Neutrino Physics

Neutrinos offered the greatest surprises in high energy physics during the last decades. In this chapter we review the main milestones of this passionate history: the first neutrino beams which established the separate neutrino identities, the Gargamelle discovery of the weak neutral currents, the LEP determination of three light neutrino species and the discovery of the intriguing phenomenon of neutrino oscillations. The experimental determination of the neutrino mass matrix elements is still in progress with several experiments either taking data or planned for the near future. We end with the present theoretical puzzles and the experiments which may help to solve them.

The Unification of Forces

The quest for a unified theory of all fundamental forces. Faraday’s unification of all “types” of electricity. Maxwell’s unification of electricity, magnetism and light. Heinrich Hertz, and radio waves. The unification of weak and electromagnetic interactions by Glashow, Weinberg, and Salam. “Weak neutral currents.” The discovery of the “Intermediate Vector Bosons.” The quest for a “Grand Unified Theory.” Proton decay. The core of the Sun. Serendipity, solar neutrinos, and the supernova SN1987A. Neutrino oscillations. What a “gauge theory” is.

Influence of Neutral Currents on Electron and Gamma Polarizations in the Processe+N→e′+N+γ

The differential cross section of electron inelastic scattering by nuclei followed byγradiation is calculated using the multipole decomposition of the hadronic currents and by taking into account the longitudinal polarization of the initial electron and the circular polarization of theγradiation. We performed the analysis of the angular and energy dependence of the degree of electron and photon polarization which can yield information on values of weak neutral currents parameters.