Fermion masses and mixing in a 4+1-dimensional SU(5) domain-wall brane model

Abstract

We study the fermion mass and mixing hierarchy problems within the context of the SU(5) 4+1d domain-wall brane model of Davies, George and Volkas. In this model, the ordinary fermion mass relations of SU(5) grand unified theories are avoided since the masses are proportional to overlap integrals of the profiles of the electroweak Higgs and the chiral components of each fermion, which are split into different 3+1d hyperplanes according to their hypercharges. We show that the fermion mass hierarchy without electroweak mixing can be generated naturally from these splittings, that generation of the CKM matrix looks promising, and that the Cabibbo angle along with the mass hierarchy can be generated for the case of Majorana neutrinos from a more modest hierarchy of parameters. We also show that under some assumptions made on the parameter space, the generation of realistic lepton mixing angles is not possible without fine-tuning, which argues for a flavour symmetry to enforce the required relations.

45 pages, ReVTeX4, 14 figures, 8 tables, references added, some minor adjustments and additions made;v4 some minor corrections to bibliography made

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• The neutrino mass bound from WMAP-3, the baryon acoustic peak, the SNLS supernovae and the Lyman-alpha forest
• The standard model on a domain-wall brane?
• Fermions, scalars and Randall-Sundrum gravity on domain-wall branes
• Kink modes and effective four dimensional fermion and Higgs brane models
• An improved limit on the neutrino mass with CMB and redshift-dependent halo bias-mass relations from SDSS, DEEP2, and Lyman-Break Galaxies
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Cited by in corpus (1)

• Large lepton mixing angles from a 4+1-dimensional SU(5) x A(4) domain-wall braneworld model