EFTs meet Higgs nonlinearity, compositeness and (neutral) naturalness

• Published in: The journal of high energy physics Vol. 2019; no. 9; pp. 1 - 40
• Main Authors: Li, Hao-Lin, Xu, Ling-Xiao, Yu, Jiang-Hao, Zhu, Shou-hua
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-09-2019; Springer Nature B.V; SpringerOpen
• Subjects: Beyond Standard Model; Classical and Quantum Gravitation; Couplings; Effective Field Theories; Elementary Particles; Field theory; Form factors; Higgs bosons; Higgs Physics; High energy physics; Nonlinearity; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Quarks; Regular Article - Theoretical Physics; Relativity Theory; String Theory; Technicolor and Composite Models; Effective Field Theories; Beyond Standard Model; Technicolor and Composite Models; Higgs Physics
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP09(2019)010

A
bstract
Composite Higgs and neutral-naturalness models are popular scenarios in which the Higgs boson is a pseudo Nambu-Goldstone boson (PNGB), and naturalness problem is addressed by composite top partners. Since the standard model effective field theory (SMEFT) with dimension-six operators cannot fully retain the information of Higgs nonlinearity due to its PNGB nature, we systematically construct low energy Lagrangian in which the information of compositeness and Higgs nonlinearity are encoded in the form factors, the two-point functions in the top sector. We classify naturalness conditions in various scenarios, and first present these form factors in composite neutral naturalness models. After extracting out Higgs effective couplings from these form factors and performing the global fit, we find the value of Higgs top coupling could still be larger than the standard model one if the top quark is embedded in the higher dimensional representations. Also we find the impact of Higgs nonlinearity is enhanced by the large mass splitting between composite states. In this case, pattern of the correlation between the
t
t
¯
h
and
t
t
¯
hh
couplings is quite different for the linear and nonlinear Higgs descriptions.