The PAMELA Positron Excess from Annihilations into a Light Boson

Abstract

Recently published results from the PAMELA experiment have shown conclusive evidence for an excess of positrons at high (~ 10 - 100 GeV) energies, confirming earlier indications from HEAT and AMS-01. Such a signal is generally expected from dark matter annihilations. However, the hard positron spectrum and large amplitude are difficult to achieve in most conventional WIMP models. The absence of any associated excess in anti-protons is highly constraining on any model with hadronic annihilation modes. We revisit an earlier proposal, whereby the dark matter annihilates into a new light (<~GeV) boson phi, which is kinematically constrained to go to hard leptonic states, without anti-protons or pi0's. We find this provides a very good fit to the data. The light boson naturally provides a mechanism by which large cross sections can be achieved through the Sommerfeld enhancement, as was recently proposed. Depending on the mass of the WIMP, the rise may continue above 300 GeV, the extent of PAMELA's ability to discriminate electrons and positrons.

4 pages, 2 figures; v3 separated pions plot, references added

References in corpus (36)

• Observation of an anomalous positron abundance in the cosmic radiation
• A Theory of Dark Matter
• Secluded WIMP Dark Matter
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• Cosmology and Astrophysics of Minimal Dark Matter
• A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
• Astrophysical Signatures of Secluded Dark Matter
• Model-independent implications of the e+, e-, anti-proton cosmic ray spectra on properties of Dark Matter
• Pulsars as the Sources of High Energy Cosmic Ray Positrons
• The WIMPless Miracle: Dark Matter Particles without Weak-scale Masses or Weak Interactions
• Exciting Dark Matter and the INTEGRAL/SPI 511 keV signal
• TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess
• Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01
• LHC Signals for a SuperUnified Theory of Dark Matter
• New Positron Spectral Features from Supersymmetric Dark Matter - a Way to Explain the PAMELA Data?
• Leptophilic Dark Matter
• Gamma-ray and radio tests of the e+e- excess from DM annihilations
• Extended Anomalous Foreground Emission in the WMAP 3-Year Data
• Heavy Dark Matter Through the Higgs Portal
• WIMPonium and Boost Factors for Indirect Dark Matter Detection
• Minimal Dark Matter predictions for galactic positrons, anti-protons, photons
• PAMELA and dark matter
• The galactic antiproton spectrum at high energies: background expectation vs. exotic contributions
• Gamma rays and positrons from a decaying hidden gauge boson
• Dissecting Galaxy Formation: I. Comparison Between Pure Dark Matter and Baryonic Models
• Dark Matter Signals from Cascade Annihilations
• Gamma-ray and Radio Constraints of High Positron Rate Dark Matter Models Annihilating into New Light Particles
• Cosmic rays from Leptonic Dark Matter
• High Energy Positrons and the WMAP Haze from Exciting Dark Matter
• Possible causes of a rise with energy of the cosmic ray positron fraction
• Early Annihilation and Diffuse Backgrounds in 1/v WIMP models
• Two dark matter components in N_{DM}MSSM and dark matter extension of the minimal supersymmetric standard model and the high energy positron spectrum in PAMELA/HEAT data
• ATIC, PAMELA, HESS, Fermi and nearby Dark Matter subhalos
• Two component dark matter
• The Via Lactea INCITE Simulation: Galactic Dark Matter Substructure at High Resolution
• Direct/indirect detection signatures of nonthermally produced dark matter

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