溫伯格角

温伯格角（英語：Weinberg angle，又叫弱混合角）是温伯格-萨拉姆的弱电统一理论^{[1] [2][3]}的一个参数。

温伯格角的由来与定义

定义θ_W

${\displaystyle \tan \theta _{W}={\frac {g'}{g}}}$ 

由参考[2]中^[2](10)及(11)式:

${\displaystyle Z_{\mu }=({g^{2}}+{g'^{2}})^{-1/2}(gA_{\mu }^{3}+g'B_{\mu })}$  ，

${\displaystyle A_{\mu }=({g^{2}}+{g'^{2}})^{-1/2}(-g'A_{\mu }^{3}+gB_{\mu })}$ .

有：

${\displaystyle {\begin{pmatrix}A\\Z\end{pmatrix}}={\begin{pmatrix}\cos \theta _{W}&\sin \theta _{W}\\-\sin \theta _{W}&\cos \theta _{W}\end{pmatrix}}{\begin{pmatrix}B\\W\end{pmatrix}}}$ 

温伯格角也可定义成:^[4]

${\displaystyle \cos \theta _{W}={\frac {m_{W}}{m_{Z}}}}$ 

温伯格角的测量值

sin²θ_W = 0.2397 ± 0.0013

參考文獻

1. S.L. Glashow. Partial-symmetries of weak interactions. Nuclear Physics. 1961, 22 (4): 579–588. Bibcode:1961NucPh..22..579G. doi:10.1016/0029-5582(61)90469-2. 
2. S. Weinberg. A Model of Leptons. Physical Review Letters. 1967, 19 (21): 1264–1266. Bibcode:1967PhRvL..19.1264W. doi:10.1103/PhysRevLett.19.1264. 
3. A. Salam. N. Svartholm , 编. Elementary Particle Physics: Relativistic Groups and Analyticity. Eighth Nobel Symposium. Stockholm: Almquvist and Wiksell: 367. 1968. 
4. L. B. Okun. Leptons and Quarks. North-Holland Physics Publishing. 1982: 214. ISBN 0-444-86924-7.