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L. Camilleri
neutrino masses, m 2
12 referred to as the solar mass difference as it is of importance
in oscillations of solar neutrinos, m 2
13 ∼ m 2
23 referred to as the atmospheric mass
difference as it drives oscillations of neutrinos produced in the atmosphere through
the decay of mesons produced in cosmic ray interactions. The flavour of interacting
neutrinos can only be determined if the interaction is via a charged current. In these,
the ν e , ν μ and ν τ respectively produce a negative electron, muon or τ lepton in the
final state. Antineutrinos produce the corresponding positive charged lepton.
8.2 Sources of Neutrinos and Their Characteristics
Naturally occurring neutrinos and man-made neutrinos are produced through
several different processes. Nature provides us with solar neutrinos emitted by
the sun, atmospheric neutrinos produced by the interaction of cosmic rays in the
atmosphere, cosmological neutrinos produced by a variety of deep space violent
events, geological neutrinos produced by nuclear decays in the earth core as well
as neutrinos produced in beta decay. Man made neutrinos are produced by nuclear
reactors or by specially designed beams at accelerators or by highly radioactive
sources. These processes are briefly described below.
8.2.1 Solar Neutrinos
They are emitted in nuclear reactions occurring in the sun [7]. The three main
reactions are p + p → d + e + + ν e , emitting a continuous spectrum of neutrinos
with an end point at 0.4 MeV, e+ 7 Be → 7 Li + ν e with a monochromatic spectrum
at 0.862 MeV and 8 B → 8 Be
∗
+ e + + ν e also with a continuous spectrum with an
end point at 15 MeV. Their total flux on earth is 6.4 × 10 +10 cm −2 s −1 .
8.2.2 Atmospheric Neutrinos
Atmospheric neutrinos [8] are produced in the decays of π and K mesons produced
in the interactions of cosmic rays in the upper atmosphere. Their energy ranges over
several orders of magnitude up to hundreds of GeV. They are observed either coming
from above or from below and in the latter case they will have traversed the earth.
This allows us to observe them from a few kilometers to about 13,000 km from their
production point, thus providing us with very different baselines over which to study
oscillations. These predominantly ν e and ν μ neutrinos are usually observed through
their charged current interactions respectively producing electrons or muons.
L. Camilleri
neutrino masses, m 2
12 referred to as the solar mass difference as it is of importance
in oscillations of solar neutrinos, m 2
13 ∼ m 2
23 referred to as the atmospheric mass
difference as it drives oscillations of neutrinos produced in the atmosphere through
the decay of mesons produced in cosmic ray interactions. The flavour of interacting
neutrinos can only be determined if the interaction is via a charged current. In these,
the ν e , ν μ and ν τ respectively produce a negative electron, muon or τ lepton in the
final state. Antineutrinos produce the corresponding positive charged lepton.
8.2 Sources of Neutrinos and Their Characteristics
Naturally occurring neutrinos and man-made neutrinos are produced through
several different processes. Nature provides us with solar neutrinos emitted by
the sun, atmospheric neutrinos produced by the interaction of cosmic rays in the
atmosphere, cosmological neutrinos produced by a variety of deep space violent
events, geological neutrinos produced by nuclear decays in the earth core as well
as neutrinos produced in beta decay. Man made neutrinos are produced by nuclear
reactors or by specially designed beams at accelerators or by highly radioactive
sources. These processes are briefly described below.
8.2.1 Solar Neutrinos
They are emitted in nuclear reactions occurring in the sun [7]. The three main
reactions are p + p → d + e + + ν e , emitting a continuous spectrum of neutrinos
with an end point at 0.4 MeV, e+ 7 Be → 7 Li + ν e with a monochromatic spectrum
at 0.862 MeV and 8 B → 8 Be
∗
+ e + + ν e also with a continuous spectrum with an
end point at 15 MeV. Their total flux on earth is 6.4 × 10 +10 cm −2 s −1 .
8.2.2 Atmospheric Neutrinos
Atmospheric neutrinos [8] are produced in the decays of π and K mesons produced
in the interactions of cosmic rays in the upper atmosphere. Their energy ranges over
several orders of magnitude up to hundreds of GeV. They are observed either coming
from above or from below and in the latter case they will have traversed the earth.
This allows us to observe them from a few kilometers to about 13,000 km from their
production point, thus providing us with very different baselines over which to study
oscillations. These predominantly ν e and ν μ neutrinos are usually observed through
their charged current interactions respectively producing electrons or muons.