21,722 research outputs found
Electroweak Limits on Non-Universal Z' Bosons
Many types of physics beyond the standard model include an extended
electroweak gauge group. If these extensions are associated with flavor
symmetry breaking, the gauge interactions will not be flavor-universal. In this
note we update the bounds placed by electroweak data on the existence of flavor
non-universal extensions to the standard model in the context of topcolor
assisted technicolor (TC2), noncommuting extended technicolor (NCETC), and the
ununified standard model (UUM). In the first two cases the extended gauge
interactions couple to the third generation fermions differently than to the
light fermions, while in the ununified standard model the gauge interactions
couple differently to quarks and leptons. The extra SU(2) triplet of gauge
bosons in NCETC and UUM models must be heavier than about 3 TeV, while the
extra Z boson in TC2 models must be heavier than about 1 TeV.Comment: 17 pages, 5 figures; added references; updated figure
Diophantine approximation in Banach spaces
In this paper, we extend the theory of simultaneous Diophantine approximation
to infinite dimensions. Moreover, we discuss Dirichlet-type theorems in a very
general framework and define what it means for such a theorem to be optimal. We
show that optimality is implied by but does not imply the existence of badly
approximable points
Testing Extended Technicolor With
We review the connection between and the vertex in ETC
models and demonstrate the power of the resulting experimental constraint on
models with weak-singlet ETC bosons. Some efforts to bring ETC models into
agreement with experimental data on the vertex are mentioned, and
the most promising one (non-commuting ETC) is discussed in detail.Comment: Talk given by E.H. Simmons at the Yukawa International Seminar `95 in
Kyoto, 21-26 August, 1995 and at the International Symposium on Heavy Flavor
and Electroweak Theory in Beijing, 17-19 August, 1995. Latex (uses PTPTeX.sty
and epsf). 9 pages. 1 figure. Full postscript version available at
http://smyrd.bu.edu/ . (minor typos corrected
Debt and Risk Preference: A Household Level Analysis
We explore the relationship between risk preference and the level of unsecured debt at the household level within the context of a two period theoretical framework, which predicts that debt is a function of risk aversion. We test the predictions of our theoretical framework for a sample of households drawn from the U.S. Panel Study of Income Dynamics (PSID) and the U.S. Survey of Consumer Finances (SCF). Using a sequence of questions from the 1996 PSID and the 1989 to 2004 SCF, we construct measures of risk preference allowing us to explore the implications of interpersonal differences in risk preference for the accumulation of unsecured debt at the household level. Our empirical findings, which accord with our theoretical priors, suggest that risk preference is an important determinant of the level of unsecured debt acquired at the household level with risk aversion serving to reduce the level of unsecured debt accumulated by households
Geology of the Mohon Mountain volcanic field, Yavapai and Mohave Counties, Arizona: A preliminary report
Field mapping has produced a preliminary picture of Mohon Mountain as a composite volcano, in which pyroclastic ash and larger tephra erupted alternately with flows of rhyodacite and dacite. An analog study which uses imagery of lunar and Martian features will compare the overall shape of the vent complex, including its breached southern flank and satellite vents, to similar landforms found on Mars and the Moon which are believed to have formed similar processes. Ash flow sheets were hypothesized to comprise the outer slopes of Olympus Mons suggesting that explosive eruptions which are more volatile-rich than those which produce basalt flows are not confined to terrestrial settings but may also be found on bodies such as Mars, which have a thicker crust and deeper magma source in the mantle. The analog study will explore further evidence for explosive eruptions on Mars and the Moon
An electric quadrupole transition in the A1pi - X1sigma system of CO
Electric quadrupole transition in carbon monoxid
Condensate Enhancement and D-Meson Mixing in Technicolor Theories
Since the pioneering work of Eichten and Lane it has been known that the
scale of the interactions responsible for the generation of the strange-quark
mass in extended technicolor theories must, absent any "GIM-like" mechanism for
suppressing flavor-changing neutral currents, be greater than of order 1000
TeV. In this note we point out that the constraint from the neutral D-meson
system is now equally strong, implying that the charm quark mass must also
arise from flavor dynamics at a scale this high. We then quantify the degree to
which the technicolor condensate must be enhanced in order to yield the
observed quark masses, if the extended technicolor scale is of order 1000 TeV.
Our results are intended to provide a framework in which to interpret and apply
the results of lattice studies of conformal strongly interacting gauge
theories, and the corresponding numerical measurements of the anomalous
dimension of the mass operator in candidate theories of "walking" technicolor.Comment: 6 pages, references added and re-ordere
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