Gravitino Dark Matter with Broken R-Paritymgrefe/files/Grefe_IFIC2012.pdfMichael Grefe (IFT...
Transcript of Gravitino Dark Matter with Broken R-Paritymgrefe/files/Grefe_IFIC2012.pdfMichael Grefe (IFT...
-
Gravitino Dark Matter with Broken R-Parity
Michael Grefe
Departamento de Fı́sica TeóricaInstituto de Fı́sica Teórica UAM/CSICUniversidad Autónoma de Madrid
Instituto de Fı́sica Corpuscular – CSIC/Universitat de València
València – 21 June 2012
Based on JCAP 0901 (2009) 029, JCAP 1004 (2010) 017,arXiv:1111.6779 [hep-ph] and ongoing work.
Collaborators: L. Covi, T. Delahaye, A. Ibarra, D. Tran, G. Vertongen
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 1 / 32
-
Outline
I Motivation for Unstable Gravitino Dark Matter
I Gravitino Dark Matter with Broken R Parity
I Indirect Detection of Gravitino Dark Matter
I Implications for the LHC
I Limits on the Amount of R-Parity Violation
I Conclusions and Outlook
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 2 / 32
-
Motivation for Unstable Gravitino Dark Matter
Motivation for Unstable Gravitino Dark Matter
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 3 / 32
-
Motivation for Unstable Gravitino Dark Matter
What Do We Know about Dark Matter?
I Dark matter is observed on various scales through its gravitational interaction
I Dark matter contributes significantly to the energy density of the universe
[van Albada et al. (1985)] [Clowe et al. (2006)] [NASA / WMAP Science Team]
I Dark matter properties known from observations:• No electromagnetic and strong interactions• At least gravitational and at most weak-scale interactions• Non-baryonic• Cold (maybe warm)• Long-lived on cosmological time scales but not necessarily stable! [NASA / WMAP Science Team]
Particle dark matter could be a (super)WIMP with lifetime� age of the universe!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 4 / 32
-
Motivation for Unstable Gravitino Dark Matter
What Do We Know about Dark Matter?
I Dark matter is observed on various scales through its gravitational interaction
I Dark matter contributes significantly to the energy density of the universe
[van Albada et al. (1985)] [Clowe et al. (2006)] [NASA / WMAP Science Team]
I Dark matter properties known from observations:• No electromagnetic and strong interactions• At least gravitational and at most weak-scale interactions• Non-baryonic• Cold (maybe warm)• Long-lived on cosmological time scales but not necessarily stable! [NASA / WMAP Science Team]
Particle dark matter could be a (super)WIMP with lifetime� age of the universe!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 4 / 32
-
Motivation for Unstable Gravitino Dark Matter
How Can We Unveil the Nature of Dark Matter?
I There are three main search strategies for dark matter:
• Direct detection of dark matter in the scattering off matter nuclei• Production of dark matter particles at colliders• Indirect detection of dark matter in cosmic ray signatures
[Max-Planck-Institut für Kernphysik]
]2WIMP Mass [GeV/c6 7 8 910 20 30 40 50 100 200 300 400 1000
]2W
IMP-
Nuc
leon
Cro
ss S
ectio
n [c
m
-4510
-4410
-4310
-4210
-4110
-4010
-3910
]2WIMP Mass [GeV/c6 7 8 910 20 30 40 50 100 200 300 400 1000
]2W
IMP-
Nuc
leon
Cro
ss S
ectio
n [c
m
-4510
-4410
-4310
-4210
-4110
-4010
-3910
DAMA/I
DAMA/Na
CoGeNT
CDMS
EDELWEISS
XENON100 (2010)
XENON100 (2011) Buchmueller et al.
[CERN] [Aprile et al. (2011)] [AMS collaboration]
A combination will be necessary to identify the nature of particle dark matter!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 5 / 32
-
Motivation for Unstable Gravitino Dark Matter
How Can We Unveil the Nature of Dark Matter?
I There are three main search strategies for dark matter:
• Direct detection of dark matter in the scattering off matter nuclei• Production of dark matter particles at colliders• Indirect detection of dark matter in cosmic ray signatures
[Max-Planck-Institut für Kernphysik]
]2WIMP Mass [GeV/c6 7 8 910 20 30 40 50 100 200 300 400 1000
]2W
IMP-
Nuc
leon
Cro
ss S
ectio
n [c
m
-4510
-4410
-4310
-4210
-4110
-4010
-3910
]2WIMP Mass [GeV/c6 7 8 910 20 30 40 50 100 200 300 400 1000
]2W
IMP-
Nuc
leon
Cro
ss S
ectio
n [c
m
-4510
-4410
-4310
-4210
-4110
-4010
-3910
DAMA/I
DAMA/Na
CoGeNT
CDMS
EDELWEISS
XENON100 (2010)
XENON100 (2011) Buchmueller et al.
[CERN] [Aprile et al. (2011)] [AMS collaboration]
A combination will be necessary to identify the nature of particle dark matter!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 5 / 32
-
Motivation for Unstable Gravitino Dark Matter
Why Are We Interested in Unstable Gravitino Dark Matter?
