Proca action
In physics, specifically field theory and particle physics, the Proca action describes a massive spin-1 field of mass m in Minkowski spacetime.The Proca equation is involved in the Standard Model and describes there the three massive vector bosons, i.e. the Z and W bosons.This article uses the (+−−−) metric signature and tensor index notation in the language of 4-vectors.The Euler–Lagrange equation of motion for this case, also called the Proca equation, is: which is equivalent to the conjunction of[3] with (in the massive case) which may be called a generalized Lorenz gauge condition.For non-zero sources, with all fundamental constants included, the field equation is: WhenIn the vector calculus notation, the source free equations are: andQuantizing the Proca action requires the use of second class constraints.