Natural suppression of symmetry violation in gauge theories: Muon- and electron-lepton-number nonconservation

Journal Article · Thu Sep 01 04:00:00 EDT 1977 · Phys. Rev., D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.16.1444· OSTI ID:5297490

Lee, B W; Shrock, R E

We analyze the circumstances under which the violations of an approximate symmetry in a unified gauge theory of weak interactions are naturally suppressed; in particular, we investigate approximate muon- and electron-type lepton-number conservation as an example of such a symmetry. Extending earlier work, we propose a unified treatment of this symmetry together with strangeness conservation by the weak neutral current and CP invariance. The rate for the decay ..mu.. ..-->.. e..gamma.. is calculated for a general SU(2) x U(1) gauge model. From this and a similar study of the decay ..mu.. ..-->.. eee-bar we derive a set of conditions which guarantees that the violation of muon- and electron-type lepton-number conservation is naturally strongly suppressed. As part of this, we compute the nondiagonal electromagnetic vertex to one-loop order for an arbitrary SU(2) x U(1) gauge theory. We then focus on the phenomenological predictions of a particular gauge model with three left-handed doublets of leptons and quarks. These include the existence of charged and neutral heavy leptons and of small violations of ..mu..-e universality and the relation G/sub F//sup ..beta../C-italic = G/sub F//sup ..mu../Other muon- and electron-number-violating effects include nonvanishing rates for the decays K/sup + -/ +- emu-bar and K/sub L/ ..-->.. emu-bar, and for the reactions ..mu.. + N ..-->.. e + N and ..nu../sub ..mu..//sub ts(tsN tsarrow-righttse-/ + X.

• Research Organization: Fermi National Accelerator Laboratory, Batavia, Illinois 60510
• OSTI ID: 5297490
• Journal Information: Phys. Rev., D; (United States), Journal Name: Phys. Rev., D; (United States) Vol. 16:5; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645203* -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- Weak Interactions & Properties
645302 -- High Energy Physics-- Particle Invariance Principles & Symmetries-- Applications to Electromagnetic & Weak Interactions-- (-1987)
645400 -- High Energy Physics-- Field Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGEBRAIC CURRENTS
BASIC INTERACTIONS
BOSONS
CONSERVATION LAWS
CURRENTS
DECAY
ELECTRON-MUON UNIVERSALITY
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HEAVY LEPTONS
INTERACTIONS
INVARIANCE PRINCIPLES
KAONS
LEPTON NUMBER
LEPTONIC DECAY
LEPTONS
LIE GROUPS
MATHEMATICAL MODELS
MESONS
MUONS
NEUTRAL CURRENTS
P INVARIANCE
PARTICLE DECAY
PARTICLE MODELS
PARTICLE PROPERTIES
POSTULATED PARTICLES
PSEUDOSCALAR MESONS
STRANGE PARTICLES
STRANGENESS
SU GROUPS
SU-2 GROUPS
SYMMETRY
SYMMETRY GROUPS
U GROUPS
U-1 GROUPS
UNIFIED GAUGE MODELS
WEAK INTERACTIONS
WEAK NEUTRAL CURRENTS