Scaling Variable Distributions for Neutrino Proton Interactions in the Fermilab 15-ft. Bubble Chamber with External Muon Identifier

The Fermilab 15-ft. liquid hydrogen bubble chamber was exposed to a one-horn neutrino beam produced by 300 GeV/c protons. Data from 75,000 pictures yielding 343 events after cuts are analyzed here. Previous publications [1] have presented scaling variable (x and y) distribution from these same data analyzed without the use of auxilliary muon identification. These previous results depended upon the use of a purely kinematic method [2] for the identification of the muon in charged current events and thus for the separation of charged current (CC) and neutral current (NC) events. Since there might be important biases and backgrounds in the kinematic selection method, it is important to re-examine the data by means of a different selection method with different, and hopefully smaller, biases. The External Muon Identifier (EMI) mounted on the bubble chamber permits such an analysis.