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- John McDonald
- 2008

In light of recent interest in minimal extensions of the Standard Model and gauge singlet scalar cold dark matter, we provide an arXiv preprint of the paper, published as Phys.Rev. D50 (1994) 3637, which presented the first detailed analysis of gauge singlet scalar cold dark matter. Abstract We consider a very simple extension of the standard model in which… (More)

- John McDonald
- 2003

We consider the possibility that a right-handed sneutrino can serve as the source of energy density perturbations leading to structure formation in cos-mology. The cosmological evolution of a coherently oscillating condensate of right-handed sneutrinos is studied for the case where reheating after inflation is due to perturbative inflaton decays. For the… (More)

- John McDonald
- 1978

We consider some of the issues surrounding the formation and evolution of Q-balls in the MSSM and its extensions. The ratio of the baryon number packed into Q-balls to that outside, f B , plays a fundamental role in determining the relationship of dark matter to the baryon number in the Universe at present. The final value of f B will depend upon the… (More)

- Shahrnaz Azizi, Douglas Cochran, John N. McDonald
- IEEE Trans. Information Theory
- 2002

Supergravity corrections due to the energy density of a right-handed sneu-trino can generate a negative mass squared for the inflaton, flattening the infla-ton potential and reducing the spectral index and inflaton energy density. For the case of D-term hybrid inflation, we show that the spectral index can be lowered from the conventional value n = 0.98 to… (More)

- Sneutrino Curvaton, John McDonald
- 2004

We consider the conditions which must be satisfied for a massive right-handed (r.h.) sneutrino associated with the seesaw mechanism of Majorana neutrino masses to play the role of the curvaton. Planck-scale suppressed non-renormalizable terms in the r.h.neutrino superpotential must be eliminated to a high order if the r.h.sneutrino curvaton is to dominate… (More)

We show that Q-balls naturally exist in the Minimal Supersymmetric Standard Model (MSSM) with soft SUSY breaking terms of the minimal N=1 SUGRA type. These are associated with the F-and D-flat directions of the scalar potential once radiative corrections are taken into account. We consider two distinct cases, corresponding to the " H u L " (slepton)… (More)

- John McDonald
- 2009

We study the cosmological constraints on unparticle interactions and the temperature of the Universe for an unparticle sector with dimensional transmu-tation scale Λ U > ∼ 1 TeV. By considering thermal background quark decay to unparticles via a scalar operator of dimension d U , we show that the condition that the Universe is not dominated by unparticles… (More)

- John McDonald
- 2008

A large neutrino asymmetry is an interesting possibility for cosmology, which can have significant observable consequences for nucleosynthesis and the cosmic microwave background. However, although it is a possibility, there is no obvious reason to expect the neutrino asymmetry to be observably large. Here we note that if the baryon asymmetry originates via… (More)

- John McDonald
- 2008

It is usually assumed that the order H 2 corrections to the SUSY-breaking mass squared terms in the early Universe must be negative in order to allow the Affleck-Dine mechanism to work. We reconsider this assumption in the context of D-term inflation models for the case where the mass squared term has a correction cH 2 with c > 0. We show that, in general,… (More)