Measurement of the Multi-Neutron νˉμ\bar{\nu}_{\mu} Charged Current Differential Cross Section at Low Available Energy on Hydrocarbon

Neutron production in antineutrino interactions can lead to bias in energy reconstruction in neutrino oscillation experiments, but these interactions have rarely been studied. MINERvA previously studied neutron production at an average antineutrino energy of ~3 GeV in 2016 and found deficiencies in leading models. In this paper, the MINERvA 6 GeV average antineutrino energy data set is shown to have similar disagreements. A measurement of the cross section for an antineutrino to produce two or more neutrons and have low visible energy is presented as an experiment-independent way to explore neutron production modeling. This cross section disagrees with several leading models' predictions. Neutron modeling techniques from nuclear physics are used to quantify neutron detection uncertainties on this result.Comment: 25 pages, 11 figures; Added ancillary files with cross section values as .csv Matches preprint accepted by publishe

Neutrino-induced coherent π+\pi^{+} production in C, CH, Fe and Pb at ⟨Eν⟩∼6\langle E_{\nu}\rangle \sim 6 GeV

MINERvA has measured the $\nu_{\mu}$-induced coherent $\pi^{+}$ cross section simultaneously in hydrocarbon (CH), graphite (C), iron (Fe) and lead (Pb) targets using neutrinos from 2 to 20 GeV. The measurements exceed the predictions of the Rein-Sehgal and Berger-Sehgal PCAC based models at multi-GeV $\nu_{\mu}$ energies and at produced $\pi^{+}$ energies and angles, $E_{\pi}>1$ GeV and $\theta_{\pi}<10^{\circ}$. Measurements of the cross-section ratios of Fe and Pb relative to CH reveal the effective $A$-scaling to increase from an approximate $A^{1/3}$ scaling at few GeV to an $A^{2/3}$ scaling for $E_{\nu}>10$ GeV

Simultaneous measurement of muon neutrino quasielastic-like cross sections on CH, C, water, Fe, and Pb as a function of muon kinematics at MINERvA

This paper presents the first simultaneous measurement of the quasielastic-like neutrino-nucleus cross sections on C, water, Fe, Pb and scintillator (hydrocarbon or CH) as a function of longitudinal and transverse muon momentum. The ratio of cross sections per nucleon between Pb and CH is always above unity and has a characteristic shape as a function of transverse muon momentum that evolves slowly as a function of longitudinal muon momentum. The ratio is constant versus longitudinal momentum within uncertainties above a longitudinal momentum of 4.5GeV/c. The cross section ratios to CH for C, water, and Fe remain roughly constant with increasing longitudinal momentum, and the ratios between water or C to CH do not have any significant deviation from unity. Both the overall cross section level and the shape for Pb and Fe as a function of transverse muon momentum are not reproduced by current neutrino event generators. These measurements provide a direct test of nuclear effects in quasielastic-like interactions, which are major contributors to long-baseline neutrino oscillation data samples.Comment: 9 pages, 8 flgures, including supplemental materia

Simultaneous measurement of muon neutrino νμ\nu_\mu charged-current single π+\pi^+ production in CH, C, H2_2O, Fe, and Pb targets in MINERvA

Neutrino-induced charged-current single $\pi^+$ production in the $\Delta(1232)$ resonance region is of considerable interest to accelerator-based neutrino oscillation experiments. In this work, high statistics differential cross sections are reported for the semi-exclusive reaction $\nu_\mu A \to \mu^- \pi^+ +$ nucleon(s) on scintillator, carbon, water, iron, and lead targets recorded by MINERvA using a wide-band $\nu_\mu$ beam with \left \approx 6~GeV. Suppression of the cross section at low $Q^2$ and enhancement of low $T_\pi$ are observed in both light and heavy nuclear targets compared to phenomenological models used in current neutrino interaction generators. The cross-section ratios for iron and lead compared to CH across the kinematic variables probed are 0.8 and 0.5 respectively, a scaling which is also not predicted by current generators.Comment: 6 pages, 6 figures, 117 pages of supplementary material; submitted to Physical Review Letter

Improved constraint on the MINERνA medium energy neutrino flux using ν¯e−→ν¯e− data

Processes with precisely known cross sections, like neutrino-electron elastic scattering (νe−→νe−) and inverse muon decay (νμe−→μ−νe) have been used by MINERνA to constrain the uncertainty on the neutrinos at the main injector (NuMI) neutrino beam flux. This work presents a new measurement of neutrino elastic scattering with electrons using the medium energy ¯νμ-enhanced NuMI beam. A sample of 578 events after background subtraction is used in combination with the previous measurement on the νμ beam and the inverse muon decay measurement to reduce the uncertainty on the νμ flux in the νμ-enhanced beam from 7.6% to 3.3% and the ¯νμ flux in the ¯νμ-enhanced beam from 7.8% to 4.7%

Improved constraint on the MINERνA medium energy neutrino flux using ν¯e−→ν¯e− data

