Indirect detection of supersymmetric particles with neutrino …irfu.cea.fr/Meetings/TeVPA/slides/20_07_pm_Souza.pdf · Introduction Iteractions Direct Indirect Conclusions Indirectdetectionofsupersymmetricparticleswith

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);



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



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.



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.



Gravitino LSP Scenarios

Processes that have to be considered:

νN → lLq

lLq promptly decay to 2lR + SM particles





νN → lLq


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





νN → lLq


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).


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).



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).



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]


Introduction Iteractions Direct Indirect Conclusions Energy spectrum Track separation

Direct detection



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).



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).


Introduction Iteractions Direct Indirect Conclusions Interactions τ at IceCube (s)tau at Euso

Indirect detection of NLSPs



Indirect detection of NLSPs

Now: considering the τ decay

τ decay −→ τ + gravitino

τ regeneration:

τ decay −→ ντ + X

ντ Ncc−→ τ + X



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).



IceCube



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 --



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



Euso (∼ 2× 105 km2)



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



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)



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



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



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



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



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



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?



Thanks!


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Indirect detection of supersymmetric particles with neutrino …irfu.cea.fr/Meetings/TeVPA/slides/20_07_pm_Souza.pdf · Introduction Iteractions Direct Indirect Conclusions Indirectdetectionofsupersymmetricparticleswith