Of Mass and Reference Frames
DOI: 10.1063/1.4796751
Wilczek replies: Ian Durham is correct in observing that four-momentum is conserved under very general circumstances. It is not the case, however, that this entails conservation of mass. Although the mass of an isolated particle can be determined from its four-momentum, that connection does not apply to multiparticle states. And since particles do interact, and even decay, a result that is only valid for single-particle states does not allow one to draw general conclusions. That is why the many specific manifestations of nonconservation of mass I discussed in my column can be—and are—perfectly consistent with special relativity in general, and with the conservation of four-momentum in particular.
More about the authors
Frank Wilczek, Massachusetts Institute of Technology, Cambridge, US .
