Multiplicities of positive and negative pions, kaons and unidentified hadrons from deep-inelastic scattering of muons off a liquid hydrogen target

TL;DR

This paper reports detailed measurements of hadron multiplicities from deep-inelastic muon scattering on liquid hydrogen, covering a broad kinematic range and improving radiative correction calculations for better accuracy.

Contribution

It provides new, precise multiplicity data for pions, kaons, and unidentified hadrons in muon-proton scattering, with enhanced radiative correction methods.

Findings

Measured multiplicities across a wide kinematic domain

Improved radiative correction calculations using DJANGOH

Data consistent with previous measurements but with increased accuracy

Abstract

The multiplicities of positive and negative pions, kaons and unidentified hadrons produced in deep-inelastic scattering are measured in bins of the Bjorken scaling variable $x$, the relative virtual-photon energy $y$ and the fraction of the virtual-photon energy transferred to the final-state hadron $z$. Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam of both electric charges and a liquid hydrogen target. These measurements cover the kinematic domain with photon virtuality $Q^2 > 1$ (GeV/$c)^2$, $0.004 < x < 0.4$, $0.1 < y < 0.7$ and $0.2 < z < 0.85$, in accordance with the kinematic domain used in earlier published COMPASS multiplicity measurements with an isoscalar target. The calculation of radiative corrections was improved by using the Monte Carlo generator DJANGOH, which results in up to 12\% larger corrections in the low-$x$ region.