148 research outputs found
Effective operator contributions to the oblique parameters
We present a model and process independent study of the contributions from
non-Standard Model physics to the oblique parameters S, T and U. We show that
within an effective lagrangian parameterization the expressions for the oblique
parameters in terms of observables are consistent, while those in terms of the
vector-boson vacuum polarization tensors are ambiguous. We obtain the
constraints on the scale of new physics derived from current data on S, T and U
and note that deviations in U from its Standard Model value would favor a
scenario where the underlying physics does not decouple.Comment: 13 pages, RevTe
Asymmetric dark matter with a possible Bose-Einstein condensate
We investigate the properties of a Bose gas with a conserved charge as a dark
matter candidate, taking into account the restrictions imposed by relic
abundance, direct and indirect detection limits, big-bang nucleosynthesis and
large scale structure formation constraints. We consider both the WIMP-like
scenario of dark matter masses 1 GeV, and the small mass scenario,
with masses eV. We determine that a Bose-Einstein
condensate will be present at sufficiently early times, but only for the
small-mass scenario it will remain at the present epoch
Non-standard t production at the NLC
The top-quark system as a probe for new physics is considered using a consistent, gauge-invariant effective Lagrangian approach. The magnitude of new effects is estimated and the results are applied to top production through W fusion. Other processes are also briefly discussed
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