Next-to-Leading Order NMSSM Decays with CP-odd Higgs Bosons and Stops

We compute the full next-to-leading order supersymmetric (SUSY) electroweak (EW) and SUSY-QCD corrections to the decays of CP-odd NMSSM Higgs bosons into stop pairs. In our numerical analysis we also present the decay of the heavier stop into the lighter stop and an NMSSM CP-odd Higgs boson. Both the EW and the SUSY-QCD corrections are found to be significant and have to be taken into account for a proper prediction of the decay widths.

Two-Loop Contributions of the Order $mathcal{O}(alpha_talpha_s)$ to the Masses of the Higgs Bosons in the CP-Violating NMSSM

We provide the two-loop corrections to the Higgs boson masses of the CP-violating NMSSM in the Feynman diagrammatic approach with vanishing external momentum at ${cal O} (alpha_t alpha_s)$. The adopted renormalization scheme is a mixture between $overline{text{DR}}$ and on-shell conditions. Additionally, the renormalization of the top/stop sector is provided both for the $overline{text{DR}}$ and the on-shell scheme. The calculation is performed in the gaugeless limit. We find that the two-loop corrections compared to the one-loop corrections are of the order of 5-10%, depending on the top/stop renormalization scheme. The theoretical error on the Higgs boson masses is reduced due to the inclusion of these higher order corrections.

Discovery Prospects for NMSSM Higgs Bosons at the High-Energy Large Hadron Collider

We investigate the discovery prospects for NMSSM Higgs bosons during the 13~TeV run of the LHC. While one of the neutral Higgs bosons is demanded to have a mass around 125~GeV and Standard Model (SM)-like properties, there can be substantially lighter, nearby or heavier Higgs bosons, that have not been excluded yet by LEP, Tevatron or the 8~TeV run of the LHC. The challenge consists in discovering the whole NMSSM Higgs mass spectrum. We present the rates for production and subsequent decay of the neutral NMSSM Higgs bosons in the most promising final states and discuss their possible discovery. The prospects for pinning down the Higgs sector of the Natural NMSSM will be analysed taking into account alternative search channels. We give a series of benchmark scenarios compatible with the experimental constraints, that feature Higgs-to-Higgs decays and entail (exotic) signatures with multi-fermion and/or multi-photon final states. These decay chains furthermore give access to the trilinear Higgs self-couplings. We briefly discuss the possibility of exploiting coupling sum rules in case not all the NMSSM Higgs bosons are discovered.

Higher Order Corrections to the Trilinear Higgs Self-Couplings in the Real NMSSM

After the discovery of a Higgs-like boson by the LHC experiments ATLAS and CMS, it is of crucial importance to determine its properties in order to not only identify it as the boson responsible for electroweak symmetry breaking but also to clarify the question if it is a Standard Model (SM) Higgs boson or the Higgs particle of some extension beyond the SM as {it e.g.} supersymmetry. In this context, the precise prediction of the Higgs parameters as masses and couplings play a crucial role for the proper distinction between different models. In extension of previous works on the loop-corrected Higgs boson masses of the Next-to-Minimal Supersymmetric Extension of the SM (NMSSM), we present here the calculation of the loop-corrected trilinear NMSSM Higgs self-couplings. The loop corrections turn out to have a substantial impact on the decay widths of Higgs-to-Higgs decays and on the production cross section of Higgs pairs via gluon fusion. They are therefore indispensable for the correct interpretation of the experimental Higgs results.

Model-independent analysis of Higgs spin and CP properties in the process $e^+ e^- to t bar t Phi$

In this paper we investigate methods to study the $tbar{t}$ Higgs coupling. The spin and CP properties of a Higgs boson are analysed in a model-independent way in its associated production with a $tbar{t}$ pair in high-energy $e^+e^-$ collisions. We study the prospects of establishing the CP quantum numbers of the Higgs boson in the CP-conserving case as well as those of determining the CP-mixing if CP is violated. We explore in this analysis the combined use of the total cross section and its energy dependence, the polarisation asymmetry of the top quark and the up-down asymmetry of the antitop with respect to the top-electron plane. We find that combining all three observables remarkably reduces the error on the determination of the CP properties of the Higgs Yukawa coupling. Furthermore, the top polarisation asymmetry and the ratio of cross sections at different collider energies are shown to be sensitive to the spin of the particle produced in association with the top quark pair.