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Anti-matter and new physics in Cosmic Rays

This paper discusses the identification and measurement of positrons, antiprotons, antideuterons, and antihelium in cosmic rays, as well as their sources and propagation. It also explores the implications for astrophysics and particle physics, specifically in relation to dark matter. The role of nuclear physics in understanding these particles is also discussed.

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Anti-matter and new physics in Cosmic Rays

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  1. Anti-matter and new physics in Cosmic Rays Fiorenza Donato Department of Physics ,Torino University & INFN, Italy INFN WHAT NEXT on Cosmic Rays Padova, December 3, 2014

  2. 1. Positron~580.000 e+ identified by AMS-02, ~25.000 by Pamela. Spectrum ~ 0.5-500 GeV AMS-02 PRL 113, 121102 (2014)

  3. 2. Antiproton ~1.500 p+ identified by Pamela. Spectrum ~ 0.06-180 GeV Pamela, PRL 105, 121101 (2010)

  4. 3. Antideuteron0 antideuteron measured, Bess upper limits. Detection perspectives in a near future, few GeV spectrum GAPS, Aaramaki et al. Astropat. Phys. 2013

  5. 4. Antihelium0 antihelia measured, Pamela upper limits. No detection perspectives in a near future Pamela, JETP Lett., 2011

  6. Transport Equation (in diffusion models) Diffusion, convection Destruction on ISM CR sources: primaries, Secondaries Reacceleration Energy losses (EM) • Milky Way: magnetic fields, convection, interstellar gas • (composition, morphology); spiral arms; diffusion zone, …….. • 2. Nuclear physics • Sources: nuclear spallations for secondaries; • pulsars; • dark matter

  7. How far these particles come from, (if sources located in the disk)? Protons (~antip) Positrons Energeticpositrons & electron are quitelocaldue to energylosses Stablehadronsarriveat Earth from fartherplaces; averaged

  8. The case for positrons

  9. Sources of positrons in the Milky Way Generically, we can list the following sources of e+ and e- in the Galaxy: 1. Secondary e+e-: spallation of cosmic p and He on the ISM (H, He) * p+H(He)  p++  p+0 & n++ (mainly below 3 GeV) * p+H(He)  p+n+ + * p+H(He)  X + K 2. Primary e- and e+ from Pulsars: pair production in the strong PULSAR magnetoshpere 3. Primary e+e- from exotic sources (i.e. Dark Matter) (4.) Primary e- from SNR: 1° type Fermi acceleration mechanism * Pamela data triggered an enormous theoretical and phenomenological activity in order to explain the positron fraction raising at high energies*

  10. Astrophysical sources for positrons Di Mauro, FD, Fornengo, Vittino JCAP 2014 • “Known” sources (pulsars) can explain the whole positron spectrum • Propagation is important (powerful: low energies disfavor small haloes!)

  11. Astrophysical sources & positron fraction “Known sources”: Pulsars emission is model dependent Di Mauro, FD, Fornengo, Vittino JCAP 2014 Effect of pulsar cut-off energy

  12. Dark matter in the positron data Cirelli, Kadastik, Raidal, Strumia 2008+2013 Leptonic annihilation channels “required” only by e+ data Strongly disfavored by other indirect searches (gamma, CMB, antiprotons) Ambiguity with components from known sources (PWN)

  13. The case for antiprotons

  14. Antiproton in CRs: data and models Theoreticalcalculationscompatible with CR models AMS-02 data expected Donato et al. PRL 2009 NO need for new phenomena (astrophysical / particle physics) Bounds to models (for source AND propagation) for DM in the galactic halo

  15. Cosmic antiprotons and dark matter and ~100 uncertainty due to propagation!!!! Effect of solar modulation Effect of DM radial density profile Effect of NUCLEAR CROSS SECTION UNCERTAINTY!!! Fornengo, Maccione, Vittino JCAP2014

  16. Secondary antiprotons in cosmic rays (CR) Produced by spallation reactions on the ISM pCR + HISM pCR + HeISM HeCR + HISM HeCR + HeISM A case for High energy particles physics: The only measured cross section is p-p  + X ALL CROSS SECTIONS INVOLVING He (projectile or target) ARE DERIVED FROM OTHER DATA!! + X

  17. Antiproton production: state of the art • p+p: σp+p  antiprotons analytical expression • (Tan & Ng, PRD26 (1982) 1179; J.Phys.G:NuclPhys 9 (1983) 227) • NA49 data: new analysis by Di Mauro, FD, Goudelis, Serpico 1408.0288, • and Kappl & Winkler 1408.0299  see next slides • p+ He, He+p, He+He: σp(He)+(p,He)  antiprotonsderived from MonteCarlo simulations, i.e. DTUNUC (Donato et al. ApJ 563 (2001) 172) verifiedon p+C,p+Al. • and heavier nuclei (Duperray et al. 2003, 2005) Data from Sugaya+1998; fit: DTUNUC Donato+ ApJ2001

