[en] The subnuclear world studies the fundamental constituents of the matter, traditionally nominated fundamental particles and their interactions. The author studies the history and standard models of fundamental particles: Leptons, quarks, and gauge bosons. (Author)

[en] On July 1997, an international company named LAESA has finished its foundational period, with the headquarters in Zaragoza. The main initial goal of the company is, based on the conceptual design of an Energy Amplifier from C. Rubbia and collaborators, to take the necessary steps for developing the engineering design and the construction of a demonstration unit of EA (approx 100 MWt in its first phase and 250 MWt in the second one). The company will be mainly charged of the technical aspects required by the construction of the prototype and its funding comes both from private and public capital, as well as the selling of services. The prototype intends to use a final accelerator current of approx 12 mA and a beam energy close to 400 MeV. The construction period is expected to be 5 to t years and the initial emphasis of the installation is to demonstrate its capability for a massive incineration of long lived radioactive waste, with the corresponding energy generation. The necessary development to prepare de engineering design is being the subject of a R and D programme in Spain. Other countries with or without companies inside LAESA are also carrying on other Rand D programmes. The expected planning foresees an integrated R and D programme, a first version of the engineering design and the initial contacts both with the Spanish Nuclear Regulatory Commission, as well as the Spanish Environmental authorities. During the Conference, the status of the engineering design will be shown. (Author) 3 refs

[en] The background spectrum in a Low Background intrinsic germanium detector was analysed. Different possible sources of background and the influence of the materials used as well as the thickness of shielding was studied. Lead, copper, nylon, delrin and teflon of different thicknesses were used. Too much shielding material could induce some gamma rays from neutron production in the shielding due to cosmic muons. The influence of cosmic muons by going underground was also analysed by using data from the underground LABAC laboratory in Calatayud (Zaragoza). (author)

[en] The (two-neutrino) double beta decay, the electron capture with positron emission and the double electron capture decay rates are estimated for several nuclides by assuming the dominance of the lowest 1⁺ state of the intermediate isobar. By using single-β decay matrix elements and energy denominators as experimental inputs we get values independently of nuclear physics calculations. The results for double β^- decay are in agreement with the recent geochemical values. Other predictions are within the present experimental sensitivity

No abstract available

[en] Measurements of the background radioactivity in a salt mine in Remolinos (Zaragoza) have been performed. The site was 200 mwe deep in a gallery far (1 Km) from the actual mining area. The detector has been a 120 cm³ Ge(Li) with conventional electronic and magnetic read-out. Neutron induced radiation was detected by surrounding the detector with borax. Different shieldings have been studied. Results are compared with laboratory data of Zaragoza. (author)

[en] The preliminary results of a search for the neutrinoless double beta decay of /sup 76/Ge are presented. The apparatus consists in a four -crystals germanium detector of a total volume of 456 cm/sup 3/ surrounded by a set of 19 NaI (T1) detectors. It is shielded with Cu(OFC) and Pb and is operating at the Underground Modane Laboratory in the Frejus tunnel (4700 mwe). The half-life limits obtained in 2478 hours of live time running are given

[en] As is well known the detection of the neutrinoless double beta decay of nuclei would indicate the violation of lepton number and - would provide significant information about the character, possible mass and chirality couplings of the neutrino. Several direct experiments aiming to detect such a rare event have been recently carried out or are being done. The authors present here the preliminary results of an attempt to search for the neutrinoless double beta decay of /sup 76/Ge, currently being done in the Frejus tunnel. The experiment (which uses a source and detector an assembly of 4 Germanium crystal) investigates the transition from the ground state 0/sup +/ of the /sup 76/Se, as well as to the excited state 2/sup +/ (559.1 KeV), of /sup 76/Se, looking for a gaussian shaped peak at E/sub 2β/=2040.7 KeV in the anti-coincidence spectrum, and at E=1481.6 KeV in the coincidence spectrum 2β/γ (E/sub γ/=559.1 KeV), respectively, by surrounding the 4-Ge detector with a 4π assembly of NaI scintillators. Transition to the 0/sub 2//sup +/ (1122.3 KeV) excited state is also investigated. The neutrinoless double beta decay is a low energy, very rare process which needs a proper matching between the helicities of the neutrinos emitted and absorbed, respectively, by two nucleons within a nucleus. In the neutrinoless 0/sup +/→0/sup +/ transitions that matching is provided by a neutrino mass term and/or by a right handed admixture in the neutrino coupling, whereas in the 0/sup +/→2/sup +/ transition, only the right handed mixture is involved. The 0/sup +/→2/sup +/ transition although is even more rare than the transition to the ground state, has the bonus of the deexcitation photon signal which help to clean the background (provided that the NaI crown be also extremely clean), and gives unambiguous information about the presence of the right handed couplings

[en] The effects induced by the Z-boson exchange in the hyperfine structure and Lamb shift of some fundamental bound systems is analyzed. The hfs of muonium appears as a promising test of the Weinberg-Salam theory. (orig.)

[en] Some of the problems of the nonleptonic Hamiltonian are analysed with V + A current of charmed quarks of de Rujula, Georgi and Glashow. Previous (questioned) results of a discrepancy of two order of magnitude in Δ 2 effects are confirmed