Spin Physics at COMPASS

The COMPASS experiment is a fixed target experiment at the CERN SPS using muon and hadron beams for the investigation of the spin structure of the nucleon and hadron spectroscopy. The main objective of the muon physics program is the study of the spin of the nucleon in terms of its constituents, quarks and gluons. COMPASS has accumulated data during 6 years scattering polarized muons off a longitudinally or a transversely polarized deuteron (6LiD) or proton (NH3) target. Results for the gluon polarization are obtained from longitudinal double spin cross section asymmetries using two different channels, open charm production and high transverse momentum hadron pairs, both proceeding through the photon-gluon fusion process. Also, the longitudinal spin structure functions of the proton and the deuteron were measured in parallel as well as the helicity distributions for the three lightest quark flavors. With a transversely polarized target, results were obtained with proton and deuteron targets for the Collins and Sivers asymmetries for charged hadrons as well as for identified kaons and pions. The Collins asymmetry is sensitive to the transverse spin structure of the nucleon, while the Sivers asymmetry reflects correlations between the quark transverse momentum and the nucleon spin. Recently, a new proposal for the COMPASS II experiment was accepted by the CERN SPS which includes two new topics: Exclusive reactions like DVCS and DVMP using the muon beam and a hydrogen target to study generalized parton distributions and Drell-Yan measurements using a pion beam and a polarized NH3 target to study transverse momentum dependent distributions.Comment: Proceedings of the Rutherford conference, Manchester, August 2011. Changes due to referees comments implemente

Economic Opportunities and Structural Effects of Sustainable Energy Supply

Renewable energy sources and increased energy efficiency are not only crucial for reducing greenhouse gas emissions and other negative impacts of conventional energy supply; they also hold enormous economic opportunity. Significant and dynamically growing sectors have emerged in the area of renewable energy over the last several years. In 2010, 26.6 billion euros were invested in Germany alone in renewable energy facilities. Altogether, renewable energy sources created 35.5 billion euros in demand for the German economy. Gross employment in the area of renewable energy is estimated at 367,400 persons for 2010. Likewise, the net economic balance for the expansion of renewables is positive. Model calculations conducted by DIW Berlin show that the gross domestic product is by 2.9 percent higher in 2030 in the "Expansion Scenario" than following a "Null Scenario" with no expansion. Depending on the labor market conditions, the net employment effects appear to be weak to moderate, but in any case positive. These scenario calculations also illustrate that the impact of the expansion differs across sectors. Furthermore, the transition from the current energy supply regime to one where renewable energy sources contribute a large share and energy efficiency has been substantially increased will require a structural change in business and the working world that will have to be followed closely in the future.Renewable energy, economic impacts, structural change, Germany

Economic Effects of Renewable Energy Expansion: A Model-Based Analysis for Germany

Increasing utilization of renewable energy sources (RES) is a priority worldwide. Germany has been a forerunner in the deployment of RES and has ambitious goals for the future. The support and use of renewables affects the economy: It creates business opportunities in sectors producing renewable energy facilities, but also comes along with costs for supporting the deployment of renewables. This paper analyses and quantifies the net balance of economic effects associated with renewable energy deployment in Germany until 2030. To this end, we use a novel model, the 'Sectoral Energy-Economic Econometric Model' (SEEEM). SEEEM is an econometric multi-country model which, for Germany, contains a detailed representation of industries, including 14 renewable energy technology sectors. Our results show that renewable energy expansion can be achieved without compromising growth or employment. The analysis reveals a positive net effect on economic growth in Germany. Net employment effects are positive. Their size depends strongly on labour market conditions and policies. Results at the industry level indicate the size and direction of the need for restructuring across the sectors of the Germany economy.