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Implications of new physics from cosmic e+- excesses

Implications of new physics from cosmic e+- excesses. Bi Xiao-Jun （毕效军） IHEP, CAS （中科院高能所） 2009-10-24. PAMELA results of antiparticles in cosmic rays. Positron fraction. Antiproton fraction. Nature 458, 607 (2009). Phys.Rev.Lett.102:051101,2009.

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Implications of new physics from cosmic e+- excesses

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  1. Implications of new physics from cosmic e+- excesses Bi Xiao-Jun （毕效军） IHEP, CAS （中科院高能所） 2009-10-24

  2. PAMELA results of antiparticles in cosmic rays Positron fraction Antiproton fraction Nature 458, 607 (2009) Phys.Rev.Lett.102:051101,2009 368 citations after submitted on 28th Oct. 2008, 1paper per day

  3. The total electron spectrum ATIC bump Fermi excess Chang et al. Nature456, 362 2008 Phys.Rev.Lett.102:181101,2009

  4. Possible explanations • The background calculation is problematic • The local astrophysical sources (pulsars, SNRs …) • High energy cosmic rays interaction with ambient photons at the early stage of acceleration of CRs • Propagation effects, no excess, … • DM annihilation or decays • …

  5. Primary positron/electrons from dark matter – implication from new data • DM annihilation/decay produce leptons mainly in order not to produce too much antiprotons. • Very hard electron spectrum -> dark matter annihilates/decay into leptons. • Very large annihilation cross section, much larger (~1000) than the requirement by relic density. ( 1) nonthermal production, 2) Sommerfeld enhancement, 3) Breit-Wigner enhancement, 4) dark matter decay.)

  6. positron ratio from DM annihilation Yin, et al.arXiv:0811.0176

  7. Upper bounds on the WW and quark branching ratios for DM annihilation Bi, Li, Zhang

  8. Constraints on some DM models (~1TeV) • Neutralino, mainly into gauge bosons; excluded • In UED KK mode of U(1)Y gauge boson, ~30% into quarks (universal KK mass); marginally allowed • U(1)’B-L, ~40% into quarks, slightly disfavored • Leptophilic models U(1)’e-mu(tau), best fit data

  9. MCMC fit to the ATIC or Fermi and PAMELA data Liu, Yuan, Bi, Li, Zhang, Astro-ph/0906.3858 Background fixed Background not fixed To determine nature of DM has to resort to colliders.

  10. Leptonic DM and neutrinos • DM models related with neutrino masses(Bi et al 0901.0176; Cao et al. 0901.1334 … )

  11. Dark matter models to produce leptons • Kinematically suppression Mass of φis about 1GeV, is Kinematically suppressed to antiprotons; • At the same time attractive interaction can enhance the annihilaition rate, Sommerfeld enhancement. (Arkani-Hamed et al. 0810.0713  ) • DM +DM -> φφ, φ-> μ+μ−; Φ can be generated at colliders by mixing with SM Higgs or gauge bosons; • Signals of such scenarios at colliders are lepton jets with invariant mass ~ 1GeV • A light pseudoscalar model with DM +DM -> sa, a -> μ+μ−, s -> aa may have different collider signals (Nomura & Thaler, arXiv: 0810.5397)

  12. Breit-Wigner enhancement

  13. U(1)’ models • Dynamically suppression, φ carries U(1)’e-μ(τ) and U(1)’B-3e,μ(τ) (Bi, He, Yuan, arXiv:0903.0122 , Bi, He, Ma, Zhang, arXiv:0910.0771  ) • Hard to have any collider tests • Neutrinos from the GC can be detected at 8.5(2.6) σfor 4 year data taking at IceCube.

  14. Emission from the GC Bi et al., 0905.1253 • Constraint on the central density of DM • Tension Exist for the annihilating DM scenario Liu et al., 0906.3858

  15. Constraints on the minimal subhalos by observations of clusters A. Pinzke et al., 0905.1948 • Standard CDM predicts the minimal subhalos • Observation constrains • Fermi limit to • DM is warm

  16. Constraints from extragalactic diffuse gamma rays S. Profumo et al., 0906.0001

  17. Summary • Anomalies observed in cosmic electrons and positrons; • The cosmic ray observations may discover new physics at the DM sector; however hard to give precise determination of its properties because of large astrophysical uncertainties. Colliders are necessary. • New data will come soon: PAMELA finally detect positron to 270GeV; antiproton to 190 GeV (published <100GeV); total e+e- to 2 TeV (not released); AMS02 launch at 2010; Re-flight of ATIC for electrons (AREL) was proposed to NASA Mar. 2009; Fermi results of diffuse gamma rays

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