Update on the Direct Detection of Dark Matter in MSSM Models with Non-Universal Higgs Masses

TL;DR

This paper assesses direct detection prospects for neutralino dark matter in MSSM variants with non-universal Higgs masses (NUHM1 and NUHM2) and contrasts them with the CMSSM. By analyzing representative parameter planes and full scans, it shows that NUHM1/NUHM2 broaden the possible spin-independent and spin-dependent cross sections, often enabling larger cross sections at higher neutralino masses due to Higgsino admixture, while also permitting very small cross sections in funnel and crossover regions. The work highlights how the extra Higgs-sector freedom shifts the LSP composition and the annihilation mechanisms (coannihilation, rapid-annihilation funnels, and focus-point-like regions), thereby altering the direct-detection landscape. These findings imply that upcoming experiments (e.g., XENON1T/LUX) could probe large portions of NUHM parameter space, offering a potential diagnostic to distinguish NUHM1/NUHM2 from CMSSM scenarios when combined with collider data. Overall, the paper emphasizes the complementary roles of direct detection and collider searches in elucidating the pattern of supersymmetry breaking.

Abstract

We discuss the possibilities for the direct detection of neutralino dark matter via elastic scattering in variants of the minimal supersymmetric extension of the Standard Model (MSSM) with non-universal supersymmetry-breaking contributions to the Higgs masses, which may be either equal (NUHM1) or independent (NUHM2). We compare the ranges found in the NUHM1 and NUHM2 with that found in the MSSM with universal supersymmetry-breaking contributions to all scalar masses, the CMSSM. We find that both the NUHM1 and NUHM2 offer the possibility of larger spin-independent dark matter scattering cross sections than in the CMSSM for larger neutralino masses, since they allow the density of heavier neutralinos with large Higgsino components to fall within the allowed range by astrophysics. The NUHM1 and NUHM2 also offer more possibilities than the CMSSM for small cross sections for lower neutralino masses, since they may be suppressed by scalar and pseudoscalar Higgs masses that are larger than in the CMSSM.

Figures (14)

• Figure 1: Panels (a) and (b) show the CMSSM $(m_{1/2},m_0)$ plane and the corresponding cosmologically viable neutralino-nucleon elastic scattering cross sections as functions of neutralino mass for $\tan \beta=10$ and $A_0 =0$. Panel (c) shows the entire potential range of neutralino-nucleon cross sections as functions of neutralino mass for the CMSSM, with $5 \leq \tan \beta \leq 55$, 0 $\leq m_{1/2} \leq 2000$ GeV, 100 GeV $\leq m_0 \leq 2000$ GeV, and $-3 m_{1/2} \leq A_0 \leq 3 m_{1/2}$ We consider $\mu<0$ only for $\tan \beta<30$. Also shown are upper limits on the spin-independent dark matter scattering cross section from CDMS II cdmsII (solid black line) and XENON10 XENON10 (solid pink line), as well as the expected sensitivities for XENON100 XENON100 (dashed pink line) and SuperCDMS at the Soudan Mine superCDMS (dashed black line).
• Figure 2: Panels (a) and (c) show the NUHM1 $(m_A,m_0)$ and $(\mu,m_0)$ planes for $m_{1/2}=500$ GeV, $\tan \beta=10$, and $A_0=0$ ($\mu > 0$ in panel (a)). Panels (b) and (d) show the corresponding neutralino-nucleon elastic scattering cross sections for cosmologically-viable models as functions of neutralino mass.
• Figure 3: As in Fig. \ref{['fig:fixm0']}, but for $m_{1/2} = 300$ GeV.
• Figure 4: Panels (a) and (c) show the NUHM1 $(m_A,m_{1/2})$ planes for $m_0=500$ GeV, $\tan \beta=10$ and 50. Panels (b) and (d) show the corresponding neutralino-nucleon elastic scattering cross sections as functions of neutralino mass.
• Figure 5: Panel (a) shows the NUHM1 $(m_A,m_{1/2})$ planes for $m_0=100$ GeV and $\tan \beta=10$. Panel (b) shows the corresponding neutralino-nucleon elastic scattering cross sections as functions of neutralino mass.