Double hadron leptoproduction in the nuclear medium

TL;DR

This study presents the first measurement of double-hadron production in deep-inelastic scattering on various nuclear targets, revealing nuclear medium effects that differ from single-hadron observations and informing hadronization models.

Contribution

It provides new experimental data on double-hadron production in nuclear media, offering insights into hadronization modifications and testing theoretical models.

Findings

Nuclear effects are observed with smaller magnitude than in single-hadron cases.

Data align with models involving partonic or pre-hadronic energy loss.

Pure absorptive models are inconsistent with the results.

Abstract

First measurement of double-hadron production in deep-inelastic scattering has been measured with the HERMES spectrometer at HERA using a 27.6 GeV positron beam with deuterium, nitrogen, krypton and xenon targets. The influence of the nuclear medium on the ratio of double-hadron to single-hadron yields has been investigated. Nuclear effects are clearly observed but with substantially smaller magnitude and reduced $A$-dependence compared to previously measured single-hadron multiplicity ratios. The data are in fair agreement with models based on partonic or pre-hadronic energy loss, while they seem to rule out a pure absorptive treatment of the final state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.