Feynman-diagram evaluation in the electroweak theory with computer algebra

Abstract

Abstract. The evaluation of quantum corrections in the theory of the electroweak and strong interactions via higherorder Feynman diagrams requires complicated and laborious calculations, which however can be structured in a strictly algorithmic way. These calculations are ideally suited for the application of computer algebra systems, and computer algebra has proven to be a very valuable tool in this field already over several decades. It is sketched how computer algebra is presently applied in evaluating the predictions of the electroweak theory with high precision, and some recent results obtained in this way are summarized.

Calculation of fermionic two-loop contributions to muon decay

“…It can be noted that light Higgs masses are favored by this analysis. Further implications of the precision calculation of M W are discussed in [30].…”

Higgs and SUSY Higgs bosons at future linear collider

“…Although ǫ b is typically O(10 −2 ), the correction to m b enters with a combination of ǫ b tan β which can be close to O(1) for a large value of tan β. Precise calculation of various branching ratios was presented taking account of these corrections [15]. For example, the ratio of B(h…”

“…Precise calculation of various branching ratios was presented taking account of these corrections [15]. For example, the ratio of B(h → τ + τ − ) and B(h → bb) is modified to…”

Colliders and cosmology

“…Details of the analysis [35] were discussed in [36,37] and here I show the net result of the χ 2 analysis in the CMSSM in Fig. 4 using the combined χ 2 values for the EWPO and BPO, computed from Eq.…”