Session D11: Neutrino Cross Sections

The simulation of the COHERENT multi-tonne NaI[Tl] detector (NaIvETE)

Coherent Elastic Neutrino-Nucleus Scattering (CEvNS), was first observed by the COHERENT Collaboration in 2017 using a 14.6-kg sodium-doped CsI scintillator detector. Efforts on measuring CEvNS in different types of nuclei in order to test the N² dependence of the cross section, are a current focal point of research. The first 5 modules of the NaI Neutrino Experiment TonnE-scale (NaIvETE) will be deployed this year in the Spallation Neutron Source (SNS) in Oak Ridge National Laboratory (ORNL) to measure CEvNS in ²³Na, as well as the inclusive cross section of the electron neutrino charged-current interactions on ¹²⁷I. Understanding background events prior to deployment of the actual detector is a key part of achieving a successful measurement of CEvNS. To that end, GEANT4 simulations have been implemented. This talk will present our results on the construction of the detector geometry using GEARS, and discuss our latest results of the simulations.   

Constraining neutrino interaction model uncertainties in NOvA with a Near Detector fit

NOvA is a long-baseline neutrino experiment based at Fermilab that studies neutrino oscillation parameters via electron neutrino appearance and muon neutrino disappearance. In these measurements, we compare the Far Detector data to a predicted energy spectrum constrained by the Near Detector (ND) data. The ND data is simulated using GENIE, with the neutrino cross section model adjusted to better describe the data by modifying the rate of Meson Exchange Current (MEC) interactions and the Final State Interactions. To characterize the performance of these adjustments, the ND simulation and data are divided into a set of samples based on the multiplicity and topology of visible particles. These samples have meaningful features that are used to constrain the neutrino interaction model and flux parameters using a chi-square fit with ND fake data.    

Measurement of the Low Eavailable Multi-Neutron Antineutrino Cross Section at <Eν> ~ 6 GeV

Measuring (anti)neutrino energy is critical for oscillation experiments.  Neutrons introduce uncertainty and bias into (anti)neutrino energy estimators because they are difficult to reconstruct.  Different rates of neutron production by neutrinos and antineutrinos and the role of neutrons in interactions on correlated nucleon pairs amplify the impact of neutron production models on oscillation experiments.  The relative paucity of antineutrino neutron production measurements makes them even more valueable.  We present a preliminary antineutrino multi-neutron cross section measurement at low E_available on the MINERvA detector's hydrocarbon scintillator at <E_ν> ~ 6 GeV.  Interactions on correlated nucleon pairs are predicted to comprise a large fraction of this channel.  We compare our result to alternative antineutrino interaction models to illuminate opportunities for advances in the theory of neutron production by antineutrinos.   

Status of the νμ charged-current coherent π+ production in the NOvA near detector

Neutrino cross sections are an essential component to any neutrino measurement. With modern neutrino experiments targeting to measure precision parameters, such as those in long-baseline oscillation experiments like NOvA, the need for a detailed understanding of neutrino interactions has become even more important. Among the neutrino-nucleus interactions, Charged-Current Coherent pion production is currently poorly understood. This talk will give an overview of the status of the Charged-Current Coherent Pion Production analysis conducted with the NOvA near detector based at Fermilab that uses Convolutional Neural Networks (CNN) to identify muons and pions. Since NOvA is a long-baseline neutrino oscillation experiment mainly aimed at measuring electron neutrino appearance in a muon neutrino beam with energy 1-5 GeV, the results of this analysis will be relevant for future experiments in this energy range, like DUNE   

Experimental Investigation of low Q2 quasielastic electron scattering on carbon

Reliable modeling of quasielastic (QE) lepton scattering on nuclei is of great interest to neutrino oscillations experiments, especially at low values  of the  3-momentum transfer  q.. We report on a phenomenological analysis of the world's QE electron scattering data on Carbon within the framework of the  superscaling model (including Pauli blocking).  We find that at low values of q there is extra suppression of the QE cross section beyond the expected suppression from Pauli blocking.  The total suppression  is larger than the  minimum suppression predicted by the Coulomb Sum Rule.   

