Alpha Symbol

The capital Greek letter Alpha (Α) is visually identical to the Latin capital A and for that reason is rarely used as a distinct symbol in technical writing. When it does appear, it functions like other capital Greek letters as a variable or label. Outside notation, Α names the alpha particle (a helium nucleus) in nuclear physics and marks the brightest star of a constellation in astronomy.

Alpha (α) is the first letter of the Greek alphabet and appears throughout mathematics and the sciences. It commonly denotes angles in geometry, angular acceleration in mechanics, and significance levels in statistics. In nuclear physics it labels alpha particles and alpha decay, and in finance α denotes the excess return of an investment above a benchmark.