Abstract

Atomic nuclei are self-organized, many-body quantum systems bound by strong nuclear forces within femtometre-scale space. These complex systems manifest a variety of shapes1–3 , traditionally explored using non-invasive spectroscopic techniques at low energies4,5 . However, at these energies, their instantaneous shapes are obscured by long-timescale quantum fluctuations, making direct observation challenging. Here we introduce the collective-flow-assisted nuclear shape-imaging method, which images the nuclear global shape by colliding them at ultrarelativistic speeds and analysing the collective response of outgoing debris. This technique captures a collision-specific snapshot of the spatial matter distribution within the nuclei, which, through the hydrodynamic expansion, imprints patterns on the particle momentum distribution observed in detectors6,7 . We benchmark this method in collisions of ground-state uranium-238 nuclei, known for their elongated, axial- symmetric shape. Our findings show a large deformation with a slight deviation from axial symmetry in the nuclear ground state, aligning broadly with previous low- energy experiments. This approach offers a new method for imaging nuclear shapes, enhances our understanding of the initial conditions in high-energy collisions and addresses the important issue of nuclear structure evolution across energy scales.

Document Type

Article

Publication Date

2024

Notes/Citation Information

© The Author(s) 2024

Digital Object Identifier (DOI)

https://doi.org/10.1038/s41586-024-08097-2

Funding Information

We thank the RHIC Operations Group and RCF at BNL, the NERSC Center at LBNL and the Open Science Grid consortium for providing resources and support. This work was supported in part by the Office of Nuclear Physics in the US DOE Office of Science, the US National Science Foundation, National Natural Science Foundation of China, Chinese Academy of Sciences, the Ministry of Science and Technology of China and the Chinese Ministry of Education, the Higher Education Sprout Project by Ministry of Education at NCKU, the National Research Foundation of Korea, Czech Science Foundation and Ministry of Education, Youth and Sports of the Czech Republic, Hungarian National Research, Development and Innovation Office, New National Excellency Programme of the Hungarian Ministry of Human Capacities, the Department of Atomic Energy and Department of Science and Technology of the Government of India, the National Science Centre and WUT ID-UB of Poland, the Ministry of Science, Education and Sports of the Republic of Croatia, German Bundesministerium für Bildung, Wissenschaft, Forschung and Technologie (BMBF), Helmholtz Association, the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), the Japan Society for the Promotion of Science (JSPS) and the Agencia Nacional de Investigación y Desarrollo (ANID) of Chile. We thank C. Shen for providing the IP-Glasma + MUSIC code and G. Nijs for providing the Trajectum code. We thank G. Giacalone, D. Lee, T. Rodriguez, B. Schenke, H. Song and Y. Zhou for their discussions and comments

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