Multiparticle Dynamics

A special issue of Universe (ISSN 2218-1997). This special issue belongs to the section "High Energy Nuclear and Particle Physics".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 21661

Special Issue Editors


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Guest Editor
1. MATE Institute of Technology, Károly Róbert Campus, Mátrai út 36, H-3200 Gyöngyös, Hungary
2. Wigner Research Center for Physics, P.O. Box 49, H-1525 Budapest, Hungary
Interests: theoretical nuclear physics; experimental nuclear physics; theoretical particle physics; experimental particle physics
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Atomic Physics, Eötvös Loránd University, Pázmány P. s. 1/A, H-1117 Budapest, Hungary
Interests: hydrodynamics in high-energy heavy ion physics; Bose–Einstein correlations; femtoscopy; forward (small-x) processes in particle physics
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Applied Informatics, Physics, MATE Institute of Technology KRC, Gyöngyös, Hungary
Interests: Bose-Einstein correlations; Lévy-stable distributions; financial mathematics; seismology for gravitational waves

Special Issue Information

Dear Colleagues,

This special issue is dedicated to the conference: 52th International Symposium on Multiparticle Dynamics (ISMD23), https://indico.cern.ch/e/ismd23.

Traditionally, the topics of the ISMD conference series cover multiparticle production in high energy particle and nuclear physics, both experiment and theory, and also include related areas in astroparticle physics, standard model and beyond standard model physics.

In 2023, we invite all contributors to publish a full paper based on their talks and posters presented at ISMD 2023 within the above main areas in general, and related to the following topics in particular:

  • Collectivity in high energy collisions: jets, flows, ...
  • Cosmic ray and astroparticle physics
  • Femtoscopy
  • Forward physics: Diffraction, Odderon and Pomeron
  • Hadronic final states in high pT interactions
  • Multiparticle correlations and fluctuations
  • Proton structure, small-x and large-x physics
  • Physics of X17 and other beyond standard model states
  • Other important new developments in HEP

There is no maximal length, and the suggested minimum is approx. 4000 words. Submitted papers should contain enough novel contents (except for reviews, which are acceptable from senior contributors). Please note that the three paper types possible for this special issue are Article, Review, and Communication (limited number). For more details, including various article types, please visit   https://www.mdpi.com/about/article_types.

Prof. Dr. Tamás Csörgő
Prof. Dr. Máté Csanád
Dr. Tamás Novák
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Universe is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (21 papers)