Neutron Cross Section Measurement in ProtoDUNE Single-Phase

The Deep Underground Neutrino Experiment (DUNE) is a long baseline, neutrino oscillation experiment aimed at quantifying CP violation in the neutrino sector using liquid argon as the primary detector medium. DUNE's main physics program is centered around measuring the flavor profile of a beam in neutrino and anti-neutrino modes as a function of energy both at the near and the far detector and will rely on accurate event reconstruction to do so. Understanding the detector response to neutrons will be critical for performing neutrino oscillation analyses in DUNE because they are a source of missing energy. In addition to the primary neutrons produced by the neutrino, subsequent interactions of any charged hadrons produced can result in secondary neutrons. ProtoDUNE Single-Phase sits in a testbeam and is a prototype for the DUNE far detector designed to validate technology and measure charged hadron cross sections at the relevant energies for DUNE; therefore, it is ideal for studying the secondary neutron component. This talk presents a search for neutrons produced in 1 GeV/c pion interactions and then shows a neutron inelastic cross section measurement in liquid argon using the sample of selected neutrons.    

Tau Neutrinos and Cross-Sections at DUNE

The high statistics and excellent resolution capabilities of DUNE's  $^{40}$Ar detector will allow us to make precision studies of oscillation parameters capable of explaining CP violation in the lepton sector, test interaction models, and of studying phenomena that have, until now, seemed too complex to measure, like $\nu_\tau$ detection and therefore, providing the completion of the 3-flavor neutrino paradigm. Good knowledge of the $\nu_\tau$ detection can impact a broad spectrum of open questions; how muon neutrinos oscillate into tau neutrinos with nearly maximal mixing \?, non-standard neutrino interactions, non-unitary constraints, energy dependence in neutrino mixing parameters, the extraction of the oscillation parameter, matter-antimatter asymmetry, look for an extra flavor (sterile neutrino) and the list continues. 

The $\nu_{\tau}$(N) and $\bar{\nu}_{\tau}$(N) cross-sections have large uncertainties as compared to the ones for $\nu_{\mu}$ and $\nu_{e}$, and some studies point out that the reason for these difference is due to the uncertainties in the nucleon structure functions. These nucleon structure functions are used to calculate the DIS cross-section by including kinematical corrections due to the $\tau$-lepton mass, and due to this mass inclusion, another two additional nucleon structure functions become non-negligible, $F_{4N}(x, Q^{2})$ and $F_{5N}(x, Q^{2})$. This presentation will show the semi-theoretical and experimental approach to the estimation of the $\nu_{\tau}$(N) and $\bar{\nu}_{\tau}$(N) cross-sections in DUNE for the DIS region. We aim to look over changes in Q$^{2}$, and the contributions of the additional nucleon structure functions $F_{4N}(x, Q^{2})$ and $F_{5N}(x, Q^{2})$.   

Neutral and Charged Current Neutrino Cross Sections for Liquid Argon Detectors

We present the neutrino neutral current cross sections on 40Ar at neutrino energies expected for supernova events. Several high energy gamma rays are emitted which offer a promising signal for studying the neutral current. In addition, we examine the charged current cross sections using large shell model calculations that are constrained by B(GT) and B(F) measurements but include operators to all orders in q2.    

Improving the MINERvA medium energy neutrino flux prediction with in-situ neutrino electron scattering measurements

Neutrino beams are an essential tool for the study of neutrino physics since they provide a high-intensity source with a tunable energy range.  A precise prediction of the neutrino flux is necessary, however, to make accurate measurements of cross-sections and neutrino oscillations. By measuring the theoretically clean process of elastic scattering of neutrinos on atomic electrons in the MINERvA detector we demonstrate that it is possible to decrease the uncertainty on the neutrino flux. This work shows a new measurement of the rate of antineutrino elastic scattering off electrons during the NuMI medium energy antineutrino-enhanced beam run. This is used in combination with the previous MINERvA results of neutrino-lepton scattering processes to further reduce the flux uncertainty.