171 research outputs found
Conformal Technicolor
We point out that the flavor problem in theories with dynamical electroweak
symmetry breaking can be effectively decoupled if the physics above the TeV
scale is strongly conformal, and the electroweak order parameter has a scaling
dimension d = 1 + epsilon with epsilon \simeq 1/few. There are many
restrictions on small values of epsilon: for epsilon << 1, electroweak symmetry
breaking requires a fine-tuning similar to that of the standard model; large-N
conformal field theories (including those obtained from the AdS/CFT
correspondence) require fine-tuning for d < 2; `walking technicolor' theories
cannot have d < 2, according to gap equation analyses. However, strong small-N
conformal field theories with epsilon \simeq 1/few avoid all these constraints,
and can give rise to natural dynamical electroweak symmetry breaking with a top
quark flavor scale of order 10^{1/epsilon} TeV, large enough to decouple
flavor. Small-N theories also have an acceptably small Peskin-Takeuchi S
parameter. This class of theories provides a new direction for dynamical
electroweak symmetry breaking without problems from flavor or electroweak
precision tests. A possible signal for these theories is a prominent scalar
resonance below the TeV scale with couplings similar to a heavy standard model
Higgs.Comment: 26 pages + References. Slight wording changes. Version appearing in
JHE
Supersymmetry in Slow Motion
We construct new theories of electroweak symmetry breaking that employ a
combination of supersymmetry and discrete symmetries to stabilize the weak
scale up to and beyond the energies probed by the LHC. These models exhibit
conventional supersymmetric spectra but the fermion-sfermion-gaugino vertices
are absent. This closes many conventional decay channels, thereby allowing
several superpartners to be stable on collider time scales. This opens the door
to the possibility of directly observing R-hadrons and three flavors of
sleptons inside the LHC detectors.Comment: A reference added. The discussion on the Higgs sector expanded. The
version accepted for publication in JHE
Mini Z' Burst from Relic Supernova Neutrinos and Late Neutrino Masses
In models in which neutrinos are light, due to a low scale of symmetry
breaking, additional light bosons are generically present. We show that the
interaction between diffuse relic supernova neutrinos (RSN) and the cosmic
background neutrinos, via exchange of these light scalars, can result in a
dramatic change of the supernova (SN) neutrinos flux. Measurement of this
effect with current or future experiments can provide a spectacular direct
evidence for the low scale models. We demonstrate how the observation of
neutrinos from SN1987A constrains the symmetry breaking scale of the above
models. We also discuss how current and future experiments may confirm or
further constrain the above models, either by detecting the ``accumulative
resonance'' that diffuse RSN go through or via a large suppression of the flux
of neutrinos from nearby < O(Mpc) SN bursts.Comment: 24 pages, 8 figures, version to be published in JHE
ODTN: Open Disaggregated Transport Network. Discovery and Control of a Disaggregated Optical Network through Open Source Software and Open APIs
ONOS discovers and manages a topology made of Transponders and a dedicated OLS, using standard protocols (NETCONF/RESTCONF) and models (OpenConfig/TAPI). The demo is a joint collaboration, towards production deployment, between 3 operators and 2 equipment vendors
Low Energy 6-Dimensional N=2 Supersymmertric SU(6) Models on Orbifolds
We propose low energy 6-dimensional N=2 supersymmetric SU(6) models on
and , where the orbifold
model can be embedded on the boundary 4-brane. For the
zero modes, the 6-dimensional N=2 supersymmetry and the SU(6) gauge symmetry
are broken down to the 4-dimensional N=1 supersymmetry and the gauge symmetry by orbifold projections. In
order to cancel the anomalies involving at least one , we add extra
exotic particles. We also study the anomaly free conditions and present some
anomaly free models. The gauge coupling unification can be achieved at TeV if the compactification scale for the fifth dimension is
TeV. The proton decay problem can be avoided by putting the quarks and
leptons/neutrinos on different 3-branes. And we discuss how to break the
gauge symmetry, solve the
problem, and generate the mass hierarchy naturally by using the
geometry. The masses of exotic particles can be at the order of 1 TeV after the
gauge symmetry breaking. We also forbid the dimension-5 operators for the
neutrino masses by gauge symmetry, and the realistic left-handed
neutrino masses can be obtained via non-renormalizable terms.Comment: Latex, 33 pages, discussion and references adde
Vectorlike Confinement at the LHC
We argue for the plausibility of a broad class of vectorlike confining gauge
theories at the TeV scale which interact with the Standard Model predominantly
via gauge interactions. These theories have a rich phenomenology at the LHC if
confinement occurs at the TeV scale, while ensuring negligible impact on
precision electroweak and flavor observables. Spin-1 bound states can be
resonantly produced via their mixing with Standard Model gauge bosons. The
resonances promptly decay to pseudo-Goldstone bosons, some of which promptly
decay to a pair of Standard Model gauge bosons, while others are charged and
stable on collider time scales. The diverse set of final states with little
background include multiple photons and leptons, missing energy, massive stable
charged particles and the possibility of highly displaced vertices in dilepton,
leptoquark or diquark decays. Among others, a novel experimental signature of
resonance reconstruction out of massive stable charged particles is
highlighted. Some of the long-lived states also constitute Dark Matter
candidates.Comment: 33 pages, 6 figures. v4: expanded discussion of Z_2 symmetry for
stability, one reference adde
KeV Warm Dark Matter and Composite Neutrinos
Elementary keV sterile Dirac neutrinos can be a natural ingredient of the
composite neutrino scenario. For a certain class of composite neutrino
theories, these sterile neutrinos naturally have the appropriate mixing angles
to be resonantly produced warm dark matter (WDM). Alternatively, we show these
sterile neutrinos can be WDM produced by an entropy-diluted thermal freeze-out,
with the necessary entropy production arising not from an out-of-equilibrium
decay, but rather from the confinement of the composite neutrino sector,
provided there is sufficient supercooling.Comment: 12 pages, 2 figures, published versio
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