Unformatted text preview: resonance state. The resultant baryonic
resonance (Á, N Ã ) decays to a variety of possible mesonic ﬁnal states producing combinations of nucleons
Deep inelastic scattering: Given enough energy, the
neutrino can resolve the individual quark constituents
of the nucleon. This is called deep inelastic scattering
and manifests in the creation of a hadronic shower.
As a result of these competing processes, the products of
neutrino interactions include a variety of ﬁnal states ranging
from the emission of nucleons to more complex ﬁnal states
including pions, kaons, and collections of mesons (Fig. 8).
This energy regime is often referred to as the ‘‘transition
region’’ because it corresponds to the boundary between
quasielastic scattering (in which the target is a nucleon) on
the one end and deep inelastic scattering (in which the target
is the constituent parton inside the nucleon) on the other.
Historically, adequate theoretical descriptions of quasielastic,
resonance-mediated, and deep inelastic scattering have been
formulated, however, there is no uniform description which Joseph A. Formaggio and G. P. Zeller: From eV to EeV: Neutrino cross sections . . .
cm2 / GeV) kaon 0.8 -38 0.7 cross section / E (10 CC (Arbitrary Units) 1
0.9 multi- 0.6
0.4 1 0.3
0.2 nucleon 0.1
0 0.5 1 1.5 2 2.5 3 3.5 4 1.4
0.8 QE 0.6 DIS 0.4 RES 0.2
0 4.5 10 -1 1 E (GeV) 10 10 2 globally describes the transition between these processes or
how they should be combined. Moreover, the full extent to
which nuclear effects impact this region is a topic that has
only recently been appreciated. Therefore, in this section, we
focus on what is currently known, both experimentally and
theoretically, about each of the exclusive ﬁnal-state processes
that participate in this region.
To start, Fig. 9 summarizes the existing measurements of
CC neutrino and antineutrino cross sections across this intermediate energy range
N ! À X; (54) N ! þ X:
" (55) These results have been accumulated over many decades
using a variety of neutrino targets and detector technologies.
We immediately notice three things from this ﬁgure. First, the
total cross sections approaches a linear dependence on neutrino energy. This scaling behavior is a prediction of the quark
parton model (Feynman, 1969), a topic we return to later, and
is expected if pointlike scattering off quarks dominates the
scattering mechanism, for example, in the case of deep
inelastic scattering. Such assumptions break down, of course,
at lower neutrino energies (i.e., lower momentum transfers).
Second, the neutrino cross sections at the lower energy end of
this region are not typically as well measured as their highenergy counterparts. This is generally due to the lack of high
statistics data historically available in this energy range and
the challenges that arise when trying to describe all of the
various underlying physical processes that can participate in
this region. Third, ant...
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