We study neutrino-induced charged-current (CC) \(\pi^0\) production on carbon nuclei using events with fully imaged final-state proton-\(\pi^0\) systems. Novel use of final-state correlations based ...on transverse kinematic imbalance enable the first measurements of the struck nucleon's Fermi motion, of the intranuclear momentum transfer (IMT) dynamics, and of the final-state hadronic momentum configuration in neutrino pion production. Event distributions are presented for i) the momenta of neutrino-struck neutrons below the Fermi surface, ii) the direction of missing transverse momentum characterizing the strength of IMT, and iii) proton-pion momentum imbalance with respect to the lepton scattering plane. The observed Fermi motion and IMT strength are compared to the previous MINERvA measurement of neutrino CC quasielastic-like production. The measured shapes and absolute rates of these distributions, as well as the cross-section asymmetries show tensions with predictions from current neutrino generator models.
Phys. Rev. D 101, 112007 (2020) MINERvA reports inclusive charged-current cross sections for muon neutrinos
on hydrocarbon in the NuMI beamline. We measured the double-differential cross
section in ...terms of the longitudinal and transverse muon momenta, as well as
the single-differential cross sections in those variables. The data used in
this analysis correspond to an exposure of $3.34 \times 10^{20}$ protons on
target with a peak neutrino energy of approximately 3.5 GeV. Measurements are
compared to the GENIE, NuWro and GiBUU neutrino cross-section predictions, as
well as a version of GENIE modified to produce better agreement with prior
exclusive MINERvA measurements. None of the models or variants were able to
successfully reproduce the data across the entire phase space, which includes
areas dominated by each interaction channel.
Two different nuclear-medium effects are isolated using a low three-momentum transfer subsample of neutrino-carbon scattering data from the MINERvA neutrino experiment. The observed hadronic energy ...in charged-current \(\nu_\mu\) interactions is combined with muon kinematics to permit separation of the quasielastic and \(\Delta\)(1232) resonance processes. First, we observe a small cross section at very low energy transfer that matches the expected screening effect of long-range nucleon correlations. Second, additions to the event rate in the kinematic region between the quasielastic and \(\Delta\) resonance processes are needed to describe the data. The data in this kinematic region also has an enhanced population of multi-proton final states. Contributions predicted for scattering from a nucleon pair have both properties; the model tested in this analysis is a significant improvement but does not fully describe the data. We present the results as a double-differential cross section to enable further investigation of nuclear models. Improved description of the effects of the nuclear environment are required by current and future neutrino oscillation experiments.
Phys. Rev. Lett. 121, 022504 (2018) Final-state kinematic imbalances are measured in mesonless production of
$\nu_\mu + A \to \mu^- + p + X$ in the MINERvA tracker. Initial- and
final-state nuclear ...effects are probed using the direction of the $\mu^-$-p
transverse momentum imbalance and the initial-state momentum of the struck
neutron. Differential cross sections are compared to predictions based on
current approaches to medium modeling. These models under-predict the cross
section at intermediate intranuclear momentum transfers that generally exceed
the Fermi momenta. As neutrino interaction models need to correctly incorporate
the effect of the nucleus in order to predict neutrino energy resolution in
oscillation experiments, this result points to a region of phase space where
additional cross section strength is needed in current models, and demonstrates
a new technique that would be suitable for use in fine grained liquid argon
detectors where the effect of the nucleus may be even larger.
Separate samples of charged-current pion production events representing two semi-inclusive channels \(\nu_\mu\)-CC(\(\pi^{+}\)) and \(\bar{\nu}_{\mu}\)-CC(\(\pi^{0}\)) have been obtained using ...neutrino and antineutrino exposures of the MINERvA detector. Distributions in kinematic variables based upon \(\mu^{\pm}\)-track reconstructions are analyzed and compared for the two samples. The differential cross sections for muon production angle, muon momentum, and four-momentum transfer \(Q^2\), are reported, and cross sections versus neutrino energy are obtained. Comparisons with predictions of current neutrino event generators are used to clarify the role of the \(\Delta(1232)\) and higher-mass baryon resonances in CC pion production and to show the importance of pion final-state interactions. For the \(\nu_\mu\)-CC(\(\pi^{+}\)) (\(\bar{\nu}_{\mu}\)-CC(\(\pi^{0}\))) sample, the absolute data rate is observed to lie below (above) the predictions of some of the event generators by amounts that are typically 1-to-2 \(\sigma\). However the generators are able to reproduce the shapes of the differential cross sections for all kinematic variables of either data set.