I Smallness of observed neutrino masses motivates seesaw mechanism
I Can explain baryon asymmetry via thermal leptogenesis [Fukugita, Yanagida (1986)]• Requires high reheating temperature after inflation: TR & 109 GeV [Davidson, Ibarra (2002)]
I Supergravity predicts the gravitino as the spin-3/2 superpartner of the graviton
I Gravitinos are abundantly produced in thermal scatterings:
Ω3/2h2 ' 0.27
(TR
1010 GeV
)(100 GeV
m3/2
)(mg̃
1 TeV
)2[Bolz et al. (2001)]
I Problem in scenarios with neutralino dark matter:
• Gravitino decays suppressed by Planck scale: τ3/2 ∼M2Pl
m33/2≈ 3 years
(100 GeV
m3/2
)3• Late decays with τ & O(1–1000 s) in conflict with BBN ⇒ Cosmological gravitino problem
Possible solution: Gravitino is the LSP and thus stable!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 6 / 32
-
Motivation for Unstable Gravitino Dark Matter
Why Are We Interested in Unstable Gravitino Dark Matter?
I Smallness of observed neutrino masses motivates seesaw mechanism
I Can explain baryon asymmetry via thermal leptogenesis [Fukugita, Yanagida (1986)]• Requires high reheating temperature after inflation: TR & 109 GeV [Davidson, Ibarra (2002)]
I Supergravity predicts the gravitino as the spin-3/2 superpartner of the graviton
I Gravitinos are abundantly produced in thermal scatterings:
Ω3/2h2 ' 0.27
(TR
1010 GeV
)(100 GeV
m3/2
)(mg̃
1 TeV
)2[Bolz et al. (2001)]
I Problem in scenarios with neutralino dark matter:
• Gravitino decays suppressed by Planck scale: τ3/2 ∼M2Pl
m33/2≈ 3 years
(100 GeV
m3/2
)3• Late decays with τ & O(1–1000 s) in conflict with BBN ⇒ Cosmological gravitino problem
Possible solution: Gravitino is the LSP and thus stable!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 6 / 32
-
Motivation for Unstable Gravitino Dark Matter
Why Are We Interested in Unstable Gravitino Dark Matter?
I Gravitino relic density:
Ω3/2h2 ' 0.27
(TR
1010 GeV
)(100 GeV
m3/2
)(mg̃
1 TeV
)2I Correct relic density possible for m3/2 > O(10) GeV ⇒ Gravitino dark matterI Still problematic:• NLSP can only decay to gravitino LSP:
τNLSP '48πM2Plm
23/2
m5NLSP≈ 9 days
( m3/210 GeV
)2 (150 GeVmNLSP
)5• Late NLSP decays are in conflict with BBN ⇒ Cosmological gravitino problem
Possible solution: R-parity is not exactly conserved!
I Other options:• Choose harmless NLSP like sneutrino [Covi, Kraml (2007)]• Dilute NLSP density by late entropy production [Buchmüller et al. (2006)]
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 7 / 32
-
Motivation for Unstable Gravitino Dark Matter
Why Are We Interested in Unstable Gravitino Dark Matter?
I Gravitino relic density:
Ω3/2h2 ' 0.27
(TR
1010 GeV
)(100 GeV
m3/2
)(mg̃
1 TeV
)2I Correct relic density possible for m3/2 > O(10) GeV ⇒ Gravitino dark matterI Still problematic:• NLSP can only decay to gravitino LSP:
τNLSP '48πM2Plm
23/2
m5NLSP≈ 9 days
( m3/210 GeV
)2 (150 GeVmNLSP
)5• Late NLSP decays are in conflict with BBN ⇒ Cosmological gravitino problem
Possible solution: R-parity is not exactly conserved!
I Other options:• Choose harmless NLSP like sneutrino [Covi, Kraml (2007)]• Dilute NLSP density by late entropy production [Buchmüller et al. (2006)]
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 7 / 32
-
Gravitino Dark Matter with Broken R-Parity
Gravitino Dark Matter with Broken R-Parity
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 8 / 32
-
Gravitino Dark Matter with Broken R-Parity
Gravitino Dark Matter with Bilinear R-Parity Violation
I Bilinear R-parity violation: W/Rp = µiHuLi , −Lsoft/Rp
= BiHu ˜̀i + m2Hd `i H∗d
˜̀i + h.c.
• Only lepton number violated ⇒ Proton remains stable!
I R-parity violation parametrized by non-vanishing sneutrino VEV: ξ =〈ν̃〉v
I Cosmological bounds on R-violating couplings• Lower bound: The NLSP must decay fast enough to evade BBN constraints: ξ & O(10−11)• Upper bound: No washout of the lepton/baryon asymmetry: ξ . O(10−7)
I Tiny bilinear R-parity violation can be related to U(1)B–L breaking [Buchmüller et al. (2007)]
I Gravitino decay suppressed by Planck scale and small R-parity violation
• Gravitino decay width: Γ3/2 ∝ξ2 m33/2
M2Pl[Takayama, Yamaguchi (2000)]
• The gravitino lifetime by far exceeds the age of the universe (τ3/2 � 1017 s)
The unstable gravitino is a well-motivated and viable dark matter candidate!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 9 / 32
-
Gravitino Dark Matter with Broken R-Parity
Gravitino Dark Matter with Bilinear R-Parity Violation
I Bilinear R-parity violation: W/Rp = µiHuLi , −Lsoft/Rp
= BiHu ˜̀i + m2Hd `i H∗d
˜̀i + h.c.
