1,035 research outputs found

    POLICY DIRECTIONS TO MITIGATE WATER-SUPPLY RISK IN IRRIGATED AGRICULTURE: A FEDERAL PERSPECTIVE

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    Water reallocation to meet mandated flow requirements and trust responsibilities, established in Federal law and water authority, can result in large uncompensated losses to irrigated agriculture. This paper discusses the nature and potential cost of water-supply interruptions due to Federal actions, and provides a comparative assessment of alternative risk-mitigation measures.Resource /Energy Economics and Policy,

    The AzTEC mm-Wavelength Camera

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    AzTEC is a mm-wavelength bolometric camera utilizing 144 silicon nitride micromesh detectors. Herein we describe the AzTEC instrument architecture and its use as an astronomical instrument. We report on several performance metrics measured during a three month observing campaign at the James Clerk Maxwell Telescope, and conclude with our plans for AzTEC as a facility instrument on the Large Millimeter Telescope.Comment: 13 pages, 15 figures, accepted for publication in Monthly Notice

    Observation of Two Narrow States Decaying into Ξc+γ\Xi_{c}^{+}\gamma and Ξc0γ\Xi_{c}^{0}\gamma

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    We report the first observation of two narrow charmed strange baryons decaying to Ξc+γ\Xi_c^+\gamma and Ξc0γ\Xi_c^0\gamma, respectively, using data from the CLEO II detector at CESR. We interpret the observed signals as the Ξc+(csu)\Xi_c^{+\prime}(c{su}) and Ξc0(csd)\Xi_c^{0\prime}(c{sd}), the symmetric partners of the well-established antisymmetric Ξc+(c[su])\Xi_c^+(c[su]) and Ξc0(c[sd])\Xi_c^0(c[sd]). The mass differences M(Ξc+)M(Ξc+)M(\Xi_c^{+\prime})-M(\Xi_c^+) and M(Ξc0)M(Ξc0)M(\Xi_c^{0\prime})-M(\Xi_c^0) are measured to be 107.8±1.7±2.5107.8\pm 1.7\pm 2.5 and 107.0±1.4±2.5MeV/c2107.0\pm 1.4\pm 2.5 MeV/c^2, respectively.Comment: 11 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Standard Model CP violation in Polarised b->d l^+ l^-

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    In the standard model, we study CP violating rate asymmetries in the decay b->d l^+ l^- when one of the leptons is polarised. We find an asymmetry of (5 -- 15)% in the polarised decay spectrum which is comparable to known results for the unpolarised case. In the kinematic region separating the rho-omega and ccˉc \bar c resonances, which is also theoretically cleanest, the polarised contribution to the asymmetry is larger than the unpolarised results. In order to observe a 3 sigma signal for direct CP violation in the polarised spectrum, assuming 100% efficiency, about 10^10 BBˉB \bar B pairs are required at a B factory. Our results indicate an asymmetric contribution from the individual polarisation states to the unpolarised CP asymmetry. Taking advantage of this, one can attribute any new physics to be most sensitive to a specific polarisation state.Comment: 23 pages, one reference adde

    Improved Measurement of the Pseudoscalar Decay Constant fDsf_{D_{s}}

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    We present a new determination of the Ds decay constant, f_{Ds} using 5 million continuum charm events obtained with the CLEO II detector. Our value is derived from our new measured ratio of widths for Ds -> mu nu/Ds -> phi pi of 0.173+/- 0.021 +/- 0.031. Taking the branching ratio for Ds -> phi pi as (3.6 +/- 0.9)% from the PDG, we extract f_{Ds} = (280 +/- 17 +/- 25 +/- 34){MeV}. We compare this result with various model calculations.Comment: 23 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Search for the Decay τ4pi3π+(π0)ντ\tau^{-}\to 4pi^{-}3\pi^{+}(\pi^{0})\nu_{\tau}

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    We have searched for the decay of the tau lepton into seven charged particles and zero or one pi0. The data used in the search were collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 4.61 fb^(-1). No evidence for a signal is found. Assuming all the charged particles are pions, we set an upper limit on the branching fraction, B(tau- -> 4pi- 3pi+ (pi0) nu_tau) < 2.4 x 10^(-6) at the 90% confidence level. This limit represents a significant improvement over the previous limit.Comment: 9 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Flavor-Specific Inclusive B Decays to Charm

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    We have measured the branching fractions for B -> D_bar X, B -> D X, and B -> D_bar X \ell^+ \nu, where ``B'' is an average over B^0 and B^+, ``D'' is a sum over D^0 and D^+, and``D_bar'' is a sum over D^0_bar and D^-. From these results and some previously measured branching fractions, we obtain Br(b -> c c_bar s) = (21.9 ±\pm 3.7)%, Br(b -> s g) K^- \pi^+) = (3.69 ±\pm 0.20)%. Implications for the ``B semileptonic decay problem'' (measured branching fraction being below theoretical expectations) are discussed. The increase in the value of Br(b -> c c_bar s) due to B>DXB -> D X eliminates 40% of the discrepancy.Comment: 12 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN
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