Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Elementary particles can be grouped into spin-classes and described by specific equations, see below:

Is there a general Lagrangian density from which all these equations can be derived?

A Lagrangian that allows for all types of spin, but after some gauge transformation settles down into a specific type?

For instance "The Proca action is the gauge-fixed version of the Stueckelberg action via the Higgs mechanism."

Spin 1/2 -- Weyl equation: describes massless spin-1/2 particles -- Dirac equation: describes massive spin-1/2 particles (such as electrons) --Majorana equation: describes a massive Majorana particle -- Breit equation: describes two massive spin-1/2 particles (such as electrons) interacting electromagnetically to first order in perturbation theory

Spin 1 -- Maxwell equations: describe a photon (massless spin-1 particle)-- Proca equation: describes a massive spin-1 particle (such as W and Z bosons)-- Kemmer equation: an alternative equation for spin-0 and spin-1 particles (gauge fields)

Spin 3/2 --Rarita-Schwinger equation: describes a massive spin-3/2 particle

Arbitrary spin-- Bargmann-Wigner equations: describe free particles of arbitrary integral or half-integral spin.

Note: I'm not looking for a simple statement of Lagrangian formalism.

share|cite|improve this question

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.