The next generation of long-baseline neutrino experiments will be capable of
precision measurements of neutrino oscillation parameters, precision
neutrino-nucleus scattering, and unprecedented sensitivity to physics beyond
the Standard Model. Reduced uncertainties in neutrino fluxes are necessary to
achieve high precision and sensitivity in these future precise neutrino
measurements. New measurements of hadron-nucleus interaction cross sections are
needed to reduce uncertainties of neutrino fluxes. We report measurements of
the differential cross-section as a function of scattering angle for
proton-carbon interactions with a single charged particle in the final state at
beam momenta of 20, 30, and 120 GeV/c. These measurements are the result of a
beam test for EMPHATIC, a hadron-scattering and hadron-production experiment.
The total, elastic and inelastic cross-sections are also extracted from the
data and compared to previous measurements. These results can be used in
current and future long-baseline neutrino experiments, and demonstrate the
feasibility of future measurements by an upgraded EMPHATIC spectrometer