Electroweak B DecaysElectroweak B Decays

T. Yoshikawa ( Nagoya )

Possibility of Large EW Penguin Possibility of Large EW Penguin contribution contribution

FPCP2004 Oct. 4 – 9, EXCO, Daegu, Korea

This talk is based on S. Mishima and T.Y. hep-ph/0408090 This talk is based on S. Mishima and T.Y. hep-ph/0408090

and T.Y. Phys.Rev. D68, 054023 (2003) .and T.Y. Phys.Rev. D68, 054023 (2003) .

B decaysB decays

ＴＴｒｒｅｅｅｅ

QCDQCD ＰＰｅｎｇｅｎｇｕｉｎｕｉｎ

CColor olor suppressed suppressed

treetree

EElectrolectroWWeakeak

PPenguin (enguin (PPEWEW))

AAnnihilatinnihilationon SSinglet QCD inglet QCD

PenguinPenguin

CColor suppressed olor suppressed

EWEW PPenguinenguin

((PPCCEWEW ))

Gronau, Hernandez,London, Rosner

b

B decaysB decays

ＴＴｒｒｅｅｅｅ

QCDQCD ＰＰｅｎｇｅｎｇｕｉｎｕｉｎ

CColor olor suppressed suppressed

treetree

EElectrolectroWWeakeak

PPenguin (enguin (PPEWEW))

AAnihilationnihilationCColor suppressed olor suppressed

EWEW PPenguinenguin

((PPCCEWEW ))

Main Contributions Main Contributions T , P T , P

usually

Negligible Negligible ContributionsContributions PPCC

EW EW , , AA

How should we treat How should we treat PPEWEW, C ?, C ?

Discrepancies between TH Discrepancies between TH and EXand EX

K - Puzzle

The direct CPVs are almost zero !! BUT the indirect CPV Ss are

How about the differences among these b-s penguin modes ?

Relations among the Relations among the branching ratiosbranching ratios Relation among Direct CP Relation among Direct CP asymmetriesasymmetries

Large BLarge B Branching ratio Branching ratio 00

CP asymmetries : B K0 (b-s penguin type modes ) vs B J/ K0

We discuss what happens in B and decays .

Fleischer-Mannel, Neubert-Rosner, Lipkin, Buras, … T.Y., Gronau - Rosner, Buras-Fleischer et al , Li, ……. Many works.

KK - -

PuzzlePuzzle KK - -

PuzzlePuzzle Experimental data do not satisfy several relations among the branching ratios.

Before ICHEP04

Theory

Experimental

There were quite large discrepancies.There were quite large discrepancies.

Before ICHEP04

After After ICHEP0ICHEP044

What What changed ?changed ?

KK - -

PuzzlePuzzle KK - -

PuzzlePuzzle 1) Experimental data do not satisfy several relations among the branching ratios.

After ICHEP04

Still remaining the Still remaining the discrepancies !!discrepancies !!

KK - -

PuzzlePuzzle KK - -

PuzzlePuzzle 2) There seems to be a discrepancy in direct CP asymmetries of Bdirect CP asymmetries of B K K ..

After ICHEP04

Theoretically,

Exeimental data,

Is the relation among the Acp s violated ?

We have to know what makes the We have to know what makes the discrepancies! discrepancies!

Do we still need large EW Penguin Do we still need large EW Penguin contribution ?contribution ?

Diagram Decomposition of B Diagram Decomposition of B K Kand and

Hierarchy in B Hierarchy in B K K

ＴＴｒｒｅｅｅｅ

QCDQCD ＰＰｅｎｇｅｎｇｕｉｎｕｉｎ

CColor olor suppressed suppressed

treetree

EWEW PPenguin enguin ((PPEWEW))

AAnnihilatinnihilation on ((EExchangexchange))

CColor suppressed olor suppressed

EWEW PPenguinenguin

((PPCCEWEW ))

Gronau, Hernandez,London, Rosner

b

Large

Small

They are rewritten as follows:

where r is the ratio of each diagram with QCD Penguin, and X is the strong phase difference.

where r is the ratio of each diagram with Tree contribution, and X is the strong phase difference. A (Exchange) and PC

EW are neglected here.

