Measurement of charm production in neutrino charged-current interactions

TL;DR

This study measures charm production rates in neutrino charged-current interactions using nuclear emulsion, providing detailed cross-section data and charmed hadron fractions, confirming previous findings with high precision.

Contribution

It introduces a new automated scanning method for identifying charmed particles in emulsion data and provides precise measurements of charm production rates and hadronization fractions.

Findings

Charm production rate relative to charged-current interactions: 5.75%

Charm hadron fractions: D0 43.7%, Lambda_c+ 19.2%, D+ 25.3%, D_s+ 11.8%

Results agree with previous measurements.

Abstract

The nuclear emulsion target of the CHORUS detector was exposed to the wide-band neutrino beam of the CERN SPS of 27 GeV average neutrino energy from 1994 to 1997. In total about 100000 charged-current neutrino interactions with at least one identified muon were located in the emulsion target and fully reconstructed, using newly developed automated scanning systems. Charmed particles were searched for by a program recognizing particle decays. The observation of the decay in nuclear emulsion makes it possible to select a sample with very low background and minimal kinematical bias. 2013 charged-current interactions with a charmed hadron candidate in the final state were selected and confirmed through visual inspection. The charm production rate induced by neutrinos relative to the charged-current cross-section is measured to be sigma(nu_mu N -> mu- C X)/sigma(CC) = (5.75 +-0.32 stat +-0.30 syst)%. The charm production cross-section as a function of the neutrino energy is also obtained. The results are in good agreement with previous measurements. The charm-quark hadronization produces the following charmed hadrons with relative fractions (in %): f_Dzero = 43.7+-4.5, f_Lambda_c^plus = 19.2+-4.2, f_Dplus = 25.3+-4.2, and f_D_splus = 11.8+-4.7.