arXiv subjects

Johann Plotnikov

Publications and source records attributed to Johann Plotnikov.

4 recordsLinked to original sources

arXiv2026

A Deep Dive into Baryon Asymmetry -- the C2HDM

In this paper, we present our new implementation of the computation of the baryon asymmetry in the code BSMPT. It is based on the WKB ansatz generalizing the transport equations to an arbitrary number of moments. Two different truncation schemes are implemented, and the profile of the vacuum expectation value (VEV) is derived from the equations of motion in addition to the modeling with the kink profile. We validate our implementation with a simple benchmark model and perform a detailed analysis within the CP-violating 2-Higgs-Doublet Model (C2HDM). Barring the collision term, however, our implementation can readily be applied to any extended Higgs sector with an arbitrary number of VEV directions. We study in detail the dependencies of the baryon asymmetry on the number of moment equations, the applied truncation scheme, the wall velocity, the wall velocity times wall width, the VEV profile, the strength of the phase transition, and the amount of CP violation in the model and present a detailed uncertainty analysis. We investigate the interplay of the generated baryon asymmetry and the gravitational waves signal at LISA. Our results guide the way for future improvements in the computation of the baryon asymmetry and give directions for model building. The uncertainty analysis is the basis for any investigation aiming at deducing model parameters from cosmological processes.

hep-ph↗

arXiv2026

NMSSMScanner: Efficient Scans in the NMSSM Parameter Space Proof of Concept

We present the first version of the new scanning tool NMSSMScanner that allows to perform efficient scans in the complex multi-parameter space of the Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM) while taking into account all relevant constraints. As a proof of concept we apply it to the search for NMSSM parameter configurations that maximize Higgs boson pair production from resonant scalar or pseudoscalar production in various final states.

hep-ph↗

arXiv2025

RelExt: A New Dark Matter Tool for the Exploration of Dark Matter Models

We present the C++ program RelExt for Standard Model (SM) extensions that feature a Dark Matter (DM) candidate. The tool allows to efficiently scan the parameter spaces of these models to find parameter combinations that lead to relic density values which are compatible with the measured value within the uncertainty specified by the user. The code computes the relic density for freeze-out (co-)annihilation processes. The user can choose between several pre-installed models or any arbitrary other model featuring a discrete $\mathbb{Z}_2$ symmetry, by solely providing the corresponding FeynRules model files. The code automatically generates the required (co-)annihilation amplitudes and thermally averaged cross sections, including the total widths in the $s$-channel mediators, and solves the Boltzmann equation to determine the relic density. It can easily be linked to other tools like e.g.~ScannerS to check for the relevant theoretical and experimental constraints, or to BSMPT to investigate the phase history of the model and possibly related gravitational waves signals.

hep-ph↗

arXiv2024

Freeze-in as a Complementary Process to Freeze-Out

There are many extensions of the Standard Model with a dark matter (DM) candidate obtained via the freeze-out mechanism. It can happen that after all experimental and theoretical constraints are taken into account, all parameter points have a relic density below the experimentally measured value. This means that the models solve only partially the DM problem, and at least one more candidate is needed. In this work we show that it is possible to further extend the model with a DM candidate obtained via the freeze-in mechanism to be in agreement with the relic density experimental measurement. Once the relic density problem is solved with this addition, new questions are raised. This new model with at least two DM candidates could have a freeze-out undetectable DM particle both in direct and indirect detection. This could happen if the freeze-out DM particle would have a very low density. Hence, a collider DM hint via excess in the missing energy with no correspondence in direct and indirect detection experiments, could signal the existence of a Feebly Interacting Massive Particle (FIMP). Conversely, if a DM particle is found and a particular model can explain all observables except the correct relic density, an extension with an extra FIMP would solve the problem. The freeze-in DM candidate, due to the small portal couplings, will not change the remaining phenomenology.

hep-ph↗