Publikationen

We present an updated calculation of the W boson pole mass in models beyond the standard model with FlexibleSUSY. The calculation has a decoupling behavior and allows for a precise W-pole mass prediction up to large new physics scales. We apply the calculation to several standard model extensions, including the MRSSM where we show that it can be compatible with large corrections to the W boson mass that would be needed to fit the recent 2022 CDF measurement.

English: There are many open questions in physics: What is Dark Matter? Why is gravity so extremely weak compared to the other forces? Can all forces be unified to one fundamental force? One approach to shed light on these questions is to make precision measurements on elementary particles and search for deviations from the predictions. The magnetic moment of the muon is one of these precision observables which deviates significantly from the prediction. It has thus drawn a lot of attention in the particle physics community, because it gives us direct hints for the existence of new particles to answer the open questions. This talk gives an overview over open questions in particle physics and explains how the magnetic moment of the muon is measured with high precision and what it tells us about the existence of new particles. German: In der modernen Physik gibt es noch viele offene Fragen: Woraus besteht Dunkle Materie? Warum ist die Gravitationskraft so extrem schwach im Vergleich zu den anderen Kräften? Können alle Kräfte zu einer einzigen Universalkraft vereinigt werden? Eine Möglichkeit um etwas Licht in das Dunkel zu bringen sind Präzisionsmessungen an Elementarteilchen und die Suche nach Abweichungen von den Vorhersagen. Das magnetische Moment des Myons ist eine dieser Präzisionsobservablen, die deutlich von der Vorhersage abweicht. Aufgrund dessen hat das magnetische Moment des Myons viel Aufmerksamkeit unter den Physikerinnen und Physikern auf sich gezogen, da es direkte Hinweise auf die Existenz neuer Elementarteilchen liefert um die offenen Fragen der Teilchenphysik zu beantworten. Dieser Vortag gibt einen Überblick über die offenen Fragen der Teilchenphysik und erläutert, wie das magnetische Moment des Myons mit hoher Präzision gemessen wird und welche Hinweise uns diese Messung in Bezug auf die Existenz neuer Elementarteilchen gibt.

We present an extension of the GM2Calc software to calculate the muon anomalous magnetic moment (a_μ^BSM) in the Two-Higgs Doublet Model. The Two-Higgs Doublet Model is one of the simplest and most popular extensions of the Standard Model. It is one of the few single field extensions that can give large contributions to a_μ^BSM. It is essential to include two-loop corrections to explain the long standing discrepancy between the Standard Model prediction and the experimental measurement in the Two-Higgs Doublet Model. The new version GM2Calc 2 implements the state of the art two-loop calculation for the general, flavour violating Two-Higgs Doublet Model as well as for the flavour aligned Two-Higgs Doublet Model and the type I, II, X and Y flavour conserving variants. Input parameters can be provided in either the gauge basis or the mass basis, and we provide an easy to use SLHA-like command-line interface to specify these. Using this interface users may also select between Two-Higgs Doublet Model types and choose which contributions to apply. In addition, GM2Calc 2 also provides interfaces in C++, C, Python and Mathematica, to make it easy to interface with other codes.

We present FlexibleDecay, a tool to calculate decays of scalars in a broad class of BSM models. The tool aims for high precision particularly in the case of Higgs boson decays. In the case of scalar and pseudoscalar Higgs boson decays the known higher order SM QED, QCD and EW effects are taken into account where possible. The program works in a modified MS scheme that exhibits a decoupling property with respect to heavy BSM physics, with BSM parameters themselves treated in the MS/DR-scheme allowing for an easy connection to high scale tests for, e.g., perturbativity and vacuum stability, and the many observable calculations readily available in MS/DR programs. Pure BSM effects are taken into account at the leading order, including all one-loop contributions to loop-induced processes. The program is implemented as an extension to FlexibleSUSY, which determines the mass spectrum for arbitrary BSM models, and does not require any extra configuration from the user. We compare our predictions for Higgs decays in the SM, singlet extended SM, type II THDM, CMSSM and MRSSM, as well as for squark decays in the CMSSM against a selection of publicly available tools. The numerical differences between our and other programs are explained. The release of FlexibleDecay officially deprecates the old effective couplings routines in FlexibleSUSY.

We compare different methods for the computation of the real dilogarithm regarding their ability for using instruction-level parallelism when executed on appropriate CPUs. As a result we present an instruction-level-aware method and compare it to existing implementations.

Predictions for the Higgs masses are a distinctive feature of supersymmetric extensions of the Standard Model, where they play a crucial role in constraining the parameter space. The discovery of a Higgs boson and the remarkably precise measurement of its mass at the LHC have spurred new efforts aimed at improving the accuracy of the theoretical predictions for the Higgs masses in supersymmetric models. The "Precision SUSY Higgs Mass Calculation Initiative" (KUTS) was launched in 2014 to provide a forum for discussions between the different groups involved in these efforts. This report aims to present a comprehensive overview of the current status of Higgs-mass calculations in supersymmetric models, to document the many advances that were achieved in recent years and were discussed during the KUTS meetings, and to outline the prospects for future improvements in these calculations.