• Only lepton number violated ⇒ Proton remains stable!
I R-parity violation parametrized by non-vanishing sneutrino VEV: ξ =〈ν̃〉v
I Cosmological bounds on R-violating couplings• Lower bound: The NLSP must decay fast enough to evade BBN constraints: ξ & O(10−11)• Upper bound: No washout of the lepton/baryon asymmetry: ξ . O(10−7)
I Tiny bilinear R-parity violation can be related to U(1)B–L breaking [Buchmüller et al. (2007)]
I Gravitino decay suppressed by Planck scale and small R-parity violation
• Gravitino decay width: Γ3/2 ∝ξ2 m33/2
M2Pl[Takayama, Yamaguchi (2000)]
• The gravitino lifetime by far exceeds the age of the universe (τ3/2 � 1017 s)
The unstable gravitino is a well-motivated and viable dark matter candidate!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 9 / 32
-
Gravitino Dark Matter with Broken R-Parity
Phenomenology of Unstable Gravitino Dark Matter
I Rich phenomenology instead of elusive gravitinos:
• A long-lived NLSP could be observed at the LHC [Buchmüller et al. (2007), Bobrovskyi et al. (2010, 2011)]
• Gravitino decays lead to possibly observable signals at indirect detection experiments[Takayama, Yamaguchi (2000), Buchmüller et al. (2007), Bertone et al. (2007), Ibarra, Tran (2008), Ishiwata et al. (2008) etc.]
Gravitinos could be indirectly observed at colliders and in the spectra of cosmic rays!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 10 / 32
-
Gravitino Dark Matter with Broken R-Parity
Bilinear R-Parity Violation: Neutralino–Neutrino Mixing
I Bilinear R-parity violation extends neutralino mass matrix to include neutrinos
I 7× 7 matrix with basis ψ0i = (−i γ̃, −i Z̃ , H̃0u , H̃0d , νi )T
M7N =
M1c2W + M2 s
2W (M2 −M1) sW cW 0 0 0
(M2 −M1) sW cW M1s2W + M2 c2W mZ sβ −mZ cβ −mZ ξj0 mZ sβ 0 −µ 00 −mZ cβ −µ 0 00 −mZ ξi 0 0 0
I Diagonalized by unitary matrix N7
I Mixing to neutrinos via neutrino–zino coupling: N7νi X ' −ξi UXZ̃I Analytical approximation shows dependence on SUSY parameters
• Uγ̃Z̃ ' mZ sin θW cos θWM2−M1M1 M2
• UZ̃ Z̃ ' −mZ(
sin2 θWM1
+cos2 θW
M2
)
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 11 / 32
-
Gravitino Dark Matter with Broken R-Parity
Bilinear R-Parity Violation: Chargino–Charged Lepton Mixing
I Bilinear R-parity violation extends chargino mass matrix to include charged leptons
I 5× 5 matrix with basis vectors ψ− = (−iW̃−, H̃−d , `−i )
T andψ+ = (−iW̃ +, H̃+u , ec +i )
T
M5C =
M2√
2 mW sβ 0√2 mW cβ µ −m`ij ξi cβ√2 mW ξi 0 m`ij
I Diagonalized by unitary matrices U5 and V 5
I Mixing to left-handed leptons via lepton–wino coupling: U5`i X ' −√
2 ξi UXW̃I Mixing to right-handed leptons suppressed and negligibleI Analytical approximation shows dependence on SUSY parameters• UW̃W̃ '
mWM2
I Bilinear R-parity also induces mass mixing in the scalar sector• Mixing between SM-like Higgs and sneutrino proportional to sneutrino VEV
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 12 / 32
-
Gravitino Dark Matter with Broken R-Parity
Gravitino Decay Channels: 2-body Decays
I Several two-body decay channels: ψ3/2 → γ νi , Z νi , W `i , h νi
+ ...
• Γγνi 'ξ2i m
33/2
32πM2Pl|Uγ̃Z̃ |
2 ∝ξ2i m
33/2
M2Pl
(M2−M1M1 M2
)2• ΓZνi '
ξ2i m33/2
32πM2Pl
(1− m
2Z
m23/2
)2{U2
Z̃ Z̃f(
m2Zm23/2
)+ ...
}• ΓW +`−i
'ξ2i m
33/2
32πM2Pl
(1− m
2W
m23/2
)2{U2
W̃W̃f(
m2Wm23/2
)+ ...
