IS THE ELECTRON A "RIGID" PARTICLE?
G. Fiorentini, M. Gasperini, GAETANO SCARPETTA · Modern Physics Letters A · 1991
We consider an extended point-particle action depending not only on the length but also on the curvature of the particle world-line. We derive constraints on such a higher derivative modification of standard dynamics, by using experimental results on the hyperfine structure of the hydrogen atom and on the electron (g − 2) anomaly.