Measurement of Neutral-Current K^{+} Production by Neutrinos using MINERvA

Area of Science:

• Particle Physics
• Neutrino Physics
• Nuclear Physics

Background:

• Neutral-current production of K+ by atmospheric neutrinos poses a background challenge for proton decay searches.
• Reactions like nu p -> nu K+ Lambda are difficult to distinguish from proton decays if Lambda decay products are undetected.

Purpose of the Study:

• To measure differential cross sections for neutral-current K+ production by atmospheric neutrinos.
• To investigate discrepancies between event generator predictions and observed data.
• To search for photons from pi^0 decay as a veto for proton decay searches.

Main Methods:

• Utilized a sample of 201 neutrino-induced neutral-current K+ events from the MINERvA detector.
• Reconstructed K+ decay-at-rest timing signatures for event identification.
• Measured differential cross sections with respect to K+ kinetic energy and non-K+ hadronic visible energy.

Main Results:

• Observed an excess of events at low hadronic visible energy compared to the prediction of the 'neut' event generator.
• Found good agreement with the cross-section predictions from the 'genie' event generator.
• Observed a 2 sigma deficit of detached photons from pi^0 decay relative to the 'genie' prediction.

Conclusions:

• The 'genie' event generator provides a better description of the observed neutral-current K+ production data than 'neut'.
• The observed photon deficit may impact the efficiency of vetoing neutral-current K+ events in proton decay searches.