Azimuthal asymmetries in heavy quark leptoproduction as a test of pQCD

作者：Ivanov NY^*

来源：Nuclear Physics B, 2003, 666(1-2): 88-104.

DOI：10.1016/S0550-3213(03)00529-7

• perturbative QCD
• heavy flavor leptoproduction
• azimuthal asymmetries

We analyze the perturbative and parametric stability of the QCD predictions for the azimuthal asymmetries in heavy quark leptoproduction. At leading order, the cosphi asymmetry vanishes whereas the cos2phi one is of leading twist and predicted to be about 15% at energies sufficiently above the production threshold. We calculate the NLO soft-gluon corrections to phi-dependent leptoproduction to the next-to-leading logarithmic accuracy. The soft-gluon approximation provides a good description of the available exact NLO results at Q(2) less than or similar to m(2). Our analysis shows that, contrary to the production cross sections, the cos2phi asymmetry is practically insensitive to soft radiation for Q(2) less than or similar to m(2) at energies of the fixed target experiments. We conclude that the cos2phi asymmetry is well defined in pQCD: it is stable both perturbatively and parametrically, and insensitive (in the case of bottom production) to nonperturbative contributions. Measurements of the azimuthal asymmetries would provide an excellent test of pQCD applicability to heavy flavor production.

• 出版日期2003-8-25