Göttingen 2012 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 13: QCD (Theorie) 3
T 13.7: Vortrag
Donnerstag, 1. März 2012, 18:15–18:30, VG 3.103
Three Loop Contributions to the Matrix Elements in the Variable Flavor Number Scheme — Johannes Blümlein1, •Alexander Hasselhuhn1, and Carsten Schneider2 — 1DESY — 2RISC, JKU Linz
The variable flavor number scheme may be used to describe parton distributions in the transition region in which one heavy quark gradually becomes a light flavor. We present first three-loop results to the massive operator matrix elements Agg and Agq for the contributions due to bubble topologies ∝ TF2 nf at general values of the Mellin variable N. The calculation has been performed using higher transcendental functions and by applying modern summation technologies encoded in the package Sigma. These massive operator matrix elements describe the universal contributions in the matching of different flavor sectors, which are the logarithmic and constant contributions in the ratio of mH2/Q2, with Q2 the virtuality and mH the respective heavy quark mass. The framework allows to derive heavy quark parton distributions which are of relevance for calculating specific processes at hadron-hadron colliders.