6533b7d4fe1ef96bd126282d
RESEARCH PRODUCT
Lepton-number violation and right-handed neutrinos in Higgs-less effective theories
Jan SternJohannes Hirnsubject
PhysicsNuclear and High Energy PhysicsParticle physicsChiral perturbation theory010308 nuclear & particles physicsElectroweak interactionHigh Energy Physics::PhenomenologyFOS: Physical sciences01 natural sciencesLepton numberCustodial symmetryStandard ModelHigh Energy Physics - PhenomenologyHigh Energy Physics - Phenomenology (hep-ph)[PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph]0103 physical sciencesEffective field theoryHiggs bosonSymmetry breaking010306 general physicsdescription
Following previous work, we identify a symmetry S_nat that generalizes the concept of custodial symmetry, keeping under control deviations from the Standard Model (SM). To realize S_nat linearly, the space of gauge fields has to be extended. Covariant constraints formulated in terms of spurions reduce S_nat back to SU(2)_L x U(1)_Y. This allows for a covariant introduction of explicit S_nat-breaking parameters. We assume that S_nat is at play in a theory of electroweak symmetry-breaking without a light Higgs particle. We describe some consequences of this assumption, using a non-decoupling effective theory in which the loop expansion procedure is based on both momentum and spurion power counting, as in Chiral Perturbation Theory. A hierarchy of lepton-number violating effects follows. Leading corrections to the SM are non-oblique. The effective theory includes stable light right-handed neutrinos, with an unbroken Z_2 symmetry forbidding neutrino Dirac masses. nu_R contribution to dark matter places bounds on their masses.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2005-04-28 |