SMEFT operators in rare multi-top processes

Abstract

Nowadays, the Standard Model Effective Field Theory (SMEFT) provides a standard framework to parameterize potential deviations from the Standard Model and to combine information from multiple processes in global analyses. This review summarizes dedicated studies that constrain dimension-six Wilson coefficients using three top-quark and four top-quark production processes. We highlight the complementarity of these channels, as well as summarize the main problems and prospects in the area. A concise introduction to the SMEFT formalism and a discussion of the problem of potential perturbative unitarity violation are also provided.

Figures (7)

• Figure 1: Representative Feynman diagrams of four top quarks LO production in SM.
• Figure 2: Representative Feynman diagrams of three top quarks LO production in SM
• Figure 3: Example diagrams for $pp \rightarrow t \bar{t} t\bar{t}$ with insertion of effective vertices, induced by four-heavy fermion SMEFT operators.
• Figure 4: (a) Projections to several high-energy scenarios of the expected limits on $C_k/\Lambda^2 \rm [TeV^{-2}]$ of 4-heavy fermion operators obtainable from four top-quark production process; (b) Comparison of the expected limits on $C_k/\Lambda^2 \rm [TeV^{-2}]$ estimated for $pp \rightarrow t\bar{t}t\bar{t}$ (4t) and $pp \rightarrow t\bar{t}t(\bar{t}) + X$ (3t) at $\sqrt{s}$ = 13 TeV (dotted) and $\sqrt{s}$ = 14 TeV (solid) Aleshko:2023rkv.
• Figure 5: Representative diagrams for $pp \rightarrow t \bar{t} t(\bar{t}) + X$ with insertion of effective vertices of types: a) 4 heavy fermions, b) 2 heavy and 2 light fermions, c) 2 heavy fermions and boson fields