  Spin- and angular-resolved photoemission spectroscopy is a basic experimental
tool for unveiling spin polarization of electron eigenstates in crystals. We
prove, by using spin-orbit coupled graphene as a model, that photoconversion of
a quasiparticle inside a crystal into a photoelectron can be accompanied with a
dramatic change in its spin polarization, up to a total spin flip. This
phenomenon is typical of quasiparticles residing away from the Brillouin zone
center and described by higher rank spinors, and results in exotic patterns in
the angular distribution of photoelectrons.
