Rare B decays, rare. tau. decays, and grand unification

Journal Article · Sun Sep 01 00:00:00 EDT 1991 · Physical Review, D (Particles Fields); (United States)

DOI:https://doi.org/10.1103/PhysRevD.44.1461· OSTI ID:5178786

Sher, M; Yuan, Y ^[1]

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1. Department of Physics, College of William and Mary, Williamsburg, Virginia (USA)

In multi-Higgs-boson extensions of the standard model, tree-level flavor-changing neutral currents exist naturally, unless suppressed by some symmetry. For a given rate, the exchanged scalar or pseudoscalar mass is very sensitive to the flavor-changing coupling between the first two generations. Since the Yukawa couplings of the first two generations are unknown and certainly very small, bounds which rely on some assumed value of this flavor-changing coupling are quite dubious. One might expect the size (and reliability) of the Yukawa couplings involving the third generation to be greater. In this paper, we consider processes involving {tau}'s and {ital B}'s, and determine the bounds on the flavor-changing couplings which involve third-generation fields. The strongest bound in the quark sector comes from {ital B}-{ital {bar B}} mixing and in the lepton sector, surprisingly, from {mu}{r arrow}{ital e}{gamma}. It is then noted that the flavor-changing couplings in the quark sector are related to those in the lepton sector in many grand unified theories, and one can ask whether an analysis of rare {tau} decays or rare {ital B} decays will provide the strongest constraints. We show that rare {ital B} decays provide the strongest bounds, and that {ital no} useful information can be obtained from rare {tau} decays. It is also noted that the most promising decay modes are {ital B}{r arrow}{ital K}{mu}{tau} and {ital B}{sub {ital s}}{r arrow}{mu}{tau}, and we urge experimenters to look for rare decay modes of the {ital B} in which a {tau} is in the final state.

• OSTI ID: 5178786
• Journal Information: Physical Review, D (Particles Fields); (United States), Vol. 44:5; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
B MESONS
LEPTONIC DECAY
COUPLING
FLAVOR MODEL
GRAND UNIFIED THEORY
HIGGS BOSONS
KAONS
MASS DIFFERENCE
MUONS
NEUTRAL CURRENTS
QUARKS
RADIATIVE DECAY
STANDARD MODEL
TAU PARTICLES
YUKAWA POTENTIAL
ALGEBRAIC CURRENTS
BASIC INTERACTIONS
BEAUTY PARTICLES
BOSONS
COMPOSITE MODELS
CURRENTS
DECAY
ELEMENTARY PARTICLES
FERMIONS
FIELD THEORIES
HADRONS
HEAVY LEPTONS
INTERACTIONS
LEPTONS
MATHEMATICAL MODELS
MESONS
NUCLEAR POTENTIAL
PARTICLE DECAY
PARTICLE MODELS
PARTICLE PROPERTIES
POSTULATED PARTICLES
POTENTIALS
PSEUDOSCALAR MESONS
QUARK MODEL
STRANGE MESONS
STRANGE PARTICLES
UNIFIED GAUGE MODELS
UNIFIED-FIELD THEORIES
WEAK INTERACTIONS
WEAK PARTICLE DECAY
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