indirect detection of supersymmetric particles with neutrino...
TRANSCRIPT
Introduction Iteractions Direct Indirect Conclusions
Indirect detection of supersymmetric particles with
neutrino telescopes
Jairo C. de Souza
University of Sao Paulo – Brazil
TeVPA 2010
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 1
Introduction Iteractions Direct Indirect Conclusions Particle Physics Gravitino LSP Scenarios
Starting point:
Neutrino Telescopes as a Direct Probe of Supersymmetry Breaking,Ivone. F. M. Albuquerque, Gustavo Burdman and Z. Chacko, PhysicalReview Letters, 92, 221802 (2004);
Direct detection of supersymmetric particles in neutrino telescopes, Ivone.F. M. Albuquerque, Gustavo Burdman and Z. Chacko, Physical Review D75, 035006 (2007);
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 2
Introduction Iteractions Direct Indirect Conclusions Particle Physics Gravitino LSP Scenarios
Starting point:
Neutrino Telescopes as a Direct Probe of Supersymmetry Breaking,Ivone. F. M. Albuquerque, Gustavo Burdman and Z. Chacko, PhysicalReview Letters, 92, 221802 (2004);
Direct detection of supersymmetric particles in neutrino telescopes, Ivone.F. M. Albuquerque, Gustavo Burdman and Z. Chacko, Physical Review D75, 035006 (2007);
Goal
Extend the results for a complementary Supersymmetry Breaking Energy Scale:
107GeV .√F . 1010GeV −→ 105GeV .
√F . 107GeV
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 2
Introduction Iteractions Direct Indirect Conclusions Particle Physics Gravitino LSP Scenarios
Outline
Theoretical context;
Interactions – cross sections, energy loss and ν flux;
What was already done – study of the direct detection of the NLSPssignals;
What is new – study of the indirect detection of the NLSPs signals.
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Introduction Iteractions Direct Indirect Conclusions Particle Physics Gravitino LSP Scenarios
Introduction
Weak scale supersymmetry (SUSY) as an extension of the StandardModel of particle physics;
R-parity → neutral and stablelightest supersymmetric particle (LSP);
The supersymmetry must be broken →√F :
If√F . 1010GeV → Gravitino LSP;
If√F & 1010GeV → Neutralino LSP.
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Introduction Iteractions Direct Indirect Conclusions Particle Physics Gravitino LSP Scenarios
Gravitino LSP Scenarios
Processes that have to be considered:
νN → lLq
lLq promptly decay to 2lR + SM particles
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 5
Introduction Iteractions Direct Indirect Conclusions Particle Physics Gravitino LSP Scenarios
Gravitino LSP Scenarios
Processes that have to be considered:
νN → lLq
lLq promptly decay to 2lR + SM particles
lR : typically the τR → Next to lightest supersymmetric particle (NLSP);
τR lifetime can be very large → can travel very long distances beforedecaying:
cτ =( √
F
107GeV
)4 (100GeVmτR
)5
10 km
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 5
Introduction Iteractions Direct Indirect Conclusions Particle Physics Gravitino LSP Scenarios
Gravitino LSP Scenarios
Processes that have to be considered:
νN → lLq
lLq promptly decay to 2lR + SM particles
lR : typically the τR → Next to lightest supersymmetric particle (NLSP);
τR lifetime can be very large → can travel very long distances beforedecaying:
cτ =( √
F
107GeV
)4 (100GeVmτR
)5
10 km
107GeV .√F . 1010GeV ⇒ direct detection (τR doesn’t decay inside
the Earth);
105GeV .√F . 107GeV ⇒ indirect detection (τR decays inside the
Earth).
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 5
Introduction Iteractions Direct Indirect Conclusions Cross-sections Energy loss ν Flux
ν-nucleon cross-sections
10-36
10-35
10-34
10-33
10-32
106
107
108
109
1010
1011
Eν (GeV)
σ (c
m2 )
The three lower curves correspond to mℓL
= 250 GeV, mw = 250GeV; and for squark masses mq = 300 GeV
(dashed) , 600 GeV (dot-dashed) and 900 GeV (dotted). The top curve corresponds to the SM charged currentinteractions and the middle one to the di-muon background.
Figure: I. F. M. Albuquerque, et al, Physical Review D 75, 035006 (2007).
