arXiv subjects
Publications and source records attributed to L. Masperi.
We show that, according to the scheme of spontaneous breakings starting from a GUT with symmetry E6, it is possible that either a superheavy particle without ordinary interactions is source of ultra-high energy cosmic rays or a not so heavy lepton mixes with muon explaining the recently observed discrepancy of the anomalous magnetic moment of the latter.
The broken-symmetry electroweak vacuum is destabilized in the presence of a magnetic field stronger than a critical value. Such magnetic field may be generated in the phase transition and restore the symmetry inside the bubbles. A numerical calculation indicates that the first-order phase transition is delayed but may be completed for a sufficient low value of the Higgs mass unless the magnetic field is extremely high.
A numerical calculation of properties of finite absorbers and of intergalactic medium based on photoionization equilibrium is performed to confront alternative UV sources in addition to quasars. It is seen that a spectrum including a large peak around the HI ionization energy due to decaying neutrinos is too soft in the region up to the HeI edge to explain the relatively small observed ratio of neutral He and H densities in Lyman-limit systems if their size is of the kpc order. The recently proposed decrease of the contribution from unstable neutrinos solves this problem but tends to spoil the consistence between IGM and Lyman-$α$ clouds, which requires a large ratio of fluxes for the HI and HeII ionization frequencies, unless there is a very fast decline of quasars above $z = 3$. On the other hand, the addition of stars to quasars may produce a spectrum sufficiently hard between HI and HeI and thereafter soft up to HeII to allow a reasonable agreement of the properties of denser absorbers with those of IGM. This model seems to favour cold dark matter with additional cosmological constant.
A reexamination of the semiclassical approach of the relativistic electron indicates a possible variation of its helicity for electric and magnetic static fields applied along its global motion due to zitterbewegung effects, proportional to the anomalous part of the magnetic moment.
We have numerically calculated topological andnon-topological solitons in two spatial dimensions with Chern-Simons term. Their quantum stability, as well as that of the Maxwell vortex, is analyzed by means of bounce instantons which involve three-dimensional strings and non-topological solitons.