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Low Mass Neutralino Dark Matter in the MSSM with Constraints from $B_s\to μ^+μ^-$ and Higgs Search Limits

Daniel Feldman, Zuowei Liu, Pran Nath

TL;DR

This study investigates whether low-mass neutralinos ($m_{ m LSP} obreak\ obreak 5$–$10$ GeV) can yield detectable spin-independent neutralino-proton cross sections within the MSSM under radiative electroweak symmetry breaking (REWSB), in light of CoGeNT/DAMA signals. The authors show that large cross sections up to $10^{-40}$ cm$^2$ are possible via Higgs exchange at high $ aneta$, but ongoing limits from Tevatron Higgs searches and the upper bound on ${ m Br}(B_s o ar{ u} u)$ severely constrain the parameter space, reducing $\sigma_{ m SI}( ilde{ chi} p)$ to about $10^{-41}$ cm$^2$ or smaller near $m_{ m LSP}\sim 10$ GeV. A comprehensive MSSM scan with REWSB and non-universal gaugino masses, using micrOMEGAs and SuSpect, finds that after imposing sparticle mass bounds and flavor constraints, the maximal cross section drops by an order of magnitude, and even larger $ aneta$ regions remain incompatible with the $B_s o ar{ u} u$ limits. Extending the analysis to broader non-universal scenarios (NUG, NUH, NU3, NUA) with millions of models does not reopen the CoGeNT/DAMA window, pushing viable $m_{ m LSP}$ above $ obreak ext{20–30 GeV}$ and $\sigma_{ m SI}( ilde{ chi} p)$ to $ obreak\$ obreak ext{(a few)} imes 10^{-42}$ cm$^2$. Overall, within MSSM spectra constrained by collider, flavor, and relic density data, a $ obreak\$10$ GeV or lighter neutralino cannot account for the low-mass dark matter hints, underscoring the tension between direct-detection signals and MSSM realizations.

Abstract

The region of low neutralino masses as low as (5-10) GeV has attracted attention recently due to the possibility of excess events above background in dark matter detectors. An analysis of spin independent neutralino-proton cross sections $\SI$ which includes this low mass region is given. The analysis is done in MSSM with radiative electroweak symmetry breaking (REWSB). It is found that cross sections as large as $10^{-40}$ cm$^2$ can be accommodated in MSSM within the REWSB framework. However, inclusion of sparticle mass limits from current experiments, as well as lower limits on the Higgs searches from the Tevatron, and the current experimental upper limit on $B_s\to μ^+μ^-$ significantly limit the allowed parameter space reducing $\SI$ to lie below $\sim 10^{-41}$cm$^2$ or even lower for neutralino masses around 10 GeV. These cross sections are an order of magnitude lower than the cross sections needed to explain the reported data in the recent dark matter experiments in the low neutralino mass region.

Low Mass Neutralino Dark Matter in the MSSM with Constraints from $B_s\to μ^+μ^-$ and Higgs Search Limits

TL;DR

This study investigates whether low-mass neutralinos (– GeV) can yield detectable spin-independent neutralino-proton cross sections within the MSSM under radiative electroweak symmetry breaking (REWSB), in light of CoGeNT/DAMA signals. The authors show that large cross sections up to cm are possible via Higgs exchange at high , but ongoing limits from Tevatron Higgs searches and the upper bound on severely constrain the parameter space, reducing to about cm or smaller near GeV. A comprehensive MSSM scan with REWSB and non-universal gaugino masses, using micrOMEGAs and SuSpect, finds that after imposing sparticle mass bounds and flavor constraints, the maximal cross section drops by an order of magnitude, and even larger regions remain incompatible with the limits. Extending the analysis to broader non-universal scenarios (NUG, NUH, NU3, NUA) with millions of models does not reopen the CoGeNT/DAMA window, pushing viable above and to obreak ext{(a few)} imes 10^{-42}^2 obreak\ GeV or lighter neutralino cannot account for the low-mass dark matter hints, underscoring the tension between direct-detection signals and MSSM realizations.

Abstract

The region of low neutralino masses as low as (5-10) GeV has attracted attention recently due to the possibility of excess events above background in dark matter detectors. An analysis of spin independent neutralino-proton cross sections which includes this low mass region is given. The analysis is done in MSSM with radiative electroweak symmetry breaking (REWSB). It is found that cross sections as large as cm can be accommodated in MSSM within the REWSB framework. However, inclusion of sparticle mass limits from current experiments, as well as lower limits on the Higgs searches from the Tevatron, and the current experimental upper limit on significantly limit the allowed parameter space reducing to lie below cm or even lower for neutralino masses around 10 GeV. These cross sections are an order of magnitude lower than the cross sections needed to explain the reported data in the recent dark matter experiments in the low neutralino mass region.

Paper Structure

This paper contains 4 sections, 4 equations, 3 figures.

Table of Contents

  1. Introduction
  2. An MSSM Analysis with REWSB
  3. Discussion and Extensions
  4. Conclusion

Figures (3)

  • Figure 1: (Color online) A display of the spin independent neutralino-proton cross section $\sigma_{\rm SI}(\chi p)$ as a function of LSP mass with inclusion of REWSB constraints. The sparticle mass limits, WMAP constraints and flavor constraints are not imposed. The analysis of this figure should be compared with the analysis of Fig(\ref{['fig2']}) which shows the large reduction in the parameter space when sparticle mass and WMAP constraint are imposed (see Bottino et al Bottino:2009km).
  • Figure 2: (Color online) A display of the spin independent neutralino-proton cross section $\sigma_{\rm SI}(\chi p)$ in MSSM with inclusion of REWSB and mass limit constraints. The tagged boxed points accommodate the WMAP results (see text) while the untagged ones do not. Shown also are the CoGeNT limitsAalseth:2010vx.
  • Figure 3: (Color online) Left: An exhibition of the spin independent neutralino-proton cross section $\sigma_{\rm SI}(\chi p)$ in MSSM as function of the CP even Higgs mass $M_H$. The blue band is the approximate range of Higgs mass disallowed by Tevatron searches. The analysis shows that the reach of the spin independent cross section is strongly constrained by the mass of the Higgses Abazov:2008huFeldman:2007fq. Right: Spin independent cross section correlated to the branching ratio $B_s \to {\mu}^{+} {\mu}^{-}$. The region of maximal $\sigma_{\rm SI}(\chi p)$ is inconsistent with constraints from CDF data on $B_s \to {\mu}^{+} {\mu}^{-}$Aaltonen. The models shown have large $\tan \beta$ and light scalars (see left panel and Sec. \ref{['XX']} for the full parameter space)