Searcharxiv⌕ Search

arXiv subjects

Toby Falk

Publications and source records attributed to Toby Falk.

25 records · Page 2Linked to original sources
arXiv1995

New Constraints on Superpartner Masses

We consider the Minimal Supersymmetric Standard Model (MSSM) without imposing relations on the superpartner masses that arise in grand unified theories. Given an arbitrary pattern of superpartner masses (consistent with experimental constraints), it may happen that the scalar potential is actually unstable, even though all scalar masses-squared are positive at the weak scale $M_W$. This is most likely to happen if the running mass-squared in a ``flat'' direction in field space becomes negative at some scale $Q_0$ which is well below the GUT scale. In this case, either this pattern of masses is ruled out, or there must be new physics (beyond the MSSM) at or below the scale $Q_0$.

hep-ph↗
arXiv1995

Phases in the MSSM, Electric Dipole Moments and Cosmological Dark Matter

We consider the effect of CP violating phases in the MSSM on the relic density of the lightest supersymmetric particle (LSP). In particular, we find that the upper limits on the LSP mass are relaxed when phases in the MSSM are allowed to take non-zero values when the LSP is predominantly a gaugino (bino). Previous limits of $\mb \la 250$ GeV for $Ωh^2 < 0.25$ can be relaxed to $\mb \la 650$ GeV. We also consider the additional constraints imposed by the neutron and electron electric dipole moments induced by these phases. Though there is some restriction on the phases, the bino mass may still be as large as $\sim$ 350 GeV and certain phases can be arbitrarily large.

hep-ph↗
arXiv1994

Heavy Sneutrinos as Dark Matter

We calculate the relic density of very heavy, stable scalar neutrinos in the minimal supersymmetric standard model. We include all two-body final states, as well as the effects of co-annihilation with scalar electrons. We find that the sneutrino relic density is in the cosmologically interesting region $0.1\ltwidΩ_{\sn}h^2\ltwid 1.0$ for $550\gev\ltwid\msn\ltwid 2300\gev$. For nominal values of the parameters of our galactic halo, recent results from the Heidelberg--Moscow direct detection experiment set an upper limit on $Ω_{\sn}$ which is lower by a factor ranging from two to ten, depending on $\msn$.

hep-ph↗
arXiv1992

The Angular Dependence of the Three-Point Correlation Function of the Cosmic Microwave Background Radiation as Predicted by Inflationary Cosmologies

Inflationary models predict a definite, model independent, angular dependence for the three-point correlation function of $ΔT/T$ at large angles (greater than $\sim 1^\circ$) which we calculate. The overall amplitude is model dependent and generically unobservably small, but may be large in some specific models. We compare our results with other models of nongaussian fluctuations.

astro-ph↗
arXiv1992

Dependence of Density Perturbations on the Coupling Constant in a Simple Model of Inflation

In the standard inflationary scenario with inflaton potential $V(Φ)=M^4-{1\over4}λΦ^4$, the resulting density perturbations $δρ/ρ$ are proportional to $λ^{1/2}$. Upper bounds on $δρ/ρ$ require $λ< 10^{-13}$. Ratra has shown that an alternative treatment of reheating results in $δρ/ρ\propto λ^{-1}$, so that an upper bound on $δρ/ρ$ does not put an obvious upper bound on $λ$. We verify that $δρ/ρ\propto λ^{-1}$ is indeed a possibility, but show that $λ< 10^{-13}$ is still required.

astro-ph↗