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.
The first direct measurement of electron-neutrino quasielastic and quasielastic-like scattering on hydrocarbon in the few-GeV region of incident neutrino energy has been carried out using the MINERvA ...detector in the NuMI beam at Fermilab. The flux-integrated differential cross sections in electron production angle, electron energy and \(Q^{2}\) are presented. The ratio of the quasielastic, flux-integrated differential cross section in \(Q^{2}\) for \(\nu_{e}\) with that of similarly-selected \(\nu_{\mu}\)-induced events from the same exposure is used to probe assumptions that underpin conventional treatments of charged-current \(\nu_{e}\) interactions used by long-baseline neutrino oscillation experiments. The data are found to be consistent with lepton universality and are well-described by the predictions of the neutrino event generator GENIE.
The total cross sections are important ingredients for the current and future neutrino oscillation experiments. We present measurements of the total charged-current neutrino and antineutrino cross ...sections on scintillator (CH) in the NuMI low-energy beamline using an {\em in situ} prediction of the shape of the flux as a function of neutrino energy from 2--50 GeV. This flux prediction takes advantage of the fact that neutrino and antineutrino interactions with low nuclear recoil energy (\(\nu\)) have a nearly constant cross section as a function of incident neutrino energy. This measurement is the lowest energy application of the low-\(\nu\) flux technique, the first time it has been used in the NuMI antineutrino beam configuration, and demonstrates that the technique is applicable to future neutrino beams operating at multi-GeV energies. The cross section measurements presented are the most precise measurements to date below 5 GeV.
Neutrino-induced charged-current coherent kaon production, \(\nu_{\mu}A\rightarrow\mu^{-}K^{+}A\), is a rare, inelastic electroweak process that brings a \(K^+\) on shell and leaves the target ...nucleus intact in its ground state. This process is significantly lower in rate than neutrino-induced charged-current coherent pion production, because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state \(K^+\), \(\mu^-\) and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at \(3\sigma\) significance.
Production of K^{+} mesons in charged-current \nu_{\mu} interactions on plastic scintillator (CH) is measured using MINERvA exposed to the low-energy NuMI beam at Fermilab. Timing information is used ...to isolate a sample of 885 charged-current events containing a stopping K^{+} which decays at rest. The differential cross section in K^{+} kinetic energy, d\sigma/dT_{K}, is observed to be relatively flat between 0 and 500 MeV. Its shape is in good agreement with the prediction by the \textsc{genie} neutrino event generator when final-state interactions are included, however the data rate is lower than the prediction by 15\%.
Single neutral pion production via muon antineutrino charged-current interactions in plastic scintillator (CH) is studied using the \minerva detector exposed to the NuMI low-energy, wideband ...antineutrino beam at Fermilab. Measurement of this process constrains models of neutral pion production in nuclei, which is important because the neutral-current analog is a background for \(\bar{\nu}_e\) appearance oscillation experiments. The differential cross sections for \(\pi^0\) momentum and production angle, for events with a single observed \(\pi^0\) and no charged pions, are presented and compared to model predictions. These results comprise the first measurement of the \(\pi^0\) kinematics for this process.
Charged pion production via charged current \(\nu_{\mu}\) interactions on plastic (CH) is studied using the MINERvA detector exposed to the NuMI wideband neutrino beam at Fermilab. Events with ...hadronic invariant mass W \(<\) 1.4 GeV are selected to isolate single pion production, which is expected to occur primarily through the \(\Delta(1232)\) resonance. Cross sections as functions of pion production angle and kinetic energy are reported and compared to predictions from different theoretical calculations and generator-based models, for neutrinos ranging in energy from 1.5 GeV to 10 GeV. The data are best described by calculations which include significant contributions from pion intranuclear rescattering. These measurements constrain the primary interaction rate and the role of final state interactions in pion production, both of which need to be well understood by neutrino oscillation experiments.
A study of charged-current muon neutrino scattering on hydrocarbon in which the final state includes a muon and a proton and no pions is presented. Although this signature has the topology of ...neutrino quasielastic scattering from neutrons, the event sample contains contributions from both quasielastic and inelastic processes where pions are absorbed in the nucleus. The analysis accepts events with muon production angles up to 70\(^{\circ}\) and proton kinetic energies greater than 110 MeV. The extracted cross section, when based completely on hadronic kinematics, is well-described by a simple relativistic Fermi gas nuclear model including the neutrino event generator modeling for inelastic processes and particle transportation through the nucleus. This is in contrast to the quasielastic cross section based on muon kinematics, which is best described by an extended model that incorporates multi-nucleon correlations. This measurement guides the formulation of a complete description of neutrino-nucleus interactions that encompasses the hadronic as well as the leptonic aspects of this process.
We present measurements of \(\nu_{\mu}\) charged-current cross section ratios on carbon, iron, and lead relative to a scintillator (CH) using the fine-grained MINERvA detector exposed to the NuMI ...neutrino beam at Fermilab. The measurements utilize events of energies \(2<E_{\nu}<20~GeV\), with \(\left< E_{\nu}\right>=8~GeV\), which have a reconstructed \(\mu^{-}\) scattering angle less than \(17^\circ\) to extract ratios of inclusive total cross sections as a function of neutrino energy \(E_{\nu}\) and flux-integrated differential cross sections with respect to the Bjorken scaling variable \(x\). These results provide the first high-statistics direct measurements of nuclear effects in neutrino scattering using different targets in the same neutrino beam. Measured cross section ratios exhibit a relative depletion at low \(x\) and enhancement at large \(x\). Both become more pronounced as the nucleon number of the target nucleus increases. The data are not reproduced by GENIE, a conventional neutrino-nucleus scattering simulation, or by the alternative models for the nuclear dependence of inelastic scattering that are considered.
Neutrino-induced coherent charged pion production on nuclei, \(\stackrel{(-)}{\nu}_\mu A\to\mu^\pm\pi^\mp A\) is a rare, inelastic interaction in which a small squared four-momentum \(| t|\) is ...transferred to the recoil nucleus leaving it intact in the reaction. In the scintillator tracker of MINERvA, we remove events with evidence of particles from nuclear breakup and reconstruct \(| t|\) from the final state pion and muon. We select low \(| t|\) events to isolate a sample rich in coherent candidates. By selecting low \(| t|\) events we produce a model-independent measurement of the differential cross section for coherent scattering of neutrinos and anti-neutrinos on carbon. We find poor agreement with the predicted kinematics in neutrino generators used by current oscillation experiments.
