A lattice evaluation of four-quark operators in the nucleon
نویسنده
چکیده
Nucleon matrix elements of various four-quark operators are evaluated in quenched lattice QCD using Wilson fermions. Some of these operators give rise to twist-four contributions to nucleon structure functions. Furthermore, they bear valuable information about the diquark structure of the nucleon. Mixing with lower-dimensional operators is avoided by considering appropriate representations of the flavour group. We find that for a certain flavour combination of baryon structure functions, twistfour contributions are very small. This suggests that twist-four effects for the nucleon might be much smaller than mp/Q 2.
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