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Дата изменения: Wed Aug 9 20:40:48 2000
Дата индексирования: Mon Oct 1 22:52:32 2012
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Quarks and leptons

The Standard Model contains three doublets of leptons with a hypercharge $Y=-1$:

$$\left( \begin{array}{c} \nu_e \\ e^- \end{array} \right) \le... ...ft( \begin{array}{c} \nu_\tau \\ \tau^- \end{array} \right)\;,$$

and three doublets of quarks with a hypercharge $Y=\frac{1}{3}$:

$$\left( \begin{array}{c} u \\ d^\prime \end{array} \right) \l... ...) \left( \begin{array}{c} t \\ b^\prime \end{array} \right)\;.$$

Neutrinos, the upper components of lepton doublets, are so far massless as a result of experimental measurements. So the mixing matrix for leptons is not needed. Meantime both the upper and down components of quark doublets have nonzero masses. The corresponding mixing matrix is named the Cabibbo-Kobayashi-Maskawa matrix. It expresses the lower components of quark doublets in terms of the real quark fields:

$$\left(\begin{array}{c} d^\prime \\ s^\prime \\ b^\prime \end... ...ight) \left(\begin{array}{c} d \\ s \\ b \end{array}\right)\;.$$