Measurement of the inclusive ${\nu }_{\mu }$ charged current cross section on iron and hydrocarbon in the T2K on-axis neutrino beam

We report a measurement of the ${\nu }_{\mu }$ inclusive charged current cross sections on iron and hydrocarbon in the Tokai-to-Kamioka (T2K) on-axis neutrino beam. The measured inclusive charged current cross sections on iron and hydrocarbon averaged over the T2K on-axis flux with a mean neutrino energy of 1.51 GeV are $(1.444\pm 0.002(\text{stat}{)}_{-0.157}^{+0.189}(\text{syst}))\times 10^{-38}{\mathrm{cm}}^2/\text{nucleon}$ and $(1.379\pm 0.009(\text{stat}{)}_{-0.147}^{+0.178}(\text{syst}))\times 10^{-38}{\mathrm{cm}}^2/\text{nucleon}$, respectively, and their cross-section ratio is $1.047\pm 0.007(\text{stat})\pm 0.035(\text{syst})$. These results agree well with the predictions of the neutrino interaction model, and thus we checked the correct treatment of the nuclear effect for iron and hydrocarbon targets in the model within the measurement precisions.

Figure 1

Overview of the 16 INGRID standard modules viewed from the beam upstream. The horizontal center module is hidden behind the vertical center module.

Figure 2

Exploded view of an INGRID standard module. It consists of iron target plates and tracking scintillator planes (left), and it is surrounded by veto scintillator planes (right).

Figure 3

The position of the proton module viewed from above.

Figure 4

Exploded view of the proton module.

Figure 5

Neutrino energy spectrum for each neutrino species at the central module predicted by jnubeam.

Figure 6

Neutrino-nucleus cross sections per nucleon of a carbon nucleus divided by the neutrino energy predicted by neut.

Figure 7

Number of active planes for the proton module. Events with more than two active planes are selected. The background events from the walls of the detector hall are normalized with beam induced muon backgrounds, as described in Sec. 4a9.

Figure 8

MC event display of a charged current neutrino event in the proton module. Red circles and black lines represent observed hits and reconstructed tracks, respectively. The areas of the red circles correspond to light yields.

Figure 9

Time difference between the measured event timing and the expected neutrino event timing for the proton module. Events within $\pm 100\mathrm{ns}$ are selected.

Figure 10

Vertex X, Y, and Z distributions for the proton module following event selection. There are jumps at X or Y $=\pm 20\mathrm{cm}$ because the proton module uses thicker scintillators in the inner region ($-20\mathrm{cm}\sim +20\mathrm{cm}$).

Figure 11

Number of active planes for the standard module. Events with more than two active planes are selected.

Figure 12

Time difference between the measured event timing and expected neutrino event timing for the standard module. Events within $\pm 100\mathrm{ns}$ are selected.

Figure 13

Event selection efficiency of CC interactions for the standard module and the proton module as a function of true neutrino energy (left) and true muon scattering angle (right). The energy spectrum and angle distribution of the CC interactions in the standard module are overlaid.

Figure 14

MC event display of a selected event and a rejected event by the acceptance cut.

Figure 15

Vertex X, Y, and Z distributions for the standard module following event selection.

Figure 16

The inclusive ${\nu }_{\mu }$ charged current cross section on Fe (left) and that on CH (right) with predictions by neut and genie. The isoscalar corrections are not applied to our data or predictions. Our data point is placed at the flux mean energy. The vertical error bar represents the total (statistical and systematic) uncertainty, and the horizontal bar represents 68% of the flux at each side of the mean energy. The MINOS, T2K ND280, SciBooNE, and NOMAD results are also plotted [12, 13, 14, 15]. Because the isoscalar correction is applied to the MINOS data, it is expected to be shifted by about $-2\%$.

Figure 17

The inclusive ${\nu }_{\mu }$ charged current cross-section ratio on Fe to CH with predictions by neut and genie. The isoscalar corrections are not applied to our data or predictions. Our data point is placed at the flux mean energy. The vertical error bar represents the total (statistical and systematic) uncertainty, and the horizontal bar represents 68% of the flux at each side of the mean energy. The $\mathrm{MINER}\nu \mathrm{A}$ result is also plotted [16].