Measurement of the gluon polarization \Delta G/G at COMPASS

One of the key objectives of the COMPASS experiment at CERN is the determination of the gluon contribution to the nucleon spin. The gluon polarization is measured via photon-gluon fusion in deep-inelastic scattering of 160 GeV/c polarized muons on a polarized 6LiD solid-state target. Photon-gluon fusion is tagged by the observation of charmed mesons or the production of hadron pairs with large transverse momenta p_t. The status of the analysis of the D0 and D0* events and of the high-p_t hadron pairs is shown. The gluon polarization \Delta G/G has been determined from the asymmetry of high-p_t hadron pairs with Q^2>1 GeV/c^2 in an analysis of the 2002/03 data as \Delta G/G=0.06 \pm 0.31 (stat.) \pm 0.06 (syst.).Comment: Proceeding of SPIN2004, Triest

Exclusively produced rho^0 asymmetries on the deuteron and future GPD measurements at COMPASS

Generalized parton distributions (GPDs) provide a new and powerful framework for a complete description of the nucleon structure. They can provide a three-dimensional picture of how the quarks and gluons form a nucleon. GPDs can be probed experimentally in hard exclusive meson production or deeply virtual Compton scattering (DVCS). The COMPASS experiment at CERN is a unique place to study these reactions. At COMPASS, a high energy polarized positive or negative muon beam is scattered off a polarized or unpolarized fixed target. First results for exclusive rho^0 meson production are shown. The transverse target spin asymmetry for exclusively produced rho^0 on a transversely polarized deuteron target has been measured. Prospects for future measurements of DVCS and exclusive meson production at COMPASS will be shown. The experiment will use the existing COMPASS spectrometer with a new target, a new recoil detector and extended calorimetry. Simulations for different models and a test of the recoil detector have been performed.Comment: 8 pages, Proceedings of Transversity 2008, Ferrara, May 200

Transverse Spin and Transverse Momentum Effects at COMPASS

The investigation of transverse spin and transverse momentum effects in deep inelastic scattering is one of the key physics programs of the COMPASS collaboration. In the years 2002-2004 COMPASS took data scattering 160 GeV muons on a transversely polarized 6LiD target. In 2007, a transversely polarized NH3 target was used. Three different channels to access the transversity distribution function have been analyzed: The azimuthal distribution of single hadrons, involving the Collins fragmentation function, the azimuthal dependence of the plane containing hadron pairs, involving the two-hadron interference fragmentation function, and the measurement of the transverse polarization of lambda hyperons in the final state. Transverse quark momentum effects in a transversely polarized nucleon have been investigated by measuring the Sivers distribution function. Azimuthal asymmetries in unpolarized semi-inclusive deep-inelastic scattering give important information on the inner structure of the nucleon as well, and can be used to estimate both the quark transverse momentum in an unpolarized nucleon and to access the so-far unmeasured Boer-Mulders function. COMPASS has measured these asymmetries in 2004 using spin-averaged 6LiD data.Comment: Proceedings of the NAPP2010 conference, Dubrovnik, Croatia, Sep. 201

Measurement of the cell membrane capacitance and conductance of colonic crypt cells of the rat using the patch clamp technique

Using the patch clamp technique the membrane capacitance and membrane conductance of colonic crypt cells of the rat was measured. The influence of the intracellular agonists Ca++, cAMP and of osmotic changes on the membrane capacitance and conductance was studied.Comment: Diploma thesis, University of Freiburg, Germany (in German

Transverse Spin Structure of the Nucleon from COMPASS

The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. In the years 2002-2004 data were taken by scattering a 160 GeV muon beam on a transversely polarized deuteron target. In 2007, additional data were collected on a transversely polarized proton target. New results for the Collins and Sivers asymmetries from the analysis of the proton data are presented.Comment: Proceedings of QCD08, Montpellier, July 200

Transversity Measurements at COMPASS

The measurement of transverse spin effects in semi-inclusive deep-inelastic scattering is an important part of the COMPASS physics program. From the analysis of the 2002-2004 data, new results for the transverse target spin asymmetry of z-ordered identified pion and kaon pairs are presented. In addition, a first result for the transverse target spin asymmetry of exclusively produced rho^0 mesons on the deuteron is shown.Comment: Proceedings of Photon07, Paris, 200

Possible natural fluid pathways from gravity pseudo-tomography in the geothermal fields of Northern Alsace (Upper Rhine Graben)

Background This study aims on investigating the regional flow field of the Soultz and adjacent geothermal fields located on the western side of the central Upper Rhine Graben and thus to provide insight into the origin of the 70% of the geothermal fluid coming from the regional inflow in the deep reservoir of the Soultz site. In an integrative approach, we consolidate conceptual models on fluid flow in the central Upper Rhine Graben. Methods Based on a 3D geological model and a new 3D temperature interpolation, we tackle the relation between tectonic structures and the occurrence of advection/convection along favourably oriented fault zones. Using sequential Butterworth filters, we study the distribution of negative residual anomalies in a pseudo-tomography down to a depth of about 6 to 8 km. Results We derived N-S-striking V-shaped negative anomalies that are consistent with the orientation of fault zones revealing major temperature anomalies to their east. Conclusions Following the concept of negative anomalies revealing zones of increased fracture porosity, and in agreement with fluid-chemistry, our findings suggest infiltration of meteoric water through the graben boundary fault and along preferential flow pathways that merge at intermediate depth. Up-flow of thermal water mixed most likely with brine from the deeper eastern part of the graben occurs along W-dipping typically rather steep structures

Environmental behaviours within ecological and social limits: integrating well-being with behavioural research for sustainability

This is the final version. Available from Elsevier via the DOI in this record. There is a pressing need to reduce inequalities and bring everyone above a foundational level of well-being whilst simultaneously staying within planetary boundaries. Yet, there is a limited understanding of how moving into and maintaining such 'safe and just' spaces affect environmental behaviours. To fill this gap, we argue for integrating human well-being and behaviour research. In particular, to 1) implement social thresholds when investigating environmental behaviours; 2) investigate the impact of social inequalities on environmental behaviours directly and 3) incorporate well-being domains with controlled behavioural experiments. Such understandings will be crucial for anticipating the implications of realising safe and just spaces for people and the planet.Swedish Research Council for Sustainable Development (Formas)Beijer Foundatio