A lowercase Greek letter commonly used to represent angles, slopes, regression coefficients, and beta particles in mathematics and physics.
Examples
Beta coefficient in linear regression
y = \beta_0 + \beta_1x + \epsilon
Beta decay in nuclear physics
n \rightarrow p + e^- + \bar{\nu}_e + \beta
Beta angle in trigonometry
\sin^2 \alpha + \sin^2 \beta = 1