27 research outputs found

    Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment

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    A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the O(10)\mathcal{O}(10) MeV neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid-argon-based detectors planned for DUNE are expected to be uniquely sensitive to the Îœe\nu_e component of the supernova flux, enabling a wide variety of physics and astrophysics measurements. A key requirement for a correct interpretation of these measurements is a good understanding of the energy-dependent total cross section σ(EÎœ)\sigma(E_\nu) for charged-current Îœe\nu_e absorption on argon. In the context of a simulated extraction of supernova Îœe\nu_e spectral parameters from a toy analysis, we investigate the impact of σ(EÎœ)\sigma(E_\nu) modeling uncertainties on DUNE's supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on σ(EÎœ)\sigma(E_\nu) must be substantially reduced before the Îœe\nu_e flux parameters can be extracted reliably: in the absence of external constraints, a measurement of the integrated neutrino luminosity with less than 10\% bias with DUNE requires σ(EÎœ)\sigma(E_\nu) to be known to about 5%. The neutrino spectral shape parameters can be known to better than 10% for a 20% uncertainty on the cross-section scale, although they will be sensitive to uncertainties on the shape of σ(EÎœ)\sigma(E_\nu). A direct measurement of low-energy Îœe\nu_e-argon scattering would be invaluable for improving the theoretical precision to the needed level.Comment: 25 pages, 21 figure

    ABSOLUTE LINE INTENSITIES OF HONO AND DONO IN THE FAR INFRARED AND REDETERMINATION OF THE ENERGY DIFFERENCE BETWEEN THE TRANS AND CIS SPECIES OF NITROUS ACID

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    Author Institution: Laboratoire Interuniversitaire des Systemes Atmospheriques, CNRS et Universites Paris 7 et Paris 12, 61 av. General de Gaulle, 94010, Creteil, France; Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, GermanyNitrous acid is an important species in the atmosphere of the Earth since it is a significant daytime source of OH radicals, known to play an important role in tropospheric ozone formation. It is also a molecule of interest for molecular dynamics and \emph{ab-initio} calculations. In this work, relative line intensities of \emph{trans-} and \emph{cis-}HONO and ??DONO have been measured using absorption spectra in the far-infrared previously recorded by high-resolution Fourier-transform spectroscopy . These relative line intensities measurements were fitted in a least-squared procedure leading to the determination of the b-component of the permanent dipole moments for those species and their rotational corrections. Scaling those values to the absolute values derived from Stark effect measurements allowed us to re-determine the energy difference between the two isomers (ΔEHONO\Delta E_{HONO}) to be 107±\pm26 cm−1^{-1}. This value is in good agreement with previous experimental studies calculations and with recent high-level \emph{ab-initio} calculations

    Collisional broadening and spectral shapes of absorption lines of free and nanopore-confined O-2 gas

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    This paper presents fully ab initio calculations of the broadenings and spectral shapes of O-2 infrared absorption lines in a free gas and when confined in nanoporous media. These calculations are performed, without use of any adjusted parameter, using a recently proposed approach [Phys. Rev. A 87, 013403 (2013)] that is based on requantized classical molecular-dynamics simulations. This involves studying the time evolutions of the translational and rotational motions of large numbers of molecules taking molecule-molecule and molecule-surface collisions into account through realistic interaction potentials. These simulations enable predictions of dipole autocorrelation functions whose Fourier-Laplace transforms yield the associated spectra. Comparisons are then made with broadening coefficients and line shapes provided by new and previous experiments. The good agreement between calculated and measured results confirms the veracity of the proposed model for a free gas and shows that the effects of confinement, which induce significant modifications to the line shapes, are correctly predicted. The need for improved characterization of the shape and size of pores in random nanoporous media is highlighted. DOI: 10.1103/PhysRevA.87.03251

    Reinvestigation of the microwave and new high resolution far-infrared spectra of cis-methyl nitrite, CH3ONO: Rotational study of the two first torsional states

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    International audienceThe first far-infrared high resolution absorption measurement of the cis-methyl nitrite molecule has been recorded in the range 15-400 cm−1 using the synchrotron AILES beamline radiation at SOLEIL with a resolution of 0.0011 cm−1. First assignments for the pure rotational transitions (15-65 cm−1) belonging to the ground Îœt (=Îœ15) = 0 and first Îœt = 1 excited torsional state are based on measurements from previous studies performed in the 13-40 GHz spectral range, as well as on new millimeter-wave measurements performed at Lille in the spectral range 75-465 GHz. A few measurements and remeasurements in the 1.8-13 GHz were also performed using the chirped FT-MW spectrometer located in North Texas. The pure rotational transitions in the far-infrared and in the microwave spectral range belonging to the two first torsional states have been globally fitted using the RAM ("Rho Axis Method") dealing with the rotation-torsion Hamiltonian and implemented in the BELGI code. A total of 708 and 713 microwave transitions (6 â©œ J â©œ 40, View the MathML source â©œ 23) belonging to the ground torsional state Îœt = 0 and 1 have been fitted with root-mean-square (rms) deviations of 37.4 kHz and 32.3 kHz respectively, and 3170 pure rotational transitions in the far-infrared range (12 â©œ Jmax â©œ 65, 0 â©œ View the MathML source â©œ 48) belonging to Îœt = 0 and 1 have been fitted with a rms deviation of 0.00017 cm−1, using 35 parameters. Since in the far-infrared spectral range, the A-E internal rotor splittings have not been observed for the transitions belonging to the torsional ground Îœt = 0 state of the cis-methyl nitrite species, another fit was performed on those lines, using a Watson type Hamiltonian for comparison

    MULTI-LEVEL POLICY COALITIONS AN INTERPRETATIVE MODEL OF WATER CONFLICTS IN THE AMERICAS

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    ABSTRACT This article proposes an analytical approach to conflicts and policy-making related to urban water management based on multi-level policy coalitions. This is necessary to articulate four main issues. First, the repositioning of social and political struggles for access to water, along with policy variables. Second, the analysis of the effects of ecological transition, including climate change. Third, the reincorporation of these struggles and challenges in a multi-level approach. Finally, the enquiry into the apparent contradiction, in contemporary policymaking. The article proposes a definition of multi-level coalitions as collective preference systems that influence the content of policies (ideas/advocacy, decisions, policy tools) and their implementation, groups of actors that arise from engagement in policy issues. In the first section, the article presents the objectives of research on urban water management in the Americas, within the framework of which this analytical approach by multi-level coalitions is fashioned. In the second section, the article details four analytical issues. In the third section, it gives a definition of multi-level coalitions

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