  18. Uncertainties on the antiproton flux from nuclear cross sections (Model from Donato et al. ApJ 2001, PRL 2009) • pp: Tan& Ng • H-He, He-H, He-He: DTUNUC MC • Maximal uncertainty from H-He: 20-25% • Functional form for the cross section derived from other reactions (includes 8% on σpp)

  19. Reactions involving helium & higher energies Uncertainties due to helium reactions range 40%-50%: Precise data for p-He (He-p) would reduce them significantly • In the literature: • - DTUNUC • Modifications of pp • cross section • Other MC are viable • but data on He do not • exist! AMS-02 will provide data with much higher precision up to hundreds of GeV!!! Their interpretation risks to be seriously limited by nuclear physics

  20. New analysis of p-ppbar data Di Mauro, FD, Goudelis, Serpico 1408.0288; Kappl, Winkler 1408.0299 Existing data

  21. Antiproton source spectrum from p-p channels All data fit Different analytical functions give similar chi2, but different extrapolation out of validity ranges  uncertainties at low and high energies

  22. Uncertainties due p-p scattering Uncertainties in the pbar production spectrum from p-p scattering are at least 10%. Conservative: 20% at low energies (GeV) up to 50% (TeV) (data expected at least up to ~ 500 GeV)

  23. COSMIC ANTiDEUTERONS FD, Fornengo, Salati PRD 2001; FD, Fornengo, Maurin PRD 2001; 2008; Kadastik, Raidal, Strumia PLB2010; Ibarra, Wild JCAP2013; Fornengo, Maccione, Vittino JCAP 2013; …ati PRD (2000) ADD In order for fusion to take place, the two antinucleons must have lowkineticenergy Kinematics of spallationreactionsprevents the formation of verylow antiprotons (antineutrons). At variance, darkmatterannihilatealmostatrest N.B: Up to now, NO ANTIDEUTERON has been detectedyet.

  24. Secondary Antideuterons Propagation uncertainties Compatibility with B/C Nuclear uncertainties Production cross sections & Pcoal Production from antiprotons Non-annihilating cross sections

  25. Antideuterons: detection perspectives Fornengo, Maccione, Vittino 1306.4171 Prospects for 3σ detection of antideuteron with GAPS (dotted lines are Pamela bounds from antiprotons) 3σ expected sensitivities Fornengo, Maccione, Vittino 1306.4171

  26. GAPS prototype flightP. von Doetinchem et al. 1307.3538

  27. The case for antihelium Cirelli, Fornengo, Taoso, Vittino, JCAP2014 (Carlson+PRD2014) Good signal-to-background ratios Predictions for most DM models Far from experimental reach Nuclear physics brings relevant effects

  28. A few considerations - I Existing data on antimatter do not require exotic (DM) interpretation If a DM component is present in the cosmic radiation, it will be seen at best as a very tiny spectral feature (or smeared in the background, or totally subdominant) POSITRONS are well fitted by known, powerful galactic sources. DM interpretation still open, but less natural ANTIPROTONS are can be a powerful constraining means on the DM annihilation intensity ANTIDEUTERONS are challenging, but with high detection potentials

  29. A few considerations - II Predictions on cosmic antimatter are affected by sizeable uncertainties Uncertainties due to propagation & nuclear physics: secondary: e+ : ~ 2-4 p-: ~ 30% D-: ~ 3-5 DM primary: e+ : ~ 5 p-: ~ 100 D-: ~ 100 astrophysical primary e+ e- : “high” It is unavoidable to afford and reduce these uncertainties along with new antimatter experimental searches

  30. A few considerations - III • Order 0 and mandatory: Understand (==measure) cosmic proton and helium fluxes with great accuracy!!!! • PROPAGATION uncertainties need better data on MANY cosmic species and • More refined models (they need to fed by many independent data on gas distribution, galactic morphology, magnetic turbulence, etc …. ) • NUCLEAR PHYSICS: we need data on cross sections: production • p + He  p- • p + He  e+ • p+ p, He  D- (fusion!) • (ancillary: p + He  gamma, for Fermi-LAT data interpretation) • MIGHT ONE DEDICATED COSMIC-LAB EXPERIMENT DO ALL AT ONCE? • SEE TALK BY G. CAVOTO

  31. Conclusions and perspectives Yes, it is worth to keep high interest on the antimatter A striking DM signal in antimatter seems now unexpected: we have to search tiny effects in important astrophysical contributions. Anisotropy may be a useful tool Major effort is needed in the understanding astrophysical backgrounds: a tough astrophysical work is needed A multi-wavelength and multi-channel approach - mandatory for backgrounds understanding – looks powerful for DM searches as well searches Small experiments (such as GAPS…) are - in my personal view - important and to be supported by INFN

  32. Antiprotons: constraining tool, with caveats effMSSM models surviving LHC constraints and two Higgs scenarios for the scalar at 126 GeV (h or H) Scopel, Fornengo, Bottino 1304.5353

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