分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-09-17
摘要: The decay of Λb → Σ(∗)c πlν¯ processes are calculated in the framework of heavy baryon chiral perturbation theory with help of the 1/Nc expansion. The decay rate distributions over v · v′ where v and v′ are the 4-vector velocities of Λb and Σ(∗)c respectively, and over the pion and lepton energies are given. The decay branching ratios amount to about 1.21(0.971)% for Λb → Σcπlν¯and 0.798(0.640)% for Λb → Σ∗cπlν¯ by using the baryonic Isgur-Wise function predicted by QCD sum rule (large Nc QCD).
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-09-17
摘要: L = 1 excited heavy baryon masses are analyzed by heavy quark and large Nc expansions. In heavy quark limit, mass is parameterized by � and it is expanded further by spin-flavor breaking operators to the zeroth order of 1/Nc. Expanding coefficients will be fixed by more data on the excited baryons in the near future.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-09-17
摘要: The mass spectrum of the L = 1 orbitally excited heavy baryons with light quarks in the spin-flavor symmetric representation is studied by the 1/Nc expansion method in the framework of the heavy quark effective theory. The mixing effect from the baryons in the mixed representation is considered.The general pattern of the spectrum is predicted which will be verified bythe experiments in the near future. The 1/mQ and SU(3) corrections are also considered. Mass relations for the baryons #3;(∗) c1 , #6;(∗)c1 , #4;(′)(∗)c1 , and (∗)c1 arederived.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-09-17
摘要: Within the HQET, the heavy to light vector meson transitions are systematically analyzed to the order of 1/mQ. Besides the four universal functions at the leading order, there are twenty-two independent universal form factors at the order of 1/mQ. Both the semileptonic decay B → #26; which is relevant to the |Vub| extraction, and the penguin induced decay B → K∗ which is important to new physics discovering, depend on these form factors.Phenomenological implications are discussed.