Physics:Beta (velocity)

β in special relativity is the velocity, v, of an object relative to the speed of light c: [math]\displaystyle{ \beta = \frac{v}{c} }[/math]

It is less commonly referred to as the Jackson Number.

β is dimensionless and equal to the velocity in natural units. Any expression which involves v, like the Lorentz factor, can be rewritten using β instead. See the Lorentz transformation.