光子的质量与真空中光速的色散

若光子是有质量的重光子，它的频率有一确定的最小值，光速则有一个确定的下限，仅低于极限速度 约10 % .与介质中光速的色散不同，由光子质量引起的色散几乎全部集中发生在最小频率附近狭窄的频率范围内，高于长波无线电频率的电磁波的速度都是饱和的，即等于极限速度 .因此，光速等于常数 的测量结果以及康普顿散射实验，都不表明光子的质量必然为零.静电场的传播速度应该等于光速的下限，后者则是光速色散的标志，所以，测量静电场的传播速度等同于观察光速的色散，从而有助于判断光子是否有质量

Photon Mass and Dispersion of the Velocity of Light in Vacuum

If photon is massive, it will have a minimum frequency and the velocity of light will not be a constant but have a low limit about 10 % lower than constant c. Different from the dispersion of the velocity of light in medium, the dispersion in vacuum caused by the photon's mass concentrically appears within a narrow frequency region nearby minimum frequency and，so that, as the frequency is higher than that of long wave radio, the dispersion becomes zero and the velocity of light should be saturated (i. e. equals to constant c). In the result, the velocity of light equals to constant c of well known and Compton scattering should not necessarily mean that the photon is massless. It is tried to demonstrate that propagation velocity of the static field should be equal to the low limit of the velocity of light, and the latter means that there is the dispersion. Therefore, experimental determination of the propagation velocity of static field equates with observation of dispersion and is helpful to answer whether the photon is massive or massless.