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• n  a stable quark with an electric charge of +2/3 and a mass 607 times that of an electron

News & Articles

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• Weak charge of proton determined for first time
  Researchers have made the first experimental determination of the weak charge of the proton. The results also include the determinations of the weak charge of the neutron, and of the up quark and down quark.
  Sept. 17, 2013 - Science Daily