Weak mixing angle and grand unified gauge theories

Journal Article · Sun Jul 01 04:00:00 EDT 1979 · Phys. Rev., D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.20.274· OSTI ID:6091412

Marciano, W J

We discuss the role of sin/sup 2/theta/sub W/ (theta/sub W/ = weak mixing angle) in the Weinberg-Salam SU(2) x U(1) model. A definition of the renormalized value of sin/sup 2/theta/sub W/ is given, the effects of radiative corrections are considered, and the possibility of precisely determining this parameter experimentally is examined. Within the framework of grand unified gauge theories, we derive an expression for the effective quantity sin/sup 2/theta/sub W/(M/sub W/) which can be compared with experiment. Our results are illustrated for the Georgi-Glashow SU(5) model and their implications regarding the predicted lifetime of the proton tau/sub p/ are discussed. For sin/sup 2/theta/sub W/(M/sub W/) approx. = 0.21--0.20, values consistent with neutral--current measurements, we estimate that the SU(5) model predicts tau/sub p/ approx. = 10/sup 30/--10/sup 33/ yr, a range that is not very far from the present experimental bound. We also show that by increasing the number of scalar multiplets, the model can accommodate larger values for sin/sup 2/theta/sub W/(M/sub W/).

• Research Organization: The Rockefeller University, New York, New York 10021
• OSTI ID: 6091412
• Journal Information: Phys. Rev., D; (United States), Journal Name: Phys. Rev., D; (United States) Vol. 20:1; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645203* -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Weak Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BARYONS
BASIC INTERACTIONS
CORRECTIONS
COUPLING CONSTANTS
ELEMENTARY PARTICLES
FERMIONS
FIELD THEORIES
HADRONS
INTERACTIONS
LIE GROUPS
LIFETIME
MATHEMATICAL MODELS
NUCLEONS
PARTICLE MODELS
PROTONS
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
RADIATIVE CORRECTIONS
RENORMALIZATION
SU GROUPS
SU-2 GROUPS
SYMMETRY GROUPS
U GROUPS
U-1 GROUPS
UNIFIED GAUGE MODELS
WEAK INTERACTIONS
WEINBERG-SALAM GAUGE MODEL