed through Dalitz plot, so 8-fold 2-fold ambiguity.

B DK

- b ucs decay includes color-allowed diagrams, so (possibly) large CP-violating effects.

- Self-tagging.

- First step: search for the (b u) SU(3)-related decays Ds

(*)a0(2)

- Due to form-factor suppression in B a0(2)X, favored and suppressed amplitudes become comparable.

B D(*)a0(2)

50

*0 106.3 aDBBr s

50

0 109.1 aDBBr s

52

*0 1020 aDBBr s

:%90@ CL

)(226 BBM

)(230 BBM

NEW

NEW

hep-ex/0509036

hep-ex/0512031

Again, Vub component is missing!


Status of Status of

= (65 ± 20)o & = (-115 ± 20)o

Combining all direct world measurements (BaBar+Belle):

• Angles measurements are still being performed at BaBar both updating old results to the full available dataset and exploring new methods.

• Some satellites measurements have been performed, which provides a better understanding of old results.

• This field is sensitive to new physics effects, expecially in the penguin diagrams

• Measurements of the angles of the Unitarity Triangle contribute to the precise determination of the allowed region in the plane.• More results are expected to come in the future.


Conclusions Conclusions

Documents

Measurements of the angles of the Unitarity Triangle at B A B AR Measurements of the angles of the Unitarity Triangle at B A B AR PHENO06 Madison,15-18