Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) – A Novel Microscopic N-Body Transport Approach for Heavy-Ion Collisions, Dynamical Cluster Formation and Hypernuclei Production J. Aichelin, E. Bratkovskaya, A. Le Fevre, V. Kireyeu, V. Kolesnikov, Y. Leifels, V. Voronyuk, G. Coci,
Phys.Rev.C 101 (2020) 4, 044905 DOIarXivInspire
Cluster and hypernuclei production in heavy-ion collisions is presently under active experimental and theoretical investigation. Since clusters are weekly bound objects, their production is very sensitive to the dynamical evolution of the system and its interactions. The theoretical description of cluster formation is related to the n-body problem. Here we present the novel n-body dynamical transport approach PHQMD (Parton-Hadron-Quantum-Molecular-Dynamics) which is designed to provide a microscopic description of nuclear cluster and hypernucleus formation as well as of general particle production in heavy-ion reactions at relativistic energies. In difference to the coalescence or statistical models, often used for the cluster formation, in PHQMD clusters are formed dynamically due to the interactions between baryons described on a basis of Quantum Molecular Dynamics (QMD) which allows to propagate the n-body Wigner density and n-body correlations in phase-space, essential for the cluster formation. The clusters are identified by the MST (Minimum Spanning Tree) or the SACA (‘Simulated Annealing Cluster Algorithm’) algorithm which finds the most bound configuration of nucleons and clusters. Collisions among hadrons as well as Quark-Gluon-Plasma formation and parton dynamics in PHQMD are treated in the same way as in the established PHSD (Parton-Hadron-String-Dynamics) transport approach.
In order to verify our approach with respect to the general dynamics we present here the first PHQMD results for general 'bulk' observables such as rapidity distributions and transverse mass spectra for hadrons ($\pi, K, \bar K$, $p$, $\bar p$, $\Lambda$, $\bar \Lambda$) from SIS to RHIC energies. We find a good description of the "bulk" dynamics which allows us to proceed with the results on cluster production, including hypernuclei.
Other publications:
PHQMD – A Microscopic Transport Approach for Heavy-Ion Collisions and Cluster Formation Jörg Aichelin, M.Winn, E. L. Bratkovskaya, Arnaud Le Fèvre, Yvonne Leifels, V. Kireyeu, V. Kolesnikov, V. Voronyuk,
Advances in Nuclear Physics: Structure and Reactions, 105-117 (SPPHY, volume 257) DOIInspire
We present the basic ideas and new results of the recently advanced transport approach called PHQMD (Parton-Hadron-Quantum Molecular Dynamics) to describe heavy-ion collisions and especially the cluster formation in these reactions. This n-body transport approach allows to address physical processes which cannot be addressed by transport approaches which calculate the time evolution of the one-body phase space density or the one-body Greens function. They include the formation of fragments, especially of hyper-fragments, as well as the study of fluctuations as a signal of a possible first-order phase transition which some models predict if the strongly interacting matter is compressed to a high baryon density. This approach is at the same time an extension of the QMD model, which has successfully been used to describe fragments and other observables in heavy-ion collisions at beam energies below 2 AGeV and the PHSD transport approach which is a microscopic covariant dynamical transport approach for the one-body Greens function which successfully described a multitude of single-particle observables in p+p, p+A and A+A collisions from lower SIS ($E_{beam}$=1 AGeV) to LHC energies ($\sqrt{s_{NN}}$ = 5.2 TeV). We present the model and discuss how the parametrization of nuclear potential interactions influences the prediction for different observables.
Dynamical mechanisms for deuteron production at mid-rapidity in relativistic heavy-ion collisions from SIS to RHIC energies G. Coci, S. Glässel, V. Kireyeu, J. Aichelin, C. Blume, E.Bratkovskaya, V. Kolesnikov, V. Voronyuk,
To be published in Phys. Rev. C, 2023 arXivInspire
The understanding of the mechanisms for the production of weakly bound clusters, such as a deuteron $d$, in heavy-ion reactions at mid-rapidity is presently one of the challenging problems which is also known as the "ice in a fire" puzzle. In this study we investigate the dynamical formation of deuterons within the Parton-Hadron-Quantum-Molecular Dynamics (PHQMD) microscopic transport approach and advance two microscopic production mechanisms to describe deuterons in heavy-ion collisions from SIS to RHIC energies: kinetic production by hadronic reactions and potential production by the attractive potential between nucleons. Differently to other studies, for the "kinetic" deuterons we employ the full isospin decomposition of the various $\pi NN \leftrightarrow \pi d$, $NNN \leftrightarrow Nd$ channels and take into account the finite size properties of the deuteron by means of an excluded volume condition in coordinate space and by the projection onto the deuteron wave function in momentum space. We find that considering the quantum nature of the deuteron in coordinate and momentum space reduces substantially the kinetic deuteron production in a dense medium as encountered in heavy-ion collisions. If we add the "potential" deuterons by applying an advanced Minimum Spanning Tree (aMST) procedure, we obtain good agreement with the available experimental data from SIS energies up to the top RHIC energy.
