Freedom Now: A New Look at the Impulse Approximation
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Recent work on a field-theoretic impulse approximation is described. The operator product expansion is organized according to powers of g(Q2), the effective coupling constant appropriate to momentum transfer Q2, instead of asymptotic dimensional analysis. This allows the calculation of all quark and target mass dependence of lepton-hadron inclusive scattering, order by order in g(Q2). To O(g°), there is scaling in a mass dependent variable, ξ. The correct incorporation of quark masses into the renormalization group analysis is presented; the consequences include the relation of constituent masses to current algebra and the magnitude and shapes of the parton distribution functions for gluons, antiquarks, and heavy quarks.
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