arXiv subjects

S. Bauberger

Publications and source records attributed to S. Bauberger.

6 recordsLinked to original sources

arXiv2017

TVID: Three-loop Vacuum Integrals from Dispersion relations

TVID is a program for the numerical evaluation of general three-loop vacuum integrals with arbitrary masses. It consists of two parts. An algebraic module, implemented in Mathematica, performs the separation of the divergent pieces of the master integrals and identifies special cases. The numerical module, implemented in C, carries out the numerical integration of the finite pieces. In this note, the structure of the program is explained and a few usage examples are given.

hep-ph↗

arXiv1997

Higgs-mass dependence of two-loop corrections to Delta r

The Higgs-mass dependence of the Standard Model contributions to the correlation between the gauge-boson masses is studied at the two-loop level. Exact results are given for the Higgs-dependent two-loop corrections associated with the fermions, i.e. no expansion in the top-quark and the Higgs-boson mass is made. The results for the top quark are compared with results of an expansion up to next-to-leading order in the top-quark mass. Agreement is found within 30% of the two-loop result. The remaining theoretical uncertainties in the Higgs-mass dependence of Delta r are discussed.

hep-ph↗

arXiv1996

Calculation of two-loop top-quark and Higgs-boson corrections in the electroweak Standard Model

A combination of algebraical and numerical techniques for calculating two-loop top-quark and Higgs-boson corrections to electroweak precision observables like $Δr$ or the $ρ$-parameter is presented. The renormalization is performed within the on-shell scheme. The results of the calculations are valid for arbitrary values of $m_t$, $M_H$ and of the gauge-boson masses. An example is treated where the full result is compared to the result obtained via an expansion up to next-to-leading order in $m_t$. As an application, results for the Higgs-mass dependent top-contributions to $Δr$ are given.

hep-ph↗

arXiv1995

Simple one-dimensional integral representations for two-loop self-energies: the master diagram

The scalar two-loop self-energy master diagram is studied in the case of arbitrary masses. Analytical results in terms of Lauricella- and Appell-functions are presented for the imaginary part. By using the dispersion relation a one-dimensional integral representation is derived. This representation uses only elementary functions and is thus well suited for a numerical calculation of the master diagram.

hep-ph↗

arXiv1994

Analytical and numerical methods for massive two-loop self-energy diagrams

Motivated by the precision results in the electroweak theory studies of two-loopFeynman diagrams are performed. Specifically this paper gives a contribution to the knowledge of massive two-loop self-energy diagrams in arbitrary and especially four dimensions.This is done in three respects firstly results in terms of generalized, multivariable hypergeometric functions are presented giving explicit series for small and large momenta. Secondly the imaginary parts of these integrals are expressed as complete elliptic integrals.Finally one-dimensional integral representations with elementary functions are derived.They are very well suited for the numerical evaluations.

hep-ph↗

arXiv1994

Calculation of two-loop self-energies in the electroweak Standard Model

Motivated by the results of the electroweak precision experiments, studies of two-loop self-energy Feynman diagrams are performed. An algebraic method for the reduction of all two-loop self-energies to a set of standard scalar integrals is presented. The gauge dependence of the self-energies is discussed and an extension of the pinch technique to the two-loop level is worked out. It is shown to yield a special case of the background-field method which provides a general framework for deriving Green functions with desirable theoretical properties. The massive scalar integrals of self-energy type are expressed in terms of generalized multivariable hypergeometric functions. The imaginary parts of these integrals yield complete elliptic integrals. Finally, one-dimensional integral representations with elementary integrands are derived which are well suited for numerical evaluation.

hep-ph↗