Temperature dependent high-resolution infrared photoabsorption cross-sections of trifluoromethyl sulphur pentafluoride

Absolute infrared photoabsorption cross-sections have been measured over the range 600-1500 cm(-1) for the powerful greenhouse gas SF5CF3 at high resolution (0.03 cm(-1)) and at temperatures between 203 and 298 K. Our data indicate that the integrated absorption intensity shows a weak negative dependence on temperature. It is concluded therefore that previous calculations of radiative forcings and global warming potentials based on room-temperature data are reasonable estimates for the atmosphere, but may be low by a few percent. (C) 2002 Elsevier Science B.V. All rights reserved.

Radiative efficiencies and global warming potentials using theoretically determined absorption cross-sections for several hydrofluoroethers (HFEs) and hydrofluoropolyethers (HFPEs)

Integrated infrared cross-sections and wavenumber positions for the vibrational modes of a range of hydrofluoroethers (HFEs) and hydrofluoropolyethers (HFPEs) have been calculated. Spectra were determined using a density functional method with an empirically derived correction for the wavenumbers of band positions. Radiative efficiencies (REs) were determined using the Pinnock et al. method and were used with atmospheric lifetimes from the literature to determine global warming potentials (GWPs). For the HFEs and the majority of the molecules in the HG series HFPEs, theoretically determined absorption cross-sections and REs lie within ca. 10% of those determined using measured spectra. For the larger molecules in the HG series and the HG′ series of HFPEs, agreement is less good, with theoretical values for the integrated cross-sections being up to 35% higher than the experimental values; REs are up to 45% higher. Our method gives better results than previous theoretical approaches, because of the level of theory chosen and, for REs, because an empirical wavenumber correction derived for perfluorocarbons is effective in predicting the positions of C–F stretching frequencies at around 1250 cm−1 for the molecules considered here.

Effect on the heavy-ion fusion and elastic scattering cross sections of common approximations assumed in coupled-channel calculations

We study the effects of several approximations commonly used in coupled-channel analyses of fusion and elastic scattering cross sections. Our calculations are performed considering couplings to inelastic states in the context of the frozen approximation, which is equivalent to the coupled-channel formalism when dealing with small excitation energies. Our findings indicate that, in some cases, the effect of the approximations on the theoretical cross sections can be larger than the precision of the experimental data.

Perylene derivatives with large two-photon-absorption cross-sections for application in optical limiting and upconversion lasing

Perylene tetracarboxylic derivatives (PTCDs) display exceptionally high two-photon absorption (2PA) cross-sections (6, see Figure). In addition, the 2PA saturation behavior and strong two-photon-pumped fluorescence suggest that PTCD compounds may be attractive candidates for applications in optical limiting and two-photon-pumped upconversion lasing.

Measurement of inclusive differential cross sections for Upsilon(1S) production in p(p)over-bar collisions at root s=1.96 TeV

We present measurements of the inclusive production cross sections of the Upsilon(1S) bottomonium state in p (p) over bar collisions at root s=1.96 TeV. Using the Upsilon(1S)->mu(+)mu(-) decay mode for a data sample of 159 +/- 10 pb(-1) collected by the D0 detector at the Fermilab Tevatron collider, we determine the differential cross sections as a function of the Upsilon(1S) transverse momentum for three ranges of the Upsilon(1S) rapidity: 0 <\y(Upsilon)\<= 0.6, 0.6 <\y(Upsilon)\<= 1.2, and 1.2 <\y(Upsilon)\<= 1.8.

Measurement of direct photon pair production cross sections in p(p)over-bar collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of differential Z/gamma* plus jet plus X cross sections in p(p)over-bar collisions at root S=1.96 TeV

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of three-jet differential cross sections d sigma(3jet)/dM(3jet) in p(p)over-bar collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurements of differential cross sections of Z/gamma* plus jets plus X events in p(p)over-bar collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of gamma + b + X and gamma + c + X Production Cross Sections in pp > Collisions at s=1.96 TeV

First measurements of the differential cross sections d(3)sigma/(dp(T)(gamma)dy(gamma)dy(jet)) for the inclusive production of a photon in association with a heavy quark (b, c) jet are presented, covering photon transverse momenta 30 < p(T)(gamma)< 150 GeV, photon rapidities |y(gamma)|< 1.0, jet rapidities |y(jet)|< 0.8, and jet transverse momenta p(T)(jet)> 15 GeV. The results are based on an integrated luminosity of 1 fb(-1) in pp collisions at s=1.96 TeV recorded with the D0 detector at the Fermilab Tevatron Collider. The results are compared with next-to-leading order perturbative QCD predictions.

Measurement of the ratio of inclusive cross sections sigma(p(p)over-bar -> Z plus b-quark jet)/sigma(p(p)over-bar -> Z plus jet) at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurements of single top quark production cross sections and vertical bar V-tb vertical bar in p(p)over-bar collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of the WZ and ZZ production cross sections using leptonic final states in 8.6 fb(-1) of p(p)over-bar collisions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of the inclusive W and Z production cross sections in pp collisions at root s = 7 TeV with the CMS experiment

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurement of the inclusive production cross sections for forward jets and for dijet events with one forward and one central jet in pp collisions at root s=7 TeV

The inclusive production cross sections for forward jets, as well for jets in dijet events with at least one jet emitted at central and the other at forward pseudorapidities, are measured in the range of transverse momenta p(T) = 35-150 GeV/c in proton-proton collisions at root s = 7 TeV by the CMS experiment at the LHC. Forward jets are measured within pseudorapidities 3.2<|eta|<4.7, and central jets within the |eta|<2.8 range. The double differential cross sections with respect to pt and eta are compared to predictions from three approaches in perturbative quantum chromodynamics: (i) next-to-leading-order calculations obtained with and without matching to parton-shower Monte Carlo simulations, (ii) PYTHIA and HERWIG parton-shower event generators with different tunes of parameters, and (iii) CASCADE and HEJ models, including different non-collinear corrections to standard single-parton radiation. The single-jet inclusive forward jet spectrum is well described by all models, but not all predictions are consistent with the spectra observed for the forward-central dijet events.