}• Γhνi '
ξ2i m33/2
196πM2Pl
(1− m
2h
m23/2
)4I Dependence on mass mixings → dependence on gaugino masses
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 13 / 32
-
Gravitino Dark Matter with Broken R-Parity
Gravitino Decay Channels: 3-body Decays
I For m3/2 < mW also three-body decays can play an important role [Choi et al. (2010)]
+ ...
•dΓZ∗νi
ds ∝ξ2i m
33/2
M2Pl((s−m2Z )
2+m2Z Γ2Z )
(1− s
m23/2
)2{s U2
Z̃ Z̃f(
sm23/2
)+ ...
}•
dΓW +∗`−i
ds ∝ξ2i m
33/2
M2Pl((s−m2W )
2+m2W Γ2W )
(1− s
m23/2
)2{s U2
W̃W̃f(
sm23/2
)+ ...
}•
dΓh∗νids ∝
ξ2i m33/2 m
2f s
M2Pl v2((s−m2h)
2+m2hΓ2h)
(1− s
m23/2
)4I I will concentrate on 2-body dacays in this talk
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 14 / 32
-
Gravitino Dark Matter with Broken R-Parity
Gravitino Branching Ratios and Final State Particle Spectra
I Branching ratios are independent of strength of R-parity violation
I Ratio between γ νi and other channels is model-dependent
ΓΝi
Γ*Z*Νi
W{i
W*{i
ZΝi
hΝi
10 100 1000 10 000
10-5
10-4
10-3
0.01
0.1
1
Gravitino Mass HGeVL
Bra
nchi
ngR
atio
ΝΤ
ΝΜ
Νe
dH´ 103L
p
e
Γ
Ν
e
Νi
Ψ32 ® Z Νi , m32 = 100 GeV
0.01 0.1 1 10 100
0.001
0.01
0.1
1
10
100
Kinetic Energy HGeVL
Spec
trum
dNdHl
og10
TL
I Gravitino decays produce spectra of stable cosmic rays: γ, e, p, νe/µ/τ , d• Two-body decay spectra generated with PYTHIA• Deuteron coalescence treated on event-by-event basis in PYTHIA [Kadastik et al. (2009)]
Basis for phenomenology of indirect gravitino dark matter searches!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 15 / 32
-
Gravitino Dark Matter with Broken R-Parity
Gravitino Branching Ratios and Final State Particle Spectra
I Branching ratios are independent of strength of R-parity violation
I Ratio between γ νi and other channels is model-dependent
ΓΝi
Γ*Z*Νi
W{i
W*{i
ZΝi
hΝi
10 100 1000 10 000
10-5
10-4
10-3
0.01
0.1
1
Gravitino Mass HGeVL
Bra
nchi
ngR
atio
ΝΤ
ΝΜ
Νe
dH´ 103L
p
e
Γ
Ν
e
Νi
Ψ32 ® Z Νi , m32 = 100 GeV
0.01 0.1 1 10 100
0.001
0.01
0.1
1
10
100
Kinetic Energy HGeVL
Spec
trum
dNdHl
og10
TL
I Gravitino decays produce spectra of stable cosmic rays: γ, e, p, νe/µ/τ , d• Two-body decay spectra generated with PYTHIA• Deuteron coalescence treated on event-by-event basis in PYTHIA [Kadastik et al. (2009)]
Basis for phenomenology of indirect gravitino dark matter searches!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 15 / 32
-
Indirect Detection of Gravitino Dark Matter
Indirect Detection of Gravitino Dark Matter
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 16 / 32
-
Indirect Detection of Gravitino Dark Matter
Cosmic-Ray Propagation
I Cosmic rays from gravitino decays propagate through the Milky Way
I Experiments observe spectra of gamma rays, charged cosmic rays and neutrinos
[NASA E/PO, SSU, Aurore Simonnet] [AMS-02 Collaboration] [IceCube Collaboration]
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 17 / 32
-
Indirect Detection of Gravitino Dark Matter
What Is the Difference of Dark Matter Annihilations and Decays?
I Different angular distribution of the gamma-ray/neutrino flux from the galactic halo:
Dark Matter Annihilation
dJhalodE
=〈σv〉DM8πm2DM
dNdE
∫l.o.s.
ρ2halo(~l) d~l
particle physics astrophysics
Dark Matter Decay
dJhalodE
=1
4π τDM mDMdNdE
∫l.o.s.
ρhalo(~l) d~l
particle physics astrophysics
value at galactic anticenter
annihilation
decay
Einasto
NFW
Isothermal
-180 ° -90 ° 0 ° 90 ° 180 °
1
10
100
Galactic Longitude
Lin
e-of
-Si
ghtI
nteg
ralN
orm
aliz
edto
Ant
icen
ter
Annihilation (e.g. WIMP dark matter)• Annihilation cross section related to relic density• Strong signal from peaked structures• Uncertainties from choice of halo profile
Decay (e.g. unstable gravitino dark matter)• Lifetime unrelated to production in the early
universe
• Less anisotropic signal• Less sensitive to the halo model
Directional detection can distinguish unstable gravitino from standard WIMPs!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 18 / 32
-
Indirect Detection of Gravitino Dark Matter
What Is the Difference of Dark Matter Annihilations and Decays?
