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What can we really learn from positron flux 'Anomalies'?

What can we really learn from positron flux 'Anomalies'?. Boaz Katz, Kfir Blum, Eli Waxman arXiv:0907.1686. PAMELA. …Our results clearly show an increase in the positron abundance at high energy that cannot be understood by standard models describing the secondary production of cosmic-rays.

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What can we really learn from positron flux 'Anomalies'?

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  1. What can we really learn from positron flux 'Anomalies'? Boaz Katz, Kfir Blum, Eli Waxman arXiv:0907.1686

  2. PAMELA …Our results clearly show an increase in the positron abundance at high energy that cannot be understood by standard models describing the secondary production of cosmic-rays.

  3. CR positrons: What do we expect? What do we know?

  4. Plan: • e+ ~ pbar / radiative losses • pbar understood • Measure e+  measure losses • 10Be agrees  secondary! • e+/pbar theoretically clean • e+ `anomaly’ ??? • Propagation models fit grammage.

  5. e+ ~ pbar / radiative losses e+ produced in pp and spallation interactions – similar to , B, Sc, Li,… e+ lose energy radiatively - (ordinarily) steep spectrum, loss suppresses flux. Ignore energy loss  upper bound on flux.

  6. Pbar understood Stable secondaries, no loss

  7. Pbar understood: Stable secondaries, no loss In general • …If*: • Propagation only depends on magnetic rigidity • Rigidity fixed on propagation • Homogenous composition *Also used the fact that spallation secondary inherits rigidity of primary

  8. Pbar understood Stable secondaries, with loss

  9. Equivalently: Pbar understood: Stable secondaries, with loss nA,in n’A,out nA,out nP,in nP,out nA,in n’’A,out nP,out nP,in Homogenous composition: Qeff works just the same!

  10. Pbar understood: Stable secondaries, with loss

  11. Pbar understood Antiprotons

  12. Pbar understood Antiprotons

  13. Pbar understood Antiprotons

  14. Why does it work so well??

  15. Why it could work: NGC 891 NIR 1.4GHz

  16. Measure e+  measure losses Positrons

  17. Measure e+  measure losses non secondary ? (very) probably secondary

  18. 10Be agrees  e+ secondary! Cooling vs Decay ~ -1

  19. 10Be agrees  e+ secondary! Atomic clocks Be/B

  20. 10Be agrees  e+ secondary! Be/B Atomic clocks Factorize out spallation losses: Agree with e+

  21. e+/pbar theoretically clean

  22. e+ anomaly?? Claims of a primary source: 2 Unknown. ? ? Unknown.

  23. Diffusion models fit grammage. Maurin, Donato, Taillet,Salati Astrophys.J.555:585-596,2001

  24. Diffusion models fit grammage. ( )

  25. ? Summary & Outlook • Interpreting e+ data • e+ ~ pbar / radiative losses; pbar understood • Measure e+  measure losses • `Anomaly’ ? Doesn’t seem so right now • 10Be agrees  secondary! • No tension with model independent estimates • Wait for further data release. PAMELA reach Ee+< 270 GeV • e+/pbar theoretically clean • define model independent tests for exotics • Propagation models fit grammage • what does it mean to be conservative?

  26. Xtras

  27. Pbar understood: Stable secondaries, no loss In general …If:

  28. protons slope ~ 2.75 above ~ 20 GeV, ~ 0.1/m^2srs above TeV TeV

  29. ρ Ophiuchi

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