Surface plasmon mode steering and negative refraction

The propagation of surface plasmon beams through singly and doubly periodic metallic gratings is analyzed both in real and Fourier spaces. Large beam steering effects are experimentally revealed by probing the isofrequency surfaces (IFS) related to propagating plasmonic Bloch waves inside the gratings. In particular, negative refraction is demonstrated close to the Bragg condition. We analyze how the local structure of the IFS can amplify the sensitivity of surface plasmon-based sensors.     

First measurement of the rho spectral function in high-energy nuclear collisions

We report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions at the CERN SPS. A significant excess of pairs is observed above the yield expected from neutral meson decays. The unprecedented sample size of 360,000 dimuons and the good mass resolution of about 2% allow us to isolate the excess by subtraction of the decay sources. The shape of the resulting mass spectrum is consistent with a dominant contribution from pi+pi- -->rho -->mu+mu- annihilation. The associated space-time averaged spectral function shows a strong broadening, but essentially no shift in mass. This may rule out theoretical models linking hadron masses directly to the chiral condensate.     

NA60 results on thermal dimuons

The NA60 experiment at the CERN SPS has measured muon pairs with unprecedented precision in 158 A GeV In–In collisions. A strong excess of pairs above the known sources is observed in the whole mass region 0.2<M<2.6 GeV. The mass spectrum for M<1 GeV is consistent with a dominant contribution from π ⁺ π ⁻→ρ→μ ⁺ μ ⁻ annihilation. The associated ρ spectral function shows a strong broadening, but essentially no shift in mass. For M>1 GeV, the excess is found to be prompt, not due to enhanced charm production, with pronounced differences to Drell–Yan pairs. The slope parameter T _eff associated with the transverse momentum spectra rises with mass up to the ρ, followed by a sudden decline above. The rise for M<1 GeV is consistent with radial flow of a hadronic emission source. The seeming absence of significant flow for M>1 GeV and its relation to parton–hadron duality is discussed in detail, suggesting a dominantly partonic emission source in this region. A comparison of the data to the present status of theoretical modeling is also contained. The accumulated empirical evidence, including also a Planck-like shape of the mass spectra at low p _T and the lack of polarization, is consistent with a global interpretation of the excess dimuons as thermal radiation. We conclude with first results on ω in-medium effects.     

The effect of forward and backward scattering on the law of darkening for the Milne problem and the spherical albedo

A synthetic kernel is used to study the effect of forward and backward scattering on the law of darkening for the Milne problem and the spherical albedo.     

Molten bisphenol-A polycarbonate—poly(ethylene terephthalate) blends. II. Kinetics of the exchange reaction.

The kinetic aspects of the bisphenol-A polycarbonate-polyethylene terephthalate exchange reaction are studied. Though the overall mechanism of transesterification is reversible, the kinetics can be treated from a more simple model of two consecutive reactions, due to the decomposition of the alkyl carbonate formed. The values of the kinetic parameters, similar to those obtained for the bisphenol-A polycarbonate-polybutylene terephthalate transesterification, suggest that the most likely mechanism is a direct ester–ester interchange reaction which can also be catalyzed by additives such as titanium derivatives.     

A study of some parameters relevant to the response of harwell PMMA dosimeters to gamma and electron irradiation

The effects on the radiation response of Harwell polymethylmethacrylate (PMMA) dosimeters of dose-rate, radiation type, temperature during irradiation and post-irradiation storage, and post-irradiation stability, are of importance to the operators of commercial irradiation facilities.

This paper describes recent studies of the effects of some of these parameters on the radiation response of Harwell Red 4034, Amber 3042, and Gammachrome YR Perspex dosimeters, and provides data on batch to batch variation and shelf-life.     

Neutrino and antineutrino charged-current inclusive scattering in iron in the energy range 20<E v <300 GeV

Inclusive charged-current interactions of high-energy neutrinos and antineutrinos have been studied with high statistics in a counter experiment at the CERN Super Proton Synchrotron. The energy dependence of the total cross-sections, the longitudinal structure function, and the nucleon structure functionsF ₂,xF ₃, and \(\bar q^{\bar v} \) are determined from these data. The analysis of theQ ²-dependence of the structure functions is used to test quantum chromodynamics, to determine the scale parameter Λ and the gluon distribution in the nucleon.     

Image restoration through aberrant media by optical phase conjugation in a type II three-wave mixing interaction

Restoration of an image through an aberrant plate has been achieved by use of optical phase conjugation in a type II parametric interaction in which the amplified signal and idler waves are reflected back through the aberrant medium. The resolution of the restored phase-conjugate images is equal to 0.18 mm, and the amplification gain is ~4dB.