Neutrinos And Gamma Rays

Term Paper Title	Neutrinos And Gamma Rays
# of Words	874
# of Pages (250 words per page double spaced)	3.5

Neutrinos and Gamma Rays

     Emission of a beta particle produces an energy change in the nucleus of an atom.  The energy change that is observed, however, does not add up to satisfy the Law of Conservation of energy.  The conservation law can be balanced if another particle, called the neutrino is part of this process.  In the time it takes to read just this sentence, more than a billion of them will have passed unnoticed through the reader's body.  Neutrinos may account for an appreciable portion of the mass of the universe,  even tending to slow it's rate of expansion.

     Originally proposed in 1931 by Wolfgang Pauli to account for mass that was mysteriously lost from certain nuclear reactions,and first observed in 1956 by Dr Frederick Reines and Dr. Clyde Cowan, neurtinos either were beleived to have no mass or to have a negligible amount of mass.  Ever since their discovery scientists wondered if this elusive particle  that has no electric charge and is able to pass through the entire earth without hitting anything might not have some negligible amount of mass.  Because they exist in great numbers in the universe, even a small mass could provide the "dark matter" that cosmologists beleive makes up the substance of the cosmos.  Having a mass, neutrinos might also be able to change into neutrinos of other types, by a process called oscillation.  They have no electrical charge and are believed to travel at or near the speed of light.  Neutrinos react very little with matter and only rarely do they react with protons or neutrons through a force !
called "the weak force".  Their discovery enabled scientists to work out a conservation of evergy, spin, and momentum for beta decay.

     There are six types of neutrinos, depending upon the subatomic particles with which they are associated: electon antineutrinos with electrons, electron neutrinos with positrons, muon neutrinos and antimeutrinos with muon reactions, and tau neutrinos and antineutrinos with massive tau particles.  Mass is what determines the rate at which the wave function of a particle vibrates.  If the waves of two neutrinos of different masses mingle, they beat against each other much like sound waves of different pitch .  If neutrinos had no mass, their waves would have the same frequency and would not be able to beat at all.

      A particle detector at Los Alamos National Laboratory has captured eight events that could be the first direct sightings of neutrino oscillations.  If verified, the observations will prove as well that neutrinos have mass.  However such experiments are not easy to carry out.  In the Liquid Scintillator Neutrino Detector experiment, a beam of protons from an acce...

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