4,518 research outputs found
Flipped Angles and Phases: A Systematic Study
We discuss systematically the fermion mass and mixing matrices in a generic
\linebreak field-theoretical flipped model, with particular
applications to neutrino and baryon number-changing physics. We demonstrate
that the different quark flavour branching ratios in proton decay are related
to the Cabibbo-Kobayashi-Maskawa angles, whereas the lepton flavour branching
ratios are undetermined. The light neutrino mixing angles observable via
oscillation effects are related to the heavy conjugate (right-handed) neutrino
mass matrix, which also plays a key role in cosmological baryogenesis. The
ratios of neutrino and charged lepton decay modes in baryon decay may also be
related to neutrino oscillation parameters. Plausible Ans\"atze for the
generation structure of coupling matrices motivate additional relations between
physical observables, and yield a satisfactory baryon asymmetry.Comment: 13 pages, no figures, latex (twice), CERN-TH.6842/93, UMN-TH-1130/93,
CTP-TAMU-11/9
N=2 Supermultiplet of Currents and Anomalous Transformations in Supersymmetric Gauge Theory
We examine some properties of supermultiplet consisting of the U(1)_{J}
current, extended supercurrents, energy-momentum tensor and the central charge
in N=2 supersymmetric Yang-Mills theory. The superconformal improvement
requires adding another supermultiplet beginning with the U(1)_{R} current. We
determine the anomalous (quantum mechanical) supersymmetry transformation
associated with the central charge and the energy-momentum tensor to one-loop
order.Comment: 8 pages, LaTe
Dual models
The author presents a review of dual models; formulations of the theory; string approach; operator formalism; dual fermions; and ends with a brief discussion of unsolved problems. (52 refs)
Cosmic Chemical Evolution with an Early Population of Intermediate Mass Stars
We explore the consequences of an early population of intermediate mass stars
in the 2 - 8 M\odot range on cosmic chemical evolution. We discuss the
implications of this population as it pertains to several cosmological and
astrophysical observables. For example, some very metal-poor galactic stars
show large enhancements of carbon, typical of the C-rich ejecta of low-mass
stars but not of supernovae; moreover, halo star carbon and oxygen abundances
show wide scatter, which imply a wide range of star-formation and
nucleosynthetic histories contributed to the first generations of stars. Also,
recent analyses of the 4He abundance in metal-poor extragalactic H II regions
suggest an elevated abundance Yp \simeq 0.256 by mass, higher than the
predicted result from big bang nucleosynthesis assuming the baryon density
determined by WMAP, Yp = 0.249. Although there are large uncertainties in the
observational determination of 4He, this offset may suggest a prompt initial
enrichment of 4He in early metal-poor structures. We also discuss the effect of
intermediate mass stars on global cosmic evolution, the reionization of the
Universe, the density of white dwarfs, as well as SNII and SNIa rates at high
redshift. We also comment on the early astration of D and 7Li. We conclude that
if intermediate mass stars are to be associated with Population III stars,
their relevance is limited (primarily from observed abundance patterns) to low
mass structures involving a limited fraction of the total baryon content of the
Universe.Comment: Submitted to MNRA
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