Flavor symmetries and fermion masses

Thesis/Dissertation · Fri Apr 01 00:00:00 EST 1994

DOI:https://doi.org/10.2172/10179336· OSTI ID:10179336

Rasin, Andrija ^[1]

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1. Univ. of California, Berkeley, CA (United States)

We introduce several ways in which approximate flavor symmetries act on fermions and which are consistent with observed fermion masses and mixings. Flavor changing interactions mediated by new scalars appear as a consequence of approximate flavor symmetries. We discuss the experimental limits on masses of the new scalars, and show that the masses can easily be of the order of weak scale. Some implications for neutrino physics are also discussed. Such flavor changing interactions would easily erase any primordial baryon asymmetry. We show that this situation can be saved by simply adding a new charged particle with its own asymmetry. The neutrality of the Universe, together with sphaleron processes, then ensures a survival of baryon asymmetry. Several topics on flavor structure of the supersymmetric grand unified theories are discussed. First, we show that the successful predictions for the Kobayashi-Maskawa mixing matrix elements, V_ub/V_cb = √m_u/m_c and V_td/V_ts = √m_d/m_s, are a consequence of a large class of models, rather than specific properties of a few models. Second, we discuss how the recent observation of the decay β → sγ constrains the parameter space when the ratio of the vacuum expectation values of the two Higgs doublets, tanβ, is large. Finally, we discuss the flavor structure of proton decay. We observe a surprising enhancement of the branching ratio for the muon mode in SO(10) models compared to the same mode in the SU(5) model.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 10179336
• Report Number(s): LBL-35586; ON: DE94018192
• Resource Relation: Other Information: TH: Thesis (Ph.D.); PBD: Apr 1994
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
FLAVOR MODEL
SYMMETRY
GRAND UNIFIED THEORY
SUPERSYMMETRY
PROTONS
WEAK PARTICLE DECAY
FERMIONS
REST MASS
KOBAYASHI-MASKAWA MATRIX
HIGGS MODEL
B MESONS
662120
662210
662360
SYMMETRY
CONSERVATION LAWS
CURRENTS AND THEIR PROPERTIES
UNIFIED THEORIES AND MODELS
DECAYS OF BARYONS