arXiv subjects

Dániel Kincses

Publications and source records attributed to Dániel Kincses.

12 recordsLinked to original sources

arXiv2026

Particle species dependence of femtoscopic source parameters in high-energy nuclear collisions

High-energy nuclear physics explores the properties of strongly interacting matter created in relativistic collisions of nuclei. Femtoscopy, a subfield of high-energy physics, utilizes quantum-statistical correlations of particles to characterize the space-time geometry of the particle-emitting source. Recent measurements and phenomenological investigations indicated that the shape of the source for identical pions can be well-described by Lévy-stable distributions. The significant power-law tail of the pion source observed both in experiment and in simulations has been shown to originate from the process of Lévy walk during the hadronic scattering phase of the collisions. To better understand the physical processes behind the formation of such power laws, an important next step is to investigate particle species dependence, especially the source shape of identical kaon and proton pairs. As a direct continuation of our previous studies, in this Letter, we present a detailed three-dimensional investigation of the two-particle source shape in simulations of Au+Au collisions at 200 GeV per nucleon pair collision energy using the EPOS3 model. We show the dependence of the extracted femtoscopic source parameters on particle species, centrality and average transverse mass. We find that the scale parameters do not show a clear transverse mass scaling between particle species, as there are systematic differences in the overlapping regions. The power-law exponents of pion and kaon pairs are compatible, while for protons it is higher, closer to the Gaussian limit. When new experimental measurements of kaon and proton correlations become available, these results will provide the basis of a data-model comparison.

hep-ph↗

arXiv2026

A self-consistent calculation of non-spherical Bose-Einstein correlation functions with Coulomb final-state interaction

Particle correlations and femtoscopy are a rich subfield of high-energy physics. As the experimental data become more precise, there is an increasing need for the theoretical calculations to provide better and more general descriptions of the measurements. One of the important new directions is the investigation of the precise shape of the Bose-Einstein correlation functions utilizing Lévy-stable distributions. This work is a direct follow-up to our previous study, in which we developed a novel method for calculating Bose-Einstein correlation functions including the Coulomb final-state interaction. In this paper, we present a self-consistent generalization of the previous approach to non-spherical source functions and investigate the validity of the previously applied approximations assuming spherical symmetry. We present a software package that includes the calculation of a fully three-dimensional correlation function including the Coulomb interaction.

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arXiv2025

Lévy walk of pions in heavy-ion collisions

The process of Lévy walk, i.e., movement patterns described by heavy-tailed random walks, plays a role in various phenomena, from chemical and microbiological systems through marine predators to climate change. Recent experiments have suggested that this phenomenon also appears in heavy-ion collisions. However, the theoretical interpretation supporting such findings is still debated. In high-energy collisions of heavy nuclei, the strongly interacting Quark Gluon Plasma is created, which, similarly to the early Universe, undergoes a rapid expansion and transition back to hadronic matter. In the subsequent expanding hadron gas, particles interact until kinetic freeze-out, when their momenta stop changing, and they freely transition toward the detectors. Measuring spatial freeze-out distributions is a crucial tool in understanding the dynamics of the created matter and the interactions among its constituents. In this paper, we introduce a three-dimensional analysis of the spatial freeze-out distribution of pions (the most abundant particles in such collisions). Utilising Monte-Carlo simulations of high-energy collisions, we show that the chain of processes ending in a final state pion has a step length distribution leading to Lévy-stable distributions. Subsequently, we show that simulated pion freeze-out distributions indeed exhibit heavy tails and can be described by a three-dimensional elliptically contoured symmetric Lévy-stable distribution.

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arXiv2024

Femtoscopy with Lévy sources from SPS through RHIC to LHC

Femtoscopy is a unique tool to investigate the space-time geometry of the matter created in ultra-relativistic collisions. If the probability density distribution of hadron emission is parametrized, then the dependence of its parameters on particle momentum, collision energy, and collision geometry can be given. In recent years, several measurements came to light that indicated the adequacy of assuming a Lévy-stable shape for the mentioned distribution. In parallel, several new phenomenological developments appeared, aiding the interpretation of the experimental results or providing tools for the measurements. In this paper, we discuss important aspects of femtoscopy with Lévy sources in light of some of these advances, including phenomenological and experimental ones.

hep-ph↗

arXiv2024

Pion interferometry with Lévy-stable sources in $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions at STAR

Measurements of femtoscopic correlations in high-energy heavy-ion collisions aim to unravel the space-time structure of the particle-emitting source (the quark-gluon plasma). Recent results indicate that the pion pair source exhibits a power-law behavior and can be described well by a Lévy distribution. In this study, Lévy fits were performed to the measured one-dimensional two-pion correlation functions in Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV. The three extracted source parameters are the Lévy scale parameter, $R$, which relates to the size of the source; the correlation strength parameter, $λ$; and the Lévy exponent, $α$, which characterizes the power-law tail of the source. In this paper, we report the current status of the analysis of the extracted Lévy source parameters and present their dependence on average transverse mass, $m_T$, and on centrality.

