861 research outputs found

    Raising the Higgs mass with Yukawa couplings for isotriplets in vector-like extensions of minimal supersymmetry

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    Extra vector-like matter with both electroweak-singlet masses and large Yukawa couplings can significantly raise the lightest Higgs boson mass in supersymmetry through radiative corrections. I consider models of this type that involve a large Yukawa coupling between weak isotriplet and isodoublet chiral supermultiplets. The particle content can be completed to provide perturbative gauge coupling unification, in several different ways. The impact on precision electroweak observables is shown to be acceptably small, even if the new particles are as light as the current experimental bounds of order 100 GeV. I study the corrections to the lightest Higgs boson mass, and discuss the general features of the collider signatures for the new fermions in these models.Comment: 30 page

    Fluid Control in Rocket Injectors with the Use of Pressurized Systems for Throttling

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    Throttling a rocket is a necessary task that must be accomplished in order to achieve proper efficiency and performance over a desired thrust range. Simply put, throttling is achieved by managing the fluid flow in a rocket injector in order to insure proper functioning. There are several different methods on how to throttle rockets, but a simple and inexpensive method is desired in some applications, such as student built University projects. A hot fire test of a hybrid rocket motor was conducted at Purdue University in May 2013, after which a throttling method was desired. The method proposed in this document outlines the use of a pressurized system to deliver oxidizer fluid. A modified throttling valve is utilized to manage oxidizer flow rate in a hybrid rocket engine by altering the pressure gradient. The goal of throttling this rocket will be to maintain a proper oxidizer to fuel (O/F) ratio by decreasing the mass flow rate of the oxidizer in a pressurized nitrogen system. Upon cold flow and hot-fire testing, results and data will provide insight on further design modifications to insure proper performance of the hybrid rocket engine mentioned above. Additional work on this topic will need to be done after the planned tests of summer 2013

    Characterization of Sprays from Dual Impinging Jets on a Splash Plate

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    The use of splash plates and dual impinging liquid jets are common methods for fuel atomization, but the combination of these methods has not been explored. The goal of this experiment is to analyze how splash plate position and orientation affect the spray geometry for this combined method. The spray patterns are observed for a single jet against a splash plate and two orientations of dual impinging jets against a splash plate. For all three cases, the spray patterns are analyzed for various splash plate angles between 30 and 60 degrees relative to the jet centerline. For the dual impinging jets, the splash plate is tested in multiple positions relative the two jets’ unimpeded impingement point. The characteristics of the spray patterns are then analyzed using high speed video. The most desirable spray characteristics occur when the splash plate is at least two jet diameters lower than the unimpeded impingement point and at an angle between 45 and 60 degrees. The spray has a clear spreading angle and minimum back-spray when the sheet formed by the jets is coincidental with the orientation axis for the splash plat

    Virtual effects of light gauginos and higgsinos: a precision electroweak analysis of split supersymmetry

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    We compute corrections to precision electroweak observables in supersymmetry in the limit that scalar superpartners are very massive and decoupled. This leaves charginos and neutralinos and a Standard Model-like Higgs boson as the only states with unknown mass substantially affecting the analysis. We give complete formulas for the chargino and neutralino contributions, derive simple analytic results for the pure gaugino and higgsino cases, and study the general case. We find that in all circumstances, the precision electroweak fit improves when the charginos and neutralinos are near the current direct limits. Larger higgsino and gaugino masses worsen the fit as the theory predictions asymptotically approach those of the Standard Model. Since the Standard Model is considered by most to be an adequate fit to the precision electroweak data, an important corollary to our analysis is that all regions of parameter space allowed by direct collider constraints are also allowed by precision electroweak constraints in split supersymmetry.Comment: 22 pages, 5 figures, v2: typos fixed and note adde

    General-elimination stability

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    General-elimination harmony articulates Gentzen's idea that the elimination-rules are justified if they infer from an assertion no more than can already be inferred from the grounds for making it. Dummett described the rules as not only harmonious but stable if the E-rules allow one to infer no more and no less than the I-rules justify. Pfenning and Davies call the rules locally complete if the E-rules are strong enough to allow one to infer the original judgement. A method is given of generating harmonious general-elimination rules from a collection of I-rules. We show that the general-elimination rules satisfy Pfenning and Davies' test for local completeness, but question whether that is enough to show that they are stable. Alternative conditions for stability are considered, including equivalence between the introduction- and elimination-meanings of a connective, and recovery of the grounds for assertion, finally generalizing the notion of local completeness to capture Dummett's notion of stability satisfactorily. We show that the general-elimination rules meet the last of these conditions, and so are indeed not only harmonious but also stable.Publisher PDFPeer reviewe

    Investigation of Combustion Control in a Dump Combustor Using the Feedback Free Fluidic Oscillator

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    A feedback free fluidic oscillator was designed and integrated into a single element rocket combustor with the goal of suppressing longitudinal combustion instabilities. The fluidic oscillator uses internal fluid dynamics to create an unsteady outlet jet at a specific frequency. An array of nine fluidic oscillators was tested to mimic modulated secondary oxidizer injection into the combustor dump plane. The combustor has a coaxial injector that uses gaseous methane and decomposed hydrogen peroxide with an overall O/F ratio of 11.7. A sonic choke plate on an actuator arm allows for continuous adjustment of the oxidizer post acoustics enabling the study of a variety of instability magnitudes. The fluidic oscillator unsteady outlet jet performance is compared against equivalent steady jet injection and a baseline design with no secondary oxidizer injection. At the most unstable operating conditions, the unsteady outlet jet saw a 67% reduction in the instability pressure oscillation magnitude when compared to the steady jet and baseline data. Additionally, computational fluid dynamics analysis of the combustor gives insight into the flow field interaction of the fluidic oscillators. The results indicate that open loop high frequency propellant modulation for combustion control can be achieved through fluidic devices that require no moving parts or electrical power to operate

    Production of singlet P-wave ccˉc \bar c and bbˉb \bar b states

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    No spin-singlet bbˉb \bar b quarkonium state has yet been observed. In this paper we discuss the production of the singlet P-wave bbˉb\bar{b} and ccˉc\bar{c} 1P1^1P_1 states hbh_b and hch_c. We consider two possibilities. In the first the 1P1^1P_1 states are produced via the electromagnetic cascades \ups(3S) \to \eta_b(2S) + \gamma \to h_b + \gamma \gamma \to \eta_b +\gamma\gamma\gamma and ψηc+γhc+γγηc+γγγ\psi'\to \eta_c' + \gamma \to h_c + \gamma \gamma \to \eta_c + \gamma\gamma\gamma. A more promising process consists of single pion transition to the 1P1^1P_1 state followed by the radiative transition to the 11S01^1S_0 state: \ups(3S)\to h_b + \pi^0 \to \eta_b + \pi^0 +\gamma and ψhc+π0ηc+π0+γ\psi' \to h_c + \pi^0 \to \eta_c + \pi^0 +\gamma. For a million \ups(3S) or ψ\psi''s produced we expect these processes to produce several hundred events.Comment: 13 pages, LaTeX, 1 figure, to be published Phys. Rev. D. Some equation numbers and one table number correcte

    Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

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    The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of ttt\overline{t}, W+bbW+b\overline{b} and W+ccW+c\overline{c} is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 ±\pm 0.02 \mbox{fb}^{-1}. The WW bosons are reconstructed in the decays WνW\rightarrow\ell\nu, where \ell denotes muon or electron, while the bb and cc quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI
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