Basis-independent methods for the two-Higgs-doublet model. III. The CP-conserving limit, custodial symmetry, and the oblique parameters S, T, U

Journal Article · Tue Mar 01 04:00:00 EST 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.055017· OSTI ID:21537457

Haber, Howard E; O'Neil, Deva ^[1]

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1. Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California 95064 (United States)

In the standard model, custodial symmetry is violated by the hypercharge U(1) gauge interactions and the Yukawa couplings, while being preserved by the Higgs scalar potential. In the two-Higgs-doublet model (2HDM), the generic scalar potential introduces new sources of custodial symmetry breaking. We obtain a basis-independent expression for the constraints that impose custodial symmetry on the 2HDM scalar potential. These constraints impose CP-conservation on the scalar potential and vacuum, and in addition add one extra constraint on the scalar potential parameters. We clarify the mass degeneracies of the 2HDM that arise as a consequence of the custodial symmetry. We also provide a computation of the oblique parameters (S, T, and U) for the most general CP-violating 2HDM in the basis-independent formalism. We demonstrate that the 2HDM contributions to T and U vanish in the custodial symmetry limit, as expected. Using the experimental bounds on S and T from precision electroweak data, we examine the resulting constraints on the general 2HDM parameter space.

• OSTI ID: 21537457
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 5 Vol. 83; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCURACY
BOSONS
COUPLING
CP INVARIANCE
ELEMENTARY PARTICLES
FIELD THEORIES
GAUGE INVARIANCE
GRAND UNIFIED THEORY
HIGGS BOSONS
HIGGS MODEL
HYPERCHARGE
INTERACTIONS
INVARIANCE PRINCIPLES
LIE GROUPS
MASS
MATHEMATICAL MODELS
NUCLEAR POTENTIAL
PARTICLE MODELS
PARTICLE PROPERTIES
POSTULATED PARTICLES
POTENTIALS
QUANTUM FIELD THEORY
STANDARD MODEL
SYMMETRY
SYMMETRY BREAKING
SYMMETRY GROUPS
U GROUPS
U-1 GROUPS
UNIFIED GAUGE MODELS
YUKAWA POTENTIAL