Neutrino-proton interactions at Fermilab energies: Experimental arrangement, analysis procedures, and qualitative features of the data

Abstract

The Fermilab 15-ft bubble chamber filled with hydrogen was exposed to a broad-momentum-band horn-focused neutrino beam produced by 300-GeV interacting protons. The selection procedure to choose a charged-current neutrino event sample is discussed. Less than three percent of the events are due to neutral hadron interactions. We present and experimentally test a method that can be used to identify the muon, estimate the incident neutrino energy, and eliminate most neutral-current interactions from the charged-current sample. Above 10 GeV the method produces an approximately 86% pure sample of charged-current events with an error in energy estimation of the order of 8% over a broad region of the data. In addition we establish experimentally several important properties of high-energy charged-current neutrino interactions. The hadrons are produced in a jet, the individual particles having sharply limited momenta perpendicular to the hadronic axis. The jet structure is maintained with constant properties to very high values of ${Q}^{2}$ and hadronic mass. The fraction of energy going into invisible particles is moderate, consistent with that expected. The average number of neutral pions rises linearly with the average number of charged particles.