| 日時: |
2005-08-04 14:00 - |
| 場所: |
研究本館２階２２０号室 |
| 会議名: |
Study of Three-body Baryonic B Decays |
| 連絡先: |
丹後 |
| 講演者: |
Dr. Shang Yuu Tsai (Academia Sinica) |
| 講演言語: |
英語 |
| アブストラクト: |
We study three-body baryonic B decays. A unique feature about three-body baryonic B decays is the threshold enhancement, where a clear peak is seen near the threshold in the baryon pair mass spectra for the modes that have been observed so far. A generalized factorization approach has been proposed, where two mechanisms of the baryon pair production are given, with one involving baryon pairs produced by a current, and the other involving baryon pairs created by a current-induced transition from the B meson. Baryon form factors are needed in parameterizing the factorized matrix elements containing the baryon pairs. In the case of baryon pairs produced by currents, all the baryon form factors can be asymptotically related to the nucleon electromagnetic form factors by using SU(3) flavor symmetry and the asymptotic behavior of the form factors as predicted by perturbative QCD. With a simple parametrization for the nonperturbative part of the form factors, the results agree well with data, which suggests that factorization may be the dominant contribution in this kind of processes. While there seems to be a great success for decays only involving a current-produced baryon pair, the understanding of the decays that also involve baryon pairs produced by the transitions from the B meson is hampered by the complicated matrix elements that contain both the baryon pair and the B meson, for which we still do not have control. In addition, the angular distribution of B+-> ppbarK+ reveals that the contribution from the transition part should be dominant in the factorization approach. The relevant data can be roughly described by a similar approach to the previous case.
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