Reaching for (present and future)

Andrey GolutvinITEP/Moscow

Unitarity TrianglesUnitarity Triangles

Bd0

Bd0

Bd0 DK*0

BS0 DSK

Bd0 D*

BS0 DS

Bd0 J/ KS

0

BS0 J/

This talk

= arg | |-V cd Vcb*

V ud Vub*

There are a few methods of determining

CP violation in DecayCP violation in Interference of

Mixing & Decay

• Rates and asymmetries in K Decays

• Amplitude triangles for B Dcp0K

(GLW method) + extensions/modifications

• Time dependent asymmetries

in Bd+- and BsK+K- decays assuming U-spin symmetry

•Time dependent flavor tagged analysis of

BsDsK- decay

BdD*+ decay

Data Samples(present and future)

Results presented today are based on 81.2 fb-1(BaBar) and 78 fb-1(BELLE)That corresponds to 88 and 85 mln BB pairs (part of data sample)

Statistics available today at B-factories 300 mln BB pairs

In 2006 one expects 1.2 bln BB pairs

In 2008 after 1 year of LHCb (and BTeV) operation 1012 bb pairs

Super Bd-factory: 1.5 to 5 bln of “clean” BB events

depending on achieved luminosity

-

-

-

-

-

KSignificant interference oftree and penguin amplitudes

fromfrom B B K K decays decays

Expect potentially large CP asymmetries

Difficulties:

Theoretical• EW penguins• SU(3) breaking + (FSI) effects

Experimental• small BF, qq background• Particle ID is crucial

Measurement of the ratios of

BF and ACP may provide

constraints on and strong

phase

dir

_

QCD penguins play the dominant role

Summary of BFs [10-6] From J.D. Olsen talkat the CKM workshop 2003

Present precision is dominated by statistical errorsIn a few years statistical and systematical errors should become comparable

Comparison of BF

No sign ofrescattering yet

A Specific Model: QCD Factorization

Inconsistent?

Data (2001)

Data (2003)

Beneke et. al., Nucl. Phys. B606, 245 (2001)

Data start to constrain models

Largest deviations: 2 each in K+(BaBar), BaBar), and K+(Belle)

CP asymmetries(allows one to eliminate dependence on the strong phase )

•In a few years statistical precision in the measurementsof Branching Fractions (BK/) should reach the levelof systematic error, 2-4% depending on decay mode

• Extraction of will be dominated by theoretical

uncertainties

BaBar: K0+

80 fb-1In 1 year BTeV expects:

4600 K0+ events (with S/B = 1)62100 K-+ events (with S/B=20)

CP-even states: K+K-, +-

CP-odd states: Ks0, Ks, Ks, Ks, Ks’

GLW method

B- DCPK- where DCP=(1/2)(D0 D0 )

A(B- DCPK-) |A(B- D0K- )| + |A(B- D0K- )|eiei

A(B- DCPK+) |A(B- D0K+ )| + |A(B- D0K+ )|e-

iei

Amplitude triangles

can be extracted from the reconstruction of two triangles

Experimental problems:

A(B-D0K-) is small squashed triangles

DCSD lead to the common final states for D0 and D0

(color suppressed A is of the same order as color favored DCSD)

R1,2

=

BF(B-

D1,2K-)

BF(B-D1,2-)

BF(B-D0K-) BF(B-D0-)

/

/

Experimental observables:

, A1 and A2

allow, in principle, to extract RDK- , and

R1=(7.41.70.6)%(8.310.350.20)%

BaBar reconstructed

D1K-

K+K-

AD1K- = 0.170.23+0.09-0.07

BELLE studied both D1K-and D2K-

R1 = 1.21 0.25 0.14

R2 = 1.41 0.27 0.15

AD1K-= +0.06 0.19 0.04AD2K-= -0.18 0.17 0.05

No constraints on possiblewith this statistics …

Needed: significantly higher statistics precision measurements of D Branching Fractions

Two comparable color-suppressed amplitudes

BF(B0 D0 K0) = (5.0 0.6) 10-5 +1.3-1.2

+1.1-1.0BF(B0 D0 K*0) = (4.8 0.6) 10-5

_ _

_ _

Hope to see soon B0 D0 K*0 decay

Present Upper Limit is

BF(B0 D0 K*0) 1.8 10-5

Triangles are not as squashed

as in B DK case

B0D0K(*)0 Mode

BELLE

ADS variant of the amplitude triangle approach:

B- D0[fi] K- and B- D0[fi]K

-, fi= K-+ or K-+0

Use large interference effects

Experimentally challenging since BF of O(10-7) are involved

Dalitz plot analysis of D KS+ - for B-DK-

and B+DK+ decays

KS+- receives contributions from:

