Breaking of isospin symmetry in theories with a dynamical Higgs mechanism

Journal Article · Mon Apr 01 04:00:00 EST 1985 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.31.1676· OSTI ID:5951001

Appelquist, T; Bowick, M J; Cohler, E; Hauser, A I

The sensitivity of physical amplitudes to the observed isospin-symmetry breaking in the fermion mass matrix is analyzed in theories where the electroweak symmetry is dynamically broken. As a first step toward discussing dynamical theories in a model-independent way, we consider a strongly interacting Higgs theory. The nonlinear sigma model coupled to an SU(2) x U(1) Yang-Mills theory and to fermions is used to generate the low-dimensional operators induced by the quantum theory. The strengths of these operators, in particular those that break isospin symmetry, are estimated using the Higgs-boson mass of the linear sigma model as a regulator. Technicolor models are next considered as a specific example of the strong-interaction physics which leads to electroweak symmetry breaking. Emphasis is placed on the effective four-fermion interactions that are natural partners of those which give mass to the ordinary fermions. New sources of isospin-symmetry breaking are found; in particular there is one which contributes directly to the rho parameter with strength that is linear in the effective Yukawa coupling of the heaviest ordinary fermion. This effect is qualitatively different from the quadratic dependence found in Higgs theories.

• Research Organization: Department of Physics, Yale University, New Haven Connecticut 06511
• OSTI ID: 5951001
• Journal Information: Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 31:7; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645303* -- High Energy Physics-- Particle Invariance Principles & Symmetries-- Applications to Strong Interactions-- (-1987)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
BASIC INTERACTIONS
FERMIONS
FUNCTIONAL ANALYSIS
HIGGS MODEL
INTERACTIONS
ISOSPIN
LIE GROUPS
MATHEMATICAL MODELS
MATHEMATICAL OPERATORS
MATHEMATICS
PARTICLE MODELS
PARTICLE PROPERTIES
QUANTUM OPERATORS
SENSITIVITY
SIGMA MODEL
STRONG INTERACTIONS
SU GROUPS
SU-2 GROUPS
SYMMETRY BREAKING
SYMMETRY GROUPS
U GROUPS
U-1 GROUPS
YANG-MILLS THEORY