5,667 research outputs found
Gauge-Higgs Unification on Flat Space Revised
Models with gauge-Higgs unification on a flat space are typically affected by
common problems, the main of which are the prediction of a too small top and
Higgs mass and a too low compactification scale. We show how, by breaking the
SO(4,1) Lorentz symmetry in the bulk and introducing a Z_2 ``mirror'' symmetry,
a potentially realistic model arises, in which all these problems are solved.Comment: 4 pages, 1 figure, to appear in Proceedings of SUSY06, the 14th
International Conference on Supersymmetry and the Unification of Fundamental
Interactions, UC Irvine, California, 12-17 June 200
The causes of the debt crisis in Europe and the role of regional integration
The factors that allow the launch of a speculative attack, such as those on he government debts of Greece, Spain, Portugal, Ireland and Italy in 2010, are always multiple. In this case, they can be found in some simultaneous events (e.g. the regional German elections of the 9th of May), in some previous faulty behaviors of the governments under attack, and in some defects of the institutional organization of the European Monetary Union. Those who believe that the operation of market forces (and of financial speculation) is always able to bring about efficiency tend to stress the role played by the faulty behaviors of the authorities. Those holding a different standpoint tend to blame the faults in the institutional organization that have prevented the authorities from operating effectively against the speculative attack. For those having faith in the âmarket efficiency hypothesisâ, the government of Greece and of the other countries under attack failed to take advantage of the positive trend of the world economy before the financial crisis.
The Electroweak Phase Transition in Models with Gauge-Higgs Unification
The dynamics of five dimensional Wilson line phases at finite temperature is
studied in the one-loop approximation. We show that at temperatures of order
, where L is the length of the compact space, the gauge symmetry is
always restored and the electroweak phase transition appears to be of first
order.
We focus on a specific model where the Wilson line phase is identified with
the Higgs field (gauge-Higgs unification). The transition is of first order
even for values of the Higgs mass above the current experimental limit. If
large localized gauge kinetic terms are present, the transition might be strong
enough to give baryogenesis at the electroweak transition.Comment: 4 pages, 2 figures, contribution to the Proceedings of the Int.
Europhysics Conf. on High Energy Physics (HEP2005), July 21-27 2005, Lisboa,
Portuga
Flavor hierarchies from dynamical scales
One main obstacle for any beyond the SM (BSM) scenario solving the hierarchy
problem is its potentially large contributions to electric dipole moments. An
elegant way to avoid this problem is to have the light SM fermions couple to
the BSM sector only through bilinears, . This possibility can be
neatly implemented in composite Higgs models. We study the implications of
dynamically generating the fermion Yukawa couplings at different scales,
relating larger scales to lighter SM fermions. We show that all flavor and
CP-violating constraints can be easily accommodated for a BSM scale of few TeV,
without requiring any extra symmetry. Contributions to B physics are mainly
mediated by the top, giving a predictive pattern of deviations in
and flavor observables that could be seen in future experiments.Comment: 25 pages, 5 figures; v2: corrections in some estimate
Resonant diphoton phenomenology simplified
open3noA framework is proposed to describe resonant diphoton phenomenology at hadron colliders in full generality. It can be employed for a comprehensive model-independent interpretation of the experimental data. Within the general framework, few benchmark scenarios are defined as representative of the various phenomenological options and/or of motivated new physics scenarios. Their usage is illustrated by performing a characterization of the 750 GeV excess, based on a recast of available experimental results.
We also perform an assessment of which properties of the resonance could be inferred, after discovery, by a careful experimental study of the diphoton distributions. These include the spin J of the new particle and its dominant production mode. Partial information on its CP-parity can also be obtained, but only for J â„ 2. The complete determination of the resonance CP properties requires studying the pattern of the initial state radiation that accompanies the resonant diphoton production.openPanico, Giuliano; Vecchi, Luca; Wulzer, AndreaPanico, Giuliano; Vecchi, Luca; Wulzer, Andre
On the Interpretation of Top Partners Searches
Relatively light Top Partners are unmistakable signatures of reasonably
Natural Composite Higgs models and as such they are worth searching for at the
LHC. Their phenomenology is characterized by a certain amount of
model-dependence, which makes the interpretation of Top Partner experimental
searches not completely straightforward especially if one is willing to take
also single production into account. We describe a model-independent strategy
by which the interpretation is provided on the parameter space of a Simplified
Model that captures the relevant features of all the explicit constructions.
The Simplified Model limits are easy to interpret within explicit models, in a
way that requires no recasting and no knowledge of the experimental details of
the analyses. We illustrate the method by concrete examples, among which the
searches for a charge 5/3 Partner in same-sign dileptons and the searches for a
charge 2/3 singlet. In each case we perform a theory recasting of the available
8 TeV Run-1 results and an estimate of the 13 TeV Run-2 reach, also including
the effect of single production for which dedicated experimental analyses are
not yet available. A rough assessment of the reach of a hypothetical 100 TeV
collider is also provided
Top Partners Searches and Composite Higgs Models
Colored fermionic partners of the top quark are well-known signatures of the
Composite Higgs scenario and for this reason they have been and will be subject
of an intensive experimental study at the LHC. Performing an assessment of the
theoretical implications of this experimental effort is the goal of the present
paper. We proceed by analyzing a set of simple benchmark models, characterized
by simple two-dimensional parameter spaces where the results of the searches
are conveniently visualized and their impact quantified. We only draw exclusion
contours, in the hypothesis of no signal, but of course our formalism could
equally well be used to report discoveries in a theoretically useful format.Comment: 32 pages, 15 figure
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