B- D0K- D0K*-+ K*- KS-

B- D0K- D0K*+- K*+ KS+

B- D0K- D0KS0 0 +-

B- D0K- D0KS0 0 +-

Enough information to extract for any magnitude of

B0D*- Mode

d

c b

u

d

b

d

__

_

_

_

_

d d

c

u

d

B0 B0_

D*-

D*-

+

+

favored suppressed

(2 + ) is extracted from the measurement of4 time-dependent asymmetries

RD* can be estimated using BF(B0Ds+-):

BF(B0Ds+-)

BF(B0D*-+) fDs2

fD*2tan2c

RD*2

Suppressed/favored < 10-2 Small CP-violating effect expected

Time evolution:

(BD*) (1+RD*2) (1-RD*2)cos(mt) 2 RD*sin(2+) sin(mt)

Evidence for B0Ds+-

Br(B0Ds+-)Br(Ds++)

BaBar (1.13 0.33 0.21)x10-6

BELLE (0.86 0.11) x10-6 +0.37-0.30

BELLE have measured Br(Ds++)=(3.720.39 ) x10-6

using full/partial reconstruction method

+0.47-0.39

RD* 0.022 0.007

20 fb-1, 6970 ± 240 events

B0 = 1.510 ± 0.040 ± 0.041 ps30 fb-1 , 3430 ± 80 events

m = 0.509 ± 0.017 ± 0.020 ps-1

D*+- Data Samples (partial reconstruction)

(sin(2+)) 0.15 for 1000 fb-1 T. Gershon (CKM workshop, 2003)

or (2+) 10o

Two decay modes with comparable amplitudes, 10-4 each

can be determined from the measurement of 4 time-dependent

asymmetries (assuming that is fixed from Bs mixing)

fromfrom BBss D D--s s KK+ + , D, D++

s s

KK--

Looks as most clean method to measure

Same principle as for B0D*-

Since is small sensitivity should not depend on the value of

Contribution from NP is unlikely !

BBss DDssDDssK K kinematics kinematics

at LHCbat LHCb

Bs K

K

, K

Ds

Dsmass (GeV)

~ 6.5 MeV/c2 = 168

m= 418 m

72k Ds

8k Ds K

Bs vtx resolution (mm)

Ds vtx resolution (mm)

Needed:

Hadronic trigger

K/separation

Good proper time resolution

Importance of Particle ID

Assumptions:

• 3k tagged BsDsK-

• 30% background• 30% mistag

Sensitivity slightly depends onstrong phase difference (T1/T2)

and xs

LHCb:

() 10º for xs = 15

() 12º for xs = 30

In one year of LHCb running:

8k BsDsK reconstructed events

BTeV: () 8º

from Bfrom B(s)(s) K KK Kproposed by R. Fleischer

Measure time-dependent asymmetries in B0 +- and Bs K+ K-

decays to extract

where dexp(i) is a function of T and P amplitudes

Assuming U-spin flavor symmetry: d=d’ and =’ can be extracted

from Bfrom B(s)(s) K KK K

dirCPA

mixCPA Evaluation of and sensitivity

from time-dependent measured asymmetry

B0 + - BS K+ K-

yield 27k 35k

B/S 0.8 0.55

xq 0.755 20

D2 0.064 0.064

-0.30 0.16

0.58 -0.17

0.0 0.0

dirCPAmixCPA

input values

BB0 0 ++ -- BBSS K K++ K K--

02

sinh2

cosh

)sin()cos()(

A

xAxAA

mixCP

dirCPth

CP

BB0 0 ++ --

BBSS K K++ K K--

BBSS K K++ K K--

increasing xs

In one year of LHCb operation :

Sensitivity to :

assuming 4 years of data taking

(4x27k Bd and 4x35k BsKK)

B/S = 0.8 and 0.55 correspondingly

tagging: D2 = 6.4%

Combining allinformation:

() = 2.50

(A dir ) (A mix ) 0.054

(A dir ) (A mix ) 0.043

Conclusions

can be measured both using CPV in decay (time-integrated) and in the interference of mixing and decay (time-dependent)

(1) Theoretically clean: b c X Amplitude triangles BsDsK

(2) Experimentally easier b hh (h = non-c) Experimental precision on BF already below 10% level

Clear theoretical strategy how to extract is still missing

Measurement of rare decays with BF 10-7could help

Only trees

Trees + loops

(1) vs (2) Sensitive probe for New Physics

ACP=ACP(dir)cos(mt) + ACP(mix)sin(mt)

—sumBdKBsKK

Bd

BsK

/K/KK/K separation:Inv. mass ~ 20 MeV/c2Kinematical variablesdE/dX Md << Ms

RunIIa: ACP(dir, mix)~0.2 (Bd) ~0.1 (BsKK) () = ±10(stat)

Expectations from CDFRun IIa