Abstract:
We study leptoproduction of (Formula presented) at large (Formula presented) within the nonrelativistic QCD (NRQCD) factorization formalism. The cross section is dominated by color-octet terms that are of order (Formula presented) The color-singlet term, which is of order (Formula presented), is shown to make a small contribution to the total cross section. We also calculate the tree diagrams for color-octet production at order (Formula presented) in a region of phase space where there is no leading color-octet contribution. We find that in this regime the color-singlet contribution dominates. We argue that nonperturbative corrections arising from diffractive leptoproduction, higher twist effects, and higher order terms in the NRQCD velocity expansion should be suppressed as (Formula presented) is increased. Therefore, the color-octet matrix elements (Formula presented) and (Formula presented) can be reliably extracted from this process. Finally, we point out that an experimental measurement of the polarization of leptoproduced (Formula presented) will provide an excellent test of the NRQCD factorization formalism. © 1998 The American Physical Society.
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