Higher Twist in Electroproduction: Flavor Non-Singlet QCD Evolution
  We present results for the one loop anomalous dimension matrix of flavor non-singlet twist-4 operators of lowest spin that contribute to the leading moment of the $F_2$ structure function in deep inelastic electron-nucleon scattering. We analyze the flavor structure of the anomalous dimension matrix and decompose the leading moment of $F_2$ into separate flavor channels. In addition to building on previous work with higher-twist operators, these results can provide a benchmark for future work that generalizes to include the higher moments as well. We include non-perturbative input from the lattice and phenomenological estimates of the twist-4 matrix elements and estimate the twist-4 contributions to the leading moment of $F_2$. The results suggest that the overall twist-4 contribution may be suppressed due to either cancellations among the twist-4 terms or inherently small twist-4 matrix elements. 
Michael J. Glatzmaier, Sonny Mantry, Michael J. Ramsey-Musolf
hep-ph nucl-th