Indirect detection of light neutralino dark matter in the next-to-minimal supersymmetric standard model

Abstract

We explore the prospects for indirect detection of neutralino dark matter in supersymmetric models with an extended Higgs sector (next-to-minimal supersymmetric standard model, or NMSSM). We compute, for the first time, one-loop amplitudes for NMSSM neutralino pair annihilation into two photons and two gluons, and point out that extra diagrams (with respect to the minimal supersymmetric standard model, or MSSM), featuring a potentially light CP-odd Higgs boson exchange, can strongly enhance these radiative modes. Expected signals in neutrino telescopes due to the annihilation of relic neutralinos in the Sun and in the Earth are evaluated, as well as the prospects of detection of a neutralino annihilation signal in space-based gamma-ray, antiproton and positron search experiments, and at lowenergy antideuteron searches. We find that in the low mass regime the signals from capture in the Earth are enhanced compared to the MSSM, and that NMSSM neutralinos have a remote possibility of affecting solar dynamics. Also, antimatter experiments are an excellent probe of galactic NMSSM dark matter. We also find enhanced two-photon decay modes that make the possibility of the detection of a monochromatic gamma-ray line within the NMSSM more promising than in the MSSM, although likely below the sensitivity of next generation gamma-ray telescopes.

Collider signatures of singlet extended Higgs sectors

“…7 We assume gaugino mass unification. 8 There are cases where the indirect detection rates of neutralino dark matter can be enhanced in these models by a light CP-odd Higgs boson [24]. 9 Additionally, an analysis of the Higgs signal at LEP in a model independent way places a lower bound on the Higgs mass at 81 GeV [25].…”

Search with EGRET for a gamma ray line from the Galactic center

“…For example, neutralinos with masses as low as 6 GeV are plausible if gaugino unification is not assumed [5]. Neutralinos with masses as low as 100 MeV are plausible in the next-to-minimal supersymmetric standard model [6,7]. Also, scalar and spin-1=2 particles with masses in the MeV range have been considered [8] to explain the 511-keV gamma-ray line observed by INTEGRAL [9,10], a line whose strength, as explained in Ref.…”

Extra U(1) as natural source of a monochromatic gamma ray line

“…However, this monochromatic ray can be enhanced in other scenarios like SUSY ones [49][50][51], extra-dimension constructions [52], singlet DM [53], decaying DM [54], including a neutrino sector [55], effective DM models [56] or inert Higgs doublet DM [57]. Internal Bremsstrahlung [58] can also exhibit a spectrum similar to the one produced by the emission of a monochromatic γ-ray line.…”