Results from a Pilot Study on the Measurement of Nuclear Fragmentation with NA61/SHINE at the CERN SPS: $^{11}\text{C}$ Production in $\text{C+p}$ Interactions at 13.5 A GeV/c

Abstract

We report the analysis of data taken during a pilot run in 2018 to study the feasibility of nuclear fragmentation measurements with the NA61/SHINE experiment at the CERN SPS. These nuclear reactions are important for the interpretation of secondary cosmic-ray nuclei production (Li, Be, and B) in the Galaxy. The pilot data were taken with $^{12}\text{C}$ projectiles at a beam momentum of 13.5 A GeV/c and two fixed targets, polyethylene (C$_2$H$_4$) and graphite. The specific focus here is the measurement of total Boron ($^{10}\text{B}$ and $^{11}\text{B}$) production cross section in $\text{C+p}$ interactions at 13.5 A GeV/c. The cosmic-ray nucleus $^{11}\text{C}$ is termed a `Ghost nucleus' on account of its short lifetime compared to the usual cosmic-ray diffusion time in the Galaxy and it ultimately decays to Boron as, $^{11}\text{C} \to ^{11}\text{B} + \beta^+$. Therefore, precise knowledge of the production cross section of $^{11}\text{C}$ is very relevant for the understanding of Boron production in the Galaxy. We present a preliminary measurement of the fragmentation cross section of $\text{C+p}\to ^{11}\text{C}$, which, together with our previously reported B-production cross section, provides a new constraint on Boron production in the Galaxy in the high-energy range relevant for modern space based cosmic-ray experiments like AMS-02.