View source for Variables Used in Elastic Scattering

=Lorentz Invariant Quantities=
As was shown earlier

[[DV_Calculations_of_4-momentum_components#4-Momentum_Invariants | shown earlier]]

the scalar product of a 4-Momentum vector with itself ,<math>{\mathbf P_1}\cdot {\mathbf P^1}=E_1E_1-\vec p_1\cdot \vec p_1 =m_{1}^2=s</math> , and the length of a 4-Momentum vector composed of 4-Momentum vectors, <math>{\mathbf P^2}=({\mathbf P_1}+{\mathbf P_2})^2=(E_1+E_2)^2-(\vec p_1 +\vec p_2 )^2=(m_1+m_2)^2=s</math>, are invariant quantities.

=Mandelstam Representation=

[[File:Mandelstam.png | 400 px]]