Cluster formation near midrapidity – can the mechanism be identified experimentally? V. Kireyeu, G. Coci, S. Glaessel, J. Aichelin, C. Blume, E. Bratkovskaya, arXivInspire
The formation of weakly bound clusters in the hot and dense environment at midrapidity is one of the surprising phenomena observed experimentally in heavy-ion collisions from a low center of mass energy of $\sqrt{s_{NN}} = 2.5$ GeV up to a ultra-relativistic energy of $\sqrt{s_{NN}} = 5$ TeV. Three approaches have been advanced to describe the cluster formation: coalescence at kinetic freeze-out, cluster formation during the entire heavy-ion collision by potential interaction between nucleons and deuteron production by hadronic reactions. We identify experimental observables, which can discriminate these production mechanisms for deuterons.
Cluster and hyper-cluster production in relativistic heavy-ion collisions within the PHQMD approach Susanne Gläßel, Viktar Kireyeu, Vadim Voronyuk, Jörg Aichelin, Christoph Blume, Elena Bratkovskaya, Gabriele Coci, Vadim Kolesnikov, Michael Winn,
Phys. Rev. C 105 (2022) 014908 DOIarXivInspire
We study cluster and hypernuclei production in heavy-ion collisions at relativistic energies employing the Parton-Hadron-Quantum-Molecular-Dynamics (PHQMD) approach, a microscopic n-body transport model based on the QMD propagation of the baryonic degrees of freedom with density dependent 2-body potential interactions. All other ingredients of PHQMD, including the collision integral and the treatment of the quark-gluon plasma (QGP) phase, are adopted from the Parton-Hadron-String Dynamics (PHSD) approach. In PHQMD the cluster formation occurs dynamically, caused by the interactions. The clusters are recognized by the Minimum Spanning Tree (MST) algorithm. We present the PHQMD results for cluster and hypernuclei formation in comparison with the available experimental data at AGS, SPS, RHIC-BES and RHIC fixed target energies. We also provide predictions on cluster production for the upcoming FAIR and NICA experiments. PHQMD allows to study the time evolution of formed clusters and the origin of their production, which helps to understand how such weakly bound objects are formed and survive in the rather dense and hot environment created in heavy-ion collisions. It offers therefore an explanation of the 'ice in the fire' puzzle.
Deuteron production in ultrarelativistic heavy-ion collisions: A comparison of the coalescence and the minimum spanning tree procedure V. Kireyeu, J. Steinheimer, J. Aichelin, M. Bleicher and E.Bratkovskaya
Phys. Rev. C 105 (2022) 044909 DOIarXivInspire
The formation of deuterons in heavy-ion collisions at relativistic energies is investigated by employing two recently advanced models—the minimum spanning tree (MST) method and the coalescence model—by embedding them in the parton-hadron quantum molecular dynamics (PHQMD) and the ultrarelativistic quantum molecular dynamics (UrQMD) transport approaches. While the coalescence mechanism combines nucleons into deuterons at the kinetic freeze-out hypersurface, the MST identifies the clusters during the different stages of time evolution. We find that both clustering procedures give very similar results for the deuteron observables in the UrQMD as well as in the PHQMD environment. Moreover, the results agree well with the experimental data on deuteron production in Pb+Pb collisions at $\sqrt{s_{NN}}$=8.8 GeV (selected for the comparison of the methods and models in this study). A detailed investigation shows that the coordinate space distribution of the produced deuterons differs from that of the free nucleons and other hadrons. Thus, deuterons are not destroyed by additional rescattering.
