1,124 research outputs found

    LHC and ILC probes of hidden-sector gauge bosons

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    Intersecting D-brane theories motivate the existence of exotic U(1) gauge bosons that only interact with the Standard Model through kinetic mixing with hypercharge. We analyze an effective field theory description of this effect and describe the implications of these exotic gauge bosons on precision electroweak, LHC and ILC observables.Comment: 6 pages, 4 figures, RevTex, PRD, v3: expanded discussions, ref

    Probing the Green-Schwarz Mechanism at the Large Hadron Collider

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    We investigate the phenomenology of new abelian gauge bosons, which we denote as XX bosons, that suffer a mixed anomaly with the Standard Model, but are made self-consistent by the Green-Schwarz mechanism. A distinguishing aspect of the resulting effective theory is the decay of XX bosons into Standard Model gauge bosons, XZZ,WW,γZX\to ZZ, WW, \gamma Z. We compute the production cross-section of the XX boson from vector boson fusion at the Large Hadron Collider. We study the ppXZZ4lpp\to X\to ZZ\to 4l signal, and analyze the prospects of discovery. We argue that such a discovery could indirectly probe high energies, even up to the string scale.Comment: 14 pages, references adde

    Probing CP-violation at colliders through interference effects in diboson production and decay

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    We define a CP-asymmetric observable that is sensitive to CP-violating interactions in the gauge-boson sector. We illustrate the utility of this observable by studying how well the LHC can measure the coefficient of a particular dimension-six WWZ operator. We find that sensitivity at the 10^{-3} level is possible at the LHC with 100 fb^{-1} of integrated luminosity, which would greatly exceed the sensitivity achieved at LEP, and would rival or may even better the indirect sensitivities inferred from related operators constrained by electric dipole moment experiments.Comment: 4 pages, 1 figure, LaTe

    Higgs Boson Exempt No-Scale Supersymmetry and its Collider and Cosmology Implications

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    One of the most straightforward ways to address the flavor problem of low-energy supersymmetry is to arrange for the scalar soft terms to vanish simultaneously at a scale McM_{c} much larger than the electroweak scale. This occurs naturally in a number of scenarios, such as no-scale models, gaugino mediation, and several models with strong conformal dynamics. Unfortunately, the most basic version of this approach that incorporates gaugino mass unification and zero scalar masses at the grand unification scale is not compatible with collider and dark matter constraints. However, experimental constraints can be satisfied if we exempt the Higgs bosons from flowing to zero mass value at the high scale. We survey the theoretical constructions that allow this, and investigate the collider and dark matter consequences. A generic feature is that the sleptons are relatively light. Because of this, these models frequently give a significant contribution to the anomalous magnetic moment of the muon, and neutralino-slepton coannihilation can play an important role in obtaining an acceptable dark matter relic density. Furthermore, the light sleptons give rise to a large multiplicity of lepton events at colliders, including a potentially suggestive clean trilepton signal at the Tevatron, and a substantial four lepton signature at the LHC.Comment: 36 pages, 16 figure

    Higgs Boson Exempt No-Scale Supersymmetry with a Neutrino Seesaw: Implications for Lepton Flavor Violation and Leptogenesis

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    Motivated by the observation of neutrino oscillations, we extend the Higgs boson exempt no-scale supersymmetry model (HENS) by adding three heavy right-handed neutrino chiral supermultiplets to generate the light neutrino masses and mixings. The neutrino Yukawa couplings can induce new lepton flavor violating couplings among the soft terms in the course of renormalization group running down from the boundary scale. We study the effects this has on the predictions for low-energy probes of lepton flavor violation(LFV). Heavy right-handed neutrinos also provide a way to generate the baryon asymmetry through leptogenesis. We find that consistency with LFV and leptogenesis puts strong requirements on either the form of the Yukawa mass matrix or the smallness of the Higgs up soft mass. In all cases, we generically expect that new physics LFV is non-zero and can be found in a future experiment.Comment: 25 pages, 11 figures; Added a referenc

    Vacuum Stability with Tachyonic Boundary Higgs Masses in No-Scale Supersymmetry or Gaugino Mediation

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    No-scale supersymmetry or gaugino mediation augmented with large negative Higgs soft masses at the input scale provides a simple solution to the supersymmetric flavor problem while giving rise to a neutralino LSP. However, to obtain a neutralino LSP it is often necessary to have tachyonic input Higgs soft masses that can give rise to charge-and-color-breaking (CCB) minima and unbounded-from-below (UFB) directions in the low energy theory. We investigate the vacuum structure in these theories to determine when such problematic features are present. When the standard electroweak vacuum is only metastable, we compute its lifetime under vacuum tunneling. We find that vacuum metastability leads to severe restrictions on the parameter space for larger tanβ30\tan\beta \sim 30, while for smaller tanβ10\tan\beta\sim 10, only minor restrictions are found. Along the way, we derive an exact bounce solution for tunneling through an inverted parabolic potential.Comment: 18 Pages, 5 Figure

    Microarray patch delivery of un-adjuvanted influenza vaccine induces potent and broad-spectrum immune responses in a phase I clinical trial

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    Microarray patches (MAPs) offer the possibility of improved vaccine thermostability and dose-sparing potential as well as the potential to be safer, more acceptable, easier to use and more cost-effective for the administration of vaccines than injection by needle and syringe. Here, we report a phase I trial (ACTRN12618000112268/ U1111-1207-3550) using the Vaxxas high-density MAP (HD-MAP) to deliver a monovalent influenza vaccine to evaluate the safety, tolerability, and immunogenicity of lower doses of influenza vaccine delivered by MAPs. To the best of our knowledge, this is the first study determining dose reduction potential using MAPs in humans. Monovalent, split inactivated influenza virus vaccine containing A/Singapore/GP1908/ 2015 [H1N1] haemagglutinin (HA) was delivered by MAP into the volar forearm or upper arm, or given intramuscularly (IM) once. Participants (20 per group) received HD-MAPs delivering doses of 15, 10, 5, 2.5 or 0 µg of HA or an IM injection of quadrivalent influenza vaccine (QIV). In two subgroups, skin biopsies were taken on days 1 (pre-vaccination) and 4 for analysis of the cellular composition from the HD-MAP application sites. All laboratory investigators were blind to treatment and participant allocation. The primary objectives of the study were safety and tolerability. Secondary objectives included immunogenicity and dose de-escalation assessments of the influenza vaccine delivered by HD-MAP. Both objectives were assessed for up to 60 days post-vaccination. Please click Download on the upper right corner to see the full abstract
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