Exploring the compactness of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>α</mml:mi></mml:math> clusters in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">O</mml:mi><mml:mprescripts/><mml:none/><mml:mn>16</mml:mn></mml:mmultiscripts></mml:math> nuclei with relativistic <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">O</mml:mi><mml:mprescripts/><mml:none/><mml:mn>16</mml:mn></mml:mmultiscripts><mml:mo>+</mml:mo><mml:mmultiscripts><mml:mi mathvariant="normal">O</mml:mi><mml:mprescripts/><mml:none/><mml:mn>16</mml:mn></mml:mmultiscripts></mml:mrow></mml:math> collisions
Yuanyuan Wang, Shujun Zhao, Boxing Cao, H. Xu, Huichao Song
Abstract
Probing the $\ensuremath{\alpha}$ cluster of $^{16}\mathrm{O}$ with the relativistic $^{16}\mathrm{O}+^{16}\mathrm{O}$ collisions has raised great interest in the heavy ion community. However, the effects of the $\ensuremath{\alpha}$ cluster on the soft hadron observables vary largely among different studies. In this paper, we explain the differences by the compactness of the $\ensuremath{\alpha}$ cluster in oxygen, using iEBE-VISHNU hydrodynamic simulations with different initial state $\ensuremath{\alpha}$ cluster configurations. We also find several observables, such as the intensive skewness of the $[{p}_{\mathrm{T}}]$ correlator ${\mathrm{\ensuremath{\Gamma}}}_{{p}_{\mathrm{T}}}$, the harmonic flows ${v}_{2}{2}, {v}_{2}{4}, {v}_{3}{2}$, and the ${v}_{n}^{2}\ensuremath{-}\ensuremath{\delta}[{p}_{\mathrm{T}}]$ correlations $\ensuremath{\rho}({v}_{2}^{2},[{p}_{\mathrm{T}}]), \ensuremath{\rho}({v}_{3}^{2},[{p}_{\mathrm{T}}])$ in $^{16}\mathrm{O}+^{16}\mathrm{O}$ collisions are sensitive to the compactness of the $\ensuremath{\alpha}$ cluster in the colliding nuclei, which can be used to constrain the configurations of $^{16}\mathrm{O}$ in the future. Our study serves as an important step toward the quantitative exploration of the $\ensuremath{\alpha}$ cluster configuration in the light nuclei with relativistic heavy ion collisions.