9,096 research outputs found

    Agricultural Trade Liberalisation and Strategic Environmental Policy

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    We use an extended partial equilibrium trade model to derive optimal environmental policy responses to tariff reduction requirements and assess the impact of such policies on the welfare of trading partners. We find that countries which attribute preferential political weights to farmers' welfare have an incentive to implement environmental policies that deviate from the Pigouvian solution - even if production is not de facto linked to environmental externalities. We clarify the conditions under which trading partners do not gain from unilateral trade liberalisation if trade concessions are accompanied by strategic environmental policy changes. We postulate a role for the WTO in overseeing the process of domestic policy formulation.trade liberalisation, strategic environmental policy, multifunctionality, agri-environmental policy, WTO, Environmental Economics and Policy, D60, F11, F18, Q17,

    AGRICULTURAL TRADE LIBERALIZATION AND STRATEGIC ENVIRONMENTAL POLICY: A FORMAL ANALYSIS

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    This paper develops an extended general equilibrium model of international trade in order to analyze the welfare effects of agricultural trade liberalization if a large country influences its terms of trade by means of environmental policy. We derive globally optimal first-best and second-best environmental and trade policy combinations as a benchmark for assessing the trade-distorting character of strategically motivated environmental policies and demonstrate that if second-best rather than first-best policies are chosen as a benchmark the conclusions may differ not only in magnitude but also in direction. We further demonstrate that if a Pigouvian instrument is transformed into a strategic environmental policy, following trade liberalization, the global welfare effect is unambiguously positive. We thereby prove that the distorting effect of an optimal tariff is generally greater than that of a strategically motivated environmental policy.International Relations/Trade,

    Determination of the Higgs boson spin with a linear e+e- collider

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    The energy dependence of the production cross section of a light Higgs boson is studied at threshold and compared to the expectations of several spin assumptions. Cross section measurements at three centre-of-mass energies with an integrated luminosity of 20 fb-1 allow the confirmation of the scalar nature of the Higgs Boson.Comment: 4 pages (Latex), 4 figures (Postscript

    The Impact of BeamCal Performance at Different ILC Beam Parameters and Crossing Angles on \tilde{tau} searches

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    The ILC accelerator parameters and detector concepts are still under discussion in the world-wide community. As will be shown, the performance of the BeamCal, the calorimeter in the very forward area of the ILC detector, is very sensitive to the beam parameter and crossing angle choices. We propose here BeamCal designs for a small (0 or 2 mrad) and large (20 mrad) crossing angles and report about the veto performance study done. As illustration, the influence of several proposed beam parameter sets and crossing-angles on the signal to background ratio in the stau search is estimated for a particular realization of the super-symmetric model.Comment: Talk given by V. Drugakov at the Linear Collider Workshop "LCWS06'', 9-13 March 2006, I.I.Sc Bangalore, Indi

    The τ\tau-W Coupling

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    We interpret the existing experimental knowledge on τ\tau decays in terms of the vector and axial vector couplings to the W boson, VτV_{\tau} and AτA_{\tau}. We deduce Vτ=1.00±0.09V_{\tau} = 1.00 \pm 0.09 and Aτ=1.00±0.09A_{\tau} = 1.00 \pm 0.09 in agreement with the Standard Model predictions of 11

    Investigation of a direction sensitive sapphire detector stack at the 5 GeV electron beam at DESY-II

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    Extremely radiation hard sensors are needed in particle physics experiments to instrument the region near the beam pipe. Examples are beam halo and beam loss monitors at the Large Hadron Collider, FLASH or XFEL. Currently artificial diamond sensors are widely used. In this paper single crystal sapphire sensors are considered as a promising alternative. Industrially grown sapphire wafers are available in large sizes, are of low cost and, like diamond sensors, can be operated without cooling. Here we present results of an irradiation study done with sapphire sensors in a high intensity low energy electron beam. Then, a multichannel direction-sensitive sapphire detector stack is described. It comprises 8 sapphire plates of 1 cm^2 size and 525 micro m thickness, metallized on both sides, and apposed to form a stack. Each second metal layer is supplied with a bias voltage, and the layers in between are connected to charge-sensitive preamplifiers. The performance of the detector was studied in a 5 GeV electron beam. The charge collection efficiency measured as a function of the bias voltage rises with the voltage, reaching about 10 % at 950 V. The signal size obtained from electrons crossing the stack at this voltage is about 22000 e, where e is the unit charge. The signal size is measured as a function of the hit position, showing variations of up to 20 % in the direction perpendicular to the beam and to the electric field. The measurement of the signal size as a function of the coordinate parallel to the electric field confirms the prediction that mainly electrons contribute to the signal. Also evidence for the presence of a polarisation field was observed.Comment: 13 pages, 7 figures, 3 table

    Testing Higgs models via the H±WZH^\pm W^\mp Z vertex by a recoil method at the International Linear Collider

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    In general, charged Higgs bosons H±H^\pm appear in non-minimal Higgs models. The H±WZH^\pm W^\mp Z vertex is known to be related to the violation of the global symmetry (custodial symmetry) in the Higgs sector. Its magnitude strongly depends on the structure of the exotic Higgs models which contain higher isospin SU(2)LSU(2)_L representations such as triplet Higgs bosons. We study the possibility of measuring the H±WZH^\pm W^\mp Z vertex via single charged Higgs boson production associated with the W±W^\pm boson at the International Linear Collider (ILC) by using the recoil method. The feasibility of the signal e+eH±Wνjje^+e^-\to H^\pm W^\mp \to \ell \nu jj is analyzed assuming the polarized electron and positron beams and the expected detector performance for the resolution of the two-jet system at the ILC. The background events can be reduced to a considerable extent by imposing the kinematic cuts even if we take into account the initial state radiation. For a relatively light charged Higgs boson whose mass mH±m_{H^\pm} is in the region of 120-130 GeV <mH±<mW+mZ< m_{H^\pm} < m_W+m_Z, the H±WZH^\pm W^\mp Z vertex would be precisely testable especially when the decay of H±H^\pm is lepton specific. The exoticness of the extended Higgs sector can be explored by using combined information for this vertex and the rho parameter.Comment: 22 pages, 23 figure

    Fourier transforming a trapped Bose-Einstein condensate by waiting a quarter of the trap period: simulation and applications

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    We investigate the property of isotropic harmonic traps to Fourier transform a weakly interacting Bose–Einstein condensate (BEC) every quarter of a trap period. We solve the Gross–Pitaevskii equation numerically to investigate the time evolution of interacting BECs in the context of the Fourier transform, and we suggest potential applications

    Spin polarization of the Ar* 2p−11/2 4s and 2p−11/2 3d resonant Auger decay

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    The spin-resolved Auger decay of the Ar 2p−11/2 3d state was measured at moderate energy resolution and compared with the decay of the 2p−11/2 4s. The former shows a lower transferred spin polarization and a similar, if not higher, dynamical spin polarization, supporting the statement that a fully resolved spectrum is not a necessary condition for observing dynamical spin polarization. An interpretation of the spin polarization as configuration interaction induced effect in the final ionic state leads to partial agreement with our relativistic distorted wave calculation utilizing a 36 configuration state function basis set. Comparison of the experimental and numerical results leads to ambiguities for at least one Auger line. A hypothetical, qualitative interpretation is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58121/2/b7_17_012.pd
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