171 research outputs found

    Conformal Technicolor

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    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

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    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

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    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

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    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 T2T^2 Orbifolds

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    We propose low energy 6-dimensional N=2 supersymmetric SU(6) models on M4×T2/(Z2)3M^4\times T^2/(Z_2)^3 and M4×T2/(Z2)4M^4\times T^2/(Z_2)^4, where the orbifold SU(3)C×SU(3)SU(3)_C\times SU(3) 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 SU(3)C×SU(2)L×U(1)Y×U(1)SU(3)_C\times SU(2)_L\times U(1)_Y\times U(1)' gauge symmetry by orbifold projections. In order to cancel the anomalies involving at least one U(1)U(1)', 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 100200100\sim 200 TeV if the compactification scale for the fifth dimension is 343\sim 4 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 SU(3)C×SU(2)L×U(1)Y×U(1)SU(3)_C\times SU(2)_L\times U(1)_Y\times U(1)' gauge symmetry, solve the μ\mu problem, and generate the ZZZ-Z' 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 U(1)U(1)' 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

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    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

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    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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