Showing papers by "Graciela B. Gelmini published in 1987"
TL;DR: In this article, an ultralow background spectrometer is used as a detector of cold dark matter candidates from the halo of our galaxy using a realistic model for the galactic halo, large regions of the mass-cross section space are excluded for important halo component particles.
244 citations
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TL;DR: The solar neutrino problem can be solved if the sun has accreted a sufficient number of weakly interacting particles from the dark matter of the galaxy as discussed by the authors, and three explicit particle physics models for these cosmions are given, each having a different mechanism for suppressing cosmion annihilations in the sun.
73 citations
TL;DR: It is shown that semiconducting Ge detectors for axions could eventually set limits F/2${x}_{e}^{\mathcal{'}}$${g10}^{8}$ GeV, which if discovered would not only allow us to study physics at energies beyond the reach of accelerators but would also provide a new laboratory tool to study the deep interior of stars.
Abstract: Laboratory bounds on the couplings to electrons of light pseudoscalars such as axions, familons, Majorons, etc., are set with an ultralow-background germanium spectrometer using a realistic model for the Sun. In particular Dine-Fischler-Srednicki axion models with F/2${x}_{e}^{\mathcal{'}}$\ensuremath{\lesssim}0.5\ifmmode\times\else\texttimes\fi{}${10}^{7}$ GeV are excluded. It should be emphasized that this is a laboratory bound. It does not rely on a detailed understanding of the dynamics and evolution of red giants, white dwarfs, or other stars as do the more speculative astrophysical bounds which are competitive with our laboratory bound. The lower limit should be improved to F/2${x}_{e}^{\mathcal{'}}$g1.8\ifmmode\times\else\texttimes\fi{}${10}^{7}$ GeV in the near future. It is shown that semiconducting Ge detectors for axions could eventually set limits F/2${x}_{e}^{\mathcal{'}}$${g10}^{8}$ GeV. If discovered, axions or other light weakly interacting bosons would not only allow us to study physics at energies beyond the reach of accelerators but would also provide a new laboratory tool to study the deep interior of stars.
50 citations
01 Jan 1987
TL;DR: In the context of cosmology, the authors showed that a viable supergravity model must also have an acceptable cosmology for solving cosmological problems of the standard Big Bang model, such as the horizon, flatnessoldness, entropy problems and the production of density fluctuations.
Abstract: There are deep connections between supersymmetry and cosmology. Supersymmetry, actually supergravity or superstring theories,1 offers the hope of unifying all particle interactions. N=1 supersymmetry at “low” (with respect to the Planck scale) energies may produce a good phenomenology of particle physics while solving the gauge hierarchy problem in Grand Unified Theories (GUT). A viable supergravity model must also have an acceptable cosmology. For example, it must produce inflation, which is required not only to solve cosmological problems of the standard Big Bang model, such as the horizon, flatnessoldness, entropy problems and the production of density fluctuations. Inflation is also required to solve internal problems of the elementary particle models, for example to dilute the number of monopoles (or walls) in GUT’s or the number of gravitinos in minimal supergravity. An important constraint on supersymmetric models is to avoid the “entropy crisis” on (Polyonyi” problem). This is a strong constraint on fields coupled only gravitationally to matter (such as the gravitino or fields in the “hidden sector” of supergravity models) which on decay generate too large entropy at late times (e.g., after nucleosynthesis). On the other hand cosmology may need supersymmetry not only to provide the Theory of Everything. Inflation may require supersymmetry to produce very flat potentials, needed to get small enough density perturbations during inflation and maybe, to have inflation at all (at least in semiclassical descriptions).
1 citations