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Research

18 pages, 980 KiB  
Article
Dip-Bump Structure in Proton’s Single Diffractive Dissociation at the Large Hadron Collider
by László Jenkovszky, Rainer Schicker and István Szanyi
Universe 2024, 10(5), 208; https://doi.org/10.3390/universe10050208 - 7 May 2024
Viewed by 470
Abstract
By extending the dipole Pomeron (DP) model, successful in describing elastic nucleon–nucleon scattering, to proton single diffractive dissociation (SD), we predict a dip-bump structure in the squared four-momentum transfer (t) distribution of proton’s SD. Structures in the t distribution of single [...] Read more.
By extending the dipole Pomeron (DP) model, successful in describing elastic nucleon–nucleon scattering, to proton single diffractive dissociation (SD), we predict a dip-bump structure in the squared four-momentum transfer (t) distribution of proton’s SD. Structures in the t distribution of single diffractive dissociation are predicted around t=4GeV2 at LHC energies in the range of 3 GeV2|t| 7 GeV2. Apart from the dependence on s (total energy squared) and t (squared momentum transfer), we predict also a dependence on missing masses. We include the minimum set of Regge trajectories, namely the Pomeron and the Odderon, indispensable at the LHC. Further generalization, e.g., by the inclusion of non-leading Regge trajectories, is straightforward. The present model contains two types of Regge trajectories: those connected with t-channel exchanges (the Pomeron, the Odderon, and non-leading (secondary) reggeons) appearing at small and moderate t, where they are real and nearly linear, as well as direct-channel trajectories α(M2) related to missing masses. In this paper, we concentrate on structures in t neglecting (for the time being) resonances in M2. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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11 pages, 637 KiB  
Article
Two-Pion Bose–Einstein Correlations in Au+Au Collisions at sNN = 3 GeV in the STAR Experiment
by Anna Kraeva
Universe 2024, 10(4), 188; https://doi.org/10.3390/universe10040188 - 20 Apr 2024
Viewed by 622
Abstract
The correlation femtoscopy technique makes it possible to estimate the geometric dimensions and lifetime of the particle emission region after the collision of ions. Measurements of the emission region characteristics not only at midrapidity but also at backward (forward) rapidity can provide new [...] Read more.
The correlation femtoscopy technique makes it possible to estimate the geometric dimensions and lifetime of the particle emission region after the collision of ions. Measurements of the emission region characteristics not only at midrapidity but also at backward (forward) rapidity can provide new information about the source and make it possible to impose constraints on the heavy-ion collision models. This work is devoted to revealing the dependence of the spatial and temporal parameters of the emission region of identical pions in Au+Au collisions at sNN = 3 GeV from the fixed-target program of the STAR experiment. The extracted femtoscopic radii, RoutRsideRlongRoutlong2, and the correlation strength, λ, are presented as a function of collision centrality, pair rapidity, and transverse momentum. Physics implications will be discussed. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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33 pages, 1038 KiB  
Article
QED Meson Description of the Anomalous Particles at ∼17 and ∼38 MeV
by Cheuk-Yin Wong
Universe 2024, 10(4), 173; https://doi.org/10.3390/universe10040173 - 7 Apr 2024
Viewed by 921
Abstract
The Schwinger confinement mechanism stipulates that a massless fermion and a massless antifermion are confined as a massive boson when they interact in the Abelian QED interaction in (1+1)D.If we approximate light quarks as massless and apply the Schwinger confinement mechanism to quarks, [...] Read more.
The Schwinger confinement mechanism stipulates that a massless fermion and a massless antifermion are confined as a massive boson when they interact in the Abelian QED interaction in (1+1)D.If we approximate light quarks as massless and apply the Schwinger confinement mechanism to quarks, we can infer that a light quark and a light antiquark interacting in the Abelian QED interaction are confined as a QED meson in (1+1)D. Similarly, a light quark and a light antiquark interacting in the QCD interaction in the quasi-Abelian approximation will be confined as a QCD meson in (1+1)D. The QED and QCD mesons in (1+1)D can represent physical mesons in (3+1)D when the flux tube radius is properly taken into account. Such a theory leads to a reasonable description of the masses of π0,η, and η, and its extrapolation to the unknown QED sector yields an isoscalar QED meson at about 17 MeV and an isovector QED meson at about 38 MeV. The observations of the anomalous soft photons, the hypothetical X17 particle, and the hypothetical E38 particle bear promising evidence for the possible existence of the QED mesons. Pending further confirmation, they hold important implications on the properties on the quarks and their interactions. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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11 pages, 826 KiB  
Article
Checking the 8Be Anomaly with a Two-Arm Electron Positron Pair Spectrometer
by Tran The Anh, Tran Dinh Trong, Attila J. Krasznahorkay, Attila Krasznahorkay, József Molnár, Zoltán Pintye, Nguyen Ai Viet, Nguyen The Nghia, Do Thi Khanh Linh, Bui Thi Hoa, Le Xuan Chung and Nguyen Tuan Anh
Universe 2024, 10(4), 168; https://doi.org/10.3390/universe10040168 - 1 Apr 2024
Cited by 2 | Viewed by 972
Abstract
