We examine the potential of the COMPASS experiment at CERN to study color transparency via exclusive vector meson production in hard muon-nucleus scattering. It is demonstrated that COMPASS has high sensitivity to test this important prediction of perturbative QCD. Expanded version of the talk presented at the Workshop on ”Nucleon Structure and Meson Spectroscopy” physics to be studied at the C...

The nucleon spin structure is studied at COMPASS via the measurement of the spin dependent properties of deep inelastic muon-deuteron scattering. Both inclusive and semi-inclusive observables are investigated, with the emphasis put on the latter. This allows to access, in particular, the gluon polarization (∆G/G) and the flavor decomposition of the quark helicity distributions. Results from mea...

Introduction ....................................................................... 1 Magnetic Compass Background ....................................... 1 Device Design Basis ......................................................... 3 PSoC Implementation ........................................................ 5 Software Description ......................................................... 6 ...

We report evidence for magnetic compass orientation by larval Drosophila melanogaster. Groups of larvae were exposed from the time of hatching to directional ultraviolet (365nm) light emanating from one of four magnetic directions. Larvae were then tested individually on a circular agar plate under diffuse light in one of four magnetic field alignments. The larvae exhibited magnetic compass ori...

The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, "Cluster N", show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of the neuronal activity marker ZENK duri...

Migratory birds use multiple compass systems for orientation, including a magnetic, star and sun/polarized light compass. To keep these compasses in register, birds have to regularly update them with respect to a common reference. However, cue-conflict studies have revealed contradictory results on the compass hierarchy, favoring either celestial or magnetic compass cues as the primary calibrat...

We have re-analyzed the world data on inclusive polarized DIS including the very precise CLAS proton and deuteron data, as well as the latest COMPASS data on the asymmetry A1, and have studied the impact of these data on polarized parton densities and higher twist effects. We demonstrate that the low Q2 CLAS data improve essentially our knowledge of higher twist corrections to the spin structur...

The COMPASS tokamak was successfully reinstalled in Prague after two and half years of intensive work. The first plasma shot was achieved on 9th December 2008. The work on the commissioning to the full performance has begun after this first shot. This paper presents results of magnetic diagnostics measurements for the first COMPASS shot and subsequent campaign. First attempts to plasma position...

The existence of non-qq̄ hadrons such as glueballs and hybrids is one of the most important qualitative questions in QCD. The COMPASS experiment offers the possibility to unambiguously identify such states and map out the glueball and hybrid spectrum. In this review I discuss the expected properties of glueballs and hybrids and how they might be produced and studied by the COMPASS collaboration.

We discuss some recent developments concerning the nucleon’s helicity parton distribution functions: New preliminary data from jet production at RHIC suggest for the first time a non-vanishing polarization of gluons in the nucleon. SIDIS measurements at COMPASS provide better constraints on the strange and light sea quark helicity distributions. Single-longitudinal spin asymmetries in W -boson ...