Correlations between epsilon'/epsilon and Rare K Decays in the Littlest Higgs Model with T-Parity
Correlations between epsilon'/epsilon and Rare K Decays in the Littlest Higgs Model with T-Parity
复制标题
DOI：
10.1088/1126-6708/2007/06/082
复制
发表时间：
2007-04
期刊：
影响因子：
--
通讯作者：
M. Blanke;A. Buras;S. Recksiegel;C. Tarantino;S. Uhlig
中科院分区：
文献类型：
--
作者：
M. Blanke;A. Buras;S. Recksiegel;C. Tarantino;S. Uhlig
计算了T宇称最小Higgs模型（LHT）中CP破坏比ε '/ε'，并研究了它与分支比K_L -> pi^0 nu {bar nu}，K_L -> pi^0 l^+ l^-和K^+ -> pi^0 nu {bar nu}的相关性.在K_L衰变的情况下，这种相关性相当强，但在K^+ -> pi^+ nu {bar nu}的情况下则不那么明显。不幸的是，他们受到大强子的不确定性ε '/ε，其在标准模型（SM）的理论预测进行审查和更新。用Q_6的矩阵元（胶子企鹅）和Q_8（电弱企鹅）在大N极限和m_s^MS（2 GeV）= 100 MeV的格点QCD中计算，（ε ′/ε）_SM结果接近数据，使得Br的显著偏离（K_L -> pi^0 nu {bar nu}）和Br（K_L -> pi^0 l^+ l^-）的可能性不大，而Br（K^+ -> pi^0 nu {bar nu}）甚至可以提高5倍。另一方面，相关的强子矩阵元与它们的大N值的适度偏离允许在LHT模型中对ε '/ε'的一致描述，伴随着Br（K_L -> pi ^0 nu {bar nu}）和Br（K_L -> pi ^0 l^+ l^-）的大幅增强，但Br（K^+ -> pi^+ nu {bar nu}）的仅适度增强。
We calculate the CP-violating ratio epsilon'/epsilon in the Littlest Higgs model with T-parity (LHT) and investigate its correlations with the branching ratios for K_L -> pi^0 nu {bar nu}, K_L -> pi^0 l^+ l^- and K^+ -> pi^+ nu {bar nu}. The resulting correlations are rather strong in the case of K_L decays, but less pronounced in the case of K^+ -> pi^+ nu {bar nu}. Unfortunately, they are subject to large hadronic uncertainties present in epsilon'/epsilon, whose theoretical prediction in the Standard Model (SM) is reviewed and updated here. With the matrix elements of Q_6 (gluon penguin) and Q_8 (electroweak penguin) evaluated in the large-N limit and m_s^MS(2 GeV) = 100 MeV from lattice QCD, (epsilon'/epsilon)_SM turns out to be close to the data so that significant departures of Br(K_L -> pi^0 nu {bar nu}) and Br(K_L -> pi^0 l^+ l^-) from the SM expectations are unlikely, while Br(K^+ -> pi^+ nu {bar nu}) can be enhanced even by a factor 5. On the other hand, modest departures of the relevant hadronic matrix elements from their large-N values allow for a consistent description of epsilon'/epsilon within the LHT model accompanied by large enhancements of Br(K_L -> pi^0 nu {bar nu}) and Br(K_L -> pi^0 l^+ l^-), but only modest enhancements of Br(K^+ -> pi^+ nu {bar nu}).