Lie-algebra approach to symmetry breaking

Journal Article · Wed Apr 15 04:00:00 EST 1981 · Phys. Rev., D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.23.1856· OSTI ID:6533610

Anderson, J T

A formal Lie-algebra approach to symmetry breaking is studied in an attempt to reduce the arbitrariness of Lagrangian (Hamiltonian) models which include several free parameters and/or ad hoc symmetry groups. From Lie algebra it is shown that the unbroken Lagrangian vacuum symmetry can be identified from a linear function of integers which are Cartan matrix elements. In broken symmetry if the breaking operators form an algebra then the breaking symmetry (or symmetries) can be identified from linear functions of integers characteristic of the breaking symmetries. The results are applied to the Dirac Hamiltonian of a sum of flavored fermions and colored bosons in the absence of dynamical symmetry breaking. In the partially reduced quadratic Hamiltonian the breaking-operator functions are shown to consist of terms of order g/sup 2/, g, and g/sup 0/ in the color coupling constants and identified with strong (boson-boson), medium strong (boson-fermion), and fine-structure (fermion-fermion) interactions. The breaking operators include a boson helicity operator in addition to the familiar fermion helicity and ''spin-orbit'' terms. Within the broken vacuum defined by the conventional formalism, the field divergence yields a gauge which is a linear function of Cartan matrix integers and which specifies the vacuum symmetry. We find that the vacuum symmetry is chiral SU(3) x SU(3) and the axial-vector-current divergence gives a PCAC -like function of the Cartan matrix integers which reduces to PCAC for SU(2) x SU(2) breaking. For the mass spectra of the nonets J/sup P/ = 0/sup -/,1/2/sup +/,1/sup -/ the integer runs through the sequence 3,0,-1,-2, which indicates that the breaking subgroups are the simple Lie groups. Exact axial-vector-current conservation indicates a breaking sum rule which generates octet enhancement. Finally, the second-order breaking terms are obtained from the second-order spin tensor sum of the completely reduced quartic Hamiltonian.

• Research Organization: National University, San Diego, California
• OSTI ID: 6533610
• Journal Information: Phys. Rev., D; (United States), Journal Name: Phys. Rev., D; (United States) Vol. 23:8; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645301* -- High Energy Physics-- Particle Invariance Principles & Symmetries-- General-- (-1987)
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR MOMENTUM
BOSONS
COUPLING CONSTANTS
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
HAMILTONIANS
HELICITY
LAGRANGIAN FUNCTION
LIE GROUPS
MAGNETIC MONOPOLES
MASS SPECTRA
MATHEMATICAL OPERATORS
MATRIX ELEMENTS
MONOPOLES
PARTICLE PROPERTIES
POSTULATED PARTICLES
QUANTUM OPERATORS
SPECTRA
SPIN
SU GROUPS
SU-2 GROUPS
SU-3 GROUPS
SYMMETRY BREAKING
SYMMETRY GROUPS