Gluon polarisation from high transverse momentum hadron pairs production (COMPASS)

A new preliminary result of a gluon polarisation \Delta G/G obtained selecting high transverse momentum hadron pairs in DIS events with Q^2>1 (GeV/c)^2 is presented. Data has been collected by COMPASS at CERN during the 2002-2004 years. In the extraction of $\Delta G/G$ contributions coming from the leading order $\gamma q$ and QCD processes are taken into account. A new weighting method based on a neural network approach is used. Also a preliminary result of \Delta G/G for events with Q^2<1 (GeV/c)^2 is presented.Comment: Advanced Studies Institute On Symmetries And Spin (SPIN-Praha-2008) 20-26 Jul 2008, Prague, Czech Republic. The proceedings of the ASI will be published in The European Physical Journal Special Topics (EJP ST) Serie

Compass Results on Gluon Polarisation from High pT hadron pairs

One of the goals of the COMPASS experiment is the determination of the gluon polarisation \Delta G/G, for a deep understanding of the spin structure of the nucleon. In DIS the gluon polarisation can be measured via the Photon-Gluon-Fusion (PGF) process, identified by open charm production or by selecting high p_T hadron pairs in the final state. The data used for this work were collected by the COMPASS experiment during the years 2002-2004, using a 160 GeV naturally polarised positive muon beam scattering on a polarised nucleon target. A new preliminary result of the gluon polarisation \Delta G/G from high p_T hadron pairs in events with Q^2>1 (GeV/c)^2 is presented. In order to extract \Delta G/G, this analysis takes into account the leading process \gamma q contribution together with the PGF and QCD Compton processes. A new weighted method based on a neural network approach is used. A preliminary \Delta G/G result for events from quasi-real photoproduction (Q^2<1 (GeV/c)^2) is also presented.Comment: prepared for the proceedings of the DSPIN09 - XIII Workshop on High Energy Spin Physics, Dubna, Russia, September 1 - 5, 200

A multilevel, multispectral data set analysis in the visible and infrared wavelength regions

There are no author-identified significant results in this report

Evaluation of Skylab data for land use mapping

There are no author-identified significant results in this report

Modelling Intermediate Age and Old Stellar Populations in the Infrared

We have investigated the spectro-photometric properties of the Asymptotic Giant Branch (AGB) stars and their contribution to the integrated infrared emission in simple stellar populations (SSP). Adopting analytical relations describing the evolution of these stars in the HR diagram and empirical relations for the mass-loss rate and the wind terminal velocity, we were able to model the effects of the dusty envelope around these stars, with a minimal number of parameters. We computed isochrones at different age and initial metal content. We compare our models with existing infrared colors of M giants and Mira stars and with IRAS PSC data. Contrary to previous models, in the new isochrones the mass-loss rate, which establishes the duration of the AGB phase, also determines the spectral properties of the stars. The contribution of these stars to the integrated light of the population is thus obtained in a consistent way. We find that the emission in the mid infrared is about one order of magnitude larger when dust is taken into account in an intermediate age population, irrespective of the particular mixture adopted. The dependence of the integrated colors on the metallicity and age is discussed, with particular emphasis on the problem of age-metallicity degeneracy. We show that, contrary to the case of optical or near infrared colors, the adoption of a suitable pass-band in the mid infrared allows a fair separation of the two effects. We suggest intermediate redshift elliptical galaxies as possible targets of this method of solving the age-metallicity dilemma. The new SSP models constitute a first step in a more extended study aimed at modelling the spectral properties of the galaxies from the ultraviolet to the far infrared.Comment: 16 pages, 10 figures, to appear in A&