arXiv subjects
Publications and source records attributed to Tim Oliver Eynck.
The techniques leading to the resummation of threshold logarithms in the Drell-Yan cross section and other processes can be used to show that also terms independent on the Mellin variable N exponentiate. Comparison with explicit two-loop calculations shows that within this class of terms the exponentiation of the one-loop result together with the running of the coupling is the dominant effect at two loops.
It has been observed that in the DIS scheme the refactorization of the Drell-Yan cross section leading to exponentiation of threshold logarithms can also be used to organize a class of constant terms, most of which arise from the ratio of the timelike Sudakov form factor to its spacelike counterpart. We extend this exponentiation to include all constant terms, and demonstrate how a similar organization may be achieved in the MSbar scheme. We study the relevance of these exponentiations in a two-loop analysis.
We compare the phase space slicing and dipole subtraction methods in the computation of the inclusive and differential next-to-leading order cross sections for heavy quark production in the simple process gamma^* -> Q Qbar. For the phase space slicing method we study the effects of improvement terms that remove restrictions on the slicing parameter s_min. For the dipole method our comparison is a first check on some of its counterterms involving massive quarks, derived recently. In our comparison we address issues such as numerical accuracy and efficiency.