25,186 research outputs found
Hybrid Performance of the Pierre Auger Observatory
A key feature of the Pierre Auger Observatory is its hybrid design, in which
ultra high energy cosmic rays are detected simultaneously by fluorescence
telescopes and a ground array. The two techniques see air showers in
complementary ways, providing important cross-checks and measurement
redundancy. Much of the hybrid capability stems from the accurate geometrical
reconstruction it achieves, with accuracy better than either the ground array
detectors or a single telescope could achieve independently. We have studied
the geometrical and longitudinal profile reconstructions of hybrid events. We
present the results for the hybrid performance of the Observatory, including
trigger efficiency, energy and angular resolution, and the efficiency of the
event selection.Comment: Contribution to the 30th International Cosmic Ray Conference, Merida
Mexico, July 200
Chiral-logarithmic Corrections to the S and T Parameters in Higgsless Models
Recently, Higgsless models have proven to be viable alternatives to the
Standard Model (SM) and supersymmetric models in describing the breaking of the
electroweak symmetry. Whether extra-dimensional in nature or their
deconstructed counterparts, the physical spectrum of these models typically
consists of ``towers'' of massive vector gauge bosons which carry the same
quantum numbers as the SM W and Z. In this paper, we calculate the one-loop,
chiral-logarithmic corrections to the S and T parameters from the lightest
(i.e. SM) and the next-to-lightest gauge bosons using a novel application of
the Pinch Technique. We perform our calculation using generic Feynman rules
with generic couplings such that our results can be applied to various models.
To demonstrate how to use our results, we calculate the leading
chiral-logarithmic corrections to the S and T parameters in the deconstructed
three site Higgsless model. As we point out, however, our results are not
exclusive to Higgsless models and may, in fact, be used to calculate the
one-loop corrections from additional gauge bosons in models with fundamental
(or composite) Higgs bosons.Comment: 45 pages, 15 figures, added references, analysis of three site model
expanded to include delocalized fermion
Higgs Boson Production with Bottom Quarks at Hadron Colliders
We present results for the production cross section of a Higgs Boson with a
pair of bottom/anti-bottom quarks, including next-to-leading order (NLO) QCD
corrections.Comment: 3 pages, 2 figures, uses ws-ijmpa.cls. Talk given by C.B. Jackson at
the Meeting of the Division of Particles and Fields (DPF2004) in Riverside,
CA, August 26-31, 200
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