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1337 I. INTRODUCTION The investigation into the basic properties of the particle
known as the neutrino has been a particularly strong and
active area of research within nuclear and particle physics.
Research conducted over the latter half of the 20th century
has revealed, for example, that neutrinos can no longer be
considered as massless particles in the standard model, representing perhaps the ﬁrst signiﬁcant alteration to the theory.
Moving into the 21st century, neutrino research continues to
expand in new directions. Researchers further investigate
the nature of the neutrino mass or explore whether neutrinos
can help explain the matter-antimatter asymmetry of the
Universe. At the heart of many of these experiments is the
need for neutrinos to interact with other standard model
particles. An understanding of these basic interaction cross
sections is often an understated but truly essential element of
any experimental neutrino program.
The known reactions of neutrinos with matter fall completely within the purview of the standard model of particle
physics. The model of electroweak interactions govern what
those reactions should be, with radiative corrections that can be
Ó 2012 American Physical Society 1308 Joseph A. Formaggio and G. P. Zeller: From eV to EeV: Neutrino cross sections . . . accurately calculated to many orders. As such, our goal in this
review is essentially already complete: we would simply write
down the electroweak Lagrangian and we would be ﬁnished.
Of course, in practice this is very far from the truth. As with
many other disciplines, many factors compound our simple
description, including unclear initial-state conditions, subtlebut-important nuclear corrections, ﬁnal-state interactions, and
other effects. One quickly ﬁnds that theoretical approximations
which work well in one particular energy regime completely
break down elsewhere. Even the language used in describing
certain processes in one context may seem completely foreign
in another. Previous neutrino experiments could avoid this
issue by virtue of the energy range in which they operated;
now, however, more experiments ﬁnd themselves ‘‘crossing
boundaries’’ between different energy regimes. Thus, the need
for understanding neutrino cross sections across many decades
of energy is becoming more imperative. To summarize our
current collective understanding, this work provides a review of
neutrino cross sections across all explored energy scales. The
range of energies covered, as well as their relevance to various
neutrino sources, is highlighted in Fig. 1. We ﬁrst establish the
formalism of neutrino interactions by considering the simplest
case of neutrino-electron scattering. Our focus will then shift to
neutrino interaction cross sections at low (1–100 MeV), intermediate (0.1–20 GeV), high (20–500 GeV), and ultrahigh
(0.5 TeV–1 EeV) energies, empha...
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