First results from the OSQAR photon regeneration experiment: No light shining through a wall

A new method to amplify the photon-axion conversions in magnetic field is proposed using a buffer gas at a specific pressure. As a first result, new bounds for mass and coupling constant for purely laboratory experiments aiming to detect any hypothetical scalars and pseudo-scalars which can couple to photons were obtained at 95% confidence level, excluding the PVLAS result newly disclaimed.Comment: 4 pages, 5 figure

Calibration of TCCON column-averaged CO2: the first aircraft campaign over European TCCON sites

The Total Carbon Column Observing Network (TCCON) is a ground-based network of Fourier Transform Spectrometer (FTS) sites around the globe, where the column abundances of CO2, CH4, N2O, CO and O2 are measured. CO2 is constrained with a precision better than 0.25% (1-σ). To achieve a similarly high accuracy, calibration to World Meteorological Organization (WMO) standards is required. This paper introduces the first aircraft calibration campaign of five European TCCON sites and a mobile FTS instrument. A series of WMO standards in-situ profiles were obtained over European TCCON sites via aircraft and compared with retrievals of CO2 column amounts from the TCCON instruments. The results of the campaign show that the FTS measurements are consistently biased 1.1% ± 0.2% low with respect to WMO standards, in agreement with previous TCCON calibration campaigns. The standard a priori profile for the TCCON FTS retrievals is shown to not add a bias. The same calibration factor is generated using aircraft profiles as a priori and with the TCCON standard a priori. With a calibration to WMO standards, the highly precise TCCON CO2 measurements of total column concentrations provide a suitable database for the calibration and validation of nadir-viewing satellite

First Results of the Full-Scale OSQAR Photon Regeneration Experiment

Recent intensive theoretical and experimental studies shed light on possible new physics beyond the standard model of particle physics, which can be probed with sub-eV energy experiments. In the second run of the OSQAR photon regeneration experiment, which looks for the conversion of photon to axion (or Axion-Like Particle), two spare superconducting dipole magnets of the Large Hadron Collider (LHC) have been used. In this paper we report on first results obtained from a light beam propagating in vacuum within the 9 T field of two LHC dipole magnets. No excess of events above the background was detected and the two-photon couplings of possible new scalar and pseudo-scalar particles could be constrained.Comment: 5 pages, 4 figures, Photon 2011 Conference, Submitted to JO

OZONE PHOTOLYSIS: STRONG ISOTOPOLOGUE/ISOTOPOMER SELECTIVITY IN THE STRATOSPHERE

Author Institution: CTMM Institut Charles Gerhardt UMR-CNRS 5253; University of Montpellier, France; Univ. Grenoble 1 / CNRS, LIPhy UMR 5588, Grenoble, F-38041, France; Department of Information Technology, University of Debrecen, P.O. Box 12, H-4010 Debrecen, HungaryUsing the visible-UV absorption cross section (Abs. XS) of five ozone isotopologues and an averaged actinic flux, we have calculated the contribution of the atmospheric ozone photolysis to the oxygen isotope and ozone isotopologue/isotopomer enrichment. Five ozone isotopologues/isotopomers are considered among which three are symmetric, $O^{16}3$ (noted 666), $O^{16}O^{17}O^{16}$ (676) and $O^{16}O^{18}O^{16}$ (686), and two are asymmetric, $O^{17}O^{16}_2$ (667) and $O^{18}O^{16}_2$ (668). The photolysis rates of the five ozone isotopologues have been calculated as a function of altitude. The Multi Configuration Time Dependent Hartree (MCTDH) method and the potential energy surfaces calculates by R. Schinke and {\it coworkers} have been used. We have used experimental actinic fluxes, averaged for latitude and season, for altitudes varying by step of 4km up to 80km. Below ~35km, the contribution of the Hartley band to the photolysis rates is restricted to its low energy range, named the Huggins band, which has strong isotopologue/isotopomer selectivity and then induces strong enrichment. Consequently, the isotopologue enrichment's due to ozone photolysis are strongly dependent of the altitude, with pronounced enrichment peaks around 35 km, the altitude corresponding to the maximum relative contribution of the Huggins band. \vspace{1em} We will also present some new simulations for the simulation of laser-induced quantum dynamics of the electronic and nuclear motion in the ozone molecule on the attosecond time scale. \vspace{1em

Multinozzle Jet set-up for Fourier Transform Interferometer Spectroscopy

info:eu-repo/semantics/publishe

ANOMALOUS BEHAVIOUR OF THE ANTICROSSING DENSITY AS A FUNCTION OF EXCITATION ENERGY IN THE C2H2 MOLECULE

$^{1}$ P. Dupre, R. Jost, M. Lombardi, P. G. Green, E. Abramson and R. W. Field, in preparation. $^{2}$ P.P. G. Green, PhD Thesis, MIT (1989). CAMBRIDGE MA (U.S.A.).Author Institution: Service National des Champs Intenses.; Service National des Champs Intenses.; Mail Stop 170-25, California Institute of Technology; Mail Stop 170-25, Service National des Champs Intenses.; Department of Chemistry, MITWe have recorded Zeenan Anticrossing (ZAC) spectra of gas phase acetylene $(HC=CH)$ in the $\bar{A} ^{1}A_{u} v_{3}= O-3 (v_{3}$ is the trans-bending normal mode of the trans-bent excited electronic state). $J = K = I = O$. levels. The energy range thus sampled was from 42,200 to 45,300 cm1 above the $\bar{X} ^{1}\Sigma_{g}$ state. The eugnetic field scanned from 0 to 8 Tesin and the ZAC spectre were recorded as variations (decreases) in the intensity of the fluorescence excited by a pulsed, frequency doubled dye laser. The ZAC spectra wore unassignably complex. We report a surprisingly rapid increase in the density of anticrossing (AC) over a $3100 cm^{-1}$ (only 7\% of the total excitation energy) energy interval, In the $v = 3$ level the ZAC spectra are unassignably complex and the anticrossing density is $10^2$ Limes larger than the maximum computed density of triplet vibrational states and quite comparable to the computed density of $\tilde{X} ^{1}\Sigma^{+}_{g}$ vibrational states. This constrasts with the AC level density observed in the $v_{3} = 0$ vibrational level where the agreement with the calculated level density is good enough. We suggest three plausible mechanisms to explain this behaviour : the existence of a dissociation limit, the potential curve crossing or the vicinity of a triplet trans- cia-bent isomerization barrier. We prefer this last explanation because this barrier should increase the $S_{1} \longleftrightarrow T$ and the $S_{0} \longleftrightarrow T$ couplings, Indeed, we suggest that the large level densities are due to $S_{1}\longleftrightarrow S_{0}$ tran-sitions induced by a triplet $level^{3}$. Moreover, the existence of the isomerization barrier is suggested by recent work using the Stark quantus beat $technique^{2}$

Multinozzle supersonic expansion for Fourier transform absorption spectroscopy

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