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arXiv2024

Coulomb Corrections for Bose-Einstein Correlations from One- And Three-Dimensional Lévy-Type Source Functions

In the study of femtoscopic correlations in high-energy physics, besides Bose--Einstein correlations, one has to take final-state interactions into account. Amongst them, Coulomb interactions play a prominent role in the case of charged particles. Recent measurements have shown that in heavy-ion collisions, Bose--Einstein correlations can be best described by Lévy-type sources instead of the more common Gaussian assumption. Furthermore, three-dimensional measurements have indicated that, depending on the choice of frame, a deviation from spherical symmetry observed under the assumption of Gaussian source functions persists in the case of Lévy-type sources. To clarify such three-dimensional Lévy-type correlation measurements, it is thus important to study the effect of Coulomb interactions in the case of non-spherical Lévy sources. We calculated the Coulomb correction factor numerically in the case of such a source function for assorted kinematic domains and parameter values using the Metropolis--Hastings algorithm and compared our results with previous methods to treat Coulomb interactions in the presence of Lévy sources.

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arXiv2023

Event-by-event investigation of the two-particle source function in $\sqrt{s_{_{\text{NN}}}}=2.76$ TeV PbPb collisions with EPOS

The investigation of the two-particle source function in lead-lead collisions simulated by the EPOS model at a center of mass energy per nucleon pair of $\sqrt{s_{_{\text{NN}}}}=2.76$ TeV is presented. The two-particle source functions are reconstructed directly on an event-by-event basis for pions, kaons and protons separately, using the final stage of EPOS. A Lévy source shape is observed for all three particle species in the individual events, deviating significantly from a Gaussian shape. The source parameters are extracted as functions of collision centrality and pair average transverse mass ($m_{\text{T}}$). The Lévy exponent is found to be ordered accordingly to particle mass. The Lévy scale parameter is found to scale for all particle species with $m_{\text{T}}$ according to Gaussian hydrodynamical predictions; however, there is no $m_{\text{T}}$-scaling found across these species. In case of pions, the effects of the decay products and hadronic rescattering are also investigated. The Lévy exponent is decreased when decay products are also included in the analysis. Without hadronic rescattering and decay products, the source shape is close to a Gaussian.

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arXiv2023

A novel method for calculating Bose-Einstein correlation functions with Coulomb final-state interaction

Measurements of Bose-Einstein correlations played a crucial role in the discovery and the subsequent detailed exploration of the Quark-Gluon-Plasma (QGP) created in high-energy collisions of heavy nuclei. Such measurements gave rise to femtoscopy, a flourishing sub-field of high-energy physics, and there are important new directions to explore and discoveries to be made in the near future. One of these important current topics is the precise investigation of the shape of the correlation functions utilizing Lévy-stable sources. In this paper, we present a novel method of calculating the shape of the two-particle correlation functions, including the Coulomb final-state interaction. This method relies on an exact calculation of a large part of the necessary integrals of the Coulomb wave function and can be utilized to calculate the correlation function for any source function with an easily accessible Fourier transform. In this way, it is eminently applicable to Lévy-stable source functions. In this particular case, we find that the new method is more robust and allows the investigation of a wider parameter range than the previously utilized techniques. We present an easily applicable software package that is ready to use in experimental studies.

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arXiv2022

Event-by-event investigation of the two-particle source function in heavy-ion collisions with EPOS

Exploring the shape of the pair-source function for particles such as pions or kaons has been an important goal of heavy-ion physics, and substantial effort has been made in order to understand the underlying physics behind the experimental observations of non-Gaussian behavior. In experiments, since no direct measurement of the source function is possible, quantum-statistical momentum correlations are utilized to gain information about the space-time geometry of the particle emitting source. Event generators, such as EPOS, however, provide direct access to the freeze-out coordinates of final state particles, and thus the source function can be constructed and investigated. The EPOS model is a sophisticated hybrid model where the initial stage evolution of the system is governed by Parton-Based Gribov-Regge theory, and subsequently a hydrodynamic evolution is utilized, followed by hadronization and hadron dynamics. EPOS has already proven to be successful in describing several different experimental observations for systems characterized by baryon chemical potential close to zero, but so far the source shape has not been explored in detail. In this paper we discuss an event-by-event analysis of the two-particle source function in $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions generated by the EPOS model. We find that when utilizing all stages of the model, Lévy-shaped distributions (unlike Gaussian distributions) provide a good description of the source shape in the individual events. Hence it is clear that it is not the event averaging that creates the non-Gaussian features in the pair distributions. Based on this observation, we determine Lévy-parameters of the source as a function of event centrality and particle momentum.

hep-ph↗

arXiv2017

Lévy analysis of HBT correlation functions in $\sqrt{s_{\rm NN}}=$ 62 GeV and 39 GeV Au+Au collisions at PHENIX

The phase diagram of strongly interacting matter can be explored by analyzing data of heavy-ion collisions at different center of mass collision energies. For investigating the space-time structure of the hadron emission source, HBT correlation measurements are among the best tools. In this paper we present the latest results from the RHIC PHENIX experiment on such measurements in $\sqrt{s_{\rm NN}}=$ 39 GeV and 62 GeV Au+Au collisions.

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arXiv2016

PHENIX results on Lévy analysis of Bose-Einstein correlation functions

The nature of the quark-hadron phase transition can be investigated through analyzing the space-time structure of the hadron emission source. For this, the Bose-Einstein or HBT correlations of identified charged particles are among the best observables. In this paper we present the latest results from the RHIC PHENIX experiment on such measurements.

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arXiv2016

PHENIX results on Bose-Einstein correlation functions

Measurement of Bose-Einstein or HBT correlations of identified charged particles provide insight into the space-time structure of particle emitting sources in heavy-ion collisions. In this paper we present the latest results from the RHIC PHENIX experiment on such measurements.

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