2007/11/27 by M. Napsuciale, S. Rodriguez, S. Rodríguez +2
Mathematics · Physics and Astronomy · #Abelian group #Black Holes and Theoretical Physics #Combinatorics #Electromagnetic field #Gauge boson #Gauge fixing #Gauge theory #Lorentz group #Lorentz transformation #Lorenz gauge condition #Mathematical physics #Mathematics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Unitarity #hep-ph
paper · pdf · doi:10.1103/physrevd.77.014009
published as Phys.Rev.D77:014009,2008 · 10 pages, 2 figures, contributed to the XI Mexican Workshop on Particles and Fields. Accepted in Phys. Rev. D
arxiv created 2007/11/27 · openalex publication_date 2008/01/09 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
On the basis of the three fundamental principles of (i) Poincar'e symmetry of space-time, (ii) electromagnetic gauge symmetry, and (iii) unitarity, we construct an universal Lagrangian for the electromagnetic interactions of elementary vector particles, i.e., massive spin-1 particles transforming in the ((1)/(2),(1)/(2)) representation space of the homogeneous Lorentz group. We make the point that the first two symmetries alone do not fix the electromagnetic couplings uniquely but solely prescribe a general Lagrangian depending on two free parameters, here denoted by \ensuremathξ and g. The first one defines the electric-dipole and the magnetic-quadrupole moments of the vector particle, while the second determines its magnetic-dipole and electric-quadrupole moments. In order to fix the parameters one needs an additional physical input suited for the implementation of the third principle. As such, one chooses Compton scattering off a vector target and requires the cross section to respect the unitarity bounds in the high-energy limit. As a result, we obtain the universal g=2 and \ensuremathξ=0 values which completely characterize the electromagnetic couplings of the considered elementary vector field at tree level. The nature of this vector particle, Abelian versus non-Abelian, does not affect this structure. Merely, a partition of the g=2 value into non-Abelian, gna, and Abelian, ga=2\ensuremath-gna, contributions occurs for non-Abelian fields with the size of gna being determined by the specific non-Abelian group appearing in the theory of interest, be it the standard model or any other theory.