4,093 research outputs found

    Neutrino Masses and the Gluino Axion Model

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    We extend the recently proposed gluino axion model to include neutrino masses. We discuss how the canonical seesaw model and the Higgs triplet model may be realized in this framework. In the former case, the heavy singlet neutrinos are contained in superfields which do not have any vacuum expectation value, whereas the gluino axion is contained in one which does. We also construct a specific renormalizable model which realizes the mass scale relationship MSUSYfa2/MUM_{SUSY} \sim f_a^2/M_U, where faf_a is the axion decay constant and MUM_U is a large effective mass parameter.Comment: 8 pages, no figur

    Realistic Gluino Axion Model Consistent with Supersymmetry Breaking at the TeV Scale

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    The recently proposed model of using the dynamical phase of the gluino to solve the strong CP problem is shown to admit a specific realization in terms of fundamental singlet superfields, such that the breaking of supersymmetry occurs only at the TeV scale, despite the large axion scale of 10^{9} to 10^{12} GeV. Phenomenological implications are discussed.Comment: 12 pp, 2 fig

    Electroweak Breaking and the mu problem in Supergravity Models with an Additional U(1)

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    We consider electroweak symmetry breaking in supersymmetric models with an extra non-anomalous U(1)' gauge symmetry and an extra standard-model singlet scalar S. For appropriate charges the U(1)' forbids an elementary mu term, but an effective mu is generated by the VEV of S, leading to a natural solution to the mu problem. There are a variety of scenarios leading to acceptably small Z-Z' mixing and other phenomenological consequences, all of which involve some but not excessive fine tuning. One class, driven by a large trilinear soft supersymmetry breaking term, implies small mixing, a light Z' (e.g., 200 GeV), and an electroweak phase transition that may be first order at tree level. In another class, with m_S^2 < 0 (radiative breaking), the typical scale of dimensional parameters, including M_{Z'} and the effective mu, is O(1 TeV), but the electroweak scale is smaller due to cancellations. We relate the soft supersymmetry breaking parameters at the electroweak scale to those at the string scale, choosing Yukawa couplings as determined within a class of string models. We find that one does not obtain either scenario for universal soft supersymmetry breaking mass parameters at the string scale and no exotic multiplets contributing to the renormalization group equations. However, either scenario is possible when the assumption of universal soft breaking is relaxed. Radiative breaking can also be generated by exotics, which are expected in most string models.Comment: 45 pages, revtex, 20 eps figures, psfig.sty; Minor numerical renormalization group results corrected. Erratum to appear in Phys. Rev.

    The CP properties of the lightest Higgs boson with sbottom effects

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    In the framework of the recently proposed gluino-axion model, using the effective potential method and taking into account the top-stop as well as the bottom-sbottom effects, we discuss the CP--properties of the lightest Higgs boson, in particular its CP--odd composition, which can offer new opportunities at collider searches. It is found that although the CP-odd composition of the lightest Higgs increases slightly with the inclusion of the sbottom effects, it never exceeds %0.17 for all values of the renormalization scale Q ranging from top mass to TeV scaleComment: 24 pp, 12 eps fig

    Relaxation of the Dynamical Gluino Phase and Unambiguous Electric Dipole Moments

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    We propose a new axionic solution of the strong CP problem with a Peccei-Quinn mechanism using the gluino rather than quarks. The spontaneous breaking of this new global U(1) at 10^{11} GeV also generates the supersymmetry breaking scale of 1 TeV (solving the so-called \mu problem at the same time) and results in the MSSM (Minimal Supersymmetric Standard Model) with R parity conservation. In this framework, electric dipole moments become calculable without ambiguity.Comment: Typos corrected and a footnote added, 10 p

    Postojanost na trošenje i koroziju novih frikcijski postojanih materijala za automobilsku industriju

