Simultaneous measurement of muon neutrino $ν_μ$ charged-current single $π^+$ production in CH, C, H$_2$O, Fe, and Pb targets in MINERvA

Abstract

Neutrino-induced charged-current single π + production in the ∆(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 νµA → µ − π + + nucleon(s) on scintillator, carbon, water, iron, and lead targets recorded by MINERvA using a wide-band νµ beam with Eν ≈ 6 GeV. Suppression of the cross section at low Q 2 and enhancement of low Tπ 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.

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

“…MINERvA recently measured charged-current charged-pion production on different nuclei [9]. Using the same neutrino beam as used here, MINERvA found that the ratio of pions produced on Fe or Pb compared to scintillator is lower than predicted by current models.…”

“…The background levels from non-quasielastic-like interactions are 36% in the scintillator and are 33 − 45% in the nuclear targets, with the lowest background in the Pb targets. The fact that the physics backgrounds are lower in Pb than in the lighter nuclei stems from the fact that pion production is suppressed in heavier nuclei relative to C, as measured by MINERvA [9].…”

“…The nuclear targets do not all have the same integrated neutrino flux because each target covers only a part of the hexagonal shape of the scintillator planes. In order to calculate the cross section on each nuclear target material, a different flux must be used for each material [9]. The cross sections shown in Figure 3 have been calculated using this prescription.…”

MINERvA results and prospects

“…MINERvA: Results and Prospects Deborah A. Harris is seeing a larger ratio for iron and lead to CH than the current models predict. This may be due in part to mis-modeling of pion absorption: MINERvA has also measured pion production in its nuclear targets [19], and sees a relative suppression of the ratio of pion production cross sections for iron or lead divided by scintillator compared to the simulation. If fewer pions are produced than predicted by the simulation, then there are two possibilities for how this might manifest in the quasielastic-like sample.…”

Neutrino-induced coherent $π^{+}$ production in C, CH, Fe and Pb at $\langle E_ν\rangle \sim 6$ GeV

“…As expected, the former is consistent with unity. 2 The CH cross sections used to calculate the ratios, were reweighted to use a flux that matched the flux used to calculate the C, Fe or Pb cross sections [18].…”