Measurement of the forward $\eta$ meson production rate in p-p collisions at $\sqrt{s}$=13 TeV with the LHCf-Arm2 detector

TL;DR

This paper reports the first measurement of forward η meson production in 13 TeV proton-proton collisions, providing crucial data to refine models of cosmic ray air showers and particle interactions.

Contribution

It presents the first observation and measurement of η mesons in the forward region at high energies, enhancing understanding of hadronic interactions in cosmic ray physics.

Findings

First measurement of η mesons in forward region at LHC

Provides data to constrain hadronic interaction models

Improves understanding of air shower development

Abstract

The forward $\eta$ mesons production has been observed by the Large Hadron Collider forward (LHCf) experiment in proton-proton collision at $\sqrt{s}$=13 TeV. This paper presents the measurement of the inclusive production rate of $\eta$ in $p_T<$ 1.1 GeV/c, expressed as a function of the Feynman-x variable. These results are compared with the predictions of several hadronic interaction models commonly used for the modelling of the air showers produced by ultra-high energy cosmic rays. This is both the first measurement of $\eta$ mesons from LHCf and the first time a particle containing strange quarks has been observed in the forward region for high-energy collisions. These results will provide a powerful constraint on hadronic interaction models for the purpose of improving the understanding of the processes underlying the air showers produced in the Earth's atmosphere by ultra-energetic cosmic rays.