2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/109940We revisit Bjorken's model of spontaneous breakdown of Lorentz invariance. We show that the model possesses zero mass, spin zero (scalar) Nambu-Goldstone boson, in addition to the zero mass, spin one (vector) photon.High Energy Physics - Theorytext