Measurements of ν̄μ and ν̄μ + νμ charged-current cross-sections without detected pions nor protons on water and hydrocarbon at mean antineutrino energy of 0.86 GeV

Abstract

We report measurements of the flux-integrated ν̄μ and ν̄μ + νμ charged-current crosssections on water and hydrocarbon targets using the T2K anti-neutrino beam, with a mean beam energy of 0.86 GeV. The signal is defined as the (anti-) neutrino chargedcurrent interaction with one induced μ } and no detected charged pion nor proton. These measurements are performed using a new WAGASCI module recently added to the T2K setup in combination with the INGRID Proton module. The phase space of muons is restricted to the high-detection efficiency region, pμ > 400 MeV/c and θμ < 30◦, in the laboratory frame. Absence of pions and protons in the detectable phase space of “pπ > 200 MeV/c and θπ < 70◦”, and “pp > 600 MeV/c and θp < 70◦” is required. In this paper, both of the ν̄μ cross-sections and ν̄μ + νμ cross-sections on water and hydrocarbon targets, and their ratios are provided by using the D’Agostini unfolding method. The results of the integrated ν̄μ cross-section measurements over this phase space are σH2O = (1.082 ± 0.068(stat.)+0.145 −0.128(syst.)) × 10−39 cm2/nucleon, σCH = (1.096 ± 0.054(stat.)+0.132 −0.117(syst.)) × 10−39 cm2/nucleon, and σH2O/σCH = 0.987 ± 0.078(stat.)+0.093 −0.090(syst.). The ν̄μ + νμ cross-section is σH2O = (1.155 ± 0.064(stat.)+0.148 −0.129(syst.)) × 10−39 cm2/nucleon, σCH = (1.159 ± 0.049(stat.) +0.129 −0.115(syst.)) × 10−39 cm2/nucleon, and σH2O/σCH = 0.996 ± 0.069(stat.)+0.083 −0.078(syst.).