Neutrino flux bounds, event rates, and their implications for an inner Earth tomography earth tomography

Nuclear

ELSEVIER

Physics

B (Proc.

Suppl.)

118 (2003)

517

Neutrino flux bounds, event rates, and their implications Earth tomography Christian

Hettlagea*,

Karl Mannheimb

“UniversitBts-Sternwarte bInstitut

GGttingen, Geismar Landstrafie

fiir Theoretische

Physik und Astrophysik,

Hadronic (and possibly non-hadronic) interactions in the universe should yield a neutrino flux detectable with next-generation i‘lerenkov telescopes. Cosmic and gamma ray observations allow the establishment of corresponding upper flux bounds (E. Waxman and J. Bahcall, Phys. Rev. D 59,023002 (1999) (“WB”); K. Mannheim et al., Phys. Rev. D 63, 023003 (2001) (“MPR”)). In order to estimate the corresponding event rates as a function of the direction of incidence, we discretize the space variable in the integrodifferential equations describing the propagation through the inner Earth, and solve the resulting set of equations analytically. The results are shown in Figure 1 and Table 1. As for a given input spectrum the event rate is a function of the Radon transform of the Earth density, one may use the former in order to obtain the latter. Hence an inner Earth tomography is possible (Figure 2, cf. P. Jain et al., Astropart. Phys. 12, 193 (1999)). *This work was deutschen Volkes.

for an inner

supported

by

the

Studienstiftung

11, 37083 GGttingen, Germany

Am Hubland,

97074 Wiirzburg,

200 -

Germany

7+i

7?,, >> 1 7m < 1

OO

0.2

0.4 06 cos(nad1r angle)

0.R

Figure 1. Muon (solid) and tauon events per year (dashed curves) with E, 3 100 GeV in a cubic kilometer detector for the MPR bounds.

des

2-

isotropic flux WB bound lower MPR bound (T,? < 1) upper MPR bound (Tag >> 1)

I$ 442 12883 16293

r;i, 76 2570 2796

Table 1 Muon and tauon events fi per year in a cubic kilometer Cerenkov detector for the WB and the MPR neutrino flux bounds. E, > 100 GeV is assumed. 0920-5632/03/s - see front matter doi:10.1016/S0920-5632(03)01396-3

0 2003 Elsevier

Science

B.V.

i OO

1000

2000

3000 4000 radiw / km

5000

6000

10

Figure 2. Simulated inner Earth tomography by means of five years of high-energy muon event observation for the upper MPR bound. The dashed curve shows the Earth model used for the simulation (A.M. Dziewonski and D.L. Anderson, Phys. Earth Planet. Inter. 25, 297 (1981)). All rights

reserved