Modelling relativistic heavy-ion collisions with dynamical transport approaches M. Bleicher and E. Bratkovskaya,
Prog. Part. Nucl. Phys. 122 (2022), 103920 DOIInspire
We discuss the basic ideas of relativistic transport models used for the interpretation and description of experimental data from heavy-ion collisions at high collision energies. We highlight selected results from microscopic simulations of these reactions with a main focus on the UrQMD and PHSD approaches. We also address the results of macroscopic approaches like hydrodynamics or coarse-grained dynamics used in different model combinations in comparison to experimental data. We address the results of such simulations for the description of QCD matter close to equilibrium in terms of transport coefficients like shear η and bulk viscosity ζ and discuss the connection of the radial flow to the equation of state and the transport properties. Then we turn to dileptons and photons as messengers from the hot and dense region before coming to the exploration of the decoupling stage. Generally, we find that microscopic simulations provide a good description of a large variety of observables over many orders of collision energies.
Comparison of heavy ion transport simulations: Ag + Ag collisions at Elab = 1.58A GeV T. Reichert, A. Elz, T. Song, G. Coci, M. Winn, E. Bratkovskaya, J.Aichelin, J. Steinheimer and M. Bleicher,
J. Phys. G49 (2022) 055108 DOIarXivInspire
Midrapidity cluster formation in heavy-ion collisions E. Bratkovskaya, S. Glässel, V. Kireyeu, J. Aichelin, M. Bleicher, C. Blume, G. Coci, V. Kolesnikov, J. Steinheimer and V. Voronyuk,
Contribution to the SQM2022 Proceedings, EPJ Web of Conferences 276, 03005 (2023) DOIarXivInspire
Dynamical cluster and hypernuclei production in heavy-ion collisions S. Glässel, V. Kireyeu, V. Voronyuk, J. Aichelin, C. Blume, E.Bratkovskaya, G. Coci, V. Kolesnikov and M. Winn,
EPJ Web Conf. 259 (2022), 11003 DOIarXivInspire
We study light cluster and hypernuclei production in heavy-ion collisions from SIS to RHIC energies based on the n-body dynamical transport approach PHQMD (Parton-Hadron-Quantum-Molecular-Dynamics). In PHQMD clusters are formed dynamically due to the interactions between baryons described on the basis of Quantum Molecular Dynamics (QMD) which allows to propagate the n-body Wigner density and n-body correlations in phase-space, which is essential for the cluster formation. The clusters are identified by the MST (Minimum Spanning Tree) or the SACA (‘Simulated Annealing Cluster Algorithm’) algorithm which finds the most-bound configuration of nucleons and clusters. Collisions among hadrons as well as Quark-Gluon-Plasma formation and parton dynamics in PHQMD are treated in the same way as in the PHSD (Parton-Hadron-String-Dynamics) transport approach. We study the time evolution of the cluster formation in the expanding medium and the stability of the clusters. We present a comparison of the PHQMD results for d, 3He as well as for the hypernuclei with experimental data.
Prospects for the study of the strangeness production within the PHQMD model V. Kireyeu, J. Aichelin, E. Bratkovskaya, V. Kolesnikov, A. Mudrokh, V. Vasendina, A. Zinchenko,
Journal of Physics: Conference Series 1690 (2020) 012113 DOIInspire
Strangeness and hypernuclei production in heavy-ion collisions is presently under active experimental and theoretical investigation and is of particular interest for the experiments at the new acceleration complex NICA (Nuclotron-based Ion Collider fAcility) which is under construction at the Joint Institute for Nuclear Research (Dubna, Russia). We study the production of (hyper)nuclei in the NICA energy range using a novel n-body dynamical transport approach called Parton-Hadron-Quantum-Molecular Dynamics (PHQMD).
Cluster dynamics studied with the phase-space minimum spanning tree approach V. Kireyeu,
Phys. Rev. C 103, 054905 (2021) DOIarXivInspire
The origin of weakly bound objects like clusters and hypernuclei, observed in heavy-ion collisions, is of theoretical and experimental interest. It is in the focus of the experiments at the BNL Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) since it is not evident how such weakly bound objects can survive in an environment whose hadronic decay products point to a temperature of the order of 150 MeV. It is also one of the key research topics in the future facilities of FAIR and NICA, which are under construction in Darmstadt (Germany) and Dubna (Russia), respectively. The first results on the cluster dynamics within the model-independent cluster recognition library “phase-space minimum spanning tree” (psMST) applied to different transport approaches: PHQMD, PHSD, SMASH, and UrQMD are presented here. The psMST is based on the “minimum spanning tree” (MST) algorithm for the cluster recognition which exploits correlations in coordinate space, and it is extended to correlations of baryons in the clusters in momentum space. The sensitivity of the cluster formation on the microscopic realization of the n-body dynamics and on the potential interactions in heavy-ion collisions is shown.