I Different angular distribution of the gamma-ray/neutrino flux from the galactic halo:
Dark Matter Annihilation
dJhalodE
=〈σv〉DM8πm2DM
dNdE
∫l.o.s.
ρ2halo(~l) d~l
particle physics astrophysics
Dark Matter Decay
dJhalodE
=1
4π τDM mDMdNdE
∫l.o.s.
ρhalo(~l) d~l
particle physics astrophysics
value at galactic anticenter
annihilation
decay
Einasto
NFW
Isothermal
-180 ° -90 ° 0 ° 90 ° 180 °
1
10
100
Galactic Longitude
Lin
e-of
-Si
ghtI
nteg
ralN
orm
aliz
edto
Ant
icen
ter
Annihilation (e.g. WIMP dark matter)• Annihilation cross section related to relic density• Strong signal from peaked structures• Uncertainties from choice of halo profile
Decay (e.g. unstable gravitino dark matter)• Lifetime unrelated to production in the early
universe
• Less anisotropic signal• Less sensitive to the halo model
Directional detection can distinguish unstable gravitino from standard WIMPs!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 18 / 32
-
Indirect Detection of Gravitino Dark Matter
Gravitino Decay Signals in Cosmic-Ray Spectra
antiproton flux isotropic diffuse gamma-ray flux
ª
ª
ª
ó
ó
ó
¨
¨§
§
§
§
òò
ò
òòò
ò
ò
òò
òòò
ø
ø
øø
øøø
øø
øø
øøø
ô
ô
ôô
ô
ô
ô
ô
ô
÷
÷
÷
÷÷÷
÷
÷
÷
ààà
à
àà
à
à
ààà
àà
ááá
áááááá
áááá
áááááááááááááááá
ì
ì
ì
ìì
æ
æ
æ
æ
ææ
ææ
ææææææ
ææææ æ æ
æ æ æ
background
Τ32 = 1027 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000
10-3
0.01
0.1
1
10
100
Kinetic Energy HGeVL
T3´
Ant
ipro
ton
FluxHG
eV2
m-
2s-
1sr-
1L
ó IMAXìAMS-01æ PAMELA
ª MASS-91¨ CAPRICE94§ CAPRICE98
ò BESS 95+97ø BESS 98ô BESS 99÷ BESS 00à BESS-Polará BESS-Polar II
ì
ì
ìì ì
ìì
ì ì ì
ìì
ìà
àààà
àà
à
à
àà
æ
æ
æ
æ
æ
ææ
ææ
Τ32 = 1027 s
m32 = 100 GeV 1 TeV 10 TeV
0.1 1 10 100 1000 10 000
0.0001
0.0003
0.001
0.003
0.01
0.03
Energy HGeVL
E2´
Gam
ma-
Ray
FluxHG
eVm-
2s-
1sr-
1L
ì EGRET HSreekumar et al.L
à EGRET HStrong et al.L
æ Fermi LAT
I Observed antiproton spectrum well described by astrophysical background• No need for contribution from dark matter
I Isotropic diffuse gamma-ray spectrum exhibits power-law behaviour• Source not completely understood, but no sign of spectral features of a particle decay
I Even without astrophysical backgrounds lifetimes below O(1026–1027) s excluded• Gravitino decay cannot be the origin of the PAMELA and Fermi LAT cosmic-ray anomalies
Astrophysical sources like pulsars required to explain cosmic-ray excesses!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 19 / 32
-
Indirect Detection of Gravitino Dark Matter
Gravitino Decay Signals in Cosmic-Ray Spectra
antiproton flux isotropic diffuse gamma-ray flux
ª
ª
ª
ó
ó
ó
¨
¨§
§
§
§
òò
ò
òòò
ò
ò
òò
òòò
ø
ø
øø
øøø
øø
øø
øøø
ô
ô
ôô
ô
ô
ô
ô
ô
÷
÷
÷
÷÷÷
÷
÷
÷
ààà
à
àà
à
à
ààà
àà
ááá
áááááá
áááá
áááááááááááááááá
ì
ì
ì
ìì
æ
æ
æ
æ
ææ
ææ
ææææææ
ææææ æ æ
æ æ æ
background
Τ32 = 1027 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000
10-3
0.01
0.1
1
10
100
Kinetic Energy HGeVL
T3´
Ant
ipro
ton
FluxHG
eV2
m-
2s-
1sr-
1L
ó IMAXìAMS-01æ PAMELA
ª MASS-91¨ CAPRICE94§ CAPRICE98
ò BESS 95+97ø BESS 98ô BESS 99÷ BESS 00à BESS-Polará BESS-Polar II
ì
ì
ìì ì
ìì
ì ì ì
ìì
ìà
àààà
àà
à
à
àà
æ
æ
æ
æ
æ
ææ
ææ
Τ32 = 1027 s
m32 = 100 GeV 1 TeV 10 TeV
0.1 1 10 100 1000 10 000
0.0001
0.0003
0.001
0.003
0.01
0.03
Energy HGeVL
E2´
Gam
ma-
Ray
FluxHG
eVm-
2s-
1sr-
1L
ì EGRET HSreekumar et al.L
à EGRET HStrong et al.L
æ Fermi LAT
I Observed antiproton spectrum well described by astrophysical background• No need for contribution from dark matter
I Isotropic diffuse gamma-ray spectrum exhibits power-law behaviour• Source not completely understood, but no sign of spectral features of a particle decay
I Even without astrophysical backgrounds lifetimes below O(1026–1027) s excluded• Gravitino decay cannot be the origin of the PAMELA and Fermi LAT cosmic-ray anomalies
Astrophysical sources like pulsars required to explain cosmic-ray excesses!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 19 / 32
-
Indirect Detection of Gravitino Dark Matter
Antideuteron Signals from Gravitino Decays
I In particular sensitive at low energies due to small astrophysical background
I AMS-02 and GAPS will be able to put strong constraints on light gravitinos
