Abstract. Measurements of the pp → pK+ Λ reaction at Tp = 2.28 GeV have been carried out at COSY-TOF. In addition to the Λp FSI and N * resonance excitation effects a pronounced narrow structure is observed in the Dalitz plot and in its projection on the pΛ-invariant mass. The strongly asymmetric structure appears at the pp → N K + Σ threshold and is interpreted as ΣN cusp effect. The observed width of about 20 MeV/c 2 is substantially broader than anticipated from previous measurements as well as theoretical predictions. Angular distributions of this cusp structure are shown to be dissimilar to those in the residual pK + Λ channel, but similar to those observed in the pK + Σ 0 channel.

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The nature of the molecular correlation in squaric acid (H2C&04, 3,4-dihydroxy-3-cyclobutene-1,2-dione) was investigated with the use of coherent and incoherent neutron scattering over a wide temperature range. Both types of experiments can be well understood within a model of weakly coupled one-dimensional Ising chains.

Abstract. The possibility to determine the pΛ scattering length from the final-state interaction in the reaction pp → pK + Λ is investigated experimentally. From a transversely polarized measurement, the K + analyzing power (AN ) which, in principle, allows one to extract the spin triplet scattering length is studied. An unexpected energy dependence of the forward/backward symmetric part of AN is found. The influence of N * resonances on the pΛ invariant mass spectrum is investigated by exploiting the large acceptance for the process pp → pK− and is found to be the main source of uncertainty for determining the pΛ scattering length.PACS. 13.75.-n Hadron-induced low-and intermediate-energy reactions and scattering (energy ≤ 10 GeV) -13.75.Ev Hyperon-nucleon interactions -25.40.Ve Other reactions above meson production thresholds (energies > 400 MeV)

We performed a phase-sensitive test of the symmetry of the superconducting order parameter of the electron doped cuprate La(2-x)Ce(x)CuO(4-y) using a superconducting quantum interferometer with spatially distributed Josephson junctions. The studies were made on a thin film grown on a SrTiO3 tetracrystal substrate. The superconducting transition temperature was about 29 K which indicates that the sample is close to optimal doping. The magnetic field dependence of the critical current gives strong evidence for a predominant dx(2)(-y(2)) order parameter symmetry of the sample measured. It also gives upper limits for the s-wave component in a mixed order parameter of the type s+idx(2)(-y(2)).