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Journals and Conferences
The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the π- π- π+ final state using a 190 GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420,000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1 GeV2/c2. The well-known… (More)
First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the… (More)
We explore the feasibility to study exclusive meson production (EMP) in hard muon-proton scattering µ p → µ p M at the COMPASS experiment. These measurements constrain the off-forward parton distributions (OFPD's) of the proton, which are related to the quark orbital contribution to the proton spin.
Recent evidence for pentaquark baryons is critically reviewed in the light of new high statistics data. The search of the WA89 experiment for the Ξ −− (1860) is presented in detail and consequences of its non-observations are discussed. 1 The Myth of Sisyphus Giving these days a talk on pentaquarks or-even worse-writing afterwards a report for the… (More)
New precise results of a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to Q² = 1 (GeV/c)² with statistical errors below 0.2%. The electric and magnetic form factors of the proton were extracted… (More)
The caloric curve of the highly excited projectile spectators emerging from peripheral collisions of two Au-nuclei at 600 AMeV was determined by measuring fragments and neutrons of its decay. This analysis will be reviewed and preliminary results obtained from the decay also of the target spectator will be presented.
The HypHI project aims to study hypernuclei by means of collisions of stable heavy ion and rare-isotope beams on stable target materials [1, 2]. As the first step (Phase 0), the feasibility of precise hypernuclear spectroscopy with heavy ion beams will be demonstrated with 6 Li beam at 2 A GeV impinged on a 12 C target by identifying 3 Λ H, 4 Λ H and 5 Λ He… (More)
A new exclusion limit for the electromagnetic production of a light U(1) gauge boson γ' decaying to e + e- was determined by the A1 Collaboration at the Mainz Microtron. Such light gauge bosons appear in several extensions of the standard model and are also discussed as candidates for the interaction of dark matter with standard model matter. In electron… (More)
A simple method to explore the interaction of antihyperons in nuclei by exclusive hyperon-antihyperon pair production close to threshold in antiproton nucleus interactions is proposed. Due to energy and momentum conservation event-by-event transverse momentum correlations of the produced hyperons and antihyperons contain information on the difference… (More)
theta(degree) 0 20 40 60 80 100 120 140 160 180 0 200 400 600 800 1000 1200 protons kaons pions neutrons Figure 1: Distribution of produced particles from background reactions. The Germanium detectors will be affected mainly by particles emitted at backward axial angle For the high resolution spectroscopy of excited hyper-nuclear states a position sensitive… (More)