BESS 97-00
GA
PSHL
DBL
GA
PSHU
LD
BL
AM
S-02
AM
S-02
background
Τ32 = 1027 s
m32 = 100 GeV 1 TeV 10 TeV
ΦF = 500 MV
0.1 1 10 100 1000
10-10
10-9
10-8
10-7
10-6
10-5
10-4
Kinetic Energy per Nucleon HGeVnL
HTnL´
Ant
ideu
tero
nFl
uxHm-
2s-
1sr-
1 L
Antideuterons are a valuable channel for light gravitino searches!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 20 / 32
-
Indirect Detection of Gravitino Dark Matter
Antideuteron Signals from Gravitino Decays
I In particular sensitive at low energies due to small astrophysical background
I AMS-02 and GAPS will be able to put strong constraints on light gravitinos
BESS 97-00
GA
PSHL
DBL
GA
PSHU
LD
BL
AM
S-02
AM
S-02
background
Τ32 = 1027 s
m32 = 100 GeV 1 TeV 10 TeV
ΦF = 500 MV
0.1 1 10 100 1000
10-10
10-9
10-8
10-7
10-6
10-5
10-4
Kinetic Energy per Nucleon HGeVnL
HTnL´
Ant
ideu
tero
nFl
uxHm-
2s-
1sr-
1 L
Antideuterons are a valuable channel for light gravitino searches!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 20 / 32
-
Indirect Detection of Gravitino Dark Matter
Neutrino Signals from Gravitino Decays
I Neutrinos provide directional information like gamma rays
I Gravitino signal features neutrino line at the end of the spectrumI Atmospheric neutrinos are the dominant background for the gravitino signal• Discrimination of neutrino flavours would allow to reduce the background• Signal-to-background ratio best at the end of the spectrum and for large gravitino masses
ô ôô
ô
ô ô
ô
ò
òò ò
òò
ò
òò
ò
ò
ì
ì
ì
ì
ì
ì
ì
ì
ì
æ
æ
æ
æ
æ
æ
æ
æ
æ
æ
æ
ΝΤΝe
ΝΜ
Τ32 = 1026 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000 100 000
10-4
10-3
0.01
0.1
1
10
100
103
EnergyHGeVL
E2´
Neu
trin
oF
luxH
GeV
m-
2s-
1sr-
1L
ô FréjusΝeò FréjusΝΜ
Super-KamiokandeΝΜAMANDA -II ForwardΝΜ
ì AMANDA -II Unfolding ΝΜIceCube-40ΝΜ
æ IceCube-40 UnfoldingΝΜ
Neutrinos are a valuable channel for heavy gravitino searches!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 21 / 32
-
Indirect Detection of Gravitino Dark Matter
Neutrino Signals from Gravitino Decays
I Neutrinos provide directional information like gamma rays
I Gravitino signal features neutrino line at the end of the spectrumI Atmospheric neutrinos are the dominant background for the gravitino signal• Discrimination of neutrino flavours would allow to reduce the background• Signal-to-background ratio best at the end of the spectrum and for large gravitino masses
ô ôô
ô
ô ô
ô
ò
òò ò
òò
ò
òò
ò
ò
ì
ì
ì
ì
ì
ì
ì
ì
ì
æ
æ
æ
æ
æ
æ
æ
æ
æ
æ
æ
ΝΤΝe
ΝΜ
Τ32 = 1026 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000 100 000
10-4
10-3
0.01
0.1
1
10
100
103
EnergyHGeVL
E2´
Neu
trin
oF
luxH
GeV
m-
2s-
1sr-
1L
ô FréjusΝeò FréjusΝΜ
Super-KamiokandeΝΜAMANDA -II ForwardΝΜ
ì AMANDA -II Unfolding ΝΜIceCube-40ΝΜ
æ IceCube-40 UnfoldingΝΜ
Neutrinos are a valuable channel for heavy gravitino searches!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 21 / 32
-
Indirect Detection of Gravitino Dark Matter
Neutrino Detection with Upward Through-Going Muons
I Muon tracks from charged current DIS of muon neutrinos off nuclei outside the detector
Advantages• Muon track reconstruction is well-understood at neutrino telescopes
Disadvantages• Neutrino–nucleon DIS and propagation energy losses shift muon spectrum to lower energies• Bad energy resolution (0.3 in log10 E) smears out cut-off energy
Upward Through-Going Muons
atmospheric background
Τ32 = 1026 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10000 100000
0.1
1
10
100
103
104
105
Energy HGeVL
MuonFluxHkm-2yr-
1L
Upward Through-Going Muons
Τ32 = 1026s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10000 100000
0.01
0.1
1
10
Energy HGeVLStatisticalSignificance
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 22 / 32
-
Indirect Detection of Gravitino Dark Matter
Neutrino Detection – Improvements Using Showers
I Hadronic and electromagnetic showers from charged current DIS of electron and tau neutrinosand neutral current interactions of all neutrino flavours inside the detector
Disadvantages• TeV-scale showers are difficult to discriminate from short muon tracks
