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 leading Isgur-Wise form factor ξ(y) parametrizing the semileptonic transitionsb → #3;1/2c1 ℓ¯ν and #3;b → #3;3/2c1 ℓ¯ν is calculated by using the QCD sum rules in the framework of heavy quark effective theory, where #3;1/2 c1 and #3;3/2 c1 is the orbitally excited charmed baryon doublet with JP = (1−/2, 3−/2). The interpolating currents with transverse covariant derivative are adopted for #3;1/2 c1 and #3;3/2 c1 in the analysis. The slope parameter ρ2 in linear approximation of the Isgur-Wise function is obtained to be ρ2 = 2.01, and the interception to be ξ(1) = 0.29. The decay branching ratios are estimated.
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.
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