arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1102.5712hep-ph
收藏

具有最小味道破坏的MSSM中的光阻衰减

Light Stop Decay in the MSSM with Minimal Flavour Violation

M. Muhlleitner, E. Popenda

摘要:

在超对称的情况下,光停止粒子$\tilde{t}_1$和最轻的超对称粒子(LSP)的质量差很小,假设是最轻的中性伴子,味道改变中性电流衰变$\tilde{t}_1 \to c \tildeχ_1^0$可以是主要的衰变通道,并可以超过四体停止衰变的某些参数值。在最小风味破坏(MFV)的框架中,这种衰减被CKM抑制,从而诱导长的停止寿命。在大型强子对撞机上的终止衰变长度测量可以用来测试那些通过标准模型汤川耦合的具有最小味道的模型。衰变宽度在一段时间以前已经通过一个近似公式给出,该公式考虑了MFV标度的主要参数。本文在MFV框架下计算了单圈衰变宽度。与近似结果的比较表明,由于近似衰减公式中忽略了非对数项,大MFV尺度的偏差为10%。分支比的差异可以忽略不计。这些大的木材必须加以修整。通过求解重整化群方程组进行重正化。精确的单回路结果和树水平的味道变化的中性电流衰减,其中包括的mummed的图表的比较,表明,remation效应是重要的,应该考虑。

英文摘要:

In supersymmetric scenarios with a light stop particle $\tilde{t}_1$ and a small mass difference to the lightest supersymmetric particle (LSP) assumed to be the lightest neutralino, the flavour changing neutral current decay $\tilde{t}_1 \to c \tildeχ_1^0$ can be the dominant decay channel and can exceed the four-body stop decay for certain parameter values. In the framework of Minimal Flavour Violation (MFV) this decay is CKM-suppressed, thus inducing long stop lifetimes. Stop decay length measurements at the LHC can then be exploited to test models with minimal flavour breaking through Standard Model Yukawa couplings. The decay width has been given some time ago by an approximate formula, which takes into account the leading logarithms of the MFV scale. In this paper we calculate the exact one-loop decay width in the framework of MFV. The comparison with the approximate result exhibits deviations of the order of 10% for large MFV scales due to the neglected non-logarithmic terms in the approximate decay formula. The difference in the branching ratios is negligible. The large logarithms have to be resummed. The resummation is performed by the solution of the renormalization group equations. The comparison of the exact one-loop result and the tree level flavour changing neutral current decay, which incorporates the resummed logarithms, demonstrates that the resummation effects are important and should be taken into account.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