Monte-Carlo studies of the MPD detector performance for the measurement of hypertritons in heavy-ion collisions at NICA energies V.I. Kolesnikov, V.A. Kireyeu, A.A. Mudrokh, V.A. Vasendina, A.I. Zinchenko, D.A. Zinchenko, J. Aichelin, and E. Bratkovskaya,
Phys.Part.Nucl.Lett. 19 (2022) 1, 46-53 DOIInspire
Heavy-ion collisions at NICA energies provide a unique opportunity for the study of the production of hypernuclei in dense baryonic matter. In this paper, the details of the reconstruction procedure for hypertritons with the MPD detector in Bi + Bi collisions at NICA energies are presented.
Prospects of studying the production of hypernuclei in heavy-ion interactions at the NICA collider at JINR V. Kireyeu, A. Mudrokh, V. Kolesnikov, A. Zinchenko, V. Vasendina, J. Aichelin and E. Bratkovskaya,
PoS PANIC2021 (2022), 220 DOIInspire
New acceleration complex NICA (Nuclotron-based Ion Collider fAcility) as well as MultiPurpose Detector (MPD) is underway at Joint Institute for Nuclear Research (Dubna, Russia) for the study of heavy ion collisions. Strangeness and hypernuclei production is presently under active experimental and theoretical investigation and is of particular interest of the NICA/MPD program. We combine several dynamical transport models and the MST cluster finding procedure to calculate the production of light nuclei and hypernuclei in heavy-ion collisions at NICA energies. The emphasis will be put on the NICA prospects for the study of the production of hypernuclei and detector performance in the reconstruction of hypernuclei species.
Parton Hadron Quantum Molecular Dynamics (PHQMD) — A Novel Microscopic N-Body Transport Approach For Heavy-Ion Dynamics and Hypernuclei Production Elena Bratkovskaya, Jörg Aichelin, Arnaud Le Fèvre, Viktar Kireyeu, Vadim Kolesnikov, Yvonne Leifels, and Vadim Voronyuk
Springer Proc.Phys. 250 (2020) 197-201 DOIarXivInspire
We present the novel microscopic n-body dynamical transport approach PHQMD(Parton-Hadron-Quantum-Molecular-Dynamics) for the description of particle production and cluster formation in heavy-ion reactions at relativistic energies. The PHQMD extends the established PHSD (Parton-Hadron-String-Dynamics) transport approach by replacing the mean field by density dependent two body interactions in a similar way as in the Quantum Molecular Dynamics (QMD) models. This allows for the calculation of the time evolution of the n-body Wigner density and therefore for a dynamical description of clusters and hypernuclei formation. The clusters are identified with the MST ('Minimum Spanning Tree') or the SACA ('Simulated Annealing Cluster Algorithm') algorithm which - by regrouping the nucleons in single nucleons and noninteracting clusters - finds the most bound configuration of nucleons and clusters. The selected results on clusters and hypernuclei production from Ref. arXiv:1907.03860 are discussed in this contribution.
Hadron production in elementary nucleon-nucleon reactions from low to ultra-relativistic energies V. Kireyeu, I. Grishmanovskii, V. Kolesnikov, V. Voronyuk, E. Bratkovskaya,
Eur.Phys.J.A 56 (2020) 9, 223 DOIarXivInspire
We study the hadron production in $p+p$, $p+n$ and $n+n$ reactions within the microscopic Parton-Hadron-Dynamics (PHSD) transport approach in comparison to PYTHIA 8.2. We discuss the details of the "PHSD tune" of the Lund string model (realized by event generators FRITIOF and PYTHIA) in the vacuum (as in $N+N$ collisions) as well as its in-medium modifications relevant for heavy-ion collisions where a hot and dense matter is produced. We compare the results of PHSD and PYTHIA 8.2 (default version) for the excitation function of hadron multiplicities as well as differential rapidity $y$, transverse momentum $p_T$ and $x_F$ distributions in $p+p$, $p+n$ and $n+n$ reactions with the existing experimental data in the energy range $\sqrt{s_{NN}} = 2.7 - 7000$ GeV. We discuss the production mechanisms of hadrons and the role of final state interactions (FSI) due to the hadronic rescattering. We also show the influence of the possible quark-gluon plasma (QGP) formation on hadronic observables in $p+p$ collisions at LHC energies. We stress the importance of developing a reliable event generator for elementary reactions from low to ultra-relativistic energies in view of actual and upcoming heavy-ion experiments.
