CPV in B → D () K () ( and B → D K ) in BaBar and Belle

Maria Różańska, INP Kraków

HEP2003 Europhysics Conference –Aachen, July 18th 1

CPV in B → D(*) K(*) (and B → D K )in BaBar and Belle

Outline:

• CPV in B→D(*)Xs

• theoretical ideas

• experimental issues

• experimental results

B∓ → D(*)0 K(*)∓

B0 → D(*)0 K(*)0

• some other approaches

• summary



CPV in B → DXs

Φ3(γ )≡ arg(-VudV*ub/

VcdV*cb)

Φ3(γ )≡ arg(-VudV*ub/

VcdV*cb)

VcdV*cb

VtdV*tbVudV*

ub

Φ3(γ)

Φ2(α)

Φ1(β)

CPV in interference between b→c & b→u

B → DXs is a good place to look

A 'A

theoretically clean: only tree diagrams

theoretically clean: only tree diagrams

interference between

B →D(*)0 K( Xs) ⊕ B→ D(*)0 K(Xs)

f

experimentally challenging:

sensitive to

experimentally challenging:

sensitive to AA

r'



D→fCP ( Gronau, London & Wyler

method)

2

DDD

00

CP

δ - relative strong phase

A(B-→D0K-)

δ

2Φ3

δ

2A(B+→DCPK+)

A(B-→D0K-)= A(B+→D0K+)

2A(B-→DCP

K-)

A(B+→D0K+)

amplitude triangles

amplitude triangles

extensions and modifications

various f

various Xs , (D)

many observables ...

statistics required:

∼ 0.5 ab-1

Ways to measure Φ3 in B→DXs

PROBLEMS:

r = A(B-→D0K-)/A(B-→D0K-) ~ 0.1(0.2)

A(B-→D0K-) difficult to measure directly



Experimental issues

*2B

*2beambc pEM

ΔE (B-→D0h-)

E -49 MeV for

DK-

075.0tan)πD(B

)KD(BR 2

2

2K

-

--

Cf

f

B

B

Use beam constraints

to reconstruct B:

Use beam constraints

to reconstruct B:

Apply tight

K-ID cut:

Apply tight

K-ID cut:

*beam

*B EEE

Mbc(GeV)

K/ separation

Babar : dE/dx in SVT & DCH, DIRC

Belle: dE/dx in CDC, TOF, ACC

≥2.5 (K/) separation up to 3.5 GeV

K/ separation

Babar : dE/dx in SVT & DCH, DIRC

Belle: dE/dx in CDC, TOF, ACC

≥2.5 (K/) separation up to 3.5 GeV



Experimental issues

Continuum suppression: multidimensional cuts exploiting event topology (Fox-Wolfram moments, thrust...) angle of B-flight direction...

Continuum suppression: multidimensional cuts exploiting event topology (Fox-Wolfram moments, thrust...) angle of B-flight direction...

Background suppression from other B decays depends on specific final states: veto for some B-decays, ....

Background suppression from other B decays depends on specific final states: veto for some B-decays, ....

Signal extraction: Maximum likelihood fits with signal shape from MC and data control samples, background from side bands and off-resonance data (combinatorial), MC (B-decays)

Signal extraction: Maximum likelihood fits with signal shape from MC and data control samples, background from side bands and off-resonance data (combinatorial), MC (B-decays)



PreliminaryB- → D0 h-

measurements

56 fb-

1

56 fb-

1

D0 →KD0 →KD0 →KD0 →KD0 →K0D0 →K0

E(GeV) E(GeV) E(GeV)

±±

±0.2)%(8.31 0.35 ±0.6 )% (7.7 0.9 ±

0.7)% (9.9 1.3 ±

)πD(B

)KD(BR

0-

-0-

BB

CLEO, hep-ex/0302026 15.3 fb-1

Babar, hep-ex/0207087 56 fb-1

Belle, PRL 87,111801(2001) 10.4 fb-1

h- identified as K

h- identified as K

Signal extracted wit ML fit to the E,Mbc,PID(/K)

For other B→D(*)K- modes see Belle, PRL 87,111801(2001)



B-→DCP K-

81.2 fb-181.2 fb-1

Preliminary

2211

32

1,2 coscosδ21

RARA

R

Φrr

32

31,2 coscosδ21

sinδsin2

Φrr

Φr

A

D1DCP=+ D2DCP=-D1DCP=+ D2DCP=-

B D1K

D1 = KKD1 = KK

D1 = D1 =

E(GeV)

24.27.2

Observables:asymmetries

branching ratios

Observables:asymmetries

branching ratiosD01,2

1,2 R/RR

)f(Bf)(B

)f (Bf)(B-

-

f

B BB B

A

3 independent equations with 3 unknowns (Φ3 ,r, )

3 independent equations with 3 unknowns (Φ3 ,r, )

2

/R

/R

fBfBf

DKD

D0DKD

1,2

00

1,21,2

B

BB

BB

= 0.17 ± 0.23(stat) ± 0.08(sys) = 1.06 ± 0.26(stat) ± 0.17(sys)

1A

1R



B-→DCP K-

D1=KK, D1=KK,

D2=Ks, Ks, Ks, Ks, Ks’ D2=Ks, Ks, Ks, Ks, Ks’

