Measurement of the Charm Structure Function of the Photon at LEP

Charm production is studied in deep-inelastic electron-photon scattering using OPAL data at e+e- centre-of-mass energies from 183 to 209 GeV. Charm quarks are identified by exclusive reconstruction of D* mesons. The cross-section of D* production is measured in a restricted kinematic region, and then extrapolated to the total charm production cross-section and the charm structure function of the photon. For x>0.1 the measurement is well described by Monte Carlo models and perturbative QCD calculations but for x<0.1 the predictions are lower than the data both in the directly measured region and after the extrapolation.Comment: Presented at Photon 200

Charm and bottom production in two-photon collisions with OPAL

A preliminary update of the previous OPAL measurement of the inclusive production of D* mesons in anti-tagged photon-photon collisions is presented together with the first preliminary OPAL measurement of bottom production in photon-photon collisions.Comment: 7 pages, Talk given at the PHOTON 2000 Conference, Ambleside, UK, August 26-31,200

Hadron production in two-photon collisions at LEP-L3

The reaction e+ e- -> e+ e- gamma* gamma* -> e+ e- hadrons is analysed for quasi-real virtual photons using data collected by the L3 detector during the LEP high energy runs at sqrt(s) = 183 and 189 GeV. Preliminary results on the cross sections sigma(e+e- -> e+e- hadrons) and sigma(gamma gamma -> hadrons) are given in the interval 5 GeV < W_{gamma gamma} < 145 GeV. The centre-of-mass energy dependence of the two-photon cross section is well described by the universal Regge parametrisation, but with a steeper rise with energy as compared to hadron-hadron cross sections. The data are also compared to the expectations of different theoretical models. To investigate diffractive processes, the elastic gamma gamma -> rho0 rho0 process and the inclusive rho0 production gamma gamma -> rho0 X are studied in the W_{gamma gamma} > 3 GeV region. In all channels a comparison is made with the Pythia and Phojet Monte Carlo generators.Comment: Presented at the Central European Triangle Symposium on Particle Physics, Zagreb, Croatia, June, 17-19, 199

Which sectors make the poor countries so unproductive?

Standard growth accounting exercises find large cross-country differences in aggregate TFP. Here we ask whether specific sectors are driving these differences, and, if this is the case, which these problem sectors are. We argue that to answer these questions we need to consider four sectors. In contrast, the literature typically considers only two sectors. Our four sectors produce services (nontradable consumption), consumption goods (tradable consumption), construction (nontradable investment), and machinery and equipment (tradable investment). Interacting the data from the 1996 benchmark study of the Penn World Tables with economic theory, we find that the TFP differences across countries are much larger in the two tradable sectors than in the two nontradable sectors. This is consistent with the Balassa--Samuelson hypothesis. We also find that within the tradable sectors the TFP differences are much larger in machinery and equipment than in consumption goods. We illustrate the usefulness of our findings by accounting for the conflicting results of the existing two--sector analyses and by developing criteria for a successful theory of aggregate TFP

Revaluating regional influences of ICT factors in Hungary

At the beginning of the 21st century ICT factors got growing importance in shaping regional differences in Hungary. Determining differences of ICT competitiveness became needful in analysing regional inequalities recently, however, according to some opinions there are ICT-like factors on the scene for longer time. Depending on theories and interpretations these factors are treated mainly as new although sometimes as traditional ones. In accordance with the generally accepted approaches ICT factors began to demonstrate their effects in the last decades. Other (wider) approaches on the contrary state that the most characteristic elements of ICT presented themselves earlier in determining regional differences that have been supplemented only with features of modern communication infrastructure. The paper focuses on measuring the spatial differentiating influence of ICT factors within Hungary. By the means of regression models it is presented what explanatory force can be connected to ICT factors in determining the level of regional competitiveness and development. In connection with the results the rank of regions could be revaluated in the socio-economic competition of the new century.