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 widths for pionic decays of lowest two excited doublets (0+, 1+) and(1+, 2+) of heavy mesons are studied with QCD sum rules in the leading order of heavy quark effective theory. The ambiguity due to presence of two distinct 1+ states are solved. The soft pion approximation is not used.
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 m asses of excited heavy m esons are studied with sum rules in the heavy quark e#11;ective theory.A setofinterpolating currentscreating (annihilating) excited heavy m esonswith arbitrary spin and parity are proposed and their propertiesarediscussed.Num ericalresultsattheleading orderofthe O (1=m Q ) expansion are obtained for the lowest doublets (0+ ;1+ ) and(1+ ;2+ ).
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: Using the framework of the Heavy Quark Effective Theory we have re-analyzed the Isgur-Wise function describing semileptonic #3;b → #3;c decays in the QCD sum rule approach.The slope parameter of the Isgur-Wise function is found to be ρ2 = 1.35 ± 0.12, which isconsistent with an experimental measurement and a lattice calculation. To O(1/mb, 1/mc)of the heavy quark expansion the integrated #3;b decay width is used to extract the CKM matrix element Vcb for which we obtain a value of |Vcb| = 0.041±0.004 in excellent agreementwith the value of |Vcb| determined from semileptonic B → D∗ decays.
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.