Scaling approach to nuclear structure in high-energy heavy-ion collisions

Abstract

In high-energy heavy-ion collisions, the energy density profile of the produced quark-gluon plasma and its space-time dynamics are sensitive to the shape and radial profiles of the nuclei, described by the collective nuclear structure parameters including quadrupole deformation β2, octupole deformation β3, radius R0 and surface diffuseness a. Using hydrodynamic model simulations, we find a general scaling relation between these parameters and a large class of experimental observables such as elliptic flow v2, triangular flow v3 and particle multiplicity distribution p(N ch ). In particular, we show that the ratio of these observables between two isobar collision systems depends only on the differences of these parameters. Using this scaling relation, we show how the nuclear structure parameters of 96 44 Ru and 96 40 Zr conspire to produce the non-monotonic centrality dependence of ratios of v2, v3 and p(N ch ) between 96 44 Ru+ 96 44 Ru and 96 40 Zr+ 96 40 Zr collisions, in agreement with measurements by the STAR Collaboration. This scaling approach towards heavy-ion observables demonstrates that isobar collisions is a precision tool to probe the shape and radial structures, including the neutron skin, of the atomic nuclei across energy scales.

Inferring nuclear structure from heavy isobar collisions using Trajectum

“…We note, however, that almost all dependence is expected to cancel when taking the ratio between isobars that are as similar as 96 44 Ru and 96 40 Zr. All of our results agree qualitatively with AMPT studies [12,30] and as such our study is an important confirmation of those conclusions using a true hydrodynamic evolution. Nevertheless, we find that our v 3 {2} differs quantitatively.…”

“…This could have been anticipated from nuclear structure analyses [9,10], though we note significant differences between studies. It is the purpose of this Letter to utilise these different studies in the state-of-the-art heavy ion code Trajectum and show how recent results from DFT can fully explain the STAR findings (see also [11,12] for a similar study using the transport model AMPT for v 2 and v 3 ).…”

Search for the chiral magnetic effect in collisions between two isobars with nuclear structures

“…The Case 3 and Cases 7-10, skin-type and halo-type cases are taken from Xu's work [33] which considers the neutron-skin effect and/or a nuclear quadrupole deformity into the WS distribution with the TRENTO model. The Cases 4-6 are taken from Jia's recent researches [35,48], among which the Case 4 and Case 5 can well reproduce some experimental results. Meanwhile, the Case 6 is also from Ref.…”

“…It is worth noting that the Cases 4-6 and the effect of β 3 have been studied in detail in Refs. [35,48,51], and their recent study suggested that the ratios calculated at the same N ch provide a better baseline for the non-CME background [52]. For simplicity, we choose the halo-type neutron skin case for doing our following study related to the CME.…”

An overview of new measurements of flow, chirality, and vorticity from STAR experiment

“…isobar baseline and background estimations. Theoretical model calculations[78][79][80][81][82][83][84][85][86][87][88][89][90] are necessary to understand above physics. Unlike RIBLL, FRIB and NICA at low and medium energies, isobar collisions open up new opportunity to study nuclear structure at a very short time scale (∼ 10 −23 s) through heavy-ion collisions.• One fundamental property of light atomic nuclei in unusual nuclear structure…”