Neutrino masses in quartification schemes

The idea of quark-lepton universality at high energies has recently been explored in unified theories based upon the quartification gauge group SU(3)^4. These schemes encompass a quark-lepton exchange symmetry that results upon the introduction of leptonic colour. It has been demonstrated that in models in which the quartification gauge symmetry is broken down to the standard model gauge group, gauge coupling constant unification can be achieved, and there is no unique scenario. The same is also true when the leptonic colour gauge group is only partially broken, leaving a remnant SU(2)_\ell symmetry at the standard model level. Here we perform an analysis of the neutrino mass spectrum of such models. We show that these models do not naturally generate small Majorana neutrino masses, thus correcting an error in our earlier quartification paper, but with the addition of one singlet neutral fermion per family there is a realisation of see-saw suppressed masses for the neutrinos. We also show that these schemes are consistent with proton decay.Comment: 12 pages, minor changes. To appear in Phys. Rev.

Jumps in Journalism

Catherine Raymond tells us an intelligent journalist can reap a variety of good position

Behind Closed Doors in Appliance Research

Catherine Raymond reports on work of graduate students in the Household Equipment Departmen

Maintenance of polymorphism in the orb weaving spider species Agalenatea redii (Araneae, Araneidae)

The maintenance of polymorphism within populations may be the consequence of several elements of species life history such as use of space, activity rhythms, predation, parasitism and reproduction. The present study focuses on the latter aspect using an orb weaving spider, Agalenatea redii, which presents five different morphs of the opisthosoma pattern in the adult stage. Over the course of four years, from 2008 to 2011, adult spiders (males, females and pairs) were observed at different sites. In 2011, we also conducted a six-week survey of a single population, observing the number of spiders of each morph and the morph of paired spiders. We collected field data on the spatial and temporal distribution of spiders based on their sex and morph. Using a distance analysis, we compared the field distribution with a simulated one in which pairs were associated at random. The results showed that although there were changes over time and space in the proportions of females of the different morphs, as well as in the proportion of the pair associations, pairing according to morphs probably occurs at random

Versatile Talents Give Homemakers Dual Personalities

Favorites avocations that enhance leisure hours are described by Catherine Raymon

Flashes From the Frontier of Bacteriology

Catherine Raymond investigates the foods work conducted by the Department of Bacteriolog

Piracy and Armed Robbery in the Malacca Strait

The Malacca Strait is a narrow waterway that extends nearly six hundred nautical miles from the Andaman Sea to the South China Sea, between Malaysia and Indonesia. The strait provides a vital shipping lane for vessels sailing from Europe and the Middle East to East Asia, as well as smaller vessels on local voyages. Unfortunately, when we think of the Malacca Strait, images of a waterway infested with pirates often spring to mind