quoteqert.blogg.se - The neutrino is

#THE NEUTRINO IS FOR FREE#
#THE NEUTRINO IS FULL#

The electron, muon, and tau, as well as their antiparticles, are allowed spins of either +½ or -½, with no exceptions.

All six of the quarks and all six of the antiquarks can have spins that are either +½ or -½, with no exceptions.

Remember how there was a 50/50 shot that an electrons would have a spin of either +½ or -½? Well, that's true for every quark and lepton in the Standard Model, except the neutrino. One of them, in particular, stands out as incongruent with every other fermion in the Standard Model: spin. Brookhaven National Laboratoryīased on the properties of the particles produced by a neutrino interaction, we can reconstruct various properties of the neutrinos and antineutrinos that we see. Here, we see the construction of the tank used in the solar neutrino experiment in the Homestake gold mine from the 1960s. the years and decades since, we've detected neutrinos from the Sun, from cosmic rays, and even from supernovae.

The neutrino was first proposed in 1930, but was not detected until 1956, from nuclear reactors. Although they were first theorized in 1930 by Wolfgang Pauli, the first neutrino detection didn't take place until the mid-1950s, and actually involved antineutrinos produced by nuclear reactors. Just as an electron has an antimatter counterpart (the positron), the neutrino has an antimatter counterpart as well: the antineutrino. Although they don't have electric charge, they do have quantum numbers all their own. Neutrinos, like electrons, are also leptons. An electron's spin, relative to any axis you choose ( x, y, and z, the electron's direction of motion, the proton's spin axis, etc.) is completely random. It's the reason why, if you bind an electron to a proton (or any atomic nucleus), there's a 50/50 shot that the electron will have its spin aligned with the proton's spin, and a 50/50 shot that they'll be anti-aligned.

#THE NEUTRINO IS FOR FREE#

For free electrons and protons, there is a 50/50 chance for them to bind together in either the aligned or anti-aligned states. This transition is part of the hyperfine structure of matter, going even beyond the fine structure we more commonly experience. The opposite-spin configuration in the n=1 energy level represents the ground state of hydrogen, but its zero-point-energy is a finite, non-zero value. combination with aligned spins (top) flips to have anti-aligned spins (bottom), emitting one particular photon of a very characteristic wavelength. The 21-centimeter hydrogen line comes about when a hydrogen atom containing a proton/electron. The bosons are responsible for the forces between all particles, and - with the exception of a few puzzles like dark matter, dark energy, and why our Universe is filled with matter and not antimatter - the rules governing these particles explains everything we've ever observed. Quarks and leptons bind together to form protons and neutrons, heavy elements, atoms, molecules, and all the visible matter we know of.

McDonald (Queen’s University) et al., The Sudbury Neutrino Observatory InstituteĮvery form of matter that we know of in the Universe is made up of the same few fundamental particles: the quarks, leptons and bosons of the Standard Model.

#THE NEUTRINO IS FULL#

With additional results from atmospheric, solar, and terrestrial observatories and experiments, we may not be able to explain the full suite of what we've observed with only 3 Standard Model neutrinos, and a sterile neutrino could still be very interesting as a cold dark matter candidate. The Sudbury neutrino observatory, which was instrumental in demonstrating neutrino oscillations and.