2,388 research outputs found
Limits on a Strong Electroweak Sector from e^+ e^- -> 2gamma + missing E at LEP2
We study the process in the context
of a strong electroweak symmetry breaking model, which can be a source of
events with two photons and missing energy at LEP2. We investigate bounds on
the model assuming that no deviation is observed from the Standard Model within
a given experimental error.Comment: 7 pages, Latex, one figur
The PTA: Promoting Swiss Tours, 1888-1939
This research examines the development from educational to commercial tourism in Britain between the late-nineteenth and early-twentieth century by questioning whether this reflected a transformed understanding of the role of travel within society. It focuses on the Polytechnic Touring Association (PTA), a London-based originally philanthropic travel organisation that became a commercial firm. During this period the PTA moved from the project of contributing to the education of citizens to the market-led imperative of ‘harnessing’ a consumer desire. In examining this transformation via the PTA’s changing approach to the visual promotion of its Swiss tours, we suggest that the development of the tourism industry in Britain should also be explored in relation to changing ideas about travel’s contribution to social formation
A linear moose model with pairs of degenerate gauge boson triplets
The possibility of the existence of a strongly interacting electroweak
symmetry breaking sector, as opposed to the weakly interacting light Higgs of
the Standard Model, is not yet ruled out by experiments. In this paper we make
an extensive study of a deconstructed model (or ``moose'' model) providing a
possible effective description of such a strong symmetry breaking sector, and
show its compatibility with experimental data for a wide portion of the model
parameters space. The model is a direct generalization of the previously
proposed D-BESS model.Comment: Latex file, 17 pages, 2 figures, published versio
Effective fermion couplings in warped 5D Higgsless theories
We consider a five dimensional SU(2) gauge theory with fermions in the bulk
and with additional SU(2) and U(1) kinetic terms on the branes. The electroweak
breaking is obtained by boundary conditions. After deconstruction, fermions in
the bulk are eliminated by using their equations of motion. In this way
Standard Model fermion mass terms and direct couplings to the internal gauge
bosons of the moose are generated. The presence of these new couplings gives a
new contribution to the epsilon_3 parameter in addition to the gauge boson
term. This allows the possibility of a cancellation between the two
contributions, which can be local (site by site) or global. Going back to the
continuum, we show that the implementation of local cancellation in any generic
warped metric leaves massless fermions. This is due to the presence of one
horizon on the infrared brane. However we can require a global cancellation of
the new physics contributions to the epsilon_3 parameter. This fixes relations
among the warp factor and the parameters of the fermion and gauge sectors.Comment: Latex file, 23 pages, 1 eps figur
Comparing electroweak data with a decoupling model
Present data, both from direct Higgs search and from analysis of electroweak
data, are starting to become rather restrictive on the possible values for the
mass of the standard model Higgs. We discuss a new physics scenario based on a
model with decoupling (both in a linear and in a non linear version) showing
how it allows for an excellent fit to the present values of the
parameters and how it widens the allowed ranges for the Higgs mass (thought as
elementary in the linear version, or as composite in the non linear one).Comment: 10 pages, 3 Figures Late
Bounds on New Physics from the New Data on Parity Violation in Atomic Cesium
We assume the latest experimental determination of the weak charge of atomic
cesium and analyze its implications for possible new physics. We notice that
the data would imply positive upper and lower bounds on the new physics
contribution to the weak charge, . The required new physics should
be of a type not severely constrained by the high energy precision data. A
simplest possibility would be new neutral vector bosons almost un-mixed to the
and with sizeable couplings to fermions. The lower positive bound would
however forbid zero or negative and exclude not only the standard
model but also models with sequential , in particular simple-minded
towers of -like excitations from extra-dimensions. The bound would also
imply an upper limit on the mass within the models allowed.
Conclusions are also derived for models of four-fermion contact interactions.Comment: 11 pages, Latex, 1 PS figure, final version for Physics Letter
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