Tutorial to SARAH

I give in this brief tutorial a short practical introduction to the Mathematica package SARAH. First, it is shown how an existing model file can be changed to implement a new model in SARAH. In the second part, masses, vertices and renormalisation group equations are calculated with SARAH. Finally, the main commands to generate model files and output for other tools are summarised.Comment: 8 pages, 1 figure; Tutorial (based on lecture arXiv:1509.07061) given at "School and Workshops on Elementary Particle Physics and Gravity", Corfu Summer Institute, September 201

Reopen parameter regions in Two-Higgs Doublet Models

The stability of the electroweak potential is a very important constraint for models of new physics. At the moment, it is standard for Two-Higgs doublet models (THDM), singlet or triplet extensions of the standard model to perform these checks at tree-level. However, these models are often studied in the presence of very large couplings. Therefore, it can be expected that radiative corrections to the potential are important. We study these effects at the example of the THDM type-II and find that loop corrections can revive more than 50% of the phenomenological viable points which are ruled out by the tree-level vacuum stability checks. Similar effects are expected for other extension of the standard model.Comment: 6 pages, 5 figures; added few explanations and fixed typos in eqs. (8)-(9), matches version accepted for publication by PL

Introduction to SARAH and related tools

I give in this lecture an overview of the features of the Mathematica package SARAH, and explain how it can be used together with other codes to study all aspects of a BSM model. The focus will be on the description of the analytical calculations which SARAH can perform and how this information is used to generate automatically a spectrum generator based on SPheno. I also summarize the main aspects of the other interfaces to public codes like HiggsBounds/HiggsSignals, FeynArts/FormCalc, CalcHep, MicrOmegas, WHIZARD, Vevacious or MadGraph. The appendix contains a short tutorial about the implementation and usage of a new model.Comment: 16 pages, Lecture given at "Summer School and Workshop on the Standard Model and Beyond", Corfu Summer Institute 2015; v2: moved to PoS styl

Precise determination of the Higgs mass in supersymmetric models with vectorlike tops and the impact on naturalness in minimal GMSB

We present a precise analysis of the Higgs mass corrections stemming from vectorlike top partners in supersymmetric models. We reduce the theoretical uncertainty compared to previous studies in the following aspects: (i) including the one-loop threshold corrections to SM gauge and Yukawa couplings due to the presence of the new states to obtain the $\bar{\text{DR}}$ parameters entering all loop calculations, (ii) including the full momentum dependence at one-loop, and (iii) including all two-loop corrections but the ones involving $g_1$ and $g_2$. We find that the additional threshold corrections are very important and can give the largest effect on the Higgs mass. However, we identify also parameter regions where the new two-loop effects can be more important than the ones of the MSSM and change the Higgs mass prediction by up to 10 GeV. This is for instance the case in the low $\tan\beta$, small $M_A$ regime. We use these results to calculate the electroweak fine-tuning of an UV complete variant of this model. For this purpose, we add a complete $\textbf{10}$ and $\bar{\textbf{10}}$ representation of $SU(5)$ to the MSSM particle content. We embed this model in minimal Gauge Mediated Supersymmetry Breaking and calculate the electroweak fine-tuning with respect to all important parameters. It turns out that the limit on the gluino mass becomes more important for the fine-tuning than the Higgs mass measurements which is easily to satisfy in this setup.Comment: 64 pages, 17 figure

Master\u27s Project: Examining Equity and Emergence: Personal Inquiry and Practice

When I awakened to the reality of my White privilege I began a transformative learning journey which implicates my personal life, professional work, and leadership practice. This project deepened and integrated my understanding of Whiteness, power, privilege, and systemic oppression. By learning the ways I perpetuate white supremacy, I create personal agency for changing such patterns, embodying leadership which builds a more equitable and justice-centered future. This personal inquiry utilized emergent strategy, relationship-building, and critical reflection to generate deep and integrated learning

Improved unitarity constraints in Two-Higgs-Doublet-Models

Two-Higgs-Doublet-Models (THDMs) are among the simplest extensions of the standard model and are intensively studied in the literature. Using on-shell parameters such as the masses of the additional scalars as input, corresponds often to large quartic couplings in the underlying Lagrangian. Therefore, it is important to check if these couplings are for instance in agreement with perturbative unitarity. The common approach for doing this check is to consider the two-particle scattering matrix of scalars in the large centre-of-mass energy limit where only point interactions contribute. We show that this is not always a valid approximation: the full calculation including all tree-level contributions at finite energy can lead to much more stringent constraints. We show how the allowed regions in the parameter space are affected. In particular, the light Higgs window with a second Higgs below 125 GeV completely closes for large values of the $Z_2$ breaking parameter $|M_{12}|$. We also compare against the loop corrected constraints, which use also the large $\sqrt{s}$ approximation, and find that (effective) cubic couplings are often more important than radiative corrections.Comment: 8 pages, 6 figure