Science: Primordial Particle

One of the most puzzling known particles of the atom is the neutron, the uncharged building block of the nucleus. To explain its lack of electrical charge, nuclear physicists have long supposed that the particle is made up of a tiny, positively charged core surrounded by a cloud of negatively charged mesons. These two charges were thought to cancel each other out, producing the neutral neutron.

For the past two years Stanford Physicist Robert Hofstadter, 42, has been probing the neutron by firing electrons down Stanford's 220-ft. accelerator at target nuclei of gaseous hydrogen and other elements. The electrons bounced off, said...

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