35,916 research outputs found
Thinking About Top: Looking Outside The Standard Model
The top quark is by far the heaviest known fermion [1]. In consequence,
experiment is just beginning to explore its properties, and some of them may
yet prove to be distinctly non-standard. The very size of the top quark's mass
even hints at the possibility of a special role for top in electroweak symmetry
breaking. This talk examines the top quark in the context of physics beyond the
standard model, and discusses how Run II can help elucidate the true nature of
top.Comment: 14 pages, 13 figures, talk presented at the Thinkshop on Top Quark
Physics at Run II, 16-18 October, 1998, Fermila
Technicolor Evolution
This talk describes how modern theories of dynamical electroweak symmetry
breaking have evolved from the original minimal QCD-like technicolor model in
response to three key challenges: R_b, flavor-changing neutral currents, and
weak isospin violation.Comment: 9 pages, 10 figures, RevTeX4.0. Talk given at Snowmass 2001; typo
corrected, references added; reference adde
Strongly-Interacting Heavy Flavors Beyond the Standard Model
The origin of mass must lie in physics beyond the Standard Model. Dynamical
electroweak symmetry breaking models like technicolor can generate masses for
the W and Z bosons. Providing the large top quark mass and large top-bottom
mass splitting while keeping rho parameter and flavor-changing neutral currents
small requires new strong dynamics for the top and bottom quarks. In
consequence, new particles are predicted at scales up to 10 TeV with signatures
in jets or heavy flavors. Searches for these states are underway at Fermilab
and LEP II.Comment: 6 pages, 3 figures, talk given at QCD Moriond (3-20-2000
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Looking for new gluon physics at the Tevatron
The impact of nonrenormalizable gluon operators upon inclusive jet cross
sections is studied. Such operators could arise in an effective strong
interaction Lagrangian from gluon substructure and would induce observable
cross section deviations from pure QCD at high transverse jet energies.
Comparison of the theoretical predictions with recent CDF data yields a lower
limit on the gluon compositeness scale . We find \Lambda > 2.03 \TeV
at ~CL
The Hunting of the MR Model
We consider experimental signatures of the standard model's minimal
supersymmetric extension with a continuous symmetry (MR model). We
focus on the ability of existing and planned electron-positron colliders to
probe this model and to distinguish it from both the standard model and the
standard model's minimal supersymmetric extension with a discrete -parity.Comment: TeX (uses harvmac). 18 pages. Revision: added text and figure about
effects of b-jet tagging at LEP II. 7 figures available on request. CTP \#
2190. HUTP-92/A05
Evaluating the Impact of Government Land Use Policies on Tree Canopy Coverage
Many communities are experiencing the negative effects associated with not sustaining a sufficient level of tree canopy coverage. Tree canopy plays a crucial role in the environment, providing benefits such as clean water and air, erosion prevention, climate control, and sustained ecological resources and native species habitat. Additionally, tree canopy plays an economic role by increasing housing values, alleviating expenditures related to erosion destruction, decreasing spending on sewer standards, increasing energy efficiency, and reducing medical costs related to health issues, such as asthma, that are associated with environmental degradation. To study how local government policies may be related to changes in tree canopy, an empirical study was performed using Greater Metropolitan Atlanta as the study area. The statistical analysis identifies local government policies that are effective, such as specific tree ordinance clauses and zoning regulations. Policies that are ineffective (e.g., a tree board) are also identified.Land Economics/Use,
ECONOMIC POLICY, INSTITUTIONS AND FISHERIES DEVELOPMENT IN THE PACIFIC
The South Pacific is home to the world's largest and most valuable tuna fishery. Despite this, the Pacific island countries have found it tremendously difficult to capture significant economic rents from the resource. It is argued in this paper that poor economic policy partly explains this. However, poor policies are preventing the implementation of strong, cost-effective institutions for the governance of the fishery which, coupled with strong institutions for broad social and economic governance, are required for development of the industry. Opportunities for policy reform that is likely to lead to significant gains from the fishery are highlighted.Resource /Energy Economics and Policy,
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Composite scalars at CERN LEP: Constraining technicolor theories
LEPI and LEPII data can be used to constrain technicolor models with light,
neutral pseudo-Nambu-Goldstone bosons, Pa. We use published limits on branching
ratios and cross sections for final states with photons, large missing energy,
jet pairs, and b bbar pairs to constrain the anomalous Pa Z0 Z0, Pa Z0 photon,
and Pa photon photon couplings. From these results, we derive bounds on the
size of the technicolor gauge group and the number of technifermion doublets in
models such as Low-scale Technicolor
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