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： 2017-11-10
摘要： An approximate rotational symmetry of a heavy-light meson is viewed from a string picture. Using a simple string configuration, we derive a formula, (M−mc)2 = πσL, whose coefficient of the r.h.s. is just 1/2 of that of a light meson with two light quarks. A numerical plot is obtained for Dmesons of experimental data as well as several theoretical models, which shows good agreement with this formula.
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： 2017-11-10
摘要： There is a puzzle in the +c family, i.e., one member with JP = 3/2+ is missing in a L = 2 multiplet which the heavy quark effective theory predicts, and JP’s of c(2765)+ and c(2940)+ are unknown. Using a light diquark picture to calculate baryon masses, we study possible assignments of two c’s with unknown JP and the missing +c with 3/2+ for L = 2, and we find the most probable possibility that the peak corresponding to c(2880)+ actually includes a missing member with spin 3/2+ for L = 2 and that quantum numbers of c(2765)+ and c(2940)+ are 2S (1/2+) and 2P(1/2−), respectively.
分类： 物理学 >> 核物理学 提交时间： 2016-08-31
摘要： Careful observation of the experimental spectra of heavy-light mesons tells us that heavy-light mesons with the same angular momentum L are almost degenerate. The estimate is given how much this degeneracy is broken in our relativistic potential model, and it is analytically shown that expectation values of a commutator between the lowest order Hamiltonian and L⃗ 2 are of the order of 1/mQ with a heavy quark mass mQ. It turns out that nonrelativistic approximation of heavy quark system has a rotational symmetry and hence degeneracy among states with the same L. This feature can be tested by measuring higher orbitally and radially excited heavy-light meson spectra for D/Ds/B/Bs in LHCb and forthcoming BelleII.
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