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One-loop tensor Feynman integral reduction with signed minors

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  • Jochem Fleischer
  • Tord Riemann
  • Valery Yundin
We present an algebraic approach to one-loop tensor integral reduction. The integrals are presented in terms of scalar one- to four-point functions. The reduction is worked out explicitly until five-point functions of rank five. The numerical C++ package PJFry evaluates tensor coefficients in terms of a basis of scalar integrals, which is provided by an external library, e.g. QCDLoop. We shortly describe installation and use of PJFry. Examples for numerical results are shown, including a special treatment for small or vanishing inverse four-point Gram determinants. An extremely efficient application of the formalism is the immediate evaluation of complete contractions of the tensor integrals with external momenta. This leads to the problem of evaluating sums over products of signed minors with scalar products of chords. Chords are differences of external momenta. These sums may be evaluated analytically in a systematic way. The final expressions for the numerical evaluation are then compact combinations of the contributing basic scalar functions.
OriginalsprogEngelsk
Artikelnummer012057
BogserieJournal of Physics: Conference Series (Online)
Vol/bind368
Udgave nummer1
Antal sider10
ISSN1742-6596
StatusUdgivet - 2012

ID: 49746139