78 fb-178 fb-1

hep-ex/0304032

179.615 165.414.5

25.06.5 22.16.1

20.55.6 29.96.5

Signal yields extracted with a likelihood fit to the E

= -0.19 ± 0.17(stat) ± 0.05(sys) = 1.41 ± 0.27(stat) ± 0.15(sys) 2A

2R

= 1.21 ± 0.25(stat) ± 0.14(sys)

= 0.06 ± 0.19(stat) ± 0.04(sys) 1A

1R

sin2(Φ3 )≤

r 1/4 | |

sin2(Φ3 )≤

r 1/4 | |

1,2R

21 -RR



Similar analysis can be performed with K*- replacing K-

Similar analysis can be performed with K*- replacing K-

88 fb-188 fb-1

Preliminary

coshel from P→PV

No indication for non-resonant DK

MK*-

D0 → K, K,K 0D0 → K, K,K 0

= -0.02 ± 0.33(stat) ± 0.07(sys) = 0.19 ± 0.50(stat) ± 0.04(sys)

1A

2A 4-*0- 10))0.6()(0.55.2()KD(B sysstatB

B-→DCP K*-

(6.1 ± 1.6(stat) ± 1.7(sys)) x 10-4 CLEO

13.14.34.4.3

D1=K+K-, +D1=K+K-, +

D2=Ks, Ks, KsD2=Ks, Ks, Ks

7.23.6 2.4



B → D*0 K*- ALL

81.2 fb-

1

81.2 fb-

1

PreliminaryB- → D*0 K*- B→V V can be also used,

angular analysis required,

B→V V can be also used,

angular analysis required,

D*0 → D0 0 D*0 → D0

)KDB(**0B

(8.0 ± 1.0(stat) ± 1.2(sys)) x 10-4 (7.7 ± 2.2(stat) ± 2.6(sys)) x 10-4 CLEO



both amplitudes are color suppressed r ~ 0.4

both amplitudes are color suppressed r ~ 0.4

B0 → D0 K(*)0

B0 → D0 K*0 , K*0 → K+- (kaon tags B0

flavour)

rates and asymmetries B0 → D1,2 K*0 ⇒ Φ3

isospin relations ⇒ extract Φ3 and

B0 → D0 K0s , B0 – B0 mixing

time dependent asymmetries

(B0-decay vertex needed)



78 fb-178 fb-1 B0 → D0 K(*)0

PRL 90, 141802 (2003)

M(D0) sidebands

27.07.3

41.08.4

E

5000

5*000

10))0.6()(1.35.0()KD(B

10))0.5()(1.14.8()KD(B

sysstat

sysstat

B

B

50*0*0

50*00

50*0*0

50*00

100.4)KD(B

108.1)KD(B

109.6)KD(B

106.6)KD(B

B

B

B

B

90% CL

Vub.

08.013.0)KD(B

)KD(B

10.025.0)KD(B

)KD(B

*-0

0*00

-0

000

BB

BB

04.022.0)D(B

)D(B2-0

000

BB



PDGPDG

| |||

||

5000

50*00

4-*0*-

4-*0-

4-0-

10))0.6()(1.35.0()KD(B

10))0.5()(1.14.8()KD(B

10))1.2()(1.08.0()KD(B

10))0.5()(5.02.5()KD(B

10)6.073.()KD(B

sysstat

sysstat

sysstat

sysstat

B

B

B

B

B 347±20 @ 78 fb-1 D K 360±20 @ 56 fb-1 D K

70±10 @ 88 fb-1 D K

10±4 @ 78 fb-1 D K

15±5 @ 78 fb-1 D K

Summary of Br’s, event yields, .....



Some other approaches

Atwood,Dunietz, Soni (ADS):

use doubly Cabibbo-suppressed D decays

Dalitz plot analysis of BDK

BDK, Dalitz plot analysis of multibody D decays

( e.g. DKs+-)

................

f)KD(B

f)K(DBallowedsuppr.

suppr.allowed

r ~ 1, Br ~ 10-7

b c b u

uu

us

cu

us

u u u u

Both amplitudes are color allowed

Both amplitudes are color allowed



Summary and outlook

No direct CPV observed in B→DXs, no direct constraints on Φ3

yet,

but there is a steady progress:

new relevant decay modes observed:

B- → D K(*)- D→fCP, CP=+,-

B0 → D K(*)0

o other analyses in progress

accelerator performance

KEKB: Lpeak>1034cm-2 s-1 PEP-II: Lpeak>61033cm-2 s-1

o Belle and BaBar aiming for ≈ 0.5 ab-1 in 2005

some meaningful constraints on Φ3 possible by that time

new theoretical ideas

precise measurements in D sector ........

CPV in B → D () K () ( and B → D K ) in BaBar and Belle

Documents

Transcript of CPV in B → D () K () ( and B → D K ) in BaBar and Belle

CPV in B → D (*) K (*) ( and B → D K ) in BaBar and Belle

Documents

Transcript of CPV in B → D (*) K (*) ( and B → D K ) in BaBar and Belle

CPV in B → D () K () ( and B → D K ) in BaBar and Belle

Transcript of CPV in B → D () K () ( and B → D K ) in BaBar and Belle