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

A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the $\mathcal{O}(10)$ 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 $\nu_e$ 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 $\sigma(E_\nu)$ for charged-current $\nu_e$ absorption on argon. In the context of a simulated extraction of supernova $\nu_e$ spectral parameters from a toy analysis, we investigate the impact of $\sigma(E_\nu)$ modeling uncertainties on DUNE's supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on $\sigma(E_\nu)$ must be substantially reduced before the $\nu_e$ 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 $\sigma(E_\nu)$ 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 $\sigma(E_\nu)$. A direct measurement of low-energy $\nu_e$-argon scattering would be invaluable for improving the theoretical precision to the needed level.Comment: 25 pages, 21 figure

L'eau au cœur du processus de paix entre Israël et l'OLP. Propositions

Nous publions ici un article sur un sujet d'actualité. L'auteur y exprime ses opinions sur la situation actuelle du partage de l'eau au Proche-Orient et propose des actions à mettre en œuvre durant le processus de paix entre Israël et l'OLP. Certains peuvent avoir des idées différentes et nous sommes prêts à recevoir leur courrier

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

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 ($\Delta E_{HONO}$) to be 107$\pm$26 cm$^{-1}$. This value is in good agreement with previous experimental studies calculations and with recent high-level \emph{ab-initio} calculations

Prediction of high-order line-shape parameters for air-broadened O2 lines using requantized classical molecular dynamics simulations and comparison with measurements

International audienceLine-shape models such as the Hartmann-Tran (HT) profile have adjustable high-order parameters that are usually determined by fits to experimental spectra. As an alternative approach, we demonstrate that fitting the HT profile to theoretical spectra provides high-order line-shape parameters for O2 transitions that are consistent with experimentally determined values. To this end, normalized absorption spectra of air-broadened O2 lines were computed without adjustable parameters using requantized classical molecular dynamics simulations (rCMDS). These theoretical calculations were made at a pressure of 203 kPa and for values of the Doppler width that cover near-Doppler-limited to collisional-broadened pressure conditions. Hartmann-Tran (HT) line profiles with adjustable line-shape parameters were then simultaneously fit to the set of rCMDS-calculated spectra in a global multispectrum analysis. The retrieved high-order line-shape parameters (i.e. the speed dependence of the line broadening and the Dicke narrowing coefficient) were subsequently used as fixed HT parameters in the analysis of seven air-broadened O2 lines of the band. The spectra were measured over a fifteen-fold range of total gas pressure at high spectral resolution and signal-to-noise ratio with a frequency-stabilized cavity ring-down spectroscopy system. We show that these predicted parameters enable all the measured lines to be fit to within 1%, which is much better than best fits of the Voigt line profile to the measured spectra. This approach opens the route for predicting high-order line-shape parameters from first-principles calculations and for their inclusion in spectroscopic databases. Furthermore, the temperature dependences of the broadening coefficient and its speed dependent component for air-broadened O2 lines were also calculated using rCMDS

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

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

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 νt (=ν15) = 0 and first νt = 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 ⩽ J ⩽ 40, View the MathML source ⩽ 23) belonging to the ground torsional state νt = 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 ⩽ Jmax ⩽ 65, 0 ⩽ View the MathML source ⩽ 48) belonging to νt = 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 νt = 0 state of the cis-methyl nitrite species, another fit was performed on those lines, using a Watson type Hamiltonian for comparison

Line-Parameter Measurements and Stringent Tests of Line-Shape Models Based on Cavity-Enhanced Absorption Spectroscopy

<p>Laser methods that are based on cavity-enhanced absorption spectroscopy (CEAS) are well-suited for measuring molecular line parameters under conditions of low optical density, and as such they are complementary to broadband Fourier-transform spectroscopy (FTS) techniques. Attributes of CEAS include relatively low detection limits, accurate and precise detuning axes and high fidelity measurements of line shape. In many cases these performance criteria are superior to those obtained using direct laser absorption spectroscopy and FTS-based systems.</p> <p>In this presentation we will survey several examples of frequency-stabilized cavity ring-down spectroscopy (FS-CRDS)¹ measurements obtained with laser spectrometers developed at the National Institute of Standards and Technology (NIST) in Gaithersburg Maryland. These experiments, which are motivated by atmospheric monitoring and remote-sensing applications that require high-precision and accuracy, involve nearinfrared transitions of carbon dioxide, water, oxygen and methane. We discuss spectra with signal-to-noise ratios exceeding 10⁶, frequency axes with absolute uncertainties in the 10 kHz to 100 kHz range and linked to a Cs clock, line parameters with relative uncertainties at the 0.2 % level and isotopic ratios measured with a precision of 0.03 %. We also present FS-CRDS measurements of CO₂line intensities which are measured at atmospheric concentration levels and linked to gravimetric standards for CO₂in air, and we quantify pressure-dependent deviations between various theoretical line profiles and measured line shapes.</p> <p>Finally we also present recent efforts to increase data throughput and spectral coverage in CEAS experiments. We describe three new high-bandwidth CEAS techniques including frequency-agile, rapid scanning spectroscopy (FARS)², which enables continuous-wave measurements of cavity mode linewidth and acquisition of ringdown decays with no dead time during laser frequency tuning, heterodyne-detected cavity ring-down spectroscopy (HD-CRDS)^3<em>,</em>4, which offers shot-noise-limited statistics by interrogating ring-down decays at high frequencies, and finally multi-heterodyne cavity-enhanced spectroscopy (MH-CEAS)⁵, which provides wavelength-multiplexed measurements of both the amplitude and phase shift of the transmitted field.</p

Liver fibrosis staging with contrast-enhanced ultrasonography: prospective multicenter study compared with METAVIR scoring

International audienceWe prospectively assessed contrast-enhanced sonography for evaluating the degree of liver fibrosis as diagnosed via biopsy in 99 patients. The transit time of microbubbles between the portal and hepatic veins was calculated from the difference between the arrival time of the microbubbles in each vein. Liver biopsy was obtained for each patient within 6 months of the contrast-enhanced sonography. Histological fibrosis was categorized into two classes: (1) no or moderate fibrosis (F0, F1, and F2 according to the METAVIR staging) or (2) severe fibrosis (F3 and F4). At a cutoff of 13 s for the transit time, the diagnosis of severe fibrosis was made with a specificity of 78.57%, a sensitivity of 78.95%, a positive predictive value of 78.33%, a negative predictive value of 83.33%, and a performance accuracy of 78.79%. Therefore, contrast-enhanced ultrasound can help with differentiation between moderate and severe fibrosis.</p