In the realm of nuclear physics, researchers are continually pushing the boundaries of our understanding, with implications that can sometimes extend to the energy sector. Among these researchers is Chunjian Zhang, whose work at the Lawrence Berkeley National Laboratory has recently shed light on the deformation properties of uranium-238 ($^{238}$U) nuclei. This research, published in the journal Physical Review Letters, employs a novel approach to study nuclear deformation through high-energy heavy-ion collisions.
Zhang and his team have developed an innovative method they term “imaging-by-smashing.” This technique involves colliding highly deformed $^{238}$U nuclei with nearly spherical gold-197 ($^{197}$Au) nuclei at high energies. By analyzing the resulting collisions, researchers can extract valuable information about the deformation parameters of $^{238}$U. The key to this method lies in the observables measured during these collisions, specifically the anisotropic-flow ($v_n$) and mean transverse momentum ($\left[p_T\right]$)-based observables.
The researchers focused on three primary observables: the variances $\left\langle v_n^2\right\rangle$, $\left\langle\left(δp_T\right)^2\right\rangle$, and the covariance $\left\langle v_n^2 δp_T\right\rangle$. By comparing the ratios of these observables between $^{238}$U+$^{238}$U and $^{197}$Au+$^{197}$Au collisions, the team was able to cancel out final-state effects, thereby isolating the influence of nuclear deformation. This approach provides a clear and precise measurement of the deformation parameters of $^{238}$U.
One of the most significant findings of this study is the first experimental indication of octupole deformation in $^{238}$U. Octupole deformation refers to a specific type of nuclear shape distortion that can have important implications for nuclear stability and behavior. The researchers were able to detect this deformation through $v_3$-based observables, which are sensitive to the octupole moments of the nucleus.
The extracted deformation parameters from this study were compared with state-of-the-art hydrodynamic model calculations and found to be consistent with low-energy nuclear structure data. This consistency underscores the robustness of the “imaging-by-smashing” approach and its potential for future applications in nuclear physics research.
For the energy sector, understanding the deformation properties of uranium nuclei is crucial for several reasons. Uranium is a key fuel in nuclear power plants, and its behavior under various conditions can significantly impact the efficiency and safety of these facilities. By gaining a deeper understanding of nuclear deformation, researchers can develop more accurate models of nuclear reactions and improve the design of nuclear reactors. Additionally, this knowledge can contribute to the development of advanced nuclear fuels and the optimization of nuclear waste management strategies.
In conclusion, the work of Chunjian Zhang and his team represents a significant advancement in the field of nuclear physics. Their innovative “imaging-by-smashing” approach provides a powerful tool for probing nuclear deformation and has the potential to yield valuable insights for the energy sector. As researchers continue to explore the implications of these findings, the benefits for nuclear energy and related technologies are likely to grow.
This article is based on research available at arXiv.