62,842 research outputs found
New Physics Searches with Photons in CDF
A brief review of searches for physics beyond the Standard Model with photons
using the CDF detector at the Tevatron is given here. These include searches
for supersymmetry, extra dimensions, excited electrons and W/Z
production, as well as anomalous photon production. Recent results from CDF Run
II experiment is presented, but some results from Run I are also reviewed.Comment: To appear in the Proceedings of SUSY 2003, held at the University of
Arizona, Tucson, AZ, 5-10 June 200
Intrinsic Brightness Temperature of Compact Radio Sources at 86 GHz
We present results on the intrinsic brightness temperature of a sample of
compact radio sources observed at 86 GHz using the Global Millimeter VLBI
Array. We use the observed brightness temperatures at 86 GHz and the observed
superluminal motions at 15 GHz for the sample in order to constrain the
characteristic intrinsic brightness temperature of the sample. With a
statistical method for studying the intrinsic brightness temperatures of
innermost jet cores of compact radio sources, assuming that all sources have
the same intrinsic brightness temperature and the viewing angles of their jets
are around the critical value for the maximal apparent speed, we find that
sources in the sample have a characteristic intrinsic brightness temperature,
K, which is lower than the
equipartition temperature for the condition that the particle energy equals to
the magnetic field energy. Our results suggest that the VLBI cores seen at 86
GHz may be representing a jet region where the magnetic field energy dominates
the total energy in the jet.Comment: 9 pages, 4 figures, one table, to appear in JKAS. Corrections made
for typos and Journal's further request
Quantum Renormalization Group and Holography
Quantum renormalization group scheme provides a microscopic understanding of
holography through a general mapping between the beta functions of underlying
quantum field theories and the holographic actions in the bulk. We show that
the Einstein gravity emerges as a long wavelength holographic description for a
matrix field theory which has no other operator with finite scaling dimension
except for the energy-momentum tensor. We also point out that holographic
actions for general large N matrix field theories respect the inversion
symmetry along the radial direction in the bulk if the beta functions of
single-trace operators are gradient flows with respect to the target space
metric set by the beta functions of double-trace operators.Comment: 5 pages; 1 figure; v2) references adde
Muon g-2 Anomaly and Dark Leptonic Gauge Boson
One of the major motivations to search for a dark gauge boson of MeV-GeV
scale is the long-standing muon g-2 anomaly. Because of active searches such as
fixed target experiments and rare meson decays, the muon g-2 favored parameter
region has been rapidly reduced. With the most recent data, it is practically
excluded now in the popular dark photon model. We overview the issue and
investigate a potentially alternative model based on the gauged lepton number
or U(1)_L. The muon g-2 favored parameter region of the U(1)_L survives all the
constraints that were critical in the dark photon case, yet it is disfavored by
the new constraints from the large flux neutrino experiments.Comment: Version to appear in PR
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