WIN-03, Lake Geneva, WisconsinSanjay K Swain Hadronic rare B decays Hadronic rare B-decays Sanjay K Swain Belle collaboration B - -> D cp K (*)- B - ->

WIN-03, Lake Geneva, Wisconsin Sanjay K SwainHadronic rare B decays

Hadronic rare B-decaysSanjay K Swain

Belle collaboration

•B- -> DcpK(*)-

•B- -> D(KS+-)K- Dalitz analysis•B -> •B -> K(*)

•Conclusion

OutlineV ud

V ub

VcdVcb

Vtd V

tb*

*

*

3()

2()

1()


Using B-DCPK- mode (GLW method)•B- DCPK- where DCP = (D0 D0 )

•A(B-DCPK-) |A(B-D0K-)|+|A(B-D0K-)|ei ei

•A(B+DCPK+) |A(B+D0K+)|+|A(B+D0K+)|e-i ei

When D0 D0

CP-even states (D1): K+K- , + - CP-odd states (D2): KS 0, KS , KS , KS , KS ’

2

1 ¯

3

3

commonfinal state

¯

¯

PLB 253(1991)483PLB 265(1991)172

}Color-favored

b

uu

cu

K

DB

-

-

--

-

o }uu

c

K

D

B-

--

-

Color-suppressed

Vcb

Vub-

s

}s

o}3=arg(Vub

) u

-

*b


GLW method cont…..

3

A(B+ D0K+)A(B- D0K-)

A(B+ D0K+)

A(B- D0K-)

A(B+ DCPK+)

A(B- DCP

K-)

=

Reconstruct the two triangles 3

—

-3

One can measure 3 even if =0( without strong phase)

Non vanishing strong phase ( 0) Direct CP violation


GLW method cont…

Solution: One can instead measure

R1,2 = R /RDCP Dnon-CP

= 1 + r2 2r cos()cos(3)

where R DCP B (B- D1,2K-) + C.C

B (B- D1,2-) + C.C=

A1,2 = B (B- D1,2K-) B (B+ D1,2K+)

B (B- D1,2K-)

-

+

2r sin()sin(3)

3 independent measurements 3 unknowns r , , 3 (solve it)

But A1R1 = - A2R2

1 + r2 2r cos()cos(3)B (B+ D1,2K+)

=

Amp(B- D0K-) 0.1 x Amp(B- D0K-)

Also B- D0[K+-]K- has same final state as B- D0[K+-]K- (DCSD)

But

_

_

r = |BKD|/|BKD|_


Kinematics to identify signal•Candidates are identified by two kinematic variables

Beam constrained mass (Mbc)= (E2beam-pB

2) Energy difference ( E) = EB - Ebeam

•But @(4S) peak energy: 24% BB 76% Continuum (qq, q =u, d, c or s)

KEKB operates here

–

We use continuum suppression variables -> LR( CosB , Fisher)

-


Results (78 fb-1) B D B D K

Flavorspecific

CPeven

CP odd

6052 88

683.432.8

648.331

347.521

47.38.9

52.49

134.414.7

15.66.4

6.35.0

E E


Double ratios(R1,2) and asymmetries(A1,2)

R1 = 1.21 0.25 0.14 and R2 = 1.41 0.27 0.15

A0 = 0.04 0.06(stat) 0.03 (sys) ( non-CP mode)

A1 = +0.06 0.19(stat) 0.04 (sys) ( CP + mode)

A2 = - 0.18 0.17 (stat) 0.05(sys) ( CP – mode)

We cannot constrain 3 with these statistics.

25.0 6.5 22.1 6.1

20.5 5.6 29.9 6.5

EE

CPeven

CPodd

( r2 = 0.31 ± 0.21 , just 1.5 away from physical boundary)

r = |BKD|/|BKD|_


B-D0K*- mode (90 fb-1 data)

Signal MCdata

Works exactly same way as B- -> DCPK- decayLook for CP asymmetries and double ratios -> constraint 3

169.5±15.4

16

Flavor specific modes


B-DCPK*- mode

Can not constraint 3 with this statistics -> need more data

CP asymmetries : A1 = -0.02 ± 0.33(stat) ± 0.07(sys)

A2 = 0.19± 0.50(stat) ± 0.04(sys)

13.1 ± 4.3

4.3

7.2 ± 3.6

2.4

CP-even

CP-odd


B±D(KS +-)K± Dalitz analysis(140 fb-1)

In case of B- DCPK- where DCP =(D0 D0 ) both D0 and D0 decays to CP eigenstates ( K+K-..)

One can write the total amplitude for B+ DK+ :

Amp(B+ ->DK+) = f(m+2,m-

2 ) + r. ei(

3 + ) f(m-

2 , m+2 )

(B- decay amplitude can be written similar way : -> ,3 -> -3)

m+2(m-

2) -> squared of invariant mass of KS+

(-)combinations f -> complex amplitude of D0-> KS+- decay

f( m+2,m-

2) = ak. ei Ak(m+2,m-

2) + b ei

-> both 2-body resonances and non-res component

--

D0K0

D0K0 D0KS


Suppose all D0K0 decays are via K*

D0K*

KS

D0K*

KS

M(KS )2

M(KS )2 Dalitz plot

interference

Simple example


D0KS

K*

KS

KS

KSf2

reality is more complex(& better)

many amplitudes &strong phases(13)lots of interference


Fit results for D ->KS +- decay

Resonance Amplitude Phase

K*-(892)+

KS0

K*+(892)-

KS

KSf0(980)

