Description
T2K is a long-baseline neutrino experiment in Japan which aims to constrain parameters of the Pontecorvo–Maki–Nakagawa–Sakata (PMNS) matrix by studying $\nu_{\mu} \rightarrow \nu_{e}~(\bar{\nu}_{\mu} \rightarrow \bar{\nu}_{e})$ oscillations. Measurements of neutrino oscillations require an accurate understanding of how neutrinos interact with matter. One significant $\text{CC} \nu_{e}$ channel which contributes to $\nu_{e}$ appearance at T2K is $\pi^{+}$ production, for which there is currently no exclusive cross-section measurement on a carbon target. This interaction also contributes to the $\nu_{e}$ appearance at NOvA and will be present at next-generation long-baseline experiments including Hyper-Kamiokande and DUNE. The $\nu_{e} \pi^{+}$ channel is also of significance because there is an observed event excess in reconstructed neutrino energy at the Super-Kamiokande far detector sample, where 15.0 events are observed with 7.8 predicted using Monte-Carlo (MC) generators [1]. This discrepancy may be resolved with higher statistics as T2K collects more data, but it could also indicate an issue with the cross-section models used for generating MC events. A constraint of the $\nu_{e} \pi^{+}$ event rate at the T2K near detector (ND280) could address this issue; ND280 also has the purpose of measuring neutrino cross-sections. In the ND280 tracker, the beam is largely $\nu_{\mu}$-dominated, but some $\nu_{e}$ interactions do occur in its fiducial volume. Measuring $\nu_{e}$ cross-sections at ND280 is difficult because charged-current $\nu_{e}$ events are relatively rare, and there are several large backgrounds which can produce electrons and mimic the $\text{CC} \nu_{e}$ signal such as $\pi^{0}$ interactions. This poster will present the status of the analysis and detail the strategies for the main developments so far, focusing on the challenging selection development and detector systematics estimation.
[1] K. Abe et al. (T2K Collaboration) Phys. Rev. D 103, 112008 (2021).
| Collaboration | T2K |
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