Advantages• 3× larger signal and 3× lower background compared to other channels• Better energy resolution (0.18 in log10 E) helps to distinguish spectral features
Shower Events
atmospheric background
Τ32 = 1026 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000 100 000
1
10
100
103
104
105
106
Energy HGeVL
Show
erR
ateHk
m-
3yr-
1 L
Shower Events
Τ32 = 1026 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000 100 000
0.01
0.1
1
10
100
Energy HGeVLSt
atis
tical
Sign
ific
ance
Showers are potentially the best channel for dark matter searches in neutrinos!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 23 / 32
-
Indirect Detection of Gravitino Dark Matter
Neutrino Detection – Improvements Using Showers
I Hadronic and electromagnetic showers from charged current DIS of electron and tau neutrinosand neutral current interactions of all neutrino flavours inside the detector
Disadvantages• TeV-scale showers are difficult to discriminate from short muon tracks
Advantages• 3× larger signal and 3× lower background compared to other channels• Better energy resolution (0.18 in log10 E) helps to distinguish spectral features
Shower Events
atmospheric background
Τ32 = 1026 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000 100 000
1
10
100
103
104
105
106
Energy HGeVL
Show
erR
ateHk
m-
3yr-
1 L
Shower Events
Τ32 = 1026 s
m32 = 100 GeV 1 TeV 10 TeV
1 10 100 1000 10 000 100 000
0.01
0.1
1
10
100
Energy HGeVLSt
atis
tical
Sign
ific
ance
Showers are potentially the best channel for dark matter searches in neutrinos!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 23 / 32
-
Indirect Detection of Gravitino Dark Matter
Limits on the Gravitino Lifetime
excluded by diffuse flux
excluded by line searches
1 10 100 1000 10 000
1024
1025
1026
1027
1028
1029
Gravitino Mass HGeVL
Gra
vitin
oL
ifet
imeHsL
Fermi LAT diffuse fluxVertongen et al. photon lineFermi LAT photon line
excluded by
antiproton flux
excluded by electron + positron flux
excluded
by
positron
fraction
antideuteron sensitivity
100 1000 10 000
1024
1025
1026
1027
1028
Gravitino Mass HGeVL
Gra
vitin
oL
ifet
imeHsL
PAMELA e+He+ + e-L
PAMELA p
Fermi LAT H.E.S.S. e+ + e-
I Cosmic-ray data give bounds on gravitino lifetime• Photon line bounds very strong for low gravitino masses• Uncertainties from charged cosmic-ray propagation• Background subtraction will improve bounds• Antideuterons can be complementary to photon line
searches for low gravitino masses
• Neutrino bounds are competitive for heavy gravitinos
Wide range of bounds from multi-messenger approach!
exclusion from
through-going muons
after 1 year at IceCube + DeepCore
100 1000 10 000
1024
1025
1026
1027
Gravitino Mass HGeVL
Gra
vitin
oL
ifet
imeHsL
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 24 / 32
-
Implications for the LHC
Implications for the LHC
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 25 / 32
-
Implications for the LHC
Implications for the LHC: Stau NLSP
I NLSP decays before BBN but may be metastable on collider scales
I Stau decay channels: τ̃R → τ νµ, µ ντ and τ̃L → t̄R bLI Characteristic signatures:• Slow particle with long ionising charged track• Displaced vertex with missing energy and muon track or jet
I Minimal decay length from washout limit: 4 mm
101 102 103
m3/2 [GeV]
102
103
m˜� 1
[G
eV
]
100
1000
10000
Stau NLSP: Minimal allowed decay length c��̃1
[m]
Min O.P.
O.P. in
scena
rio (B)
m3/2>m�̃1
EWPT
[Huang et al. (2011)]
I Gamma-ray limits from galaxy clusters constrain decay length [Huang et al. (2011)]
I Minimal decay lengths from current limits: O(100) m – O(10) kmMichael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 26 / 32
-
Implications for the LHC
Implications for the LHC: Neutralino NLSP
I Neutralino decay channels: χ̃01 → Z νi ,W +`−i , h νiI Bino decay length is directly related to gravitino decay widthI Characteristic signatures:• Displaced vertices far from the interaction point• For too small R-parity violation indistinguishable from stable neutralino
decay chain with secondary vertices
101 102 103
m3/2 [GeV]
102
103
m˜�
0 1 [
GeV
]
1
10
100 1
000
1000
0
Neutralino NLSP: Minimal allowed decay length χ��̃01 [m]
Min O.P.
