10,236 research outputs found
A Simple-Minded Unitarity Constraint and an Application to Unparticles
Unitarity, a powerful constraint on new physics, has not always been properly
accounted for in the context of hidden sectors. Feng, Rajaraman and Tu have
suggested that large (pb to nb) multi-photon or multi-lepton sugnals could be
generated at the LHC through the three-point functions of a
conformally-invariant hidden sector (an "unparticle" sector.) Because of the
conformal invariance, the kinematic distributions are calculable. However, the
cross-sections for many such processes grow rapidly with energy, and at some
high scale, to preserve unitarity, conformal invariance must break down.
Requiring that conformal invariance not be broken, and that no signals be
already observed at the Tevatron, we obtain a strong unitarity bound on
multi-photon events at the (10 TeV) LHC. For the model of Feng et al., even
with extremely conservative assumptions, cross-sections must be below 25 fb,
and for operator dimension near 2, well below 1 fb. In more general models,
four-photon signals could still reach cross-sections of a few pb, though bounds
below 200 fb are more typical. Our methods apply to a wide variety of other
processes and settings
Complete minimal surfaces in R3 with a prescribed coordinate function
In this paper we construct complete simply connected minimal surfaces with a
prescribed coordinate function. Moreover, we prove that these surfaces are dense
in the space of all minimal surfaces with this coordinate function (with the topol-
ogy of the smooth convergence on compact sets).Ministerio de Educación y Ciencia MTM2007-61775Ministerio de Educación y Ciencia MTM2007-6450
Analysis of the Scientific Production of the Spanish Software Engineering Community
Our group has been working on a report for the Spanish Society of Software Engineering and Software Development Technologies (SISTEDES) to provide a general overview of the Spanish scientific
production and its contributions worldwide in the field of Software Engineering. Although a Database solution could have been used, we decided to employ Model-Driven Development (MDD) techniques in order to evaluate their applicability, suitability and fitness for these kinds of purposes, and to learn from the experience in this domain, which combines data integration, large scale models, and complex queries.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Analysis of the scientific production of the Spanish Software Engineering Community
Our group has been working on a report for the Spanish Society of Software Engineering and Software Development Technologies (SISTEDES) to provide a general overview of the Spanish scientific production and its contributions worldwide in the field of Software Engineering. Although a Database solution could have been used, we decided to employ Model-Driven Development (MDD) techniques in order to evaluate their applicability, suitability and fitness for these kinds of purposes, and to learn from the experience in this domain, which combines data integration, large scale models, and complex queries.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Electroweak and supersymmetry breaking from the Higgs discovery
We will explore the consequences on the electroweak breaking condition, the
mass of supersymmetric partners and the scale at which supersymmetry is broken,
for arbitrary values of the supersymmetric parameters tan(beta) and the stop
mixing X_t, which follow from the Higgs discovery with a mass m_H\simeq 126 GeV
at the LHC. Within the present uncertainty on the top quark mass we deduce that
radiative breaking requires tan(beta) \gtrsim 7 for maximal mixing X_t\simeq
\sqrt{6}, and tan(beta) \gtrsim 20 for small mixing X_t\lesssim 1. The scale at
which supersymmetry is broken \mathcal M can be of order the unification or
Planck scale only for large values of tan(beta) and negligible mixing X_t\simeq
0. On the other hand for maximal mixing and large values of tan(beta)
supersymmetry should break at scales as low as \mathcal M\simeq 10^5 GeV. The
uncertainty in those predictions stemming from the uncertainty in the top quark
mass, i.e. the top Yukawa coupling, is small (large) for large (small) values
of tan(beta). In fact for tan(beta)=1 the uncertainty on the value of \mathcal
M is of several orders of magnitude.Comment: 16 pages, 7 figures; v2: numerical typo corrected in codes, and 2
loop radiative corrections added. Some conclusions slightly change
General Focus Point in the MSSM
The minimal supersymmetric extension of the Standard Model (SM) is a well
motivated scenario for physics beyond the SM, which allows a perturbative
description of the theory up to scales of the order of the Grand Unification
scale, where gauge couplings unify. The Higgs mass parameter is insensitive to
the ultraviolet physics and is only sensitive to the scale of soft
supersymmetry breaking parameters. Present collider bounds suggest that the
characteristic values of these parameters may be significantly larger than the
weak scale. Large values of the soft breaking parameters, however, induce large
radiative corrections to the Higgs mass parameter and therefore the proper
electroweak scale may only be obtained by a fine tuned cancellation between the
square of the holomorphic \mu-parameter and the Higgs supersymmetry breaking
square mass parameter. This can only be avoided if there is a correlation
between the scalar and gaugino mass parameters, such that the Higgs
supersymmetry breaking parameter remains of the order of the weak scale. The
scale at which this happens is dubbed as focus point. In this article, we
define the general conditions required for this to happen, for different values
of the messenger scale at which supersymmetry breaking is transmitted to the
observable sector, and for arbitrary boundary conditions of the sfermion,
gaugino, and Higgs mass parameters. Specific supersymmetry breaking scenarios
in which these correlations may occur are also discussed.Comment: 19 pages, 9 figures, new refs. adde
A Fat Higgs with a Fat Top
A new variant of the supersymmetric Fat Higgs model is presented in which the
MSSM Higgses as well as the top quark are composite. The underlying theory is
an s-confining SU(3) gauge theory with the MSSM gauge groups realized as gauged
sub-groups of the chiral flavor symmetries. This motivates the large Yukawas
necessary for the large top mass and SM-like Higgs of mass>>M_Z in a natural
way as the residual of the strong dynamics responsible for the composites. This
removes fine-tuning associated with these couplings present in the original Fat
Higgs and New Fat Higgs models, respectively.Comment: 17 pages, 4 figures, Latex2e, uses JHEP3.cls and youngtab.sty, new
references adde
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