Abstract—The SPIN experiment is carried out with the aim of studying inclusive production of charged particles with high transverse momenta in hard proton−nucleus and nucleus−nucleus interactions. A single-arm narrow-aperture spectrometer is used in the study. The uniqueness of the experiment is in the high intensity of the proton (1012−1013 protons/s) and ion (of the order of 5 × 109 ions/s) beams ejected from the U-70 accelerator, which makes it possible to measure inclusive cross sections varying by seven orders of magnitude. The SPIN setup is able to detect particles with momenta in a kinematic domain of nucleon−nucleon interactions as well as beyond its limits. The spectrometer equipment and the features of the measurement procedure are described.

An Erratum to this paper has been published: https://doi.org/10.1134/S0020441223010293

Data on the production of positively charged particles emitted at an angle of 40 $${}^{\circ}$$ (in the laboratory frame) with transverse momenta of up to 2.7 GeV $$/c$$ in the interaction of 50-GeV $$/c$$ protons with carbon, aluminum, copper, and tungsten nuclear targets are presented. Particular attention is given to studying the production of light nuclear fragments, such as deuterons ( $$d$$ ) and tritons ( $$t$$ ). An analysis of data on $$d$$ and $$t$$ particles gives grounds to state that these fragments arise via a local mechanism of their direct knockout from nuclei. The results were obtained in the SPIN experiment at the Institute for High Energy Physics (IHEP, Protvino).

The first data on the yield of the lightest nuclear fragments (protons p, deuterons d, and tritons t) with high transverse momenta pT at an angle of 40° in the laboratory reference frame from nuclear targets bombarded by 50-GeV/c protons and 20A-GeV/c carbon nuclei obtained in the SPIN experiment (IHEP, Protvino, Russia) have been reported. It has been shown that the pA and CA data can be described within a common scaling approach, which possibly indicates that the mechanism of formation of high-pT nuclear fragments is common for these reactions.

The yields of cumulative protons and π ± mesons emitted at a laboratory angle of 40° from carbon and heavier nuclear targets irradiated by a proton beam from the U70 accelerator (Institute for High Energy Physics, Protvino) have been studied in the SPIN experiment. It has been found that the effect of the target nucleus on the yield of particles with large transverse momenta is weakened.