Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
AMS-02 Antiprotons Reloaded
Rolf Kappl
Bethe Center for Theoretical Physics & Physikalisches Institut der UniversitätBonn
based on RK, Annika Reinert, Martin Wolfgang WinklerJCAP 10 (2015) 034, arXiv:1506.04145
Theory Seminar ULB Brussels,October 23th 2015
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Outline
Motivation
Cosmic Ray Propagation
Antiprotons Reloaded – Dark Matter Under Siege
Conclusions
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
AMS-02 – A Precision Experiment For Cosmic Rays
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Origin Of Cosmic Rays – Astrophysics At Work
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Primaries vs. Secondaries – Dark Matter?
• PrimariesSpallation−−−−−−→ Secondaries
• Dark matter annihilation
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Primaries vs. Secondaries – Dark Matter?
• PrimariesSpallation−−−−−−→ Secondaries
• Dark matter annihilation
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Primaries vs. Secondaries – Dark Matter?
• PrimariesSpallation−−−−−−→ Secondaries
• Dark matter annihilation
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Primaries vs. Secondaries – Dark Matter?
• PrimariesSpallation−−−−−−→ Secondaries
• Dark matter annihilation
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Primaries vs. Secondaries – Dark Matter?
• PrimariesSpallation−−−−−−→ Secondaries
• Dark matter annihilation
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Transport Of Cosmic Rays – Fokker-Planck
• Two-zone diffusion model
∇(−K ∇Ni + Vc Ni) + ∂E (btot Ni − KEE ∂ENi) + Γann Ni = qi
qi
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Transport Of Cosmic Rays – Fokker-Planck
• Two-zone diffusion model
∇(−K ∇Ni + Vc Ni) + ∂E (btot Ni − KEE ∂ENi) + Γann Ni = qi
qi
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Transport Of Cosmic Rays – Fokker-Planck
• Two-zone diffusion model
∇(−K ∇Ni + Vc Ni) + ∂E (btot Ni − KEE ∂ENi) + Γann Ni = qi
qi
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Transport Of Cosmic Rays – Fokker-Planck
• Two-zone diffusion model
∇(−K ∇Ni + Vc Ni) + ∂E (btot Ni − KEE ∂ENi) + Γann Ni = qi
qi
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Transport Of Cosmic Rays – Fokker-Planck
• Two-zone diffusion model
∇(−K ∇Ni + Vc Ni) + ∂E (btot Ni − KEE ∂ENi) + Γann Ni =
qi
qi
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Bethe’s Legacy – Boron As A Tracer
Bethe Center forTheoretical Physics Bethe, Phys.Rev. 55 (1939) 434-456• CNO cycle shows that boron is not produced in stars• Boron is produced by spallation of interstellar matter
• Injected boron qBPropagation−−−−−−−→ Measured boron at AMS-02
• Task:
qB = 4π∑
i∈{C,N,O,Ne,Mg,Si}
∫dT ′
dσdT
nISM Φi(T ′)
Φi(T ′)
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Bethe’s Legacy – Boron As A Tracer
Bethe Center forTheoretical Physics Bethe, Phys.Rev. 55 (1939) 434-456• CNO cycle shows that boron is not produced in stars• Boron is produced by spallation of interstellar matter
• Injected boron qBPropagation−−−−−−−→ Measured boron at AMS-02
• Task:
qB = 4π∑
i∈{C,N,O,Ne,Mg,Si}
∫dT ′
dσdT
nISM
Φi(T ′)
Φi(T ′)
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Cosmic Ray Primaries
10-1 1 101 102 10310-13
10-12
10-11
10-10
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
1
101
102
T [GeV/n]
Φ iTOA·T2.7
[m-2sr
-1 s-1 (G
eV/n)1.7
]
Carbon
Oxygen·10-2
Nitrogen·10-4
Neon·10-6
Magnesium·10-8
Silicon·10-10
CREAM-IIHEAOPAMELA
ACE
• We considered C, N, O,Ne, Mg, Si as the maincontributions for boronproduction
• Fits to measured fluxes
Φi(T ) = A(
TT + b
)cT−γ
• Yet no AMS-02 data• Solar modulation
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Cosmic Ray Primaries
10-1 1 101 102 10310-13
10-12
10-11
10-10
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
1
101
102
T [GeV/n]
Φ iTOA·T2.7
[m-2sr
-1 s-1 (G
eV/n)1.7
]
Carbon
Oxygen·10-2
Nitrogen·10-4
Neon·10-6
Magnesium·10-8
Silicon·10-10
CREAM-IIHEAOPAMELA
ACE
• We considered C, N, O,Ne, Mg, Si as the maincontributions for boronproduction
