Pre-Equilibrium Clustering in Production of Spectator Fragments in Collisions of Relativistic Nuclei

Nepeivoda, Roman; Svetlichnyi, Aleksandr; Kozyrev, Nikita; Pshenichnov, I.

doi:10.3390/particles5010004

Cited by 7 publications

(7 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The apparent differences between the experimental data and our predictions in the UCC region at higher collision energies could point to possible background particles from the interaction region that reach ZDC acceptance. A recent calculation by the Abrasion-Ablation Monte Carlo model for colliders [72] also significantly underpredicts the ZDC data for neutrons from the ALICE Collaboration [73], suggesting background contributions in the UCC region. We estimate the possible background contribution using the widely used AMPT model [74].…”

Section: Spectator Particle Yieldmentioning

confidence: 99%

Free spectator nucleons in ultracentral relativistic heavy-ion collisions as a probe of neutron skin

Liu

Zhang

et al. 2022

Phys. Rev. C

View full text Add to dashboard Cite

Besides the yield ratio of free spectator neutrons produced in ultracentral 96 Zr+ 96 Zr to 96 Ru+ 96 Ru collisions [1], we propose that the yield ratio Nn Np of free spectator neutrons to protons in a single collision system at RHIC and LHC can be a more sensitive probe of the neutron-skin thickness ∆rnp and the slope parameter L of the symmetry energy. The idea is demonstrated based on the proton and neutron density distributions of colliding nuclei obtained from Skyrme-Hartree-Fock-Bogolyubov calculations, and a Glauber model that provides information of spectator matter. The final spectator particles are produced from direct emission, clusterization by a minimum spanning tree algorithm or a Wigner function approach, and deexcitation of heavy clusters by GEMINI. A larger ∆rnp associated with a larger L value increases the isospin asymmetry of spectator matter and thus leads to a larger Nn Np, especially in ultracentral collisions where the multiplicity of free nucleons are free from the uncertainties of cluster formation and deexcitation. We have further shown that the double ratio of Nn Np in isobaric collision systems or in collisions by isotopes helps to cancel the detecting efficiency for protons. Effects from nuclear deformation and electromagnetic excitation are studied, and they are found to be subdominant compared to the expected sensitivity to ∆rnp.

show abstract

Section: Spectator Particle Yieldmentioning

confidence: 99%

Free spectator nucleons in ultracentral relativistic heavy-ion collisions as a probe of neutron skin

Liu

Zhang

et al. 2022

Phys. Rev. C

View full text Add to dashboard Cite

show abstract

“…In order to resolve this issue, a hybrid parameterization of the prefragment excitation energy was introduced in AAMCC-MST in Ref. [29] to improve the description of ALICE data [38]. In peripheral events for prefragments with α > α sw the excitation energy is calculated on the basis of Ericson formula, while for events with low relative mass of prefragments α < α sw their excitation energy is calculated according to the ALADIN parameterization.…”

Section: Calculation Of Prefragment Excitation Energymentioning

confidence: 99%

“…Our suggestion to study ultracentral collisions of 208 Pb-208 Pb at the CERN SPS and LHC complements proposals [21][22][23], which considered peripheral collisions of these nuclei at the LHC to study NS. Previous studies of 208 Pb-208 Pb collisions at both facilities [2,4] [29]. Each collision event is modelled with AAMCC-MST in several stages.…”

Section: Introductionmentioning

confidence: 99%

Peeling away neutron skin in ultracentral collisions of relativistic nuclei

Kozyrev¹,

Svetlichnyi²,

Nepeivoda³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

In heavy nuclei the ratio between local densities of neutrons and protons increases towards the nuclear periphery. This phenomenon is known as the neutron skin (NS), and it is characterized by a subtle difference (< 0.5 fm) between the r.m.s radii of the distributions of neutrons and protons. We show that the existence of NS in 208 Pb translates into the excess of spectator neutrons in ultracentral 208 Pb-208 Pb collisions. The yields of spectator neutrons and protons in such collisions at the CERN SPS and LHC were calculated within a new version of Abrasion-Ablation Monte Carlo for Colliders model (AAMCC-MST) taking into account NS and pre-equilibrium clustering of spectator matter. The average numbers of spectator neutrons and protons in ultracentral collisions vary insignificantly in calculations with different parameterizations of neutron and proton densities. In contrast, the cross sections of emission of certain numbers of spectrator neutrons in events with 0,1,...5 spectator protons are changed by 50-250% depending on the thickness of NS and relations between the halfdensity radii of neutron and proton density distributions and diffuseness parameter for neutrons. We argue that the measurements of such cross sections make it possible to restrict the existing variety of neutron density parameterizations in 208 Pb. These cross sections can be proposed for measurements by the ALICE experiment at the LHC by means of ALICE Zero Degree Calorimeters.

show abstract

“…It is important to find out whether the tetrahedral geometry of α-clustered states in 16 O [4,5] is consistent with enhanced production of 4 He as spectators. The first comparison of the measurements [13] with results of an early version of our Abrasion-Ablation Monte Carlo for Colliders model with the Minimum Spanning Tree clusterization algorithm (AAMCC-MST), which took into account the pre-equilibrium clusterization of spectator matter [14], but neglected the α-clustering in initial 16 O, was presented in Ref. [15].…”

Section: Introductionmentioning

confidence: 99%

“…In the present paper, a new version of the AAMCC-MST model is used to simulate 16 O- 16 O collisions at the LHC. As described in Section 2, the model takes into account the admixture of α-clustered states and SRC in 16 O [16] and also pre-equilibrium clusterization of spectator matter [14,19]. Multiplicity distributions of spectator neutrons and deuterons as well as yields of secondary nuclei calculated for 16 O- 16 O collisions at the nucleon-nucleon center-of-mass energy, √ s NN = 6.37 TeV are presented in Section 3.…”

Section: Introductionmentioning

confidence: 99%

Clustering in Oxygen Nuclei and Spectator Fragments in 16O–16O Collisions at the LHC

Svetlichnyi

Savenkov

Nepeivoda

et al. 2023

Physics

Self Cite

View full text Add to dashboard Cite

A new version of the Abrasion–Ablation Monte Carlo for Colliders model with the Minimum Spanning Tree clusterization algorithm (AAMCC-MST) is used to simulate 16O–16O collisions at the LHC, accounting for the presence of alpha-clustered states in 16O. The yields of He, Li, Be, B, C and N spectator nuclei are calculated taking into account the pre-equilibrium clusterization of spectator matter and short-range correlations (SRC) between nucleons in 16O. The impact of α-clustering and SRC on the production of spectator neutrons and deuterons is investigated. The results on the production of spectator nucleons and fragments can help in evaluating the performance of Zero Degree Calorimeters in future studies of 16O–16O collisions at the LHC.

show abstract

Pre-Equilibrium Clustering in Production of Spectator Fragments in Collisions of Relativistic Nuclei

Cited by 7 publications

References 31 publications

Free spectator nucleons in ultracentral relativistic heavy-ion collisions as a probe of neutron skin

Free spectator nucleons in ultracentral relativistic heavy-ion collisions as a probe of neutron skin

Peeling away neutron skin in ultracentral collisions of relativistic nuclei

Clustering in Oxygen Nuclei and Spectator Fragments in 16O–16O Collisions at the LHC

Contact Info

Product

Resources

About