The claim some years ago, contrary to all textbooks, that the angular momentum of a photon (and
gluon) can be split in a gauge-invariant way into an orbital and spin term, sparked a major controversy
in the Particle Physics community, exacerbated by the realization that many different forms of the
angular momentum operators are, in principle, possible. A further cause of upset was the realization
that the gluon polarization in a nucleon, a supposedly physically meaningful quantity, corresponds only
to the gauge-variant gluon spin derived from Noether’s theorem, evaluated in a particular gauge. On the
contrary, Laser Physicists have, for decades, been happily measuring physical quantities which correspond
to photon orbital and spin angular momentum evaluated in a particular gauge. This paper reconciles the
two points of view, and shows that it is the gauge invariant version of the canonical angular momentum
which agrees with the results of a host of laser optics experiments