O.P. in
scena
rio (A)
m3/2>m� 01
EWPT
[Bobrovskyi et al. (2011)] [Huang et al. (2011)]
I Gamma-ray limits from galaxy clusters constrain decay length [Huang et al. (2011)]
I Minimal decay lengths from current limits: O(100) m – O(10) km
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 27 / 32
-
Limits on the Amount of R-Parity Violation
Limits on the Amount of R-Parity Violation
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 28 / 32
-
Limits on the Amount of R-Parity Violation
Limits on the Amount of R-Parity Violation
I Limits on gravitino lifetime constrain the strength of R-parity violation: τ3/2 ∝M2Pl
ξ2 m33/2• Limits from photon line searches dominate for small gravitino masses• For heavier gravitino bounds from all cosmic-ray channels are comparable
cosmic-ray limits LHC sensitivity for bino-like NLSP decaysΞ = 10-7
Ξ = 10-11
1 10 100 1000 10 000
10-12
10-11
10-10
10-9
10-8
10-7
Gravitino Mass HGeVL
R-
Pari
tyV
iola
ting
Para
met
erΞ
IceCube ΝΜ prospects
Super-Kamiokande ΝΜ
GAPSAMS-02 d prospects
PAMELA p
Fermi LAT diffuse Γ
Fermi LAT Γ line
[Bobrovskyi et al. (2011)]I The LHC has the potential to detect NLSP decays beyond cosmic-ray constraints• Good sensitivity with clean decay chain: χ̃01 → Z νi and Z → µ
+µ−
• Taking all channels can improve sensitivity another order of magnitude [Bobrovskyi et al. (2011)]
Indirect and collider searches probe interesting range of R-parity violation!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 29 / 32
-
Limits on the Amount of R-Parity Violation
Limits on the Amount of R-Parity Violation
I Limits on gravitino lifetime constrain the strength of R-parity violation: τ3/2 ∝M2Pl
ξ2 m33/2• Limits from photon line searches dominate for small gravitino masses• For heavier gravitino bounds from all cosmic-ray channels are comparable
cosmic-ray limits LHC sensitivity for bino-like NLSP decaysΞ = 10-7
Ξ = 10-11
1 10 100 1000 10 000
10-12
10-11
10-10
10-9
10-8
10-7
Gravitino Mass HGeVL
R-
Pari
tyV
iola
ting
Para
met
erΞ
IceCube ΝΜ prospects
Super-Kamiokande ΝΜ
GAPSAMS-02 d prospects
PAMELA p
Fermi LAT diffuse Γ
Fermi LAT Γ line
[Bobrovskyi et al. (2011)]I The LHC has the potential to detect NLSP decays beyond cosmic-ray constraints• Good sensitivity with clean decay chain: χ̃01 → Z νi and Z → µ
+µ−
• Taking all channels can improve sensitivity another order of magnitude [Bobrovskyi et al. (2011)]
Indirect and collider searches probe interesting range of R-parity violation!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 29 / 32
-
Conclusions and Outlook
Conclusions and Outlook
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 30 / 32
-
Conclusions and Outlook
Conclusions
• Gravitino dark matter with broken R-parity is well motivated from cosmology
• Consistent with thermal leptogenesis and big bang nucleosynthesis
• The Gravitino lifetime is naturally in the range of indirect detection experiments
• Cannot explain the PAMELA and Fermi LAT excesses due to constraints fromgamma rays and antiprotons
• Multi-messenger approach constrains gravitino lifetime and strength of R-parityviolation
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 31 / 32
-
Conclusions and Outlook
Outlook
• Forthcoming experiments like AMS-02 will greatly improve cosmic-ray data
• Antideuteron searches will probe light gravitino dark matter
• Neutrino experiments like IceCube will probe heavy gravitino dark matter
• LHC may discover decays of metastable NLSPs beyond cosmic-ray constraints onR-parity violation
• We are living in interesting times for dark matter searches!
Thanks for your attention!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 32 / 32
-
Conclusions and Outlook
Outlook
• Forthcoming experiments like AMS-02 will greatly improve cosmic-ray data
• Antideuteron searches will probe light gravitino dark matter
• Neutrino experiments like IceCube will probe heavy gravitino dark matter
• LHC may discover decays of metastable NLSPs beyond cosmic-ray constraints onR-parity violation
• We are living in interesting times for dark matter searches!
Thanks for your attention!
Michael Grefe (IFT UAM/CSIC) Gravitino Dark Matter with Broken R-Parity IFIC València – 21 June 2012 32 / 32
Motivation for Unstable Gravitino Dark MatterGravitino Dark Matter with Broken R-ParityIndirect Detection of Gravitino Dark MatterImplications for the LHCLimits on the Amount of R-Parity ViolationConclusions and Outlook