2. C.Q. Geng ( 耿朝強） National Tsing Hua University ( The 3rd Int. Conf. on Flavor Physics, NCU, Oct. 3-8, 2005) T Violation in Baryonic B Decays Outline 1. Motivation 2. T-odd triple product correlations 3. T violating effects in baryonic B decays 4. Summary ● Work done with Dr. Y.K. Hsiao.

3. 1. Motivation: CP violation K system: indirect (ε) and direct (  L  ) B system: mixed induced (B  J/  s )+ direct (B  K  ) T violation K system: indirect (ε) B system: ? CPT Theorem: CP violation ⇔ T violation ● To look for direct T violating effects in B system in the standard model Goal: → To test the SM and find out New Physics

4. → ☺ Three-body charmless baryonic B decays: ● Rich spin and momentum structures: many T-odd correlations can be constructed! ● Measurable Λ polarization: Λ→pπ ● T violating effects in the SM are accessible at the current B-factories! ● Large BRs: Br(B→BB’P) >> Br(B→BB’) See HY.Cheng’s Talk

5. 2. T-odd triple product correlations (TPCs) T-odd asymmetry TPC asymmetry with the conjugate process Weak Strong phase δ=0 → ≠ 0 (maximal) Unlike the direct CP asymmetry: → 0 if δ=0

6. 3. T violating effects in baryonic B decays Using the generalized factorization method: C. Q. G.+Y.K. Hsiao PRD72:037901,2005 Chua, Hou,Tsai, PRD66 (2002) 054004. Chua,Hou, Eur. Phys. J. C 29 (2003) 27.. (see Hsiao’s talk)

7. Four components of Λ spin: Three polarization directions: The longitudinal, normal and transverse Λ polarizations: The Integrated transverse Λ polarizations:

8. The CKM parameters: The weak phase γ: At the scale m b and N c =3: PDG, Phys. Lett. B592 (2004) 1. γ=60 0  ( ,  )=(0.20,0.35)

9. To observe T violating asymmetries of 10—7% at 2  level Need ~ ♥ The SM effect For the rate CP asymmetry: Too small to be observed! ☺ It is accessible at the current B-factories and could be the first process to observe direct T violating effect!!!

10. Using the generalized factorization method: Amplitude: C. Q. G + Y. K. Hsiao, PLB619:305,2005.

11. T-odd TPC asymmetries in the standard model

12. ● Some Remarks: a. Nonfactorizable effects are small for and b. The errors due to the CKM and other fitting parameters are expected to be less than 10% d. An interesting mode: ● The indirect (mixing-induced) CP asymmetry: sin 2β ● The direct (rate) CP asymmetry: A CP = O (1%) ● The direct T asymmetry: A T = O (1%) Too small c. The final state interactions have been ignored (see C.K.Chua’s talk)

13. 4. Summary ♠ The triple momentum correlations in baryonic B decays are unique observables to search for T violation. ♥ There are many possible three-body baryonic B decays in which T violating effects can be large. ♦ They are accessible at the current B-factories. ♣ They could be the first measurable direct T violating effects. In the standard model

14. Thank you! 謝謝！

16. ● Calculation the decay branching ratio Matrix elements and form factors:

17. Input parameters: QCD counting rules: The effective Wilson coefficients (WCs):