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    In this study, after a NiCr bond layer was deposited on a pearlitic, grey cast iron rotor disc of the kind used in a production passenger car (Toyota Corolla 1600 cc), Cr3C2-NiCr and Al2O3-TiO2powders were sprayed using High Velocity Oxygen Fuel(HVOF) and plasma spray processes, respectively. The discs were subjected to cosmetic corrosion test according to SAE J2334 test standard. Additionally, wear tests were carried out using a reciprocating wear tester by rubbing a 10 mm diameter Al2O3 ball on the specimens machined from rotor discs in salt solution. It was found that the Cr3C2-NiCr coating (HSCN) sprayed using HVOF method exhibited highest hardness and highest corrosion and wear resistances.Nakon nanošenja NiCr sloja na disk od sivog lijeva tipa koji se koristi u proizvodnji putničkog automobila (Toyota Corolla 1600 CC), Cr3C2-NiCr i Al2O3-TiO2 prašak je nanešen naštrcavanjem HVOF i plazma postupkom. Disk je izložen korozijskom ispitivanju sukladno standardu SAE J2334. Dodatno je provedeno ispitivanje na trošenje na testeru za uzajamno trošenje 10 mm zrna Al2O3 na uzorcima izrađenim iz rotacijskog diska u slanoj komori. Utvrđeno je da je Cr3C2-NiCr sloj (HSCN) naštrca HVOF postupkom pokazao veću tvrdoću i veću korozijsku postojanost i otpornost na koroziju

    Supersymmetric origin of a low aJ/psia_{J/psi} CP asymmetry

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    We show that general Minimal Supersymmetric extensions of the Standard Model (MSSM) allow for a CP asymmetry in B --> J/psi K(S) well bellow the SM expectations with dominant Supersymmetric contributions to epsilon_K and epsilon'/epsilon. Indeed, we provide an explicit example of an MSSM with non-universal soft breaking terms fully consistent with the low results of this asymmetry recently announced by Babar and Belle collaborations.Comment: 6 pages, no figures. Reference added, typos correcte

    Effect of Preventive Supplementation with Zinc and other Micronutrients on Non-Malarial Morbidity in Tanzanian Pre-School Children: A Randomized Trial.

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    The efficacy of preventive zinc supplementation against diarrhea and respiratory illness may depend on simultaneous supplementation with other micronutrients. We aimed to assess the effect of supplementation with zinc and multiple micronutrients on diarrhea and other causes of non-malarial morbidity. Rural Tanzanian children (n = 612) aged 6-60 months and with height-for-age z-score < -1.5 SD were randomized to daily supplementation with zinc (10 mg) alone, multi-nutrients without zinc, multi-nutrients with zinc, or placebo. Children were followed for an average of 45 weeks. During follow-up, we recorded morbidity episodes. We found no evidence that concurrent supplementation with multi-nutrients influenced the magnitude of the effect of zinc on rates of diarrhea, respiratory illness, fever without localizing signs, or other illness (guardian-reported illness with symptoms involving skin, ears, eyes and abscesses, but excluding trauma or burns). Zinc supplementation reduced the hazard rate of diarrhea by 24% (4%-40%). By contrast, multi-nutrients seemed to increase this rate (HR; 95% CI: 1.19; 0.94-1.50), particularly in children with asymptomatic Giardia infection at baseline (2.03; 1.24-3.32). Zinc also protected against episodes of fever without localizing signs (0.75; 0.57-0.96), but we found no evidence that it reduced the overall number of clinic visits. We found no evidence that the efficacy of zinc supplements in reducing diarrhea rates is enhanced by concurrent supplementation with other micronutrients. By reducing rates of fever without localizing signs, supplementation with zinc may reduce inappropriate drug use with anti-malarial medications and antibiotics. ClinicalTrials.gov NCT00623857

    s-Channel Production of MSSM Higgs Bosons at a Muon Collider with Explicit CP Violation

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    A muon collider with controllable energy resolution and transverse beam polarization provides a powerful probe of the Higgs sector in the minimal supersymmetric standard model with explicit CP violation, through s-channel production of Higgs bosons. The production rates and the CP-even and CP-odd transverse-polarization asymmetries are complementary in diagnosing CP violation in the Higgs sector.Comment: 12 pages, 5 figures. Some statements for clarity and references added. To appear in Phys. Rev.
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