Sensitivity to triple Higgs couplings via di-Higgs production in the RxSM at the (HL-)LHC and future e+e− colliders

The real Higgs singlet extension of the Standard Model (SM) without Z2 symmetry, the RxSM, is the simplest extension of the SM that features a First Order Electroweak Phase Transition (FOEWPT) in the early universe. The FOEWPT is one of the requirements needed for electroweak baryogenesis to explain...

Descripción completa

Detalles Bibliográficos
Autores: Arco, F., Heinemeyer, S., Mühlleitner, M., Parra Arnay, A., Rivero González, N., Verduras Schaeidt, A.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:dnet:digitalcsic_::ae527e09a9307d747cc8d82195c623f7
Acceso en línea:http://hdl.handle.net/10261/429305
https://www.scopus.com/pages/publications/105009292227?origin=resultslist
Access Level:acceso abierto
Palabra clave:Higgs Properties
Multi-Higgs Models
Specific BSM Phenomenology
Descripción
Sumario:The real Higgs singlet extension of the Standard Model (SM) without Z2 symmetry, the RxSM, is the simplest extension of the SM that features a First Order Electroweak Phase Transition (FOEWPT) in the early universe. The FOEWPT is one of the requirements needed for electroweak baryogenesis to explain the baryon asymmetry of the universe (BAU). Thus, the RxSM is a perfect example to study features related to the FOEWPT at current and future collider experiments. The RxSM has two CP-even Higgs bosons, h and H, with masses mh< mH, where we assume that h corresponds to the Higgs boson discovered at the LHC. Our analysis is based on a benchmark plane that ensures the occurence of a strong FOEWPT, where mH> 2mh is found. In a first step we analyze the di-Higgs production at the (HL-)LHC, gg → hh, with a focus on the impact of the trilinear Higgs couplings (THCs), λhhh and λhhH. The interferences of the resonant H-exchange diagram involving λhhH and the non-resonant diagrams result in a characteristic peak-dip (or dip-peak) structure in the mhh distribution. We analyze how λhhH can be accessed, taking into account the experimental smearing and binning. We also demonstrate that the approximation used by ATLAS and CMS for the resonant di-Higgs searches may fail to capture the relevant effects and lead to erroneous results. In a second step we analyze the benchmark plane at a future high-energy e+e− collider with s = 1000 GeV (ILC1000). We analyze the potential sensitivity to λhhH via an experimental determination at the ILC1000 and demonstrate that it is nearly independent of the heavy Higgs-boson mass, as long as it is kinematically accessible. © The Author(s) 2025.