2025/06/07 by Saar, Rein, Groote, Stefan
#FOS: Physical sciences #General Physics (physics.gen-ph)
paper · doi:10.48550/arxiv.2506.12079
The Lorentz group Lor1,3=SO0(1,3) has two point fixgroups, namely SO(3) for time-like translations and SO0(1,1)× R2 for light-like translations. However, for light-like translations it is reasonable to consider a line fixgroup that leads to the Borel structure of the Lorentz group and gives appropriate helicities for massless particles. Therefore, whether a particle is massless or massive is not so much a physical question but rather a question of the underlying Lie group symmetry.