Quarks Leptons and the Big Bang

Dark Matter

Dark Matter At the Kitt Peak National Observatory in ‘Arizona, Vera Rubin and her co-worker Kent Ford measured the rotational rates of a number of distant galaxies. They did so by measuring the Doppler shifts of bright clusters of stars located within each galaxy at various distances from the galactic center. As shows, their results were surprising: The orbital …

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The Basic Forces and Messenger Particles

The Basic Forces and Messenger Particles We turn now from cataloging the particles to considering the forces between them. The Electromagnetlc Force At the atomic level, we say that two electrons exert electromagnetic forces on each other according to Coulomb’s law. At a deeper level, this interaction is described by a highly successful theory called quantum electrodynamics (QED). …

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Still Another Conservation Law

Still Another Conservation Law Particles have intrinsic properties in addition to the ones we have listed so far: mass, “charge, spin, lepton number, and baryon number. The find of these additional properties was discovered when researchers observed that certain new particles, such as the bone (K) and the sigma (~), always seemed to be produced in pairs. It …

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The Leptons

The Leptons In this and the next section. we discuss some of the particles of one of our classification schemes: lepton or hadron. We. begin with the leptons. those particles on which the strong force does not act. So far. we have encountered. as leptons. the familiar electron and the neutrino that accompanies it in beta decay. ‘The …

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