6 research outputs found
Production of {\pi}+ and K+ mesons in argon-nucleus interactions at 3.2 AGeV
First physics results of the BM@N experiment at the Nuclotron/NICA complex
are presented on {\pi}+ and K+ meson production in interactions of an argon
beam with fixed targets of C, Al, Cu, Sn and Pb at 3.2 AGeV. Transverse
momentum distributions, rapidity spectra and multiplicities of {\pi}+ and K+
mesons are measured. The results are compared with predictions of theoretical
models and with other measurements at lower energies.Comment: 29 pages, 20 figure
Creation of the precision magnetic spectrometer SCAN-3
The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article
Unperturbed inverse kinematics nucleon knockout measurements with a carbon beam
From superconductors to atomic nuclei, strongly-interacting many-body systems
are ubiquitous in nature. Measuring the microscopic structure of such systems
is a formidable challenge, often met by particle knockout scattering
experiments. While such measurements are fundamental for mapping the structure
of atomic nuclei, their interpretation is often challenged by quantum
mechanical initial- and final-state interactions (ISI/FSI) of the incoming and
scattered particles. Here we overcome this fundamental limitation by measuring
the quasi-free scattering of 48 GeV/c 12C ions from hydrogen. The distribution
of single protons is studied by detecting two protons at large angles in
coincidence with an intact 11B nucleus. The 11B detection is shown to select
the transparent part of the reaction and exclude the otherwise large ISI/FSI
that would break the 11B apart. By further detecting residual 10B and 10Be
nuclei, we also identified short-range correlated (SRC) nucleon-nucleon pairs,
and provide direct experimental evidence for the separation of the pair
wave-function from that of the residual many-body nuclear system. All measured
reactions are well described by theoretical calculations that do not contain
ISI/FSI distortions. Our results thus showcase a new ability to study the
short-distance structure of short-lived radioactive atomic nuclei at the
forthcoming FAIR and FRIB facilities. These studies will be pivotal for
developing a ground-breaking microscopic understanding of the structure and
properties of nuclei far from stability and the formation of visible matter in
the universe.Comment: Accepted for publication in Nature Physics. 28 pages, 19 figures, and
1 table including main text, Methods, and Supplementary material