[en] We comment on the first indication of geo-neutrino events from KamLAND and on the prospects for understanding Earth energetics. Practically all models of terrestrial heat production are consistent with data within the presently limited statistics, the fully radiogenic model being closer to the observed value (∼9 geo-events). In a few years KamLAND should collect sufficient data for a clear evidence of geo-neutrinos, however discrimination among models requires a detector with the class and size of KamLAND far away from nuclear reactors. We also remark that the event ratio from thorium and uranium decay chains is well fixed N(Th)/N(U)≅0.25, a constraint that can be useful for determining neutrino oscillation parameters. We show that a full spectral analysis, including this constraint, further reduces the oscillation parameter space compared to an analysis with an energy threshold E_vis>2.6 MeV

[en] Exact calculation of the quark momentum distribution of a one-dimensional confining quark model of hadronic matter and comparison with approximations based on an effective hadronic theory provide an instructive, controlled test of the approximations commonly used in describing quark degrees of freedom in nuclei. The hadron-hadron correlation function in the effective theory when corrected for quark antisymmetry agrees well with that in the exact ground state. The package or convolution approximation, which approximates the quark wave function by the product of the many-hadron wave function multiplied by the ground-state wave function for the quarks in each hadron, is shown to produce a poor description of the quark momentum distribution and appropriate antisymmetrization of this product is shown to yield an excellent approximation at densities relevant to nuclear matter

[en] It is investigated if a magnetic monopole, passing close to a sufficiently high-Z atom, may ionize it and originate a supercritical vacuum, this being followed by a spontaneous emission of a positron during the vacuum decay. Despite the lack of knowledge of the monopole structure, the relativistic equations describing the system monopole plus atom are solved by resorting to the numerical results already obtained in ion-ion collisions by Greiner and collaborators. It is found that the process of e⁺e^- formation occurs for the atomic numbers Z greater than 74

[en] We have examined those features of the solar interior that make it different from both a classical plasma and an ideal gas. Collective and collisional properties of the particles in the solar core (electrons and ions) suggest that the equilibrium distribution function is only nearly equal to a Maxwellian distribution: the difference consists in a depleted or enhanced high-energy tail. Such distributions are proper of the non-extensive Tsallis statistics. On this basis, the solar neutrino problem becomes less serious. In fact, the nuclear rates calculated with the Tsallis' statistics are different from those of the Standard Solar Models (SSM's), which assume Maxwellian distributions. The resulting solar fluxes are considerably closer the the SSM's ones to the experimental results. (author)

[en] New measurements of the geo-neutrino flux are available from two independent and complementary experiments: Borexino and KamLAND. These new data decrease uncertainties on the flux and the derived radiogenic contribution to the terrestrial heat flow begins to be significant. The derived heat flow has a theoretical uncertainty from the accepted model of Earth. In the new future the range of the prediction should degrease mainly because of larger statistics collected by the two experiments and new data from SNO+ should contribute to discriminate among different models of the production in the Earth.

[en] Quark correlation functions and Bethe-Salpeter wave functions for the pion, rho, and nucleon are calculated in quenched lattice QCD and compared with the MIT bag and Skyrme models. Correction for finite lattice image effects allows reconstruction of density-density correlation functions out to the asymptotic region of exponential decay, and the use of extended bag model sources greatly improves the overlap with physical hadrons. (orig.)

[en] After a brief, critical review of the Drell et al. method, we propose an alternative approach suitable for the study of dyon and dyon-negative-electron (Dy-e) system interactions with hydrogen and helium. This method, called the impact parameter method (IPM), has been used already in atomic collisions and allows the calculation of energy losses in H and He. We report these quantities and comment on their behaviour versus the relative velocities between Dy or Dy-e and atoms; we compare them to the monopole results. Conclusions in relation to planned experiments are outlined. (orig.)

[en] We study the formation of monopolium by Auger-like processes, starting from monopole-proton or monopole-electron bound states: (MX)+anti M->(Manti M)+X. Both relativistic and non-relativistic bound states are envisaged. The ratio of Auger to radiative rate is of order 10¹³ at temperatures allowing the existence of (MX) bound states. In spite of this, also the Auger mechanism is unable to match theoretical and experimental previsions on the present monopole density in the universe. (orig.)

[en] In fusion reactions, the Coulomb barrier selects particles from the high-momentum part of the distribution. Therefore, small variations of the high-momentum tail of the velocity distribution can produce strong effects on fusion rates. In plasmas several potential mechanisms exist that can produce deviations from the standard Maxwell-Boltzmann distribution. Quantum broadening of the energy-momentum dispersion relation of the plasma quasi-particles modifies the high-momentum tail and could explain the fusion-rate enhancement observed in low-energy nuclear reaction experiments. (authors)

[en] The Skyrme effective field theory is tested by evaluating nucleon ground-state matrix elements of the correlation functions for two flavor density operators and two pseudoscalar density operators in the Skyrme model and comparing them with results in quenched lattice QCD. The possibility of using quenched lattice QCD to study higher-order terms in effectve field theory is also discussed. (orig.)