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T Violation in Baryonic B Decays

Chao-Qiang Geng ( 耿朝強 ） National Tsing Hua University (Taiwan) ( Int. Conf. on QCD and Hadronic Physics , Beijing, June. 16-20, 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.

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T Violation in Baryonic B Decays

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  1. Chao-Qiang Geng (耿朝強） National Tsing Hua University (Taiwan) (Int. Conf. on QCD and Hadronic Physics, Beijing, June. 16-20, 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 ● The work was done with Dr. Y.K. Hsiao.

  2. 1. Motivation: K system: indirect (ε) and direct (L) B system: mixed induced (BJ/s)+ direct (BK) CP violation K system: indirect (ε) B system: ? T violation 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

  3. ☺Three-body charmless baryonic B decays: → ● Large BRs: Br(B→BB’P) >> Br(B→BB’) ● 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!

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

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

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

  7. The CKM parameters: The weak phase γ: PDG, Phys. Lett. B592 (2004) 1. γ=600 (,)=(0.20,0.35) At the scale mband Nc=3:

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

  9. C. Q. Geng and Y. K. Hsiao, arXiv:hep-ph/0503264. Using the generalized factorization method: Amplitude:

  10. T-odd TPC asymmetries in the standard model

  11. ●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% c. The final state interactions have been ignored (see H.Y.Cheng’s talk) d. An interesting mode: ● The indirect (mixing-induced) CP asymmetry: sin 2β ● The direct (rate) CP asymmetry: ACP = O(1%) ● The direct T asymmetry: AT= O(1%) Too small

  12. 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. In the standard model ♦ They are accessible at the current B-factories. ♣ They could be the first measurable direct T violating effects.

  13. Thank you! 謝謝！

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

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

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