KSf0(1370)

KSf2(1270)

K*0-(1430)+

K*2-(1430)+

K*-(1680)+

KS1(M=535±6 MeV, =460±15

MeV) KS2(M=1063±7 MeV, =101±12

MeV) Non-resonance

1.706 ± 0.0151.0(fixed)0.136 ± 0.0080.032 ± 0.0020.385 ± 0.0110.49 ± 0.041.66 ± 0.052.09 ± 0.051.2 ± 0.051.62 ± 0.0241.66 ± 0.090.31 ± 0.046.51 ± 0.22

138 ± 0.90 (fixed)330 ± 3114 ± 3214.2 ± 2.3311 ± 6341.3 ± 2.3353.6 ± 1.8316.9 ± 2.184 ± 10217.3 ± 1.4257 ± 11149 ± 1.6


B B+

B±D(KS +-)K± Dalitz analysis

Fit Dalitz distributions for B+ and B- decay simultaneously-> r , 3 , as free parameters

Use D0KS to make Dalitz-plot model fit 58K events with 13 amplitudes

Select B±K± D0(KS events 107 ± 12 events in 142 fb-1 Belle data

Form Dalitz plots for B+ & B



Weak phase 3 = 950 ±250(stat) ±130 (sys)±100

strong phase = 1620 ±250(stat) ±120(sys) ±240

(3rd error is model uncertainty) r = 0.33 ± 0.10(stat)

@90% C.L :0.15<r<0.5 ,610<3<1420, 1040<<2140

3

r

3

r = |BKD|/|BKD|_


B -> +0 mode(first observation)data used:78 fb-1

B(B+ -> +0) =(31.77.1(stat) 6.4(sys) 2.1(pol))x10-6

ACP(B -> 0) = (0.1 ±22.4(stat)

±2.8(sys))%

First observation of charmless vector-vector mode

0

+

0

+

B+

B+

u

b

d

-

W

--

-

u

u

u

u

u

b

d

u

u

-

-

W

Z/

EWP


Helicity analysis

0 momentum requirement

final state is vector-vector system -> give S ,P or D wave

Both longitudinal and transverse polarization are possible

Longitudinal pol. ratio , = (94.810.6(stat) 2.1(sys))%

L

fit result


B ->K(*) (78 fb-1) BF’s

- -b

s

u

-

Penguin

Mode BF x 10 -6

K+

K0

K*0

K*+

9.4 ± 1.1 ± 0.79.0 ± 2.2 ± 0.710.0 ± 1.6 ± 0.86.7 ± 2.1 ± 1.0

s

s

u

W

u , c, t---136±15

35.6±8.4

58.5±9.1

8±4.311.3±4.5

Vts


B -> K* (78 fb-1) polarizationK+

|A0|2 = 0.43 ± 0.09 ± 0.04|A |2 = 0.41 ± 0.10 ± 0.04 (CP odd and CP even states) andarg(A ) = 0.48 ± 0.32 ± 0.06arg(A ) = -2.57 ± 0.39 ± 0.09

T

T

=

Distribution of decays->A0 , A , A , tr , , tr T =

K*

Ax -> complex amplitudes

Amplitudes are determined byunbinned max likelihood fit:

z tr


Summary

•Now we have better measurement on CP asymmetries and ratio of BF’s in B- -> DCPK- mode

• Constrained 3 using Dalitz analysis of B- -> D(KS+-)K- decay

• Measured the branching fractions and different helicity amplitudes in B -> mode.

• Measured the branching fractions and helicity amplitudes in B -> K(*) mode

• Lot more other hadronic rare B-decays……..


MC with3 = 70o

B+ / B


~2.4σ separation

B

B+


Fit Dalitz distributions for B+ and B- decay simultaneously-> r , 3 , as free parameters


KEKB Accelerator

Two separate rings

Finite crossing angle

Ldesigned= 1034 cm-2s-1

Achieved:

Lpeak > 1034 cm-2s-1

Integrated Luminosity

~ 158 fb-1

Ee = 3.5 GeV

Ee = 8.0 GeV

+

-


Detector Performance

K/ separation is done using:

ACC, TOF, dE/dx( CDC)

PID(K) =

Wide momentum range

L(K)

L(K) + L()


Background Suppression•Variables to distinguish signal from continuum events

CosB

•Event Shape variable: (Fisher) BB : SphericalContinuum: back-to-back(jet-like)

–

Be+ e-

B

CONTINUUM

SIGNAL


CosB Fisher

Likelihood ratio

Background Suppression

Signal

Continuum


Main question: “Is V unitary” ?

Three generation quark mixing matrix(V)

V =

tbtstd

cbcscd

ubusud

VVV

VVV

VVV

3 = arg(V* )ub

(Also known as )

VudVub+ VcdVcb+ VtdVtb = 0

Orthogonality of 1st and 3rd column gives:

* **a

b

-b

= arg( )a-b

*–3 = arg( )VcdVcb

VudVub*

V udV ub

VcdVcb

Vtd V

tb*

*

*

3()

2()

1()

Documents

WIN-03, Lake Geneva, WisconsinSanjay K Swain Hadronic rare B decays Hadronic rare B-decays Sanjay K Swain Belle collaboration B - -> D cp K (*)- B - ->