Multiplicity distributions in ν¯μp interactions

We present the multiplicity distributions of the hadrons produced in antineutrino-proton interactions. The data sample, which consists of 2025 charged-current events with antineutrino energy greater than 5 GeV, comes from exposures of the 15-foot hydrogen bubble chamber to the broad-band antineutrino beam at Fermilab. The distributions in hadronic mass W has an average value of 3.7 GeV but extends up to 10 GeV. The mean multiplicity of charge hadrons depends on the hadronic mass W and varies as = (-0.44 +- 0.13) + (1.48 +- 0.06)lnW/sup 2/ for W/sup 2/>4 GeV/sup 2/. The mean multiplicities for events with three or more charged tracks averaged over the total data sample are = 1.68 +- 0.03 and = 1.11 +- 0.07 for ..pi../sup -/ and ..pi../sup 0/ production, respectively. The mean ..pi../sup 0/ multiplicity is found to increase slowly with n/sub -/. The integrated correlation coefficient f/sup - -//sub 2/ and the dispersion D/sup -/ are given as a function of n/sub -/. When compared to the distributions characteristic of other leptonic and hadronic reactions, we find a similarity between the nu-bar data and results from hadronic reactions that have no diffractive component. Multiplicity data for the heavier particles K/sup 0/, rho/supmore » 0/, and ..lambda.. are also summarized. The pion multiplicities in the current fragmentation region exceed those for the target fragmentation at all W values. They also satisfy the isospin relation 2 = + required for the fragmentation of an I = 1/2 quark when a W>4 GeV selection is imposed.« less