Fragmentation Cross Sections for the Understanding of Cosmic-Ray Transport in the Galaxy: Results and Prospects from NA61/SHINE

TL;DR

This paper reports precise measurements of cosmic-ray fragmentation cross sections from NA61/SHINE, crucial for understanding cosmic-ray transport, including new results at 13.5 GeV/c and plans for high-energy data collection to improve cosmic-ray models.

Contribution

It provides new fragmentation cross section data for carbon and other nuclei at energies relevant to cosmic-ray physics, and discusses future high-statistics measurements at higher energies.

Findings

Cross sections for carbon breakup into boron and carbon isotopes at 13.5 GeV/c.

High-statistics data collection covering nuclei from lithium to silicon.

Upcoming measurements at 150 GeV/c to observe cross section behavior at high energies.

Abstract

Accurate measurements of cosmic-ray fragmentation cross sections are essential for maximizing the physics potential of precise measurements of secondary and primary cosmic-ray fluxes from current balloon and space-borne experiments. NA61/SHINE, operating at the CERN SPS H2 beamline, is uniquely suited to studying these interactions at energies above 10 GeV/c per nucleon. In this contribution, we present the fragmentation cross sections for the breakup of carbon into $^{10}$B, $^{11}$B and $^{11}$C at 13.5 GeV/c per nucleon that are needed for interpreting the cosmic-ray boron-to-carbon ratio. These results are based on data from a pilot run conducted in 2018. We also give an overview of the high-statistics data-taking campaign in 2024, which covered projectile nuclei from lithium to silicon. With over 40 million recorded beam triggers, this data set will enable the reconstruction of the full reaction network required to study light secondary cosmic rays. Furthermore, we report on data collected in 2025 with a primary oxygen beam at 150 GeV/c per nucleon, aimed at verifying the expected flattening of fragmentation cross sections at high energies.