Figure 1

The improved golden region: We have scanned the supersymmetric parameter space with constraints imposed from the bound on the Higgs mass, fine-tuning, and other experimental constraints including $b\to s\gamma$ to find an improved golden region; here we have fixed ${\theta }_t=\frac{\pi }{4}$ and $\tan \beta =10$ in our “default scan” in parameter space. The fine-tuning parameter is set to be 33.3. For comparison, the area enclosed by the solid line shows the corresponding golden region previously found in Fig. 2 of 2 with the top-quark mass 171.4 GeV. The area enclosed by the dashed-dotted line corresponds to our value of the top-quark mass, 174.3 GeV. Note that our lowest value of $\delta m=150\mathrm{GeV}$ is lower than that in the previous work, as discussed in the text. (We have actually redrawn Perelstein and Spethmann’s golden region using their code, fixing the $D$-terms in the $m_{\tilde{b}}$ mass [10].)Reuse & Permissions

Figure 2

Neutralino relic density ${\Omega }_{\chi }{h}^2$ as a function of neutralino mass $m_{\chi }$ for our default scan in parameter space ($\tan \beta =10$, ${\theta }_t=\pi /4$, ${\Delta }_t=33.3$). Each dot represents a point in supersymmetric parameter space that lies within the golden region. The horizontal band shows the $2\sigma$ range in the measured value of the cosmological density of cold dark matter [1]. Notice that there are points falling into the cosmological band for $m_{\chi }\le 300\mathrm{GeV}$.Reuse & Permissions

Figure 3

Same as Fig. 2 except that $M_1$, $M_2$, and $M_3$ are related through the GUT relations, Eqs. (16, 17). Notice that there are points falling into the cosmologically interesting band.Reuse & Permissions

Figure 4

Neutralino relic density ${\Omega }_{\chi }{h}^2$ as a function of $\frac{Z_g}{1-Z_g}$ for our default scan in parameter space. Each dot represents a point in supersymmetric parameter space that lies within the golden region. The horizontal band shows the $2\sigma$ range in the measured value of the density of cold dark matter [1]. Notice that there are points only above $\log \frac{Z_g}{1-Z_g}=0$. One can see that the neutralino is typically predominantly gaugino rather than Higgsino.Reuse & Permissions

Figure 5

Neutralino relic density ${\Omega }_{\chi }{h}^2$ as a function of $M_1$ for (a) our default scan in parameter space and (b) an extended scan with $0.5<\tan \beta <30$ and $100\mathrm{GeV}<M_1<2000\mathrm{GeV}$. Each dot represents a point in supersymmetric parameter space that lies within the golden region. The horizontal band shows the $2\sigma$ range in the measured value of the density of cold dark matter [1]. Notice that there are points in the golden region with the right cosmological neutralino density provided $M_1<300\mathrm{GeV}$.Reuse & Permissions