Session T07: Neutrino Interactions

νμ - 40Ar charged current interactions with no pions in the final state with the MicroBooNE detector

The MicroBooNE detector is a single-phase liquid argon time projection chamber with an active mass of 85 tons. It is located on the Booster Neutrino Beam, where it collected data from 2015 to 2020. As part of a broad physics program, MicroBooNE aims to extract precise cross-section measurements of muon neutrino - argon charged current interactions. This presentation will discuss the channel where no pions have been detected in the final state (??0π). Such measurements are important to improve our understanding of nuclear modeling (e.g. final-state interactions, Fermi motion) for analyses that require accurate estimation of the neutrino energy including neutrino oscillations.   

Charged-pion Cross-section Measurements in the NOvA Near Detector

 

The NuMI Off-Axis  Appearance experiment is designed to study neutrinos and their interaction properties with matter. NOvA is a long-baseline neutrino oscillation experiment consisting of a Near Detector at Fermi National Accelerator and Far Detector in Ash River, Minnesota aiming to determine the neutrino mass hierarchy, and constrain the charge parity violation phase. In addition to oscillation measurements, the NOvA Near Detector has detected a vast number of neutrinos, making it an ideal candidate for measuring neutrino cross-sections, which are important for constraining uncertainties in oscillation analyses.  Here, we present the status of an analysis that will use an accumulated  protons on target from the NuMI beam peaked at 1.8GeV of neutrino energy to measure the cross-section of ν_μ + N  → μ^±  + Nπ^±  + X as a function of muon and pion kinematics, where Nπ^± is any number of charged pions, X represents any particles in the final state and the muon is contained.   

First Measurements of Differential Cross Sections In Kinematic Imbalance Variables With The MicroBooNE Detector

Making high-precision measurements of neutrino oscillation parameters requires an unprecedented understanding of neutrino-nucleus scattering. In this presentation, we present the first muon neutrino charged current double-differential cross sections in kinematic imbalance variables. These variables characterize the imbalance in the plane transverse to an incoming neutrino. We use events with a single muon above 100 MeV/c, a single final state proton above 300 MeV/c, and no recorded final state pions. Thus, these variables act as a direct probe of nuclear effects such as final state interactions, Fermi motion, and multi-nucleon processes. We also present a complementary ongoing analysis using electron neutrinos. This channel is of the utmost importance for the extraction of neutrino oscillation parameters by making high-precision measurements. Our measurements allow us to constrain systematic uncertainties associated with neutrino oscillation results performed by near-future experiments of the Short Baseline Neutrino (SBN) program, as well as by future large-scale experiments like DUNE.   

Classifying Muon Neutrino Interactions in the MINERνA Detector using Gradient-Boosted Decision Trees

Gradient-boosted decision trees are used to classify muon neutrino interactions in the MINERνA detector, with the goal of identifying charged-current quasielastic-like scattering events on hyrdocarbon. Decision trees are a popular method used in machine learning for the purposes of both classification and regression, and involve the partitioning of a feature space into rectangular regions for which discrete or continuous values are assigned. Boosting assists this method by forming an ensemble of decision trees that collectively outperforms any individual tree. Packages being used to implement gradient-boosted decision trees are provided by the Toolkit for Multivariate Data Analysis (TMVA) within the ROOT data analysis framework. Preliminary results demonstrate both higher efficiencies and higher purities compared to those produced by conventional cut-based selection methods.   

A GiBUU-Based Monte Carlo Simulation for Neutrino Experiments

This talk presents a Monte Carlo simulation implemented with the GiBUU model tailored for neutrino experiments. Specifically, we focus on its implementation, generating events in a generic liquid argon time projection chamber and comparing them with other neutrino event generators such as GENIE. The simulation generates realistic neutrino event samples, contributing to the prediction and interpretation of experimental outcomes. Our results demonstrate the robust performance of the GiBUU-based simulation framework and highlight its fidelity to the original GiBUU cross-section model. This implementation also enables current work for developing infrastructure to address systematic uncertainties.   

Neutrino cross sections and weak structure functions for low momentum transfers

Deep-inelastic scattering of neutrinos and antineutrinos on nucleon and nuclear targets probes the partonic content of the targets. As the momentum transfer Q decreases, the parton model-based approach is not applicable. We adapt the low-Q electromagnetic structure functions by Capella et al. to neutrino scattering by matching to next-to-leading order weak structure functions based on the parton model at Q=2 GeV. For charged-current scattering with final state invariant masses larger than 1.4-2.0 GeV, we show the impact on the cross section of a PCAC structure function correction. We compare our cross section results with the those using the Bodek-Yang prescription and with the recent Candido et al. low-Q weak structure functions modeled by a machine-learning parameterization of neutrino and antineutrino scattering data. We find discrepancies between the cross sections evaluated at low-Q using our approach and using the Candido et al. low-Q structure functions for isoscalar nucleon targets, however, there is good agreement for heavier targets. We discuss the relevance of the low-Q weak structure functions to experiments at a future Forward Physics Facility at the Large Hadron Collider.