| Non-spectator Contributions to Lifetime of ∧b |
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| 作者姓名： | CHANGChao-Hsi GUOPeng LIXue-Qian WANGGuo-Li |
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| 作者单位： | [1]InstituteofTheoreticalPhysics,AcademiaSinica,P.O.Box2735,Beijing100080,China [2]DepartmentofPhysics,NankaiUniversity,Tianjin300071,China |
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| 摘 要： | ![]()
In this work, we study the contributions of non-spectator effects to the lifetimes of ∧b and B-mesons comparatively. Based on the well-established theoretical framework about the effective weak Lagrangian, we derive the formulation of the non-spectator effects at the quark level. Especially, for ∧b we have considered two pictures: the three-valence-quark picture and the quark-diquark picture. In the two pictures, the interference contributions to the total width are different, in this work, we investigate the interference effects in detail As a preliminary estimate on the lifetimes, we evaluate the hadronic matrix elements appearing in the final formulas of the lifetimes by means of a simple phenomenological model for both pictures. Our results show that the contributions of the non-spectator effects can reduce the ratio of lifetime of ∧b to that of B-mesons by 5-7％. It is noted that in the quark-diquark picture the ratio can be further reduced if excited states of the diquark system are taken into account. We conclude that the measured ratio τ(∧b)/τ(B^o)-0.79 [The Data Group, Phys. Rev. D66 (2002) 010001] can be partly understood by the non-spectator effects, although the problem on the discrepancy between theoretical prediction and experimental measurement is not fullv solved.
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| 关 键 词： | 寿命 粒子物理学 重夸克效应 衰退轨道 |
| 收稿时间： | 2004-04-16 |
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