Measurement of single $\ddot{I}{€}^0$ production by coherent neutral-current $\hat{I}½$ Fe interactions in the MINOS Near Detector

Abstract

Forward single $\ddot{I}{€}^0$ production by coherent neutral-current interactions, $\hat{I}½\mathcal{A}\to \hat{I}½\mathcal{A}\ddot{I}{€}^0$, is investigated using a 2.8$\times 10^{20}$ protons-on-target exposure of the MINOS Near Detector. For single-shower topologies, the event distribution in production angle exhibits a clear excess above the estimated background at very forward angles for visible energy in the range~1-8 GeV. Cross sections are obtained for the detector medium comprised of 80% iron and 20% carbon nuclei with $⟨\mathcal{A}⟩=48$, the highest-$⟨\mathcal{A}⟩$ target used to date in the study of this coherent reaction. The total cross section for coherent neutral-current single-$\ddot{I}{€}^0$ production initiated by the $\hat{I}{½}_{\hat{I}}¼$ flux of the NuMI low-energy beam with mean (mode) $E_{\hat{I}}½$ of 4.9 GeV (3.0 GeV), is $77.6\pm 5.0(\text{stat}{)}_{-16.8}^{+15.0}(\text{syst})\times 10^{-40}{\text{cm}}^2\text{per nucleus}$. The results are in good agreement with predictions of the Berger-Sehgal model.

19 pages, 14 figures Supplementary Materials, MINOS Collaboration