A new review of excitation functions of hadron production in pp collisions in the NICA energy range V. Kolesnikov, V. Kireyeu, V. Lenivenko, A. Mudrokh, K. Shtejer, D. Zinchenko, E. Bratkovskaya,
Physics of Particles and Nuclei Letters, 2020, Vol. 17, No. 2, pp. 142–153. DOIarXivInspire
Data on hadron multiplicities from inelastic proton-proton interactions in the energy range of the NICA collider have been compiled. The compilation includes recent results from the NA61/SHINE and NA49 experiments at the CERN SPS accelerator. New parameterizations for excitation functions of mean multiplicities $\left< \pi^{\pm}\right>$, $\left< K^{\pm}\right>$, $\left< K^{0}_S\right>$, $\left< \Lambda\right>$, $\left< p\right>$, $\left< \bar{p}\right>$ are obtained in the region of collision energies $3<\sqrt{s_{NN}}<31$~GeV. The energy dependence of the particle yields, as well as variation of rapidity and transverse momentum distributions are discussed. A standalone algorithm for hadron phase space generation in $pp$ collisions is suggested and compared to model predictions using an example of the PHQMD generator.
The investigation has been performed at the Laboratory of High Energy Physics, JINR.
PHQMD Model for the Formation of Nuclear Clusters and Hypernuclei in Heavy Ion Collisions, V. Kireyeu, J. Aichelin, E. Bratkovskaya, A. Le Fèvre, V. Lenivenko, V. Kolesnikov, Y. Leifels, V. Voronyuk,
Izvestiya Rossiiskoi Akademii Nauk, Seriya Fizicheskaya, 2020, Vol. 84, No. 8, pp. 1161–1166 DOIarXivInspire
A new n-body dynamic transport approach, PHQMD (Parton-Hadron-Quantum-Molecular-Dynamics), is used to describe heavy-ion collisions and the formation of clusters and hypernuclei. The first results are presented from using PHQMD to study the rates of production of strange hadrons, nuclear clusters, and hypernuclei in elementary and heavy-ion collisions at NICA energies. The sensitivity of bulk observables toward the hard and soft equations of state in the PHQMD model is investigated.
Progress in the construction of the NICA accelerator complex V. I. Kolesnikov et al.,
Phys.Scripta 95 (2020) 9, 094001 DOIInspire
The Nuclotron-based Ion Collider fAcility (NICA) is currently under construction at JINR (Dubna, Russia). The new facility will be a significant extension of the existing Nuclotron accelerator chain and comprises a sequence of machines for providing beams from protons to gold ions, as well as polarized protons and deuterons. The main goal of the Multi-Purpose Detector (MPD) experiment at NICA will be the study of a variety of phenomena in the region of the highest net-baryon density. This paper covers the scope of the NICA/MPD project and describes the recent progress in its realization.
Prospects for Studying Hyperons and Hypernuclei on the NICA Collider V. I. Kolesnikov, A. I. Zinchenko, V. A. Vasendina,
Bulletin of the Russian Academy of Sciences: Physics, 2020, Vol. 84, No. 4, pp. 451–454. DOIPDFInspire
NICA is a new flagship project in Dubna aimed at constructing a new accelerator complex for heavy ions. The main goal of the project is experimental exploration of the still poorly known region of the nuclear matter phase diagram of the highest net-baryon density. The MPD detector is a multi-purpose large acceptance spectrometer for studying heavy-ion collisions. An overview is presented of the NICA physics program for studying strangeness production and present MPD performance for reconstructing hyperons and hypernuclei.
Перспективы изучения гиперонов и гиперядер на коллайдере NICA В. И. Колесников, А. И. Зинченко, В. А. Васендина,
Известия РАН, Серия физическая, том 84, No 4, с. 575–579. PDF
Основной целью нового флагманского проекта NICA является строительство в Дубне ускорительного комплекса тяжелых ионов для экспериментального исследования плохо изученной области фазовой диаграммы сильно взаимодействующей материи с максимальной барионной плотностью. Многофункциональный детектор MPD сконструирован как спектрометр большого аксептанса для регистрации ядерных столкновений. В данной работе представлено краткое описание физической программы NICA по изучению рождения странности, а также приводятся характеристики детектора MPD для реконструкции гиперонов и гиперяд.
