论文标题
$ d^0- \ bar {d}^0 $混合的理论方面
Theoretical aspects of $D^0-\bar{D}^0$ mixing
论文作者
论文摘要
$ d^0- \ bar {d}^0 $混合中的可观测值可以由操作员产品扩展（OPE）对其进行分析，其中$ 1/m_c $被视为扩展参数。由于Glashow-iliopoulos-Maiani（GIM）机制极大地抑制了四夸克操作员的贡献，因此在OPE分析中，宽度差的数量级仍未得到复制。鉴于这个问题，对$ d^0- \ bar {d}^0 $混合的Quark-Hadron二重性（默认地做出的假设）进行了研究。特别是，可以在“ thooft”模型中比较独家的宽度差和包容性对应物，即大$ n_c $限制中的二维QCD。结果表明，相对于四夸克运算符的4D样构成贡献，独家宽度差的数量级增强了，这与对$ d^0- \ bar {d}^0 $混合的现实观察在质上是一致的。
Observables in the $D^0-\bar{D}^0$ mixing can be theoretically analyzed by the operator product expansion (OPE), in which $1/m_c$ is regarded as an expansion parameter. Since the contributions of four-quark operators are strongly suppressed by the Glashow-Iliopoulos-Maiani (GIM) mechanism, the order of magnitude of the width difference is still not reproduced in the OPE analysis. In view of this issue, quark-hadron duality, an assumption that is tacitly made in the OPE, is studied for the $D^0-\bar{D}^0$ mixing. In particular, the exclusive width difference and the inclusive counterpart can be compared within the 't Hooft model, two-dimensional QCD in the large-$N_c$ limit. It is shown that the order of magnitude of the exclusive width difference is enhanced relative to the 4D-like inclusive contributions of the four-quark operators, that is qualitatively consistent with the realistic observation of the $D^0-\bar{D}^0$ mixing.
