The PAMELA excess from neutralino annihilation in the NMSSM

Abstract

We examine whether the cosmic ray positron excess observed by PAMELA can be explained by neutralino annihilation in the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The main dark matter annihilation products are the lightest CP-even scalar h1 plus the lightest CP-odd scalar a1, with the a1 decaying into two muons. The energetic positrons needed to explain PAMELA are thus obtained in the NMSSM simply from kinematics. The required large annihilation cross section is obtained from an s-channel resonance with the heavier CP-odd scalar a2. Various experiments constrain the PAMELA-favored NMSSM parameter space, including collider searches for a light a1. These constraints point to a unique corner of the NMSSM parameter space, having a lightest neutralino mass around 160 GeV and a very light pseudoscalar mass less than a GeV. A simple parameterized formula for the charge-dependent solar modulation effects reconciles the discrepancy between the PAMELA data and the estimated background at lower energies. We also discuss the electron and gamma ray spectra from the Fermi LAT observations, and point out the discrepancy between the NMSSM predictions and Fermi LAT preliminary results and possible resolution. An NMSSM explanation of PAMELA makes three striking and uniquely correlated predictions: the rise in the PAMELA positron spectrum will turn over at around 70 GeV, the dark matter particle mass is less than the top quark mass, and a light sub-GeV pseudoscalar will be discovered at colliders.

25 pages, 9 figures; final version for PRD

References in corpus (17)

• PYTHIA 6.4 Physics and Manual
• Observation of an anomalous positron abundance in the cosmic radiation
• A Theory of Dark Matter
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
• Non-thermal Dark Matter and the Moduli Problem in String Frameworks
• Minimal Dark Matter predictions for galactic positrons, anti-protons, photons
• The galactic antiproton spectrum at high energies: background expectation vs. exotic contributions
• Bounds on Cross-sections and Lifetimes for Dark Matter Annihilation and Decay into Charged Leptons from Gamma-ray Observations of Dwarf Galaxies
• The NMSSM Close to the R-symmetry Limit and Naturalness in $h\to aa$ Decays for $m_a<2\mb$
• TeV Scale Singlet Dark Matter
• Radiative Upsilon decays and a light pseudoscalar Higgs in the NMSSM
• Many Light Higgs Bosons in the NMSSM
• Measuring the Dark Force at the LHC
• Radiative quarkonium decays and the NMSSM Higgs interpretation of the HyperCP Sigma+ --> p mu+mu- events
• R-parity preserving super-WIMP decays
• Search for neutral Higgs bosons at high tan(beta) in the b(h/H/A)->btautau channel

Cited by in corpus (10)

• The Dawn of FIMP Dark Matter: A Review of Models and Constraints
• Explaining PAMELA and WMAP data through Coannihilations in Extended SUGRA with Collider Implications
• Extended MSSM Neutralinos as the Source of the PAMELA Positron Excess
• Indirect detection of gravitino dark matter including its three-body decays
• Dark Matter in the Singlet Extension of MSSM: Explanation of Pamela and Implication on Higgs Phenomenology
• Higgsino dark matter model consistent with galactic cosmic ray data and possibility of discovery at LHC-7
• Dark Stars and Boosted Dark Matter Annihilation Rates
• Dark matter in the MSSM and its singlet extension
• SUSY Dark Matter In Light Of CDMS/XENON Limits
• Inverse Compton gamma-rays from Galactic dark matter annihilation: Anisotropy signatures