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Introduction Iteractions Direct Indirect Conclusions Cross-sections Energy loss ν Flux
Energy loss for muon and stau
Three main contributions – bremsstrahlung, pair production and photonuclear
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
x 10-5
104
105
106
107
108
109
pair
Eµ (GeV)
b (c
m2 /g
)
bremph nuc
10-13
10-12
10-11
10-10
10-9
10-8
10-7
106
107
108
109
1010
1011
pair
Estau (GeV)
b (c
m2 /g
)
bremph nuc
Figures: M. H. Reno, I. Sarcevic and S. Su, Astroparticle Physics 24, 107 (2005); Ivone F. M. Albuquerque, et al,
Physical Review D 75, 035006 (2007).
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Introduction Iteractions Direct Indirect Conclusions Cross-sections Energy loss ν Flux
Neutrino flux
Waxman and Bahcall (WB) limit – the
observed cosmic ray flux implies an upper
bound on the high energy astrophysical
neutrino flux.
(
dφν
dE
)
WB= (1−4)×10−8
E2
GeV cm−2s−1 sr−1
Mannheim, Protheroe and Rachen (MPR)
limit – upper limit on the diffuse neutrino
sources.
10-18
10-17
10-16
10-15
10-14
10-13
105
106
107
108
109
1010
1011
Eν (GeV)
E d
Φν/
dE (
cm-2
s-1sr
-1)
WB limit
MPR limit (transparent sources)
MPR limit (opaque sources)
Figure: I. F. M. Albuquerque et al, arXiv:0803.3479v1[hep-ph]
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 8
Introduction Iteractions Direct Indirect Conclusions Energy spectrum Track separation
Direct detection
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 9
Introduction Iteractions Direct Indirect Conclusions Energy spectrum Track separation
Direct detection – Energy spectrum
lR pair events per km2, per year, at the
detector. Curves that do not reach y
axis; from top to bottom: mq = 300,
600 and 900 GeV. Here,
mlR
= 150 GeV and mw = 250 GeV.
Also shown are the neutrino flux at
earth and the µ and the di-muon flux
through the detector (curves that reach
y axis; from top to bottom
respectively). In all cases we make use
of the WB limit for the neutrino flux.
Figure: I. F. M. Albuquerque, et al,
Physical Review D 75, 035006 (2007).
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 9
Introduction Iteractions Direct Indirect Conclusions Energy spectrum Track separation
For track separations above 100 m there should not be any significant contribution from the di-muon background.
00.10.20.30.40.50.60.70.80.9
1
0 100 200 300 400 500 600track separation (m)
dist
ribu
tion
stau (300)stau (600)stau (900)
0123456789
10
0 20 40 60 80 100 120 140 160 180 200track separation (m)
dist
ribu
tion
µ+µ-
The relative normalization corresponds to the relative number of events for signal and background. Note thedifferent horizontal scales, as well as different binning between the two figures.
Figure: I. F. M. Albuquerque, et al, Physical Review D 75, 035006 (2007).
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 10
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
Indirect detection of NLSPs
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 11
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
Indirect detection of NLSPs
Now: considering the τ decay
τ decay −→ τ + gravitino
τ regeneration:
τ decay −→ ντ + X
ντ Ncc−→ τ + X
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 11
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
τ survival probability (decay)
x (m)-610 -510 -410 -310 -210 -110 1 10 210 310 410 510 610
τ∼P
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
GeV 4 = 10F
GeV 5 = 10F
GeV 6 = 10F
GeV7 = 10F
GeV6 10× = 5 νE
Different√F (energy fixed).
x (m)1 10 210 310 410 510 610 710 810 910 1010
τ∼P
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
GeV 6 10×E = 5
GeV 8E = 10
GeV 9E = 10
GeV11E = 10
GeV6 10× = 1 F
Different energies (√F fixed).
