arXiv subjects

A. Lovlein

Publications and source records attributed to A. Lovlein.

4 recordsLinked to original sources

arXiv2019

Neutron measurements from anti-neutrino hydrocarbon reactions

Charged-current anti-neutrino interactions on hydrocarbon scintillator in the MINERvA detector are used to study activity from their final-state neutrons. To ensure that most of the neutrons are from the primary interaction, rather than hadronic reinteractions in the detector, the sample is limited to momentum transfers below 0.8 GeV/c. From 16,129 interactions, 15,246 neutral particle candidates are observed. The reference simulation predicts 64\% of these candidates are due to neutrons from the anti-neutrino interaction directly, but also overpredicts the number of candidates by 15\% overall, which is beyond the standard uncertainty estimates for models of neutrino interactions and neutron propagation in the detector. Using the measured distributions for energy deposition, time of flight, position, and speed, we explore the sensitivity to the details those two aspects of the models. We also use multiplicity distributions to evaluate the presence of a two-nucleon knockout process. These results provide critical new information toward a complete description of the hadronic final state of neutrino interactions, which is vital to neutrino oscillation experiments.

hep-ex↗

arXiv2019

Identification of nuclear effects in neutrino-carbon interactions at low three-momentum transfer

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 $ν_μ$ interactions is combined with muon kinematics to permit separation of the quasielastic and $Δ$(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 $Δ$ 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.

hep-ex↗

arXiv2019

Antineutrino Charged-Current reactions on Hydrocarbon with Low Momentum Transfer

We report on multinucleon effects in low momentum transfer ($< 0.8$ GeV/c) anti-neutrino interactions on plastic (CH) scintillator. These data are from the 2010-2011 antineutrino phase of the MINERvA experiment at Fermilab. The hadronic energy spectrum of this inclusive sample is well described when a screening effect at low energy transfer and a two-nucleon knockout process are added to a relativistic Fermi gas model of quasielastic, $Δ$ resonance, and higher resonance processes. In this analysis, model elements introduced to describe previously published neutrino results have quantitatively similar benefits for this antineutrino sample. We present the results as a double-differential cross section to accelerate investigation of alternate models for antineutrino scattering off nuclei.

hep-ex↗

arXiv2015

MINERvA neutrino detector response measured with test beam data

The MINERvA collaboration operated a scaled-down replica of the solid scintillator tracking and sampling calorimeter regions of the MINERvA detector in a hadron test beam at the Fermilab Test Beam Facility. This article reports measurements with samples of protons, pions, and electrons from 0.35 to 2.0 GeV/c momentum. The calorimetric response to protons, pions, and electrons are obtained from these data. A measurement of the parameter in Birks' law and an estimate of the tracking efficiency are extracted from the proton sample. Overall the data are well described by a Geant4-based Monte Carlo simulation of the detector and particle interactions with agreements better than 4%, though some features of the data are not precisely modeled. These measurements are used to tune the MINERvA detector simulation and evaluate systematic uncertainties in support of the MINERvA neutrino cross section measurement program.

physics.ins-det↗