Non-standard signatures of Composite Higgs models and their impact for searches at present and future colliders

• Applicant: Professor Dr. Werner R. Porod
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 506512996

The discovery of the Higgs boson at the LHC in 2012 has certainly been the crowning of many decades of research in fundamental physics and a success story for the Standard Model of particle physics. However, it cannot be considered a successful completion because the Brout-Englert-Higgs mechanism appears in the Standard Model as a mere description of the electroweak symmetry breaking, without any understanding of its dynamical origin. The discovery of a scalar resonance at 125 GeV has materialised this problem, often referred to as the naturalness problem. Furthermore, long standing evidences of new physics beyond the Standard Model are still waiting for a valid particle physics explanation: neutrino masses, dark matter and the baryon asymmetry of the Universe. In addition there remains the riddle what causes the structures of the observered quark and lepton mass spectra. Composite Higgs models offer a dynamical explanation of the Higgs boson as a pseudo Nambu-Goldstone-boson. The largeness of the top-mass is explained via mixing with so-called hyperbaryons. The LHC collaborations have established servere bounds on these hyperbaryons and other bound states taking the minimal composite Higgs model as guideline. While the minimal model is quite useful to get a first idea on potential signatures, the situation in more realistic models is much more complex. For example, they contain not only additional electroweak pseudo Nambu-Goldstone-bosons but also ones charged under the strong interaction. Their existence change significantly the decay pattern of the hyperbaryons and other bound states. Moreover, relistic models often predict additional hyperbaryons with a significantly larger production cross section at hadron colliders compared to the ones of the minimal model. This has profound implications on the signatures for collider searches such as the ones at the LHC. In this project we will investigate this in detail: firstly we will explore if there are traces of such altered signatures in the existing LHC data. Secondly we will work out the implications for the reach of upcoming LHC runs and a prospective 100 TeV proton proton collider.

• DFG Programme: Research Grants
• International Connection: France, South Korea, Sweden
• Cooperation Partners: Dr. Giacomo Cacciapaglia; Professor Dr. Gabriele Ferretti; Dr. Thomas Flacke; Professor Dr. Benjamin Fuks