Implication of recent cosmic ray data Qiang Yuan Institute of High Energy Physics Collaborated with Xiaojun Bi, Hong Li, Jie Liu, Bing Zhang & Xinmin Zhang Lorentz & CPT Violation workshop, Beijing

Outline Introduction to the newest observational data On the electron/positron data On the hardening of the nuclei spectra Summary

PAMELA, 2009, Nature, 458, 607 Introduction PAMELA discovery of the positron excess

PAMELA, 2010, PRL, 105, Introduction PAMELA observation of the antiproton flux

PAMELA, 2011, arXiv: Introduction PAMELA observation of the electron spectrum

ATIC, 2008, Nature, 456, 362 Introduction ATIC observation of the electron+positron spectra

Fermi, 2010, PRD, 82, Introduction Fermi observation of the electron+positron spectra

HESS, 2008, PRL, 101, , A & A, 508, 561 Introduction HESS observation of the electron+positron spectra

CREAM, 2010, ApJ, 714, L89 Introduction CREAM measurement of the CR nuclei spectra

PAMELA, 2011, Science, 332, 69 Introduction PAMELA measurement of the proton and Helium spectra

We have many new CR data with very high quality recently, which may imply something new in astrophysics In the electron/positron data, strong evidence shows excesses in addition to the background model The hardening of CR nuclei spectra also challenge the conventional understanding of the acceleration and propagation of CR particles Introduction Short summary of the data

Outline Introduction to the newest observational data On the electron/positron data On the hardening of the nuclei spectra Summary

e+/- excess Really excesses? To explain simultaneously positron and electron data, we need exotic electron/positron sources.

The observed positron spectrum is as hard as E -2.7 (before propagation is ~E -2.0 ), which is much harder than expected from background model e+/- excess Derived absolute positron flux

Dark Matter  Annihilation or decay  Leptonic, quark or gauge bosonic final states  Smooth or subhalo … Many can work but some general conclusions:  TeV scale DM  Lepton dominated  Large annihilation or decay rate Models Astrophysical  Pulsar, SNR, microquasar GRB  Hadronic or leptonic  Single or population  Burst or continuous injection  Propagation model … e+/- excess

Whatever the real physics is, it is possible to parameterize the exotic source component and derive the model parameters Pulsar like scenario Dark matter scenario e+/- excess

Pulsar like scenario

e+/- excess Pulsar like scenario

e+/- excess Dark matter scenario Preliminary!

e+/- excess Dark matter scenario: antiprotons The quark branching ratio is strongly suppressed Preliminary!

The data are precise enough to encourage us to do the global fitting to extract the underlying physics Both the background and source parameters can be determined However, we do not know whether the excesses come from astrophysical sources or dark matter The current fit may suffer from systematical uncertainties from e.g., CR propagation, hadronic interaction models What can we know from the fit? e+/- excess

Outline Introduction to the newest observational data On the electron/positron data On the hardening of the nuclei spectra Summary

CR hardening Basic picture: superposition of sources with a dispersion in the source injection spectra

CR hardening Fermi data indeed show the dispersion of the photon spectrum (hence CR spectrum) of SNRs YQ, Yin & Bi, arXiv:

CR hardening Fit the CR data YQ, Zhang & Bi, arXiv:

CR hardening Implication on secondary particles YQ, Zhang & Bi, arXiv:

CR hardening An alternative explanation of the ankle-GZK structure? YQ, Zhang & Bi, arXiv:

Summary It is an era of discoveries in CR field Using the global fitting method we can determine both the background and source parameters from the electron/positron data, although we do not know what the sources are A simple scenario with dispersion of the source injection spectra is proposed to explain the CR nuclei hardening

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