The {\tt Mathematica} package {\tt TopoID} and its application to the Higgs boson production cross section

We present the {\tt Mathematica} package {\tt TopoID} which aims at the automation of several steps in multiloop calculations. The algorithm which lies at the very core of the package is described and illustrated with an example. The main features of {\tt TopoID} are stated and some of them are briefly demonstrated for NLO or NNLO Higgs boson production.Comment: 5 pages, 1 figure, contribution to the proceedings of ACAT, 18 - 22 January 2016, UTFSM, Valparaiso, Chile v2: updated references, added preprint number DESY 16-03

Can the Internet Swing the Vote? Results from a study of the 2007 Danish parliamentary election

This article investigates whether political use of the Internet affects users politically. Using a combination of log- and survey data from a study of Internet use during the Danish 2007 parliamentary election, and inspired by theories on agenda setting and on the active/interactive user, three hypotheses are tested: 1) that those who use the Internet most intensively politically are also the most politically affected, 2) that "net activists" (web 2.0 users) are affected more by their political Internet use than "information seekers" (web 1.0 users), and 3) that those who are somewhat or little interested in politics are those most affected by their political Internet use in an election period. All three hypotheses are verified with some modifications. Furthermore, it is demonstrated that socio-demographic factors like age, gender, education and income are of little importance in explaining variation in how voters are affected by their political Internet use. Rather, the level and type of political activity on the Internet and political interest seem to be the most important factors in explaining the degree to which voters are politically affected by their Internet use.political Internet use, parliamentary election, political effects of Internet use, web 2.0, political interest, political media

Adequate bases of phase space master integrals for gg→hgg \to h at NNLO and beyond

We study master integrals needed to compute the Higgs boson production cross section via gluon fusion in the infinite top quark mass limit, using a canonical form of differential equations for master integrals, recently identified by Henn, which makes their solution possible in a straightforward algebraic way. We apply the known criteria to derive such a suitable basis for all the phase space master integrals in afore mentioned process at next-to-next-to-leading order in QCD and demonstrate that the method is applicable to next-to-next-to-next-to-leading order as well by solving a non-planar topology. Furthermore, we discuss in great detail how to find an adequate basis using practical examples. Special emphasis is devoted to master integrals which are coupled by their differential equations.Comment: 33 pages, 6 figure

Higgs boson pair production: top quark mass effects at NLO and NNLO

We compute next-to-next-to-leading order QCD corrections to the gluon-induced production cross section of Higgs boson pairs in the large top quark mass limit using the soft-virtual approximation. In the limit of infinitely-heavy top quark we confirm the results in the literature. We add two more expansion terms in the inverse top quark mass to the $M_t\to\infty$ result. Since the $1/M_t$ expansion converges poorly, we try to improve on it by factorizing the exact leading order cross section. We discuss two ways of doing that and conclude that the finite top quark mass effects shift the cross section at most by about 10\% at next-to-leading order and by about 5\% at next-to-next-to-leading order.Comment: 25 page

Methods for multiloop calculations and Higgs boson production at the LHC

The main topics of this thesis are Higgs boson production and the program package TopoID. We calculated results for all collinear counterterms up to N3LO. For a particular class of triple-real integrals we obtained results with full dependence on x. TopoID is designed to be a process independent tool for topology identification, FORM code generation and finding non-trivial relations among integrals that remain after applying a reduction algorithm