A variant of 3-3-1 model for the generation of the SM fermion mass and mixing pattern

We propose an extension of the 3-3-1 model with an additional symmetry group $Z_{2}\times Z_{4} \times U(1)_{L_g}$ and an extended scalar sector. To our best knowledge this is the first example of a renormalizable 3-3-1 model, which allows explanation of the SM fermion mass hierarchy by a sequential loop suppression: tree-level top and exotic fermion masses, 1-loop bottom, charm, tau and muon masses; 2-loop masses for the light up, down, strange quarks as well as for the electron. The light active neutrino masses are generated from a combination of linear and inverse seesaw mechanisms at two loop level. The model also has viable fermionic and scalar dark matter candidates.Comment: 35 pages, 4 figures. Version accepted for publication in JHE

Localized spectral asymptotics for boundary value problems and correlation effects in the free Fermi gas in general domains

We rigorously derive explicit formulae for the pair correlation function of the ground state of the free Fermi gas in the thermodynamic limit for general geometries of the macroscopic regions occupied by the particles and arbitrary dimension. As a consequence we also establish the asymptotic validity of the local density approximation for the corresponding exchange energy. At constant density these formulae are universal and do not depend on the geometry of the underlying macroscopic domain. In order to identify the correlation effects in the thermodynamic limit, we prove a local Weyl law for the spectral asymptotics of the Laplacian for certain quantum observables which are themselves dependent on a small parameter under very general boundary conditions

Correctness of an STM Haskell implementation

A concurrent implementation of software transactional memory in Concurrent Haskell using a call-by-need functional language with processes and futures is given. The description of the small-step operational semantics is precise and explicit, and employs an early abort of conflicting transactions. A proof of correctness of the implementation is given for a contextual semantics with may- and should-convergence. This implies that our implementation is a correct evaluator for an abstract specification equipped with a big-step semantics

Suboptimal filtering. Part 2 - Compensation for modeling errors in orbit determination problems Final report

Compensation for dynamic and measurement model errors in real time orbit determination system

Fragmentation of spherical radioactive heavy nuclei as a novel probe of transient effects in fission

Peripheral collisions with radioactive heavy-ion beams at relativistic energies are discussed as an innovative approach for probing the transient regime experienced by fissile systems evolving towards quasi-equilibrium. A dedicated experiment using the advanced technical installations of GSI, Darmstadt, permitted to realize ideal conditions for the investigation of relaxation effects in the meta-stable well. Combined with a highly sensitive experimental signature, it provides a measure of the transient effects with respect to the flux over the fission barrier. Within a two-step reaction process, 45 proton-rich unstable spherical isotopes produced by projectile-fragmentation of a stable 238U beam have been used as secondary projectiles. The fragmentation of the radioactive projectiles on lead results in nearly spherical compound nuclei which span a wide range in excitation energy and fissility. The decay of these excited systems by fission is studied with a dedicated set-up which permits the detection of both fission products in coincidence and the determination of their atomic numbers with high resolution. The width of the fission-fragment nuclear charge distribution is shown to be specifically sensitive to pre-saddle transient effects and is used to establish a clock for the passage of the saddle point. The comparison of the experimental results with model calculations points to a fission delay of (3.3+/-0.7).10-21s for initially spherical compound nuclei, independent of excitation energy and fissility. This value suggests a nuclear dissipation strength at small deformation of (4.5+/-0.5).1021s-1. The very specific combination of the physics and technical equipment exploited in this work sheds light on previous controversial conclusions.Comment: 38 pages, 15 figure

Quasideuteron configurations in 46V and 58Cu

The data on low spin states in the odd-odd nuclei 46V and 58Cu investigated with the 46Ti(p,ngamma)46V, 32S(16O,pn)46V and 58Ni(p,ngamma)58Cu reactions at the FN-TANDEM accelerator in Cologne are reported. The states containing large quasideuteron components are identified from the strong isovector M1 transitions, from shell model calculations and from experimental data for low-lying states.Comment: 6 pages, 3 figures, proceedings of the "Nuclear Structure 2000" conference, East Lansing, Michigan, USA, August 15-19, 2000; to appear in Nucl. Phys.

Precursor phenomena at the magnetic ordering of the cubic helimagnet FeGe

We report on detailed magnetic measurements on the cubic helimagnet FeGe in external magnetic fields and temperatures near the onset of long-range magnetic order at $T_C= 278.2(3)$ K. Precursor phenomena display a complex succession of temperature-driven crossovers and phase transitions in the vicinity of $T_C$. The A-phase region, present below $T_C$ and fields $H<0.5$ kOe, is split in several pockets. Relying on a modified phenomenological theory for chiral magnets, the main part of the A-phase could indicate the existence of a $+\pi$ Skyrmion lattice, the adjacent A$_2$ pocket, however, appears to be related to helicoids propagating in directions perpendicular to the applied field.Comment: 5 pages, 4 figure