Axions
are particles invoked to resolve the strong CP violation
problem [74]. Without these particles, the level of CP violation seen in the
decay would give rise to a neutron electric dipole moment in
excess of the limits already established. The allowable mass
range for the axion is constrained by astrophysical arguments to
to
.
WIMPs
are naturally predicted in supersymmetry theories in which a
higher level symmetry is obtained in the particle families by
introducing new particles to match each of the known particles.
In the so-called minimal supersymmetry models (MSSM), the
lightest supersymmetric particle (LSP) is likely to be a
neutralino
, which is a mixture of two neutral gauginos and two neutral
higgsinos [79
]:
There are numerous parameters required to specify a particular
MSSM configuration. It turns out that there is a wide range of
parameter space in which the production and annihilation rates in
the early universe are such that
[45
]. The mass range for neutralinos is
, where the lower limit comes from accelerator data from
LEP [66
].
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Experimental Searches for Dark Matter
Timothy J. Sumner http://www.livingreviews.org/lrr-2002-4 © Max-Planck-Gesellschaft. ISSN 1433-8351 Problems/Comments to livrev@aei-potsdam.mpg.de |