Hierarchy Hierarchy AssumptionAssumption

ＰＱＣＤ

in B in B K K

O(0.1)

O(0.01)

Hierarchy Hierarchy AssumptionAssumption

in B in B

O(0.1)

negligible

Branching ratios under the Branching ratios under the assumptionassumption

by neglecting r2 terms including rC, rcEW , rA (smaller terms than O(0.01 ). )

Fleischer-Mannel bound

We can find several relations We can find several relations among them. among them.

Some relations among the Some relations among the branching ratiosbranching ratios

These relation seems to be proportional to r2 so that they should be O(0.01) quantities .

=0 or not ?

Branching Branching ratios ratios

Rough estimation under assumption

~ 1 ?

Experimental dataExperimental data

> 0.1 > 0.1

1.04

+ + = 2 = 2

- = - = 00

=

=

=

Do we need large EW penguin Do we need large EW penguin contribution ? contribution ?

Relations

1

1

0.14

From the 1 From the 1 bound of Rbound of Rcc-R-Rnn, S, R, S, R++ -2 with -2 with rrTT = =0.2 0.2

We may still need slightly large EW penguin contribution. To discuss more detail, we need the information about strong phases.

If flavor SU(3) sym. is good, EW

and will be constrained by ACP .

Consider about direct CP asymmetries !! Consider about direct CP asymmetries !!

What can we expect

No strong phase difference between tree and EW(Z) penguin

bbWWzz

us

K

K BB

1)

2)

3)

under SU(3) symmetry. Because the diagrams are topologically same.

tree

EW Penguin

Neubert-Rosner,

Buras and Fleischer

Direct CP asymmetries in B in B K K

Relation among the CP asymmetries :

Large EW Penguin ? Or Still early Large EW Penguin ? Or Still early ? ?

Cos T > 0 is favored. T should be around 20o.

Fleischer-Mannel bound

-0.114 0.020

as a function of T with rT = 0.2 .

CPA T should be around 20o or 1

50o

T

++

Maximum bound of Rc-Rn under constraints from ACP and R with rT = 0.2 .

We still need large EW penguin contribution and large strong phase difference.

is disfavored.

How about B ?

where .

It seems to be difficult to explain by only It seems to be difficult to explain by only EW penguin EW penguin

because it will be sub-leading because it will be sub-leading contribution.contribution.

To explain the large ratios, we need

1) To suppress the denominator . with

2) Larger rP

<<

00 00

Large may be possible if there is SU(3) breaking effect between b-s P and b-d Penguins . BUT the magnitude will be constrainted from B KK (pure b-d penguin ) modes.

d

s

sK

K

Pure b-s penguin

Pure b-d penguin

At largest, At largest, PP is 1.5 times is 1.5 times larger. larger. We can not take so large .

How about B ?

where .

It seems to be difficult to explain by only It seems to be difficult to explain by only EW penguin EW penguin

because it will be sub-leading because it will be sub-leading contribution.contribution.

To explain the large ratios, we need

1) To suppress the denominator . with

2) Larger rP

3) Larger (color suppressed tree )

Or New Physics ??New Physics ?? with new CP phase

Before considering about New Physics, review the contribution from Before considering about New Physics, review the contribution from rrCC . .

An example: EWC =

Relaxing the hierarchy assumptionRelaxing the hierarchy assumption = keeping = keeping rr22CC terms terms in

The lower bound of rC to satisfy Rc-Rn, S, R+ -2 at 1bound.

s are free parameters

2) EWcase

If large is allowed, it may explain the discrepancies. Chiang-Gronau-Rosner-Suprum

But it seems to be too largetoo large though it is color suppressed tree-type contribution.

The usual estimation is 0.02 .

Charn ｇ -Li

ConclusionConclusion The allowed region of The allowed region of rrEWEW should be larger than about 0.2 should be larger than about 0.2 . . Still remaining the discrepancies !Still remaining the discrepancies ! Large strong phase differences are needed. Large strong phase differences are needed. SU(3) breaking ?SU(3) breaking ? As a possibility, we need to consider Large As a possibility, we need to consider Large rrc case also. c case also. Direct CP asymmetries will be more important to understanDirect CP asymmetries will be more important to understan

d d which is the origin of the discrepancies. which is the origin of the discrepancies. To keep , need new CP phase in To keep , need new CP phase in

Penguin type diagrams. Penguin type diagrams. Or LargeOr Large r rcc case. case.

If PEW is including New CP Phase, the effect must appear in CP asymmetries, Acp00 and SK

0

or

+

+

Large

SU(3) breaking

Possibility of New Physics ?

or