论文标题
在SM中重新访问顶级夸克铬磁偶极力矩
Revisiting the top quark chromomagnetic dipole moment in the SM
论文作者
论文摘要
我们在标准模型中重新审视异常的铬磁偶极力矩，并表明其三重Gluon顶点的贡献（带有壳上的gluon（$ q^2 = 0 $））生成红外发射极极。因此，不应在$ q^2 = 0 $上扰动地评估铬磁性偶极子。专注于这个顶级夸克异常，表示为$ \hatμ_t（q^2）$，我们用较大的动量转移来计算它，就像$α_s（m_z^2）$会议量表一样，这两个spacelike $ q^2 = 2 = -m_z^2 $ q^2 = -m_z^2 $ Q^2 $ q^$ q^2 = m______z^2 $ ____z^2 $ s^2 $ ___z^2 $。我们发现$ \hatμ_t（-m_z^2）$ = $ = $ $ -0.0224 $ $ -0.000925I $和$ \hatμ__T（m_z^2）$ = $ = $ -0.0133 $ -0.0133 $ -0.0267i $。我们的$ \ mathrm {re} \ thinspace \hatμ_t（-m_z^2）$与当前的实验值匹配$ \hatμ_T^\ Mathrm {exp} = - 0.024 _ { - 0.009}^{+0.013}（\ m atrm {stat}）_ { - 0.011}^{+0.016}（+0.016}（\ syst}） $ \ mathrm {im} \ thinspace \hatμ_t（-m_z^2）$零件是由调味的带电电流引起的。
We revisit the anomalous chromomagnetic dipole moment in the Standard Model and show that its triple gluon vertex contribution, with the on-shell gluon ($q^2=0$), generates an infrared divergent pole. Consequently, the chromomagnetic dipole should not be perturbatively evaluated at $q^2=0$. Focusing on this top quark anomaly, denoted as $\hatμ_t(q^2)$, we compute it with the off-shell gluon with a large momentum transfer, just as the $α_s(m_Z^2)$ convention scale, for both spacelike $q^2=-m_Z^2$ and timelike $q^2=m_Z^2$ cases. We found that $\hatμ_t(-m_Z^2)$ $=$ $-0.0224$ $-0.000925i$ and $\hatμ_t(m_Z^2)$ $=$ $-0.0133$ $-0.0267i$. Our $\mathrm{Re}\thinspace\hatμ_t(-m_Z^2)$ matches well with the current experimental value $\hatμ_t^\mathrm{Exp}=-0.024_{-0.009}^{+0.013}(\mathrm{stat})_{-0.011}^{+0.016}(\mathrm{syst})$, and the $\mathrm{Im}\thinspace\hatμ_t(-m_Z^2)$ part is induced by flavour changing charged currents.
