Hadron Spectroscopy with COMPASS at CERN

The aim of the COMPASS hadron programme is to study the light-quark hadron spectrum, and in particular, to search for evidence of hybrids and glueballs. COMPASS is a fixed-target experiment at the CERN SPS and features a two-stage spectrometer with high momentum resolution, large acceptance, particle identification and calorimetry. A short pilot run in 2004 resulted in the observation of a spin-exotic state with $J^{PC} = 1^{-+}$ consistent with the debated $\pi1(1600)$. In addition, Coulomb production at low momentum transfer data provide a test of Chiral Perturbation Theory. During 2008 and 2009, a world leading data set was collected with hadron beam which is currently being analysed. The large statistics allows for a thorough decomposition of the data into partial waves. The COMPASS hadron data span over a broad range of channels and shed light on several different aspects of QCD.Comment: 4 pages, 5 figure

Multidimensional entropy landscape of quantum criticality

The Third Law of Thermodynamics states that the entropy of any system in equilibrium has to vanish at absolute zero temperature. At nonzero temperatures, on the other hand, matter is expected to accumulate entropy near a quantum critical point (QCP), where it undergoes a continuous transition from one ground state to another. Here, we determine, based on general thermodynamic principles, the spatial-dimensional profile of the entropy S near a QCP and its steepest descent in the corresponding multidimensional stress space. We demonstrate this approach for the canonical quantum critical compound CeCu6-xAux near its onset of antiferromagnetic order. We are able to link the directional stress dependence of S to the previously determined geometry of quantum critical fluctuations. Our demonstration of the multidimensional entropy landscape provides the foundation to understand how quantum criticality nucleates novel phases such as high-temperature superconductivity.Comment: 14 pages, 4 figure

Assessment of the genetic diversity of native apple cultivars in the south eastern ranges of the Alps with three selected microsatellite loci

The regional diversity of native apple cultivars in parts of the south eastern ranges of the Alps (Styria, Austria and northern parts of Slovenia) was examined. As the application of conventional pomological methods to characterise cultivars may sometimes be ambiguous, we regard the application of molecular methods to be essential for thorough cultivar diversity assessments. Five hundred samples were collected from different climatic and edaphic regions and analysed using three selected microsatellite loci. With this approach we were able to distinguish 190 named varieties at which we chose 50 as reference varieties. The high diversity of native races suggests that the Southern alpine ranges represent a „hot spot“ of cultivar diversity. This can be attributed to historical effects and the local persistence of a traditional management practice with orchards of widely spaced and old-grown trees of various races. Because these „old“ native races could harbour interesting genetic traits (pathogen resistance, taste, etc.) that will be important in future food production, measures for their conservation are overdue. Our approach will not only show which local cultivars/genotypes require rapid action for their protection, but due to the international nature of our project we can also show which old and untraceable local names in different languages correspond with the same cultivars