Processes with precisely known cross sections, like neutrino-electron elastic scattering (νe−→νe−) and inverse muon decay (νμe−→μ−νe) have been used by MINERνA to constrain the uncertainty on the neutrinos at the main injector (NuMI) neutrino beam flux. This work presents a new measurement of neutrino elastic scattering with electrons using the medium energy ¯νμ-enhanced NuMI beam. A sample of 578 events after background subtraction is used in combination with the previous measurement on the νμ beam and the inverse muon decay measurement to reduce the uncertainty on the νμ flux in the νμ-enhanced beam from 7.6% to 3.3% and the ¯νμ flux in the ¯νμ-enhanced beam from 7.8% to 4.7%

First operation of an ALICE OROC operated in high pressure Ar-CO2_{2} and Ar-CH4_{4}

New neutrino-nucleus interaction cross-section measurements are required to improve nuclear models sufficiently for future long-baseline neutrino experiments to meet their sensitivity goals. A time projection chamber (TPC) filled with a high-pressure gas is a promising detector to characterise the neutrino sources planned for such experiments. A gas-filled TPC is ideal for measuring low-energy particles as they travel much further in gas than solid or liquid neutrino detectors. Using a high-pressure gas increases the target density, resulting in more neutrino interactions. This paper will examine the suitability of multiwire proportional chambers (MWPCs) taken from the ALICE TPC to be used as the readout chambers of a high-pressure gas TPC. These chambers were previously operated at atmospheric pressure. We tested one such MWPC at up to almost 5 bar absolute (barA) with the UK high-pressure test stand at Royal Holloway, University of London. This paper reports the successful operation of an ALICE TPC outer readout chamber (OROC) at pressures up to 4.8 bar absolute with Ar-CH$_{4}$ mixtures with a CH$_{4}$ content between 2.8% and 5.0%, and so far up to 4 bar absolute with Ar-CO$_{2}$ (90-10). We measured the charge gain of this OROC using signals induced by an $^{55}$Fe source. The largest gain achieved at 4.8 bar was $64\pm2)\cdot10^{3}$ at stable conditions with an anode wire voltage of 2990 V in Ar-CH$_{4}$ (95.9-4.1). In Ar-CO$_{2}$ a gain of $(4.2\pm0.1)\cdot10^{3}$ was observed at an anode voltage of 2975 V at 4 barA gas pressure. Based on all our gain measurements, we extrapolate that, at the 10 barA pressure necessary to fit 1 tonne of gas into the ALICE TPC volume, a gain of 5000 in Ar-CO$_{2}$ (90-10) (10000 in Ar-CH$_{4}$ with $\sim\!$ 4% CH$_{4}$ content) may be achieved with an OROC anode voltage of 4.2 V ($\sim\!$ 3.1 kV)

First operation of an ALICE OROC operated in high pressure Ar-CO 2 and Ar-CH 4

New neutrino–nucleus interaction cross-section measurements are required to improve nuclear models sufficiently for future long baseline neutrino experiments to meet their sensitivity goals. A time projection chamber (TPC) filled with a high-pressure gas is a promising detector to characterise the neutrino sources used for such experiments. A gas-filled TPC is ideal for measuring low-energy particles, which travel further in gas than in solid or liquid detectors and using high-pressure increases the target density, resulting in more neutrino interactions. We examine the suitability of multiwire proportional chambers (MWPCs) from the ALICE TPC for use as the readout chambers of a high-pressure gas TPC. These chambers were previously operated at atmospheric pressure. We report the successful operation of an ALICE TPC outer readout chamber (OROC) at pressures up to 4.2 bar absolute (barA) with Ar-CH4 mixtures with a CH4 content between 2.8 and 5.0%, and so far up to 4 bar absolute with Ar-CO2 (90-10). The charge gain of the OROC was measured with signals induced by an 55Fe source. The largest gain achieved at 4.2 bar was (29±1)·103 in Ar-CH4 with 4.0% CH4 with an anode voltage of 2975V. In Ar-CO2 with 10% CO2 at 4 barA, a gain of (4.2±0.1)·103 was observed with anode voltage 2975V. We extrapolate that at 10 barA, an interesting pressure for future neutrino experiments, a gain of 5000 in Ar-CO2 with 10% CO2 (10,000 in Ar-CH4 with ∼4%CH4) may be achieved with anode voltage of 4.6kV (∼3.6kV)

Electron Scattering and Neutrino Physics

A thorough understanding of neutrino-nucleus scattering physics is crucial for the successful execution of the entire US neutrino physics program. Neutrino-nucleus interaction constitutes one of the biggest systematic uncertainties in neutrino experiments - both at intermediate energies affecting long-baseline Deep Underground Neutrino Experiment (DUNE), as well as at low energies affecting coherent scattering neutrino program - and could well be the difference between achieving or missing discovery level precision. To this end, electron-nucleus scattering experiments provide vital information to test, assess and validate different nuclear models and event generators intended to be used in neutrino experiments. In this white paper, we highlight connections between electron- and neutrino-nucleus scattering physics at energies ranging from 10s of MeV to a few GeV, review the status of ongoing and planned electron scattering experiments, identify gaps, and layout a path forward that benefits the neutrino community. We also highlight the systemic challenges with respect to the divide between the nuclear and high-energy physics communities and funding that presents additional hurdle in mobilizing these connections to the benefit of neutrino programs