Electroweak two-loop contribution to the mass splitting within a new heavy SU(2)L fermion multiplet

2009/06/30 by Youichi Yamada
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ph

paper · pdf · doi:10.1016/j.physletb.2009.11.044

published as Phys.Lett.B682:435-440,2010 · 14 pages, style changed, analytic forms of two-loop functions added

openalex publication_date 2009/11/24 · arxiv created 2009/11/25 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01

Abstract

New heavy particles in an SU(2)L multiplet, sometimes introduced in extensions of the standard model, have highly degenerate tree-level mass M if their couplings to the Higgs bosons are very small or forbidden. However, loop corrections may generate the gauge-symmetry-breaking mass splitting within the multiplet, which does not vanish in the large M limit due to the threshold singularity. We calculate the electroweak contribution to the mass splitting for a heavy fermion multiplet, to the two-loop order. Numerically, two-loop electroweak contributions are typically O (MeV).

Citations

• Review of Particle Physics
• The complete radiative corrections to the gaugino and Higgsino masses in the minimal supersymmetric model
• Minimal dark matter
• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)