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 12
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
IceCube
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 13
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
IceCube
τ energy at the detector and number of τ regenerations
Entries 141790Mean 4.756RMS 0.4387
(GeV))τν
Log10(E2 3 4 5 6 7 8
Eve
nts
0
0.2
0.4
0.6
0.8
1
Entries 141790Mean 4.756RMS 0.4387
GeV510× = 1F -- τ
= 300 GeVq~ at detector -- mτE
(GeV)νE610 710 810 910 1010 1110
Reg
ener
atio
ns
3
4
5
6
7
8
9
GeV510× = 1F
GeV610× = 1F
GeV610× = 5F
that reach the detectorτRegenerations --
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 13
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
τ ’s flux atIceCube
∼ 10−6
events
× km−2 ×year−1
(GeV)νE
610 710 810 910 1010 1110
)-1
.y-2
(km
νdN
/dE
νE
-1410
-1210
-1010
-810
-610
-410
-210
1
210
410
-- 29 710× = 5F : genτ∼
-- 6 710× = 5F : detτ∼
-610× -- 1510× = 1F : detτ
-710× -- 9610× = 1F : detτ
-710× -- 2610× = 5F : detτ
WB flux
= 300 GeVq~ -- mν E×Events
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 14
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
Euso (∼ 2× 105 km2)
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 15
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
Euso (∼ 2× 105 km2)
τ and τ at the atmosphere
(GeV)νE
610 710 810 910 1010 1110
)-1
.y-2
(km
νdN
/dE
νE
-610
-510
-410
-310
-210
-110
1
10
210
310
410
510
610 Gen = 29τ∼ TotalAtm = 6.1τ∼ NotDecay = 1.8τ∼ DecayAtm = 1.3τ∼
WB Fluxν
GeV610× = 5F
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 15
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
Euso (∼ 2× 105 km2)
τ and τ at the atmosphere
(GeV)νE
610 710 810 910 1010 1110
)-1
.y-2
(km
νdN
/dE
νE
-610
-510
-410
-310
-210
-110
1
10
210
310
410
510
610 Gen = 29τ∼ TotalAtm = 6.1τ∼ NotDecay = 1.8τ∼ DecayAtm = 1.3τ∼
WB Fluxν
GeV610× = 5FProblem: air fluorescence
is related to the number
of charged particles (Ne):
dNdx
= NfNe ,
Nf ∼ 4.8 photons × m−1
× (charged particle)−1
Ne = 1, 2 (τ case)
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 15
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
Checking the τ
produced at theatmosphere:
(GeV)νE
610 710 810 910 1010 1110
)-1
.y-2
(km
νdN
/dE
νE
-610
-510
-410
-310
-210
-110
1
10
210
310
410
510
610 Gen = 29τ∼
BothDecayAtm = 0.15τ∼
TotalDecayAtm = 1.3τ∼
WB Fluxν
GeV610× = 5F
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 16
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
Checking the τ
produced at theatmosphere:
Flux with a goodnumber of detectableshowers:
∼ 3 × 104
events × year−1
for the coincidence
case.
(GeV)νE
610 710 810 910 1010 1110
)-1
.y-2
(km
νdN
/dE
νE
-610
-510
-410
-310
-210
-110
1
10
210
310
410
510
610 Gen = 29τ∼
BothDecayAtm = 0.15τ∼
TotalDecayAtm = 1.3τ∼
WB Fluxν
GeV610× = 5F
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 16
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
τ pair decaying coincidently at the atmosphere
Distance between showers ⇒ distinguishable signal with acceptable timming.
Entries 48540
Mean 191.6
RMS 108.2
Distance between staus (km)0 100 200 300 400 500 600
Eve
nts
0
0.2
0.4
0.6
0.8
1
Entries 48540
Mean 191.6
RMS 108.2
GeV 610× = 5F Entries 48540
Mean -6.363
RMS 0.2658
log10(time(s))-8 -7.5 -7 -6.5 -6 -5.5 -5
Eve
nts
0
0.2
0.4
0.6
0.8
1Entries 48540
Mean -6.363
RMS 0.2658
GeV 610× = 5F
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 17
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
But, there is still aproblem:
Entries 2577530
Mean 4.91
RMS 0.5064
log10(E(GeV))1 2 3 4 5 6 7 8 9
Eve
nts
0
0.2
0.4
0.6
0.8
1
Entries 2577530
Mean 4.91
RMS 0.5064
Atmτ∼ GeV6 10× = 5 F
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 18
Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso
But, there is still aproblem:
The (s)tau energyat the atmosphereis too low whencompared with thedetector threshold.
Entries 2577530
Mean 4.91
RMS 0.5064
log10(E(GeV))1 2 3 4 5 6 7 8 9
Eve
nts
0
0.2
0.4
0.6
0.8
1
Entries 2577530
Mean 4.91
RMS 0.5064
Atmτ∼ GeV6 10× = 5 F
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 18
Introduction Iteractions Direct Indirect Conclusions
Conclusions
The flux of τ (from τ) at IceCube is too low. So, if the√F is
lower than ∼ 107 GeV, the NLSP detection with this detectorit is not possible;
The number of showers produced at the atmosphere is enoughfor a detector with an area like the Euso’s. The limitation isthe energy threshold. Maybe a different experiment?
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 19
Introduction Iteractions Direct Indirect Conclusions
Thanks!
Jairo C. de Souza Indirect detection of supersymmetric particles Slide: 20