Abstract: We report the measurements of the single and double differential cross section of muon neutrino charged-current interactions on carbon with a single positively charged pion in the final state at the T2K off-axis near detector using 5.56 x 10(20) protons on target. The analysis uses data control samples for the background subtraction and the cross section signal, defined as a single negatively charged muon and a single positively charged pion exiting from the target nucleus, is extracted using an unfolding method. The model-dependent cross section, integrated over the T2K off-axis neutrino beam spectrum peaking at 0.6 GeV, is measured to be sigma = (11.76 +/- 0.44(stat) +/- 2.39(syst)) x 10(-40) cm(2) nucleon(-1). Various differential cross sections are measured, including the first measurement of the Adler angles for single charged pion production in neutrino interactions with heavy nuclei target.

Abstract: We report the first measurement of the neutrino-oxygen neutral-current quasielastic (NCQE) cross section gamma It is obtained by observing nuclear deexcitation. rays which follow neutrino-oxygen interactions at the Super-Kamiokande water Cherenkov detector. We use T2K data corresponding to 3.01 x 10(20) protons on target. By selecting only events during the T2K beam window and with well-reconstructed vertices in the fiducial volume, the large background rate from natural radioactivity is dramatically reduced. We observe 43 events in the 4-30 MeV reconstructed energy window, compared with an expectation of 51.0, which includes an estimated 16.2 background events. The background is primarily nonquasielastic neutral-current interactions and has only 1.2 events from natural radioactivity. The flux-averaged NCQE cross section we measure is 1.55 x 10(-38) cm(2) with a 68% confidence interval of (1.22, 2.20) x 10(-38) cm(2) at a median neutrino energy of 630 MeV, compared with the theoretical prediction of 2.01 x 10(-38) cm(2).

Abstract: We report on measurements of neutrino oscillation using data from the T2K long-baseline neutrino experiment collected between 2010 and 2013. In an analysis of muon neutrino disappearance alone, we find the following estimates and 68% confidence intervals for the two possible mass hierarchies: normal hierarchy: sin(2)theta(23) = 0.514(-0.055)(+0.056) and Delta m(32)(2) = (2.51 +/- 0.10) x 10(-3) eV(2)/c(4) and inverted hierarchy: sin(2)theta(23) = 0.511 +/- 0.055 and Delta m(13)(2) = (2.48 +/- 0.10) x 10(-3) eV(2)/c(4). The analysis accounts for multinucleon mechanisms in neutrino interactions which were found to introduce negligible bias. We describe our first analyses that combine measurements of muon neutrino disappearance and electron neutrino appearance to estimate four oscillation parameters, vertical bar Delta m(2)vertical bar, sin(2)theta(23), sin(2)theta(13,) delta(CP), and the mass hierarchy. Frequentist and Bayesian intervals are presented for combinations of these parameters, with and without including recent reactor measurements. At 90% confidence level and including reactor measurements, we exclude the region delta(CP) = [0.15; 0.83]pi for normal hierarchy and delta(CP) = [-0.08; 1.09]pi for inverted hierarchy. The T2K and reactor data weakly favor the normal hierarchy with a Bayes factor of 2.2. The most probable values and 68% one-dimensional credible intervals for the other oscillation parameters, when reactor data are included, are sin(2)theta(23) = 0.528(-0.055)(+0.038) and vertical bar Delta m(32)(2)vertical bar = (2.51 +/- 0.11) x 10(-3) eV(2)/c(4).

Abstract: We report a measurement of the nu(mu)-nucleus inclusive charged-current cross section (= sigma(cc)) on iron using data from the INGRID detector exposed to the J-PARC neutrino beam. The detector consists of 14 modules in total, which are spread over a range of off-axis angles from 0 degrees to 1.1 degrees. The variation in the neutrino energy spectrum as a function of the off-axis angle, combined with event topology information, is used to calculate this cross section as a function of neutrino energy. The cross section is measured to be sigma(cc) (1.1 GeV) = 1.10 +/- 0.15 (10(-38) cm(2)/nucleon), sigma(cc) (2.0 GeV) = 2.07 +/- 0.27 (10(-38) cm(2)/nucleon), and sigma(cc) (3.3 GeV) = 2.29 +/- 0.45 (10(-38) cm(2)/nucleon), at energies of 1.1, 2.0, and 3.3 GeV, respectively. These results are consistent with the cross section calculated by the neutrino interaction generators currently used by T2K. More importantly, the method described here opens up a new way to determine the energy dependence of neutrino-nucleus cross sections.

Abstract: We report a measurement of the nu(mu) charged current quasielastic cross-sections on carbon in the T2K on-axis neutrino beam. The measured charged current quasielastic cross-sections on carbon at mean neutrino energies of 1.94 GeV and 0.93 GeV are (11.95 +/- 0.19(stat)(-1.47)(+1.82)(syst)) x 10(-39) cm(2)/neutron, and (10.64 +/- 0.37(stat)(-1.65)(+2.03)(syst)) x 10(-39) cm(2)/neutron, respectively. These results agree well with the predictions of neutrino interaction models. In addition, we investigated the effects of the nuclear model and the multi-nucleon interaction.