![]() ![]() The first experimental observation of the neutrino interacting with matter was made by Frederick Reines, Clyde Cowan, Jr, and collaborators in 1956 at the Savannah River Plant in South Carolina. Why do we say that neutrinos are left-handed? Their interactions are usually represented in terms of Feynman diagrams. Neutrinos interact only by the weak interaction. Bahcall's modeling of the solar neutrino flux led to the prediction of about 5 x 10 6 neutrinos/cm 2s.Ī remarkable opportunity for observing neutrinos came with Supernova 1987A when the Japanese observing team detected neutrinos almost coincident with the discovery of the light from the supernova. This leads to the statement "Solar neutrinos shine down on us during the day, and shine up on us during the night!". The sun emits vast numbers of neutrinos which can pass through the earth with little or no interaction. ![]() The background temperature for neutrinos is lower than that for the microwave background (2.7K) because the neutrino transparency point came earlier. This remnant neutrino density is put at 100 per cubic centimeter at an effective temperature of 2K (Simpson). In the standard Big Bang model, the neutrinos left over from the creation of the universe are the most abundant particles in the universe. The mean free path of a neutrino in water would be on the order of 10x the distance from the Earth to the Sun. This elusive particle, with no charge and almost no mass, could penetrate vast thicknesses of material without interaction. Enrico Fermi called the particle a neutrino and developed a theory of beta decay based on it, but it was not experimentally observed until 1956. The apparent violation of conservation of energy and momentum was most easily avoided by postulating another particle. The electron neutrino (a lepton) was first postulated in 1930 by Wolfgang Pauli to explain why the electrons in beta decay were not emitted with the full reaction energy of the nuclear transition. The history of a particle that appeared to have no charge and no mass is an interesting one. More precisely, these bursts may result from the development of the instability at the subsequent nonlinear stage, which has yet to be studied theoretically-in particular, on the basis of non-one-dimensional numerical models of neutrino hydrodynamics.Neutrinos Electron Neutrinos and Antineutrinos The increment of the development of a convective instability is obtained at a linear stage, this giving sufficient grounds to introduce the hypothesis that the instability in question plays a key role in the origin of observed gamma-ray bursts. On one hand, the numerical solutions constructed in the present study give an idea of the physical conditions in the immediate vicinity of a protoneutron star in the course of its continuing gravitational collapse on the other hand, they make it possible to obtain exhaustive information about its convective instability, which is the most important property of a so-called soundless collapse-that is, a collapse not accompanied by an explosion of a supernova scale. =, are varied within broad intervals in accordance with the hydrodynamic theory of a collapse.
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