$$ t\overline{t}t\overline{t} $$ signatures through the lens of color-octet scalars

Abstract

We reinterpret two recent LHC searches for events containing four top quarks $$ \left(t\overline{t}t\overline{t}\right) $$ t t ¯ t t ¯ in the context of supersymmetric models with Dirac gauginos and color-octet scalars (sgluons). We explore whether sgluon contributions to the four-top production cross section $$ \sigma \left( pp\to t\overline{t}t\overline{t}\right) $$ σ pp → t t ¯ t t ¯ can accommodate an excess of four-top events recently reported by the ATLAS collaboration. We also study constraints on these models from an ATLAS search for new phenomena with high jet multiplicity and significant missing transverse energy $$ \left({E}_{\mathrm{T}}^{\mathrm{miss}}\right) $$ E T miss sensitive to signals with four top quarks. We find that these two analyses provide complementary constraints, with the jets + $$ {E}_{\mathrm{T}}^{\mathrm{miss}} $$ E T miss search exceeding the four-top cross section measurement in sensitivity for sgluons heavier than about 800 GeV. We ultimately find that either a scalar or a pseudoscalar sgluon can currently fit the ATLAS excess in a range of reasonable benchmark scenarios, though a pseudoscalar in minimal Dirac gaugino models is ruled out. We finally offer sensitivity projections for these analyses at the HL-LHC, mapping the 5σ discovery potential in sgluon parameter space and computing exclusion limits at 95% CL in scenarios where no excess is found.

Changing patterns in electroweak precision with new color-charged states: Oblique corrections and the $W$ boson mass

“…Likely the most familiar are scalars in the fundamental representation of SU(3) c appearing in models of leptoquarks -in which they can also carry weak quantum numbers -or as squarks in supersymmetric scenarios. Also thoroughly studied are electroweak-singlet color-octet scalars, whose collider phenomenology has been explored, for example, in [46][47][48][49][50][51][52][53]. Color-sextet fields have enjoyed less attention [54,55], but have seen renewed interest of late [56].…”

Phenomenology of unusual top partners in composite Higgs models

“…set-ups (sgluons) [65][66][67][68][69][70][71][72]. In the following we will assume that π 8 can either decay into t t and/or g g. 3 Current bounds on the π 8 mass from LHC searches for pair production with dominant decays into t t and gg lie at ∼ 1.05 TeV and ∼ 0.85 TeV, respectively, while bounds from single production are strongly model dependent [40].…”

Exploring the phenomenology of weak adjoint scalars in minimal R-symmetric models

“…Recently, particular attention has been paid to the strong sectors of such models and the interactions of the color-octet sgluons [10][11][12][13][14][15]. Here, we turn our attention to the weak sector and examine the behavior of the scalar singlet and SU(2) triplet fields.…”