Helicity is an important quantity in fluid mechanics that indicates the presence of linked or knotted hydrodynamic vortex filaments. Such flow structures are not only promising elementary to study mass and momentum transfer turbulent flows but also potent analogs for other topological problems arising particle physics, liquid crystals, plasma physics. However, experimental studies knots links h...

Any divergenceless vector field defined in a 3-dimensional manifold defines an integral quantity called the helicity that measures the way in which any pair of integral lines curl to one another. In the case of Classical Electrodynamics in vacuum, the natural helicity invariant, called the electromagnetic helicity, has an important particle meaning: the difference between the numbers of rightan...

The helicity flip of a spin2 Dirac particle interacting gravitationally with a scalar field is analyzed in the context of linearized quantum gravity. It is shown that massive fermions may have their helicity flipped by gravity, in opposition to massless fermions which preserve their helicity. 04.20.Cv, 04.60.+n Typeset using REVTEX 1 The behavior of a spinning particle in a gravitational field ...

After a very brief review of twentieth century elementary particle physics, prospects for the next century are discussed. First and most important are technological limits of opportunities; next, the future experimental program, and finally the status of the theory, in particular its limitations as well as its opportunities. Invited talk given at the International Conference on Fundamental Scie...

The theory of elementary particles permitting to explain their constitution, sizes, bond energy, possible channels of decay, spectrum of weights and other properties is offered.

Gauge symmetries: These are local symmetries that act differently at each space-time point x = (t,x) . They create particularly stringent constraints on the structure of a theory. For example, gauge symmetry automatically determines the interaction between particles by introducing bosons that mediate the interaction. All current models of elementary particles incorporate gauge symmetry. (Detail...

We calculate the helicity and chirality effects experienced by a spin-1/2 particle subjected to classical electromagnetic and gravitational fields. The helicity evolution is then determined in the non-relativistic, relativistic, and ultra-relativistic regimes. We find that inertia-gravitation can distinguish between helicity and chirality. Helicity is not conserved, in general, even when the pa...

We derive compact analytical formulae of the Bonneau-Martin type for the reaction e + e − → ¯ f f γ with cuts on minimal energy and acollinearity of the fermions, where the photons may be emitted both from the initial or final states. Soft-photon exponentiation is also taken into account. One of the cleanest scattering processes at elementary particle accelerators is fermion-pair production in ...