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提出了一个基于SU(3)L×U(1)X群的弱电相互作用模型.在该模型中,每一代轻子均包含两个中性粒子.计算了新的中性轻子(N粒子)的寿命,并估计了它的质量上限,从而说明N粒子可以看作暗物质的候选者. 相似文献
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研究了一个SU(3)L×U(1)X弱电统一模型·要求M2Z1–M2W/cos2θw小于实验值,得到了MZ′的下限.再利用MZ′和MU(MV)之间的关系得到MU(MV)的下限.进而考虑了由于Z′交换引起的KL–KS质量差,并获得了更严格的Mz′和MU(MV)的下限. 相似文献
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First-principle studies of the geometries and electronic properties of Cum Sin (2≤m+n≤7)clusters 下载免费PDF全文
The equilibrium geometries and electronic properties of CumSin (2 ≤m + n ≤ 7) clusters have been studied by using density functional theory at the B3LYP/6-311+G (d) level. Our results indicate that the structure of CuSin (n 〈6) keeps the frame of the corresponding Sin cluster unchanged, while for CunSi clusters, the rectangular pyramid structure of Cu4Si is shown to be a building block in many structures of larger CunSi clusters. The growth patterns of CumSin clusters become more complicated as the number of Cu atoms increases. Both the binding energies and the fragmentation energies indicate that the Si-Si bond is stronger than the Cu-Si bond, and the latter is stronger than the Cu-Cu bond. Combining the fragmentation energies in the process CumSin →Cu+Cum-l Sin and the second-order difference △2E(m) against the number of Cu atoms of CumSin, we conclude that CumSin clusters with even number of Cu atoms have higher stabilities than those with odd rn. According to frontier orbital analyses, there exists a mixed ionic and covalent bonding picture between Cu and Si atoms, and the Cud orbitals contribute little to the Cu-Si bonding. For a certain cluster size (m + n = 3, 4, 5, 6, 7), the energy gaps of the most stable CumSin clusters show odd-even oscillation with changing m, the clusters with odd m exhibit stronger chemical reactivity than those with even m.[第一段] 相似文献
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将SU(2)L×SU(2)R手征对称的σ模型推广到带电磁场情况下的手征σ模型,采用研究自恰性方程的方法研究了同时具有动力学破缺和真空自发破缺的手征SU(2)L×SU(2)R×U(1)σ模型,得到了考虑动力学自发破缺、真空自发破缺和电磁相互作用后,σ、π介子和核子都出现了不同的质量修正,并得到此模型中σ,π和核子以不同方式依赖于动力学破缺的具体表示. 相似文献
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本文利用类张量的方法计算了量子代数SUq(4)在SUq(4)>SUq(2)+SUq(2)基上的不可约表示,得到了求矩阵元的递推公式. 相似文献
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本文给出了确定量子代数SLq(3)的不可约表示和Wigner系数的方法.文中引入满足Serre类关系的两辅助元素,指出它们以及另两个元素是SLq(2)的1/2阶张量算符,它们的约化矩阵元可由一组"递推公式"算出.从这些公式也可导出SLq(3)的同位旋标量因子的递推公式.这也意味着对于SLq(3),Racah因子分解定理也适用. 相似文献
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