Benefits of Apprenticeship Training and Future Challenges – Empirical Results and Lessons from Switzerland and Germany

We calculate the two-loop corrections to heavy-quark pair production in the gluon fusion channel which arise from diagrams involving a closed light-quark loop. The calculation is carried out by keeping the exact dependence on the heavy-quark mass. The analytic results are written in terms of logarithms, classical polylogarithms Lin(n = 2, 3, 4), andgenuinemultiplepolylogarithmsLi2,2.Thefunctionalargumentsarerationalexpressionsoftwoindependentexternalinvariantsandtheyarechoseninsuchawaythatthefunctionsarerealinallthephysicalphase− spacepoints.Throughsystematicchangesinthefunctionalbasis, weobtainexpansionsoftheresultsinboththeproductionthresholdandsmallmasslimits. DOI: https://doi.org/10.1007/JHEP12(2013)038 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-90656 Published Version Originally published at: Bonciani, R; Ferroglia, A; Gehrmann, T; Manteuffel, A; Studerus, C (2013). Light-quark two-loop corrections to heavy-quark pair production in the gluon fusion channel. Journal of High Energy Physics, 2013:38. DOI: https://doi.org/10.1007/JHEP12(2013)038