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Produced by the NASA Center for Aerospace Information (CASI)
JULY 1978
f
NASA
s
Technical Memorandum
79609
Diffuse Fluxes of Cosmic
High Energy Neutrinos
(NISI-T!l-79609) DIPPQSE FLUXES OF CCSHIC
1178-31040
HIGH ENEEGY WFUT8I110S (NASI) 30 p EC A03/RF
A01
CSCL 03E
Dnclas
G3/93
29420
F. W Stocker
National
Aeronautics
and
Space
Administration
Goddard Spew Flight Confer
Greenbelt, Maryland 20771
Diffuse Fluxes of Cosmic High Energy Neutrinos
F. W. Stecker
Laboratory for High Energy Astrophysics
NASA/Goddard Space Flight Center
Received
Jj
1.
Introduction
There have been a number of recent papers estimating high-energy
neutrino fluxes and spectra from various astrophysical processes (Berezinsky
and Zatsepin 1970, Stecker
1973a,
Berezinsky and Zatsepin 1977 and references
therein, Silberberg and Shapiro 1977, Margolis, Schramm and Silberberg 1978,
Eichler 1978.) In this work, I reexamine the problem by 1) presenting
the results of a detailed calculation of galactic v-production in cosmic-ray
interactions with interstellar gas and extragalactic v-production by inter-
actions of ultrahigh energy cosmic rays with the 3K universal background
radiation, 2) using these results together with present y-ray observations
to predict neutrino fluxes and event rates, and 3) reexamining some of the
assumptions and results of previous work, pointing out significant differences.
2.
Production Rates
The first basic production process for high energy cosmic neutrinos
is the decor} of charged pions produced in cosmic ray interactions with
interstellar gas, primarily pp interactions. This process will henceforth
be referred to as "pp", although the effects of ap pHe and orHe interactions
are included in the calculation. The second process involves the photo-
production of n-mesons by interaction of ultrahigh energy cosmic rays with
the 3K universal microwave background radiation (henceforth referred to as
yp) and subsequent meson decay. Both of these types of interactions involve
the accompanying production of n° mesons and their decay into cosmic y-rays.
Thus, the production rates of cosmic y-rays and neutrinos are generically
linked.
A detailed discussion of the kinematics of the production and decay of
sec
r
-dary particles produced in "pp" interactions may be found in Stecker
A
1 1
; ,
l
1
i
s
4
i
1-TO
1.
Introduction
There have been a number of recent papers estimating high-energy
neutrino fluxes and spectra from various astrophysical processes (Berezinsky
and Zatsepin 1970, Stecker 1973a, Berezinsky and Zatsepin 1977 and references
therein, Silberberg and Shapiro 1977, Margolis, Schramm and Silberberg 1978,
Eichler 1978.) In this work, I reexamine the problem by 1) presenting
the results of a detailed calculation of galactic v-production in cosmic-ray
interactions with interstellar gas and extragalactic v-production by inter-
actions of ultrahigh energy cosmic rays with the 3K universal background
radiation, 2) using these results together with present y-ray observations
to predict neutrino fluxes and event rates, and 3) reexamining some of the
assumptions and results of previous work, pointing out significant differences.
2.
Production Rates
The first basic production process for high energy cosmic neutrinos
is the decor} of charged pions produced in cosmic ray interactions with
interstellar gas, primarily pp interactions. This process will henceforth
be referred to as "pp",although the effects of
a'p
pHe and dHe interactions
are included in the calculation. The second process involves the photo-
production of
Tr-
mesons by interaction of ultrahigh energy cosmic rays with
the 3K universal microwave background radiation (henceforth referred to as
yp) and subsequent meson decay. Both of these types of interactions involve
the accompanying production of n° mesons and their decay into cosmic y-rays.
Thus, the production rates of cosmic y-rays and neutrinos are generically
linked.
A detailed discussion of the kinematics of the production and decay of
sec
o
ndary particles produced in "pp" interactions may be found in Stecker
