2,723 research outputs found
The Supersymmetric Higgs
In the Minimal Supersymmetric Standard Model (the MSSM), the electroweak
symmetry is restored as supersymmetry-breaking terms are turned off. We
describe a generic extension of the MSSM where the electroweak symmetry is
broken in the supersymmetric limit. We call this limit the "sEWSB" phase, short
for supersymmetric electroweak symmetry breaking. We define this phase in an
effective field theory that only contains the MSSM degrees of freedom. The
sEWSB vacua naturally have an inverted scalar spectrum, where the heaviest
CP-even Higgs state has Standard Model-like couplings to the massive vector
bosons; experimental constraints in the scalar Higgs sector are more easily
satisfied than in the MSSM.Comment: 34 pages, 5 figure
Workforce participation: developing a theoretical framework for longitudinal research
This paper describes and evaluates an action research project on workforce participation at Viewpoint Research Community Interest Company (CIC). By setting out the research protocols devised by Viewpoint to stimulate and study co-operative management, it is possible to abstract a theoretical framework that emerged from a pilot case study. The paper contributes to theory by highlighting not only the potential of action research to catalyse interest in co operative management but also how to engage theoretically with the paradox of a workforce voting to limit its own participation in ownership, governance and management. In this study, the authors interpreted that participants did not automatically equate participatory management with workplace democracy leading to a theoretical perspective that “democratic management is the propensity and capacity of management systems to respond to members’ desires regarding the scope, depth, level and quality of participation in management”. The paper concludes by evaluating the efficacy of Viewpoint’s action research methodology as a strategy for deepening knowledge on workforce participation in co-operatives and employee-owned businesses
BMSSM Higgs Bosons at the Tevatron and the LHC
We study extensions of the Minimal Supersymmetric Standard Model (MSSM) with
new degrees of freedom that couple sizably to the MSSM Higgs sector and lie in
the TeV range. After integrating out the physics at the TeV scale, the
resulting Higgs spectrum can significantly differ from typical supersymmetric
scenarios, thereby providing a window Beyond the MSSM (BMSSM). Taking into
account current LEP and Tevatron constraints, we perform an in-depth analysis
of the Higgs collider phenomenology and explore distinctive characteristics of
our scenario with respect to both the Standard Model and the MSSM.
We propose benchmark scenarios to illustrate specific features of BMSSM Higgs
searches at the Tevatron and the LHC.Comment: 18 pages, 9 figures; added parameters for each benchmark point, typos
corrected, final version published by Phys. Rev.
Electroweak Phase Transition, Higgs Diphoton Rate, and New Heavy Fermions
We show that weak scale vector-like fermions with order one couplings to the
Higgs can lead to a novel mechanism for a strongly first-order electroweak
phase transition (EWPhT), through their tendency to drive the Higgs quartic
coupling negative. These same fermions could also enhance the loop-induced
branching fraction of the Higgs into two photons, as suggested by the recent
discovery of a ~125 GeV Higgs-like state at the CERN Large Hadron Collider
(LHC). Our results suggest that measurements of the diphoton decay rate of the
Higgs and its self coupling, at the LHC or perhaps at a future lepton collider,
could probe the EWPhT in the early Universe, with significant implications for
the viability of electroweak baryogenesis scenarios.Comment: 6 pages, 1 figure. Revised version shows that the original
conclusions hold in a distinct region of parameter space. New discussion on
collider probes adde
Minimal Composite Higgs Models at the LHC
We consider composite Higgs models where the Higgs is a pseudo-Nambu
Goldstone boson arising from the spontaneous breaking of an approximate global
symmetry by some underlying strong dynamics. We focus on the SO(5) -> SO(4)
symmetry breaking pattern, assuming the partial compositeness paradigm. We
study the consequences on Higgs physics of the fermionic representations
produced by the strong dynamics, that mix with the Standard Model (SM) degrees
of freedom. We consider models based on the lowest-dimensional representations
of SO(5) that allow for the custodial protection of the Z -> b b coupling, i.e.
the 5, 10 and 14. We find a generic suppression of the gluon fusion process,
while the Higgs branching fractions can be enhanced or suppressed compared to
the SM. Interestingly, a precise measurement of the Higgs boson couplings can
distinguish between different realizations in the fermionic sector, thus
providing crucial information about the nature of the UV dynamics.Comment: 55 pages, 18 figures, References adde
The Dynamical Composite Higgs
We present a simple microscopic realization of a pseudo-Nambu-Goldstone
(pNGB) boson Higgs scenario arising from the breaking of . The Higgs constituents are explicitly identified as well as the
interactions responsible for forming the bound state and breaking the
electroweak symmetry. This outcome follows from the presence of four-fermion
interactions with a super-critical coupling, and uses the Nambu-Jona-Lasinio
mechanism to break the global symmetry. The Higgs potential is found to
be insensitive to high energy scales due to the existence of an approximate
infrared fixed point. The appearance of vector resonances is described and the
correspondence with other proposals in the literature established. The model
described here is significantly simpler than other recent ultraviolet
completions of pNGB scenarios. The observed Higgs mass can be accommodated, and
agreement with electroweak precision tests achieved in certain regions of
parameter space. There are also new vector-like fermions, some of which may lie
within reach of the LHC. In addition, we predict a heavy standard model singlet
scalar in the multi-TeV range. The amount of fine-tuning required in the model
is studied. Finally, we show that such a scheme can be completed in the
ultraviolet by a renormalizable theory.Comment: 32 pages plus appendices, 7 figures - reference adde
Calculable Dynamical Supersymmetry Breaking on Deformed Moduli Spaces
We consider models of dynamical supersymmetry breaking in which the
extremization of a tree-level superpotential conflicts with a quantum
constraint. We show that in such models the low-energy effective theory near
the origin of moduli space is an O'Raifeartaigh model, and the sign of the
mass-squared for the pseudo-flat direction at the origin is calculable. We
analyze vector-like models with gauge groups SU(N) and Sp(2N) with and without
global symmetries. In all cases there is a stable minimum at the origin with an
unbroken U(1)_R symmetry.Comment: 8 pages, LaTeX2e, no figure
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