AMS-02 Antiprotons Reloaded

Transcription

1 AMS-02 Antiprotons Reloaded Rolf Kappl Bethe Center for Theoretical Physics & Physikalisches Institut der Universität Bonn based on RK, Annika Reinert, Martin Wolfgang Winkler JCAP 10 (2015) 034, arxiv: Theory Seminar ULB Brussels, October 23th 2015

2 Outline Motivation Cosmic Ray Propagation Antiprotons Reloaded Dark Matter Under Siege Conclusions

3 AMS-02 A Precision Experiment For Cosmic Rays

4 Motivation Cosmic Ray Propagation Antiprotons Reloaded Dark Matter Under Siege Conclusions Origin Of Cosmic Rays Astrophysics At Work

5 Primaries vs. Secondaries Dark Matter? Spallation Primaries Secondaries Dark matter annihilation

6 Primaries vs. Secondaries Dark Matter? Spallation Primaries Secondaries Dark matter annihilation

7 Primaries vs. Secondaries Dark Matter? Spallation Primaries Secondaries Dark matter annihilation

8 Primaries vs. Secondaries Dark Matter? Spallation Primaries Secondaries Dark matter annihilation

9 Primaries vs. Secondaries Dark Matter? Spallation Primaries Secondaries Dark matter annihilation

10 Transport Of Cosmic Rays Fokker-Planck Two-zone diffusion model ( K N i + V c N i ) + E (b tot N i K EE E N i ) + Γ ann N i = q i

11 Transport Of Cosmic Rays Fokker-Planck Two-zone diffusion model ( K N i + V c N i ) + E (b tot N i K EE E N i ) + Γ ann N i = q i

12 Transport Of Cosmic Rays Fokker-Planck Two-zone diffusion model ( K N i + V c N i ) + E (b tot N i K EE E N i ) + Γ ann N i = q i

13 Transport Of Cosmic Rays Fokker-Planck Two-zone diffusion model ( K N i + V c N i ) + E (b tot N i K EE E N i ) + Γ ann N i = q i

14 Transport Of Cosmic Rays Fokker-Planck Two-zone diffusion model ( K N i + V c N i ) + E (b tot N i K EE E N i ) + Γ ann N i = q i

15 Bethe s Legacy Boron As A Tracer Bethe Center for Theoretical Physics Bethe, Phys.Rev. 55 (1939) CNO cycle shows that boron is not produced in stars Boron is produced by spallation of interstellar matter Propagation Injected boron q B Measured boron at AMS-02 Task: q B = 4π i {C,N,O,Ne,Mg,Si} dt dσ dt n ISM Φ i (T )

16 Bethe s Legacy Boron As A Tracer Bethe Center for Theoretical Physics Bethe, Phys.Rev. 55 (1939) CNO cycle shows that boron is not produced in stars Boron is produced by spallation of interstellar matter Propagation Injected boron q B Measured boron at AMS-02 Task: q B = 4π i {C,N,O,Ne,Mg,Si} dt dσ dt n ISM Φ i (T )

17 Cosmic Ray Primaries [ m -2 sr -1 s -1 (GeV/n) 1.7 ] Carbon Oxygen 10-2 Nitrogen 10-4 Neon 10-6 We considered C, N, O, Ne, Mg, Si as the main contributions for boron production Fits to measured fluxes ( ) T c Φ i (T ) = A T γ T + b Φ i TOA T Magnesium 10-8 Yet no AMS-02 data Solar modulation Silicon ACE PAMELA HEAO CREAM-II T [GeV/n]

18 Cosmic Ray Primaries [ m -2 sr -1 s -1 (GeV/n) 1.7 ] Carbon Oxygen 10-2 Nitrogen 10-4 Neon 10-6 We considered C, N, O, Ne, Mg, Si as the main contributions for boron production Fits to measured fluxes ( ) T c Φ i (T ) = A T γ T + b Φ i TOA T Magnesium 10-8 Yet no AMS-02 data Solar modulation Silicon ACE PAMELA HEAO CREAM-II T [GeV/n]

19 Interlude Cosmic Rays In The Heliosphere Force field approximation for solar modulation Φ TOA (T Z φ) = (T Z φ)2 + 2m(T Z φ) T 2 Φ IS (T ) + 2mT Force field parameter φ takes care of the solar activity

20 Back To The Injection Cross Sections Reloaded Source term: q B = 4π i {C,N,O,Ne,Mg,Si} dt dσ dt n ISMΦ i (T ) Parametrization from Webber et al., AJSS 144 (2003) 153 Large uncertainties, poor experimental data 50 σ ( ) [ ] [ ]

21 Nuclear Physics Meets Astrophysics Source term q B for boron determined Fokker-Planck equation solved with semi-analytical approach in two dimensions Maurin et al., Astrophys.J. 555 (2001) With the fit to the carbon flux B/C ratio computed (Secondary/Primary ratio) Scanned over a sample of random propagation parameters and kept only configurations which passed χ 2 test Propagation parameters fixed with highest precision!

22 B/C Before AMS-02 Best data before AMS-02 from the PAMELA experiment Adriani et al., Astrophys. J. 791 (2014), 93 Clear trend but still large uncertainties

23 B/C In The AMS-02 Precision Era Low experimental errors and data up to high rigidities Still preliminary data Data quality will further increase

24 p/p Ratio With Old Propagation Parameters p/p ratio computed with outdated (unknown?) propagation parameters

25 Protons And Helium Primaries Reloaded Source term for p production: q p = 4π dt dσ dt n ISM Φ i (T ) i {H,He} Φ i TOA T 2.7 [ m -2 sr -1 s -1 (GeV/n) 1.7 ] Proton Helium AMS-02 Fits to measured fluxes with spectral break Φ i (T ) = ( ) T c A k T γ k T + b k CREAM T [GeV/n]

26 New p Production Cross Sections Source term for p production: q p = 4π dt i {H,He} dσ dt n ISMΦ i (T ) mb GeV 2 o f pp p x R NA49 Data, Fit p T p T p T p T 0.1 GeV 0.5 GeV 0.9 GeV 1.3 GeV New results from NA49 experiment with huge phase space coverage Anticic et al., Eur. Phys. J. C65 (2010) 9 Tracking of uncertainties, hyperon feed-down effects, isospin effects,... RK and Winkler, JCAP 09 (2014) 051

27 p/p Ratio With New Propagation Parameters p/p ratio computed with new cross sections New propagation parameters derived from boron Good agreement for antiprotons No need for antiprotons from dark matter annihilation Good probe to constrain dark matter models

28 Outlook Positrons, Better Cross Section Data, Φ TOA T 3 [ m -2 sr -1 s -1 GeV 2 ] AMS-02 e + data e + best fit in sample propagation uncertainties T [GeV] Data on positrons can be used to further constrain propagation parameters

29 Outlook Positrons, Better Cross Section Data, σ ( ) [ ] [ ] New cross section measurements would dramatically decrease the uncertainty

30 Outlook Positrons, Better Cross Section Data, σ ( ) [ ] [ ] New cross section measurements would dramatically decrease the uncertainty

31 Conclusions With AMS-02 the precision era for indirect dark matter detection started We estimated the antiproton background with very high precision The new antiproton data together with our background calculation will be a perfect probe for dark matter models Thank you for your attention!