Tuning the GENIE Pion Production Model with MINERvA Data

Faced with unresolved tensions between neutrino interaction measurements at few-GeV neutrino energies, current experiments are forced to accept large systematic uncertainties to cover discrepancies between their data and model predictions. In this paper, the widely used pion production model in GENIE is compared to four MINERvA charged current pion production measurements using NUISANCE. Tunings, ie, adjustments of model parameters, to help match GENIE to MINERvA and older bubble chamber data are presented here. We find that scattering off nuclear targets as measured in MINERvA is not in good agreement with scattering off nucleon (hydrogen or deuterium) targets in the bubble chamber data. An additional ad hoc correction for the low-$Q^2$ region, where collective effects are expected to be large, is also presented. While these tunings and corrections improve the agreement of GENIE with the data, the modeling is imperfect. The development of these tunings within the NUISANCE frameworkallows for straightforward extensions to other neutrino event generators and models, and allows omitting and including new data sets as they become available

Measurement of quasielastic-like neutrino scattering at (E-v) similar to ~3.5 GeV on a hydrocarbon target

MINERvA presents a new analysis of neutrino induced quasielastic-like interactions in a hydrocarbon tracking target. We report a double-differential cross section using the muon transverse and longitudinal momentum. In addition, differential cross sections as a function of the square of the four-momentum transferred and the neutrino energy are calculated using a quasielastic hypothesis. Finally, an analysis of energy deposited near the interaction vertex is presented. These results are compared to modified genie predictions as well as a NuWro prediction. All results use a data set produced by 3.34 × 10^20 protons on target creating a neutrino beam with a peak energy of approximately 3.5 GeV

Measurement of ¯ ν μ charged-current single π − production on hydrocarbon in the few-GeV region using MINERvA

The antineutrino scattering channel ¯ ν μ CH → μ + π − X (nucleon(s)) is analyzed in the incident energy range 1.5 to 10 GeV using the MINERvA detector at Fermilab. Differential cross sections are reported as functions of μ + momentum and production angle, π − kinetic energy and production angle, and antineutrino energy and squared four-momentum transfer. Distribution shapes are generally reproduced by simulations based on the GENIE, NuWro, and GiBUU event generators, however GENIE (GiBUU) overestimates (underestimates) the cross section normalizations by 8% (10%). Comparisons of data with the GENIE-based reference simulation probe conventional treatments of cross sections and pion intranuclear rescattering. The distribution of nontrack vertex energy is used to decompose the signal sample into reaction categories, and cross sections are determined for the exclusive reactions μ + π − n and μ + π − p . A similar treatment applied to the published MINERvA sample ¯ ν μ CH → μ + π 0 X [nucleon(s)] has determined the μ + π 0 n cross section, and the latter is used with σ ( π − n ) and σ ( π − p ) to carry out an isospin decomposition of ¯ ν μ -induced CC ( π ) . The ratio of magnitudes and relative phase for isospin amplitudes A 3 and A 1 thereby obtained are: R ¯ ν = 0.99 ± 0.19 and ϕ ¯ ν = 9 3 ° ± 7 ° . Our results are in agreement with bubble chamber measurements made four decades ago

Nuclear binding energy and transverse momentum imbalance in neutrino-nucleus reaction

Observables based on the final state kinematic imbalances are measured in the mesonless production of $\nu_\mu+A\rightarrow\mu^-+p+X$ in the MINERvA tracker. Components of the muon-proton momentum imbalances parallel ($\delta p_{Ty}$) and perpendicular($\delta p_{Tx}$) to the momentum transfer in the transverse plane are found to be sensitive to the nuclear effects such as Fermi motion, binding energy and non-QE contributions. The QE peak location in $\delta p_{Ty}$ is particularly sensitive to the binding energy. Differential cross sections are compared to predictions from different neutrino interaction models. None of the Fermi gas models simultaneously describe every feature of the QE peak width, location, and non-QE contribution to the signal process. Correcting the GENIE's binding energy implementation according to theory causes better agreement with data. Hints of proton left-right asymmetry is observed in $\delta p_{Tx}$. Better modelling of the binding energy can reduce bias in neutrino energy reconstruction and these observables can be applied in current and future experiments to better constrain nuclear effects

Measurement of ¯ ν μ charged-current single π − production on hydrocarbon in the few-GeV region using MINERvA