Phys. Rev. D 96, 072003 (2017) The semi-exclusive channel
$\nu_{\mu}+\textrm{CH}\rightarrow\mu^{-}\pi^{0}+\textrm{nucleon(s)}$ is
analyzed using MINERvA exposed to the low-energy NuMI $\nu_{\mu}$ ...beam with
spectral peak at $E_{\nu} \simeq 3$ GeV. Differential cross sections for muon
momentum and production angle, $\pi^{0}$ kinetic energy and production angle,
and for squared four-momentum transfer are reported, and the cross section
$\sigma(E_{\nu})$ is obtained over the range 1.5 GeV $\leq E_{\nu} <$ 20 GeV.
Results are compared to GENIE and NuWro predictions and to published MINERvA
cross sections for $\nu_{\mu}\textrm{-CC}(\pi^{+})$ and
$\bar{\nu}_{\mu}\textrm{-CC}(\pi^{0})$. Disagreements between data and
simulation are observed at very low and relatively high values for muon angle
and for $Q^2$ that may reflect shortfalls in modeling of interactions on
carbon. For $\pi^{0}$ kinematic distributions however, the data are consistent
with the simulation and provide support for generator treatments of pion
intranuclear scattering. Using signal-event subsamples that have reconstructed
protons as well as $\pi^{0}$ mesons, the $p\pi^{0}$ invariant mass distribution
is obtained, and the decay polar and azimuthal angle distributions in the rest
frame of the $p\pi^{0}$ system are measured in the region of $\Delta(1232)^+$
production, $W < 1.4$ GeV.
We present measurements of the neutrino and antineutrino total charged-current cross sections on carbon and their ratio using the MINERvA scintillator-tracker. The measurements span the energy range ...2-22 GeV and were performed using forward and reversed horn focusing modes of the Fermilab low-energy NuMI beam to obtain large neutrino and antineutrino samples. The flux is obtained using a sub-sample of charged-current events at low hadronic energy transfer along with precise higher energy external neutrino cross section data overlapping with our energy range between 12-22 GeV. We also report on the antineutrino-neutrino cross section ratio, Rcc, which does not rely on external normalization information. Our ratio measurement, obtained within the same experiment using the same technique, benefits from the cancellation of common sample systematic uncertainties and reaches a precision of 5% at low energy. Our results for the antineutrino-nucleus scattering cross section and for Rcc are the most precise to date in the energy range \(E_{\nu} <\) 6GeV.
Phys. Rev. Lett. 119, 011802 (2017) Neutral-current production of $K^{+}$ by atmospheric neutrinos is a
background in searches for the proton decay $p \rightarrow K^{+} \bar{\nu}$.
Reactions such as ...$\nu p \rightarrow \nu K^{+} \Lambda$ are indistinguishable
from proton decays when the decay products of the $\Lambda$ are below detection
threshold. Events with $K^{+}$ are identified in MINERvA by reconstructing the
timing signature of a $K^{+}$ decay at rest. A sample of 201 neutrino-induced
neutral-current $K^{+}$ events is used to measure differential cross sections
with respect to the $K^{+}$ kinetic energy, and the non-$K^{+}$ hadronic
visible energy. An excess of events at low hadronic visible energy is observed
relative to the prediction of the NEUT event generator. Good agreement is
observed with the cross section prediction of the GENIE generator. A search for
photons from $\pi^{0}$ decay, which would veto a neutral-current $K^{+}$ event
in a proton decay search, is performed, and a 2$\sigma$ deficit of detached
photons is observed relative to the GENIE prediction.
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