Figure 1

(Left panel) The solid red curve shows the variation of ${\kappa }_{\gamma }$, following Eq. (16), with $v_R$, for $v_L=1\mathrm{GeV}$. The black dashed horizontal line denotes the current $2\sigma$ upper limit on ${\kappa }_{\gamma }$ at the LHC13 ($\sqrt{s}=13\mathrm{TeV}$, $36{\mathrm{fb}}^{-1}$ of data) [28, 44]. The dark-green (dash-dotted) and light-green (dotted) horizontal lines denote the projected accuracy of on ${\kappa }_{\gamma }$ from the HL-LHC (2%) data and $\mathrm{HL}-\mathrm{LHC}+\mathrm{ILC}$ (1%) combined data, respectively [45, 46]. Note that, for the displayed region in the parameter space, the variation of ${\kappa }_{\gamma }$ with $v_R$ and subsequently the limits on $v_R$ do not crucially depend on $g_R$. (Right panel) The shaded area in black denotes the region in the $g_R\text{−}{M}_{W^{\prime }}$ plane, excluded at 95% C.L. from determination of ${\kappa }_{\gamma }$ at the LHC13. The dark- and light-green shaded regions denote the excluded regions for the projected accuracy of ${\kappa }_{\gamma }$ determination from the HL-LHC (2%) and $\mathrm{HL}-\mathrm{LHC}+\mathrm{ILC}$ (1%) combined data, respectively. While extracting bounds using the projected accuracies at the HL-LHC and $\mathrm{HL}-\mathrm{LHC}+\mathrm{ILC}$, in both panels, we have assumed the central value of ${\kappa }_{\gamma }$ to be unity, i.e., consistent with the SM.