The antineutrino scattering channel ¯ ν μ CH → μ + π − X (nucleon(s)) is analyzed in the incident energy range 1.5 to 10 GeV using the MINERvA detector at Fermilab. Differential cross sections are reported as functions of μ + momentum and production angle, π − kinetic energy and production angle, and antineutrino energy and squared four-momentum transfer. Distribution shapes are generally reproduced by simulations based on the GENIE, NuWro, and GiBUU event generators, however GENIE (GiBUU) overestimates (underestimates) the cross section normalizations by 8% (10%). Comparisons of data with the GENIE-based reference simulation probe conventional treatments of cross sections and pion intranuclear rescattering. The distribution of nontrack vertex energy is used to decompose the signal sample into reaction categories, and cross sections are determined for the exclusive reactions μ + π − n and μ + π − p . A similar treatment applied to the published MINERvA sample ¯ ν μ CH → μ + π 0 X [nucleon(s)] has determined the μ + π 0 n cross section, and the latter is used with σ ( π − n ) and σ ( π − p ) to carry out an isospin decomposition of ¯ ν μ -induced CC ( π ) . The ratio of magnitudes and relative phase for isospin amplitudes A 3 and A 1 thereby obtained are: R ¯ ν = 0.99 ± 0.19 and ϕ ¯ ν = 9 3 ° ± 7 ° . Our results are in agreement with bubble chamber measurements made four decades ago

Measurement of the axial vector form factor from antineutrino-proton scattering.

Scattering of high energy particles from nucleons probes their structure, as was done in the experiments that established the non-zero size of the proton using electron beams1. The use of charged leptons as scattering probes enables measuring the distribution of electric charges, which is encoded in the vector form factors of the nucleon2. Scattering weakly interacting neutrinos gives the opportunity to measure both vector and axial vector form factors of the nucleon, providing an additional, complementary probe of their structure. The nucleon transition axial form factor, FA, can be measured from neutrino scattering from free nucleons, νμn → μ-p and [Formula: see text], as a function of the negative four-momentum transfer squared (Q2). Up to now, FA(Q2) has been extracted from the bound nucleons in neutrino-deuterium scattering3-9, which requires uncertain nuclear corrections10. Here we report the first high-statistics measurement, to our knowledge, of the [Formula: see text] cross-section from the hydrogen atom, using the plastic scintillator target of the MINERvA11 experiment, extracting FA from free proton targets and measuring the nucleon axial charge radius, rA, to be 0.73 ± 0.17 fm. The antineutrino-hydrogen scattering presented here can access the axial form factor without the need for nuclear theory corrections, and enables direct comparisons with the increasingly precise lattice quantum chromodynamics computations12-15. Finally, the tools developed for this analysis and the result presented are substantial advancements in our capabilities to understand the nucleon structure in the weak sector, and also help the current and future neutrino oscillation experiments16-20 to better constrain neutrino interaction models

Measurement of quasielastic-like neutrino scattering at (E-v) similar to 3.5 GeV on a hydrocarbon target

MINERvA presents a new analysis of neutrino induced quasielastic-like interactions in a hydrocarbon tracking target. We report a double-differential cross section using the muon transverse and longitudinal momentum. In addition, differential cross sections as a function of the square of the four-momentum transferred and the neutrino energy are calculated using a quasielastic hypothesis. Finally, an analysis of energy deposited near the interaction vertex is presented. These results are compared to modified genie predictions as well as a NuWro prediction. All results use a data set produced by 3.34×1020 protons on target creating a neutrino beam with a peak energy of approximately 3.5 GeV

Measurement of quasielastic-like neutrino scattering at (E-v) similar to 3.5 GeV on a hydrocarbon target

MINERvA presents a new analysis of neutrino induced quasielastic-like interactions in a hydrocarbon tracking target. We report a double-differential cross section using the muon transverse and longitudinal momentum. In addition, differential cross sections as a function of the square of the four-momentum transferred and the neutrino energy are calculated using a quasielastic hypothesis. Finally, an analysis of energy deposited near the interaction vertex is presented. These results are compared to modified genie predictions as well as a NuWro prediction. All results use a data set produced by 3.34×1020 protons on target creating a neutrino beam with a peak energy of approximately 3.5 GeV

Tuning the GENIE pion production model with MINERvA data

Faced with unresolved tensions between neutrino interaction measurements at few-GeV neutrino energies, current experiments are forced to accept large systematic uncertainties to cover discrepancies between their data and model predictions. The widely used pion production model in genie is compared to four MINERνA charged current pion production measurements using nuisance. Tunings, i.e., adjustments of model parameters, to help match genie to MINERνA and older bubble chamber data are presented. We find that scattering off nuclear targets as measured in MINERνA is not in good agreement with expectations based upon scattering off nucleon (hydrogen or deuterium) targets in existing bubble chamber data. An additional ad hoc correction for the low-Q2 region, where collective nuclear effects are expected to be large, is presented. While these tunings and corrections improve the agreement of genie with the data, the modeling is imperfect. The development of these tunings within the nuisance framework allows for straightforward extensions to other neutrino event generators and models, and allows omitting and including new datasets as they become available