In theoretical physics, the Veneziano amplitude refers to the discovery made in 1968 by Italian theoretical physicist Gabriele Veneziano that the Euler beta function, when interpreted as a scattering amplitude, has many of the features needed to explain the physical properties of strongly interacting mesons, such as symmetry and duality.[1] Conformal symmetry was soon discovered. This discovery can be considered the birth of string theory,[2] as the invention of string theory came about as a search for a physical model which would give rise to such a scattering amplitude. In particular, the amplitude appears as the four tachyon scattering amplitude in oriented open bosonic string theory. Using Mandelstam variables and the beta function [math]\displaystyle{ B(x,y) }[/math], the amplitude is given by[3]
where [math]\displaystyle{ \alpha' }[/math] is the string constant, [math]\displaystyle{ k_i }[/math] are the tachyon four-vectors, [math]\displaystyle{ g_o }[/math] is the open string theory coupling constant, and [math]\displaystyle{ \alpha(x) = -1-\alpha'x }[/math].
Original source: https://en.wikipedia.org/wiki/Veneziano amplitude.
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