Large transition magnetic moment of the neutrino from horizontal symmetry

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Physical Review, D (Particles Fields); (USA)

DOI:https://doi.org/10.1103/PhysRevD.42.3778· OSTI ID:5827493

Babu, K S; Mohapatra, R N ^[1]

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1. Department of Physics and Astronomy, University of Maryland, College Park, Maryland 20742 (USA)

The apparent anticorrelation of the solar-neutrino signal with the 11-yr sunspot cycle observed by Davis can be understood if the electron neutrino has a large magnetic moment. We discuss extensions of the standard model, where the existence of a leptonic SU(2){sub {ital H}}-horizontal symmetry between the electron and muon generations provides a way to understand such a large magnetic moment, while keeping the neutrino mass naturally small. A global {ital l}{sub {ital e}}{endash}{ital l}{sub {mu}} symmetry ({ital l}{sub {ital i}}={ital i}th lepton number) is maintained even after spontaneous gauge symmetry breaking, so that the neutrino is of Zeldovich-Konopinski-Mahmoud type with {ital m}{sub {nu}{sub {ital e}}}{sup 2}{minus}{ital m}{sub {nu}{sub {mu}}}{sup 2}=0. This condition automatically guarantees that the neutrino spin precession in the magnetic field of the Sun is not suppressed. Of the two extensions of the standard model that we discuss, the first one is a local SU(2){sub {ital H}} model with the horizontal symmetry broken completely at a TeV scale. We show how a global U(1){sub {ital l}{sub {ital e}}{minus}{ital l}{sub {mu}}} can be maintained although {ital l}{sub {ital e}}{minus}{ital l}{sub {mu}} is a subgroup of the gauged SU(2){sub {ital H}}. The second example is the minimal supersymmetric extension of the standard model with {ital R}-parity-violating (but ({ital l}{sub {ital e}}{endash}{ital l}{sub {mu}})-conserving) interactions. An approximate SU(2){sub {ital H}} symmetry between the {ital e}-{mu} families is imposed in order to suppress the neutrino mass, but not its magnetic moment. We provide a detailed theoretical and phenomenological investigation of these two models and discuss their tests at the colliders as well as in low-energy experiments. The models generally predict {ital m}{sub {nu}{sub {ital e}}}{approx equal}1--10 eV and the existence of charged scalar particles in the mass range of 100 GeV.

• OSTI ID: 5827493
• Journal Information: Physical Review, D (Particles Fields); (USA), Journal Name: Physical Review, D (Particles Fields); (USA) Vol. 42:11; ISSN PRVDA; ISSN 0556-2821
• 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
ANGULAR MOMENTUM
DIFFERENTIAL EQUATIONS
DIRAC EQUATION
ELECTRON NEUTRINOS
ELEMENTARY PARTICLES
EQUATIONS
ERUPTIVE VARIABLE STARS
FERMIONS
GAUGE INVARIANCE
INVARIANCE PRINCIPLES
LEPTONS
LIE GROUPS
MAGNETIC MOMENTS
MASS
MASSLESS PARTICLES
MATHEMATICAL MODELS
MUONS
NEUTRINOS
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE MODELS
PARTICLE PROPERTIES
RADIATIONS
SOLAR ACTIVITY
SOLAR CYCLE
SOLAR NEUTRINOS
SOLAR PARTICLES
SOLAR RADIATION
SPIN
STANDARD MODEL
STARS
STARSPOTS
STELLAR ACTIVITY
STELLAR RADIATION
SU GROUPS
SU-2 GROUPS
SUNSPOTS
SUPERNOVAE
SUPERSYMMETRY
SYMMETRY
SYMMETRY BREAKING
SYMMETRY GROUPS
U GROUPS
U-1 GROUPS
UNIFIED GAUGE MODELS
VARIABLE STARS
WAVE EQUATIONS