arXiv subjects

Keith Olive

Publications and source records attributed to Keith Olive.

21 records · Page 2Linked to original sources

arXiv1996

Supersymmetric Dark Matter in the Light of LEP 1.5

We discuss the lower limit on the mass of the neutralino $χ$ that can be obtained by combining data from $e^+e^-$ annihilation at LEP and elsewhere with astrophysical and theoretical considerations. Loopholes in the purely experimental analysis of ALEPH data from the Z peak and LEP 1.5, which appear when $μ<0$ for certain values of the sneutrino mass $m_{\tildeν}$ and the ratio $\tanβ$ of supersymmetric Higgs vacuum expectation values, may be largely or totally excluded by data from lower-energy $e^+e^-$ data, the hypothesis that most of the cosmological dark matter consists of $χ$ particles, and the assumption that electroweak symmetry breaking is triggered by radiative corrections due to a heavy top quark. The combination of these inputs imposes $m_χ \ge 21.4~\gev$, if soft supersymmetry-breaking masses are assumed to be universal at the grand-unification scale.

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

Cosmic Ray Models for Early Galactic Lithium, Beryllium, and Boron Production

To understand better the early galactic production of Li, Be, and B by cosmic ray spallation and fusion reactions, the dependence of these production rates on cosmic ray models and model parameters is examined. The sensitivity of elemental and isotopic production to the cosmic ray pathlength magnitude and energy dependence, source spectrum, spallation kinematics, and cross section uncertainties is studied. Changes in these model features, particularly those features related to confinement, are shown to alter the Be- and B-versus-Fe slopes {}from a na\"ıve quadratic relation. The implications of our results for the diffuse $γ$-ray background are examined, and the role of chemical evolution and its relation to our results is noted. It is also noted that the unmeasured high energy behavior of $α+α$ fusion can lead to effects as large as a factor of 2 in the resultant yields. Future data should enable Population II Li, Be, and B abundances to constrain cosmic ray models for the early Galaxy.

astro-ph↗