Exploring fine-tuning of the Next-to-Minimal Composite Higgs Model

• Main Authors: Daniel Murnane, Martin White, Anthony G. Williams
• Format: Article
• Language: English
• Published: SpringerOpen 2019-04-01
• Series: Journal of High Energy Physics
• Subjects: Beyond Standard Model; Technicolor and Composite Models; Effective Field Theories; Global Symmetries
• Online Access: http://link.springer.com/article/10.1007/JHEP04(2019)076

Abstract We perform a detailed study of the fine-tuning of the two-site, 4D, Next-to-Minimal Composite Higgs Model (NMCHM), based on the global symmetry breaking pattern SO(6) → SO(5). Using our previously-defined fine-tuning measure that correctly combines the effect of multiple sources of fine-tuning, we quantify the fine-tuning that is expected to result from future collider measurements of the Standard Model-like Higgs branching ratios, in addition to null searches for the new resonances in the model. We also perform a detailed comparison with the Minimal Composite Higgs Model, finding that there is in general little difference between the fine-tuning expected in the two scenarios, even after measurements at a high-luminosity, 1 TeV linear collider. Finally, we briefly consider the relationship between fine-tuning and the ability of the extra scalar in the NMCHM model to act as a dark matter candidate, finding that the realisation of a Z 2 symmetry that stabilises the scalar is amongst the most natural solutions in the parameter space, regardless of future collider measurements.