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 PAMELA released data on the positron/electron ratio up to about 100 GeV, which show clear excess above ~10 GeV. The low energy data is affected by the solar environment and we do not need care it too much. Nature 458, 607 (2009) Phys.Rev.Lett.102:051101,2009 368 citations after submitted on 28th Oct. 2008, 1paper per day

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

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 …

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.)

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

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

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

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.

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

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)

Breit-Wigner enhancement

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. U(1)’ models

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

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

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

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