Charged-particle multiplicities in charged-current neutrino– and anti-neutrino–nucleus interactions

Abstract

The CHORUS experiment, designed to search for ν µ → ν τ oscillations, consists of a nuclear emulsion target and electronic detectors. In this paper, results on the production of charged particles in a small sample of charged-current neutrino-and anti-neutrino-nucleus interactions at high energy are presented. For each event, the emission angle and the ionization features of the charged particles produced in the interaction are recorded, while the standard kinematic variables are reconstructed using the electronic detectors. The average multiplicities for charged tracks, the pseudo-rapidity distributions, the dispersion in the multiplicity of charged particles and the KNO scaling are studied in different kinematical regions. A study of quasi-elastic topologies performed for the first time in nuclear emulsions is also reported. The results are presented in a form suitable for use in the validation of Monte Carlo generators of neutrino-nucleus interactions.

Atmospheric neutrino oscillation analysis with external constraints in Super-Kamiokande I-IV

“…Uncertainties from that fit have been propagated as systematic uncertainties in the present analysis. Differences in the expected number of pions in the final state between the NEUT prediction and measurements from the CHORUS experiment [28] are considered as an additional source of systematic uncertainty affecting the event selection presented above.…”

Study of KNO scaling in the emulsion based neutrino experiments

“…A randomly selected 627 events visually inspected and measured in detail. In their analysis, particle classification was not based on ionization features but particles were classified by using the pseudo-rapidity variable η = -ln tan ( θ / 2 ), where θ is emission angle of shower particles with respect to beam axis as shown in Figure 3 [7].…”

“…The charged hadron multiplicity distribution is a very important parameter to understand the characteristics of the final hadronic states and particle production mechanism in neutrino interactions. As it provides the information about the interaction dynamics of charged particles, it has been studied in many experiments with different energies and beams up to now [1][2][3][4][5][6][7][8]. Indeed, such studies are also very useful to improve hadronic multiparticle production models for use in neutrino event generators.…”

“…However, the multiplicity data in neutrino interactions are very rare. Only recently two emulsion based neutrino experiments CHORUS and OPERA published multiplicity distributions and also tested KNO scaling with a reliable statistics[7,8]. Their multiplicity distributions follow a negative binomial distribution exhibiting approximate KNO scaling.…”

PYTHIA hadronization process tuning in the GENIE neutrino interaction generator

“…z = n/ n and an input parameter c. The input parameter is used to tune the function to agree with data, which is mainly taken from the Fermilab 15-foot bubble chamber experiment [23]. Although more recent hadron multiplicity data are available from CHORUS [24], the heavy target data require more sophisticated final state interaction models to access to the primary hadron multiplicity information, and we do not take these into account in this article. At higher energy regions the AGKY model gradually transitions from the KNO scalingbased model to PYTHIA discussed previously.…”