Neutrino Scattering Measurements on Hydrogen and Deuterium: A Snowmass White Paper

Abstract

Neutrino interaction uncertainties are a limiting factor in current and next-generation experiments probing the fundamental physics of neutrinos, a unique window on physics beyond the Standard Model. Neutrino-nucleon scattering amplitudes are an important part of the neutrino interaction program. However, since all modern neutrino detectors are composed primarily of heavy nuclei, knowledge of elementary neutrino-nucleon amplitudes relies heavily on experiments performed in the 1970s and 1980s, whose statistical and systematic precision are insufficient for current needs. In this white paper, we outline the motivation for attempting measurements on hydrogen and deuterium that would improve this knowledge, and we discuss options for making these measurements either with the DUNE near detector or with a dedicated facility.

Form factor and model dependence in neutrino-nucleus cross section predictions

“…Alternative strategies for constraining nucleon axial form factors without nuclear uncertainties are to perform neutrino scattering experiments with hydrogen targets, see Ref. [111] for a discussion of current proposals and challenges, and to calculate nucleon axial form factors theoretically using LQCD, as reviewed in Refs. [53][54][55].…”

“…The LQCD results of Refs. [30,34] lead to nearly indistinguishable cross-section results that will be denoted of 3 to account for systematic uncertainties arising from lattice spacing and quark mass effects [111].…”

Experimental neutrino physics in a nuclear landscape

“…Future neutrino-scattering measurements-whether via the near detectors of short-or long-baseline oscillation experiments or via dedicated experiments such as ANNIE [108], NINJA [109] or nuSTORM [110]-will help illuminate these issues, although in these measurements, it is challenging to disentangle the specific physics mechanisms underlying any discrepancies. Neutrino-nucleon scattering measurements on hydrogen or deuterium targets may help disambiguate results [111].…”

Snowmass Neutrino Frontier Report

“…Support is needed for all stages of achieving this understanding, including new experimental measurements (e.g. [82]), improvements to theoretical neutrino scattering models [83], and refinements to interaction simulations.…”