The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation γ-ray spectrometer. AGATA is based on the technique of γ-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a γ ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of γ-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector-response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer

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The nuclei 138 Nd and 139 Nd have been studied at very high spins via the 48 Caϩ 94 Zr reaction. Several new rotational bands were observed, four in 138 Nd and two in 139 Nd. The J (2) moments of inertia calculated from the observed ␥-ray energies are very small and almost constant, indicating that these bands are triaxial. Cranked Nilsson-Strutinsky calculations reproduce the general behavior of the bands, supporting this interpretation and suggesting an approximately constant ␥ value of ϳϩ35°over a large spin range up to the highest observed spins. These bands and a few similar bands in other nuclei of the NϷ80 region are a unique example of almost undisturbed triaxial bands.

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.

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)

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