We have repeated the experiment performed recently by ATOMKI Laboratory (Debrecen, Hungary), which may indicate a new particle called X17 in the literature. In order to obtain a reliable and independent result, we used a different structure of the electron–positron pair spectrometer at [...] Read more.
We have repeated the experiment performed recently by ATOMKI Laboratory (Debrecen, Hungary), which may indicate a new particle called X17 in the literature. In order to obtain a reliable and independent result, we used a different structure of the electron–positron pair spectrometer at the VNU University of Science. The spectrometer has two arms and simpler acceptance and efficiency as a function of the correlation angle, but the other conditions of the experiment were very similar to the published ones. We could confirm the presence of the anomaly measured at Ep = 1225 keV, which is above the Ep = 1040 keV resonance. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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6 pages, 407 KiB  
Communication
Femtoscopy for the NAno-Plasmonic Laser Inertial Fusion Experiments (NAPLIFE) Project
by L. P. Csernai, T. Csörgő, I. Papp, K. Tamosiunas, M. Csete, A. Szenes, D. Vass, T. S. Biró and N. Kroó
Universe 2024, 10(4), 161; https://doi.org/10.3390/universe10040161 - 29 Mar 2024
Viewed by 796
Abstract
Hanbury-Brown and Twiss analysis is used to determine the size and timespan of emitted particles. Here, we propose to adapt this method for laser-induced nanoplasmonic inertial confinement fusion to determine the parameters of emitted Deuterium and Helium4 nuclei. This communication is a [...] Read more.
Hanbury-Brown and Twiss analysis is used to determine the size and timespan of emitted particles. Here, we propose to adapt this method for laser-induced nanoplasmonic inertial confinement fusion to determine the parameters of emitted Deuterium and Helium4 nuclei. This communication is a short article that presents part of a larger study over multiple years. It presents a cutting edge method that is new in the field of Inertial Confinement Fusion. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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7 pages, 789 KiB  
Communication
Nuclear Modification Factor of Inclusive Charged Particles in Au+Au Collisions at sNN = 27 GeV with the STAR Experiment
by Alisher Aitbayev
Universe 2024, 10(3), 139; https://doi.org/10.3390/universe10030139 - 13 Mar 2024
Viewed by 981
Abstract
The Beam Energy Scan (BES) program at RHIC aims to explore the QCD phase diagram, including the search for the evidence of the 1st order phase transition from hadronic matter to Quark-Gluon Plasma (QGP) and the location of the QCD critical point. One [...] Read more.
The Beam Energy Scan (BES) program at RHIC aims to explore the QCD phase diagram, including the search for the evidence of the 1st order phase transition from hadronic matter to Quark-Gluon Plasma (QGP) and the location of the QCD critical point. One of the features previously observed in the study of QGP is the effect of suppression of particle production with high transverse momenta pT (>2 GeV/c) at energies sNN = 62.4200 GeV, which was deduced from the charged-particle nuclear modification factor (RCP) measured using the data from Beam Energy Scan Program Phase I (BES-I) of STAR experiment. In 2018, STAR has collected over 500 million events from Au+Au collisions at sNN = 27 GeV as a part of the STAR BES-II program, which is about a factor of 10 higher than BES-I 27 GeV data size. In this report, we present new measurements of charged particle production and the nuclear modification factor RCP, from this new 27 GeV data set and compare them with the BES-I results. The new measurements extend the previous BES-I results to higher transverse momentum range, which allows better exploration of the jet quenching effects at low RHIC energies, and may help to understand the effects of the formation and properties of QGP at these energies. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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21 pages, 1673 KiB  
Article
Simple Lévy α-Stable Model Analysis of Elastic pp and pp¯ Low-|t| Data from SPS to LHC Energies
by Tamás Csörgő, Sándor Hegyi and István Szanyi
Universe 2024, 10(3), 127; https://doi.org/10.3390/universe10030127 - 6 Mar 2024
Viewed by 928
Abstract
A simple Lévy α-stable (SL) model is used to describe the data on elastic pp and pp¯ scattering at low-|t| from SPS energies up to LHC energies. The SL model is demonstrated to describe the data [...] Read more.
A simple Lévy α-stable (SL) model is used to describe the data on elastic pp and pp¯ scattering at low-|t| from SPS energies up to LHC energies. The SL model is demonstrated to describe the data with a strong non-exponential feature in a statistically acceptable manner. The energy dependence of the parameters of the model is determined and analyzed. The Lévy α parameter of the model has an energy-independent value of 1.959 ± 0.002 following from the strong non-exponential behavior of the data. We strengthen the conclusion that the discrepancy between TOTEM and ATLAS elastic pp differential cross section measurements arises only in the normalization and not in the shape of the distribution of the data as a function of t. We find that the slope parameter has different values for pp and pp¯ elastic scattering at LHC energies. This may be the effect of the odderon exchange or the jump in the energy dependence of the slope parameter in the energy interval 3 GeV s 4 GeV. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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9 pages, 2185 KiB  
Communication
Heavy Flavor Physics at the sPHENIX Experiment
by Zhaozhong Shi
Universe 2024, 10(3), 126; https://doi.org/10.3390/universe10030126 - 6 Mar 2024
Viewed by 1022
Abstract
The sPHENIX experiment is a state-of-the-art jet and heavy flavor