b decays beyond the standard model

B Decays Beyond the Standard ModelB Decays Beyond the Standard Model

Xiao-Gang He

NTU

1. Introduction2. B to K pi and pi pi3. B to phi Ks and B to K* gamma decays4. Same sign diplepton decays in B–barB mixing5. Discussions

1. Introduction “Rare B decays are good probes of new physics beyond the Standard Model.”

Is there any confirmed experiments need new physics beyond the minimal Standard Model?

Yes, but not in B decays. Neutrino Oscillations!

What is the situation in B decays?There are some indications. Time dependent.

Why then new physics?

CP violation in B to phi KsCP violation in B to phi Ks _227M BB [hep-ex/0408072]

_275M BB [hep-ex/0409049]

“sin21” = 0.50 0.25 A = 0.00 0.23 0.05

Not confirmed. Need More DataNot confirmed. Need More Data

“sin21” = 0.06 0.33 0.09 A = 0.08 0.22 0.09

It is wrong to average different modes which have different It is wrong to average different modes which have different sources of contaminations. sources of contaminations.

There are deviations from both QCDF and pQCD compared with data. There are deviations from both QCDF and pQCD compared with data. But large hadronic uncertainties prevent clear statements about new But large hadronic uncertainties prevent clear statements about new physics. However, new physics cannot be ruled out.physics. However, new physics cannot be ruled out.

B to pi pi and K pi

B to Xs gamma, K* gamma

There are many other processes also show deviations from theoretical calculations,

polarization in B to phi K*…. All need to be further confirmed from experiments.

There are large theoretical uncertainties in the SM for some processes, such as B to K pi, pipi,

and polarization in B to phi K*. Difficult to make clear cut statements about NP. But then try to

see if NP can improve the situation and take them as evidences.

There are certain processes for which SM predictions are “free” from hadronic uncertainties,

such as B to Xs gamma, CP in B to K* gamma and B to phi Ks. Good probes for NP.

Recently Belle has also tried to measure the same sign dilepton decays in B—barB

Mixing with

Also a good probe for new physics.

What NP?

There are many models, needs new physics in the flavor sector. Take SUSY as illustration.

( 0.13 0.60 0.56)% Belle

N NN N

Flavor changing interaction in the SM

c1=1.081, c2=-0.190, c3=0.014, c4=-0.036, c5=0.009, c6=-0.042c1=1.081, c2=-0.190, c3=0.014, c4=-0.036, c5=0.009, c6=-0.042c7=-0.011/137, c8=0.060/137, c9=-1.254/137, c10=0.223/137c7=-0.011/137, c8=0.060/137, c9=-1.254/137, c10=0.223/137c11=-0.151, c12=-0.318c11=-0.151, c12=-0.318

SUSY gluonic dipole interactionSUSY gluonic dipole interaction

ratio of gluino mass to

squark masse

C11,12= C(susy), C’11,12 change delta(LR) to delta(RL)

Neglect small contributions from c7 and c8 (He and McKellar, Neglect small contributions from c7 and c8 (He and McKellar, hep-ph/0410098)hep-ph/0410098)

2. B to K pi and pi pi 2. B to K pi and pi pi

With 4 K pi branching ratios and CP in K- pi+

P = 1, Solutions

Fit all K pi data

chi-square-minimal 5

With 3 pi pi branching ratios and CP A, S in pi+pi- Solutions

Fit with K pi, pi pi branching ratios and CP in K-pi+

chi-square-minmal 8

Fit with all data

chi-squae-minmal 22

• QCDF and pQCD cannot account for data in B to K pi , pipi. Improvements needed.

• Problem with SU(3) ? SU(3) breaking…• Problem with data? Need improved data• New physics?

Tree? (R-parity violation…)

Strong penguin? (SUSY, Left-Right model…)

Electroweak penguin (SUSY, Left-Right mode…)

SUSY gluonic dipole contributions to B to K piSUSY gluonic dipole contributions to B to K pi(He, Li and Yang, hep-ph/0409338)(He, Li and Yang, hep-ph/0409338)

Constraints from B to Xs gamma on SUSY Constraints from B to Xs gamma on SUSY parameters parameters

(He, Li and Yang, hep-ph/0409338)(He, Li and Yang, hep-ph/0409338)

3. B to phi Ks and B to K* gamma3. B to phi Ks and B to K* gammaTime dependent CP violation in these decays are very good probes for

NP beyond the SM.

In the Standard ModelIn the Standard Model

S(J/psi Ks) => sin(2beta) = 0.726S(J/psi Ks) => sin(2beta) = 0.726S(phi Ks) => sin(2beta)S(phi Ks) => sin(2beta)

SUSY gluonic dipole contributions to B to phi KsSUSY gluonic dipole contributions to B to phi Ks

Barbar Belle Barbar Belle

(He, Li and Yang, hep-ph/0409338)(He, Li and Yang, hep-ph/0409338)

B to K* gamma to Ks pi0 gammaB to K* gamma to Ks pi0 gamma

Babar Belle

4. Same sign dilepton decays in B-barB 4. Same sign dilepton decays in B-barB (Sanda) (Sanda)

5. Discussions and conclusions5. Discussions and conclusions• There is no immediate needs of New Physics from current B decay

data. But can constrain NP.

• There are some indications in B to K pi, pi pi decays, (and other hadronic decays). There are large hadronic uncertainties to make clear cut sttaements about NP. Need further improvement both in theoretical calculations in the SM and data. But NP can improve the agreements of theoretical results with data.

• There are many B decays where hadronic uncertainties can be eliminated, such as CP violations in B to phi Ks, K* gamma, and same sign dilepton decays in B-barB mixing. NP can change the SM predictions. Good probeds for NP.

• More data are coming. A bright future ahead. Many models beyond SM need to be examined, such as susy, R-parity violating susy, left-right, little higgs, ... Models.

谢谢 !