• Fits to measured fluxes
Φi(T ) = A(
TT + b
)cT−γ
• Yet no AMS-02 data• Solar modulation
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Interlude – Cosmic Rays In The Heliosphere
• Force field approximation for solar modulation
ΦTOA(T − Zφ) = (T − Zφ)2 + 2m(T − Zφ)
T 2 + 2mTΦIS(T )
• Force field parameter φ takes care of the solar activity
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Back To The Injection – Cross Sections Reloaded
• Source term:
qB = 4π∑
i∈{C,N,O,Ne,Mg,Si}
∫dT ′ dσdT nISMΦi(T
′)
• Parametrization from Webber et al., AJSS 144 (2003) 153• Large uncertainties, poor experimental data
10-1 1 10130
35
40
45
50
� [���]
σ(���
→�)[��]
���������� ��������
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Nuclear Physics Meets Astrophysics
• Source term qB for boron determined• Fokker-Planck equation solved with semi-analytical
approach in two dimensions Maurin et al., Astrophys.J. 555(2001) 585-596
• With the fit to the carbon flux⇒ B/C ratio computed(Secondary/Primary ratio)
• Scanned over a sample of random propagation parametersand kept only configurations which passed χ2 test
Propagation parameters fixed with highest precision!
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
B/C Before AMS-02
• Best data before AMS-02 from the PAMELA experimentAdriani et al., Astrophys. J. 791 (2014), 93
• Clear trend but still large uncertainties
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
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
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
p̄/p Ratio With Old Propagation Parameters
• p̄/p ratio computed with outdated (unknown?) propagationparameters
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Protons And Helium – Primaries Reloaded
• Source term for p̄ production:
qp̄ = 4π∑
i∈{H,He}
∫dT ′
dσdT
nISM Φi(T ′)
1 101 102 103 104 105
103
104
T [GeV/n]
Φ iTOA·T2.7
[m-2sr
-1 s-1 (G
eV/n)1.7
] Proton
Helium
CREAM
AMS-02
• Fits to measured fluxes withspectral break
Φi(T ) =(
TT + b
)c ∑k
AkT−γk
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
New p̄ Production Cross Sections
• Source term for p̄ production:
qp̄ = 4π∑
i∈{H,He}
∫dT ′ dσdT nISMΦi(T
′)
0.0 0.1 0.2 0.3 0.4 0.5
10-4
10-3
10-2
10-1
1
xR
f pp
®p
o@m
bGe
V2
D
pT = 1.3 GeV
pT = 0.9 GeV
pT = 0.5 GeV
pT = 0.1 GeVNA49 Data, Fit • New results from NA49
experiment with hugephase space coverageAnticic et al., Eur. Phys. J.C65 (2010) 9
• Tracking of uncertainties,hyperon ’feed-down’effects, isospin effects, ...RK and Winkler, JCAP 09(2014) 051
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
p̄/p Ratio With New Propagation Parameters
• p̄/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
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Outlook – Positrons, Better Cross Section Data, . . .
1 101 1020
5
10
15
20
25
30
T [GeV]
ΦTOA·T3 [
m-2 s
r-1s-1
GeV
2 ]propagation uncertaintiese+ best fit in sampleAMS-02 e+ data
• Data on positrons can be used to further constrainpropagation parameters
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Outlook – Positrons, Better Cross Section Data, . . .
10-1 1 10130
35
40
45
50
� [���]
σ(���→�)
[��]
���������� ��������
• New cross section measurements would dramaticallydecrease the uncertainty
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Outlook – Positrons, Better Cross Section Data, . . .
10-1 1 10130
35
40
45
50
� [���]
σ(���→�)
[��]
���������� ��������
• New cross section measurements would dramaticallydecrease the uncertainty
Motivation Cosmic Ray Propagation Antiprotons Reloaded – Dark Matter Under Siege Conclusions
Conclusions
• With AMS-02 the precision era for indirect dark matterdetection started
• We estimated the antiproton background with very highprecision
• The new antiproton data together with our backgroundcalculation will be a perfect probe for dark matter models
Thank you for your attention!
MotivationCosmic Ray PropagationAntiprotons Reloaded – Dark Matter Under SiegeConclusions
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