Determining From

Ying Li

Institute of High Energy Physics, CAS

DBs

Outline

Introduction Proposition Summary

Introduction

Measuring the angle gamma is one of the most important work in LHC-b.

Angle gamma is very sensitive to new physics contributions.

Compared with alpha 、 beta, gamma is still not measured precisely now.

Many methods have been proposed to measure this angle.

What about LHC-b ?

• LHC-b experiment will provide us Bs data. Using these data, how will we determine the angle gamma?

Similar to above cases, we can use the channel Bs->Ds K, Bs->Ds Pi.

How about others?

BsD Pi

The mixing of Bs and Bs

If the experiments can give the normalized time-dependent decay rate of this decay.

1. These five parameters can be determined!

2. From above equation, we can get R.

3. Using the last equations, we can solve out the weak phase and strong phase without any uncertainty.

• If the Standard Model is correct theory,

If the experiments tell us that :

New Physics?

This method is applicable

We do not worry that R is too small, which is about 1.8.

PQCD approach tells us these branching ratios are at order of 10^-6, which should be measured in LHC-b.

We can use this channel check the results from decay Bs->DsK.

summary

Some knowledge about CKM are reviewed.

We proposed one new channel to measure angle gamma.

We hope hear from good news from LHC-b.