Figure 1

Constraints on the $m_s-\sin \chi$ plane arising from the scalar potential’s global minimum condition (13), for $m_s\ge 150\mathrm{GeV}$. The panels correspond to three representative values of the $\mathcal{A}$ pseudoscalar mass [c.f. (6)]. A heavy $m_{\mathcal{A}}$ generally disfavors a light $m_s$ for any scalar mixing angle value.Reuse & Permissions

Figure 2

Diagrams contributing to the $WW$ scattering. The top row illustrates the $s$ and $t$ channels of the electroweak gauge boson exchange, as well as the four-point contact interaction. The bottom row diagrams are due to scalar exchange.Reuse & Permissions

Figure 3

The most stringent unitarity constraints on the $m_s-\sin \chi$ plot for $m_s\ge 150\mathrm{GeV}$. The top row panels represent the bounds for a singlet VEV $v_s=500\mathrm{GeV}$ and for several values of the scalar color-octet mass, $m_{G_H}$. The panels in the middle (bottom) row correspond to $v_s=1000(2000)\mathrm{GeV}$, which yield additional allowed parameter space and also a larger $m_{G_H}$. In each panel, the three curves correspond (from bottom to top, $m_{\mathcal{A}}\in \{0,\frac{1}{2}{m}_{G_H},m_{G_H}\}$, and the resulting plots are superimposed, demonstrating a moderate dependence of the unitarity constraints on this parameter. A larger $m_{\mathcal{A}}$ slightly weakens the exclusion bounds.Reuse & Permissions

Figure 4

Illustrative model predictions for the electroweak corrections $S$ and $T$, and comparison with allowed region [48]. Note that either a larger $m_s$ or a larger $\sin \chi$ pushes $S$ towards more positive values and $T$ towards more negative values. Left: Variation with scalar mixing angle for two examples of fixed $m_s$ in the $S\mathrm{\text{−}}T$ plane with $0\le \sin \chi \le 1$. The 95% C.L. contour has also been depicted, defining the allowed region. The black dots denote representative values of the mixing angle for the corresponding masses of the $s$ state, including the maximum allowed value. Right: Variation with $m_s$ for two examples of fixed $\sin \chi$ with $150\le m_s\le 3000\mathrm{GeV}$. The black dots denote representative values of the $s$ scalar mass for the corresponding mixing angles, including the maximum allowed value.Reuse & Permissions

Figure 5

Constraints from the electroweak precision tests in the $m_s-\sin \chi$ plane at 95% C.L. for $m_s\ge 150\mathrm{GeV}$, based on the electroweak fits of 48. The data excludes large mixing, due to the high sensitivity of the oblique parameters to the scalar mixing angle, whereas the dependence on $m_s$ is only logarithmic for large values.Reuse & Permissions

Figure 6

One-loop diagrams, containing physical degrees of freedom, contributing to the new-physics contributions to $h\to gg$. The columns represent, from left to right, the contributions of the heavy vector color-octets ($C_{\mu }^a$), scalar color-octets ($G_H^a$), and the spectator fermions ($Q$) in the loop.Reuse & Permissions

Figure 7

New-physics one-loop diagrams contributing $h\to \gamma \gamma$. Only the heavy spectator fermions in the loop contribute to this process.Reuse & Permissions

Figure 8

The constraints on the $v_s-\sin \chi$ plane derived from the properties of the 125 GeV scalar observed by the LHC; the grey region is excluded at 95% CL. We choose $m_{\mathcal{A}}=0$, which allows for the invisible decay $h\to \mathcal{A}\mathcal{A}$, in the first row and $m_{\mathcal{A}}=100\mathrm{GeV}$ (which forbids that invisible decay) in the second row. The three columns are for zero, one, and three generations of spectator quarks, reading from left to right. Note that the sign of $\sin \chi$ matters.Reuse & Permissions

Figure 9

For the parameter set Eq. (62). Left: ${\kappa }_{gg}^s$, the ratio of the gluon-fusion production cross section of $s$ relative to that for a standard model Higgs of mass $m_s$, as a function of $m_s$ for a given set of $\sin \chi$, $N_Q$. The pink (light gray) and blue (dark gray) lines are for $\sin \chi =0.1$, 0.3, and thick, dashed and dotted lines for $N_Q=0$, 1, 3, respectively. Right: $\mathrm{BR}(s\to VV)/\mathrm{BR}(H\to VV)$ as a function of $m_s$ for different $\sin \chi$, where the red and blue lines are for $\sin \chi =0.1$, 0.3, respectively.Reuse & Permissions

Figure 10

The black dashed line denotes the strongest exclusion at 95% C.L. from $H\to ZZ$ and $H\to WW$ channels at CMS [60] and ATLAS [61], respectively. Using the model parameter values of Eq. (62), the pink (light gray) and blue (dark gray) lines in each panel are for $\sin \chi =0.1$, 0.3; and the panels from left to right are for $N_Q=0$, 1, 3, respectively.Reuse & Permissions

Figure 11

Constraints on the $m_s-|\sin \chi |$ plane for $m_s\ge 150\mathrm{GeV}$. All colored regions are excluded. Theoretical bounds arise from stability (solid curves) and unitarity (dot-dashed) analyses, whereas the experimental constraints, at 95% C.L., are due to electroweak precision tests (dotted), and LHC direct searches (dashed, vertical). The top row shows bounds for a singlet VEV $v_s=500\mathrm{GeV}$, where several values of the scalar color-octet mass, $m_{G_H}$, are plotted; the middle (bottom) row corresponds to $v_s=1000(2000)\mathrm{GeV}$. In each panel, the illustrative value for the pseudoscalar mass, $m_{\mathcal{A}}=\frac{1}{2}{m}_{G_H}$ is shown, since dependence on $m_{\mathcal{A}}$ is modest. Sensitivity to the coloron and spectator fermion masses, $M_C$ and $M_Q$ is negligible. The allowed parameter space for $v_s=500\mathrm{GeV}$ is tightly constrained, while a larger singlet VEV leaves more scope.Reuse & Permissions

Figure 12

Trilinear couplings of the $h$ boson with the coloron, the spectator fermion, and the other physical (pseudo-)scalars present in the theory.Reuse & Permissions

Figure 13

Trilinear couplings of a gluon with a pair of vector color-octets ($C_{\mu }^a$), and a pair of scalar color-octets ($G_H^a$). In each diagram, all momenta flow towards the vertex.Reuse & Permissions

Figure 14

Quartic couplings of a pair of gluons with a pair of vector color-octets ($C_{\mu }^a$), and a pair of scalar color-octets ($G_H^a$).Reuse & Permissions

Figure 15

Scalar quartic vertices, involving the colored bosons.Reuse & Permissions