9 research outputs found
Precise numerical evaluation of the two loop sunrise graph Master Integrals in the equal mass case
We present a double precision routine in Fortran for the precise and fast
numerical evaluation of the two Master Integrals (MIs) of the equal mass
two-loop sunrise graph for arbitrary momentum transfer in d=2 and d=4
dimensions. The routine implements the accelerated power series expansions
obtained by solving the corresponding differential equations for the MIs at
their singular points. With a maximum of 22 terms for the worst case expansion
a relative precision of better than a part in 10^{15} is achieved for arbitrary
real values of the momentum transfer.Comment: 11 pages, LaTeX. The complete paper is also available via the www at
http://www-ttp.physik.uni-karlsruhe.de/Preprints/ and the program can be
downloaded from http://www-ttp.physik.uni-karlsruhe.de/Progdata
Two-loop Integral Reduction from Elliptic and Hyperelliptic Curves
We show that for a class of two-loop diagrams, the on-shell part of the
integration-by-parts (IBP) relations correspond to exact meromorphic one-forms
on algebraic curves. Since it is easy to find such exact meromorphic one-forms
from algebraic geometry, this idea provides a new highly efficient algorithm
for integral reduction. We demonstrate the power of this method via several
complicated two-loop diagrams with internal massive legs. No explicit elliptic
or hyperelliptic integral computation is needed for our method.Comment: minor changes: more references adde
Massive Feynman integrals and electroweak corrections
There are steady advances in the calculation of electroweak corrections to
massive scattering problems at colliders, from the very beginning in the
nineteen seventies until contemporary developments. Recent years brought a
remarkable progress due to new calculational technologies. This was motivated
by demands from phenomenological applications at particle accelerators: higher
multiplicities of the final states, extreme kinematics, need of higher
precision and thus of higher orders in perturbation theory. We describe
selected contributions from the project "Massive particle production" of
Sonderforschungsbereich/Transregio 9 of Deutsche Forschungsgemeinschaft.Comment: Material presented at the final Workshop of Sonderforschungsbereich
Transregio 9 "Advances in Computational Physics" of Deutsche
Forschungsgemeinschaft (DFG), 15-19 Sep 2014, Durbach, Germany, to appear in
the proceedings, 16 pages, 16 figures, 3 tables; references added in v
The complete set of two-loop master integrals for Higgs + jet production in QCD
In this paper we complete the computation of the two-loop master integrals
relevant for Higgs plus one jet production initiated in arXiv:1609.06685,
arXiv:1907.13156, arXiv:1907.13234. We compute the integrals by defining
differential equations along contours in the kinematic space, and by solving
them in terms of one-dimensional generalized power series. This method allows
for the efficient evaluation of the integrals in all kinematic regions, with
high numerical precision. We show the generality of our approach by considering
both the top- and the bottom-quark contributions. This work along with
arXiv:1609.06685, arXiv:1907.13156, arXiv:1907.13234 provides the full set of
master integrals relevant for the NLO corrections to Higgs plus one jet
production, and for the real-virtual contributions to the NNLO corrections to
inclusive Higgs production in QCD in the full theory.Comment: 32 pages, references added, minor revisio