First Measurement of the Charged Current $\overline{\nu}_{\mu}$ Double Differential Cross Section on a Water Target without Pions in the final state

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This paper reports the first differential measurement of the charged-current $\overline{\nu}_{\mu}$ interaction cross section on water with no pions in the final state.

• The unfolded flux-averaged measurement using the T2K off-axis near detector is given in double differential bins of $\mu^+$ momentum and angle.
• The integrated cross section in a restricted phase space is $\sigma=\left(1.11\pm0.18\right)\times10^{-38}$ cm$^{2}$ per water molecule.
• Comparisons with several nuclear models are also presented.