Lepton-nucleus cross section measurements for DUNE with the LDMX detector

Abstract

We point out that the LDMX (Light Dark Matter eXperiment) detector design, conceived to search for sub-GeV dark matter, will also have very advantageous characteristics to pursue electron-nucleus scattering measurements of direct relevance to the neutrino program at DUNE and elsewhere. These characteristics include a 4-GeV electron beam, a precision tracker, electromagnetic and hadronic calorimeters with near 2π azimuthal acceptance from the forward beam axis out to ∼40 • angle, and low reconstruction energy threshold. LDMX thus could provide (semi)exclusive cross-section measurements, with detailed information about final-state electrons, pions, protons, and neutrons. We compare the predictions of two widely-used neutrino generators (genie, gibuu) in the LDMX region of acceptance to illustrate the large modeling discrepancies in electron-nucleus interactions at DUNE-like kinematics. We argue that discriminating between these predictions is well within the capabilities of the LDMX detector.

Assessing the accuracy of the GENIE event generator with electron-scattering data

“…In the short term, these data have the potential to stimulate improving accuracy of Monte Carlo generators employed in neutrino physics. In particular, the CLAS data has an excellent coverage in the kinematic space of DUNE, as summarized in Appendix C. We also strongly encourage future dedicated data-taking campaigns, at various experiments at Jefferson Laboratory and at the proposed LDMX experiment at SLAC [69].…”

“…This requires a combined theory-experiment effort, with theory frameworks that respect quark-hadron duality benchmarked against new experimental data with detailed information about hadronic final states. An example of an experiment that could accomplish this is provided by CLAS and by the LDMX setup [69]. Finally, a connection to neutrino data should be discussed.…”

Deep Underground Neutrino Experiment (DUNE) Near Detector Conceptual Design Report

“…The DUNE ND will be able to test the improved cross section predictions from CLAS. Other experiments, such as Light Dark Matter eXperiment (LDMX) [233], are also exploring the possibility of making charged lepton scattering measurements to help DUNE, making this a promising avenue to pursue.…”

Recent highlights from GENIE v3

“…The community is also in the process of reviewing and improving the electron scattering data. For example, high-statistics datasets from the CLAS6 detector at Jefferson Laboratory were analysed [27] and new experiments (e4ν, Mainz, and LDMX) designed to support neutrino interaction experiments will start data taking in 2021 [28][29][30]. Major emphasis in these new measurements will be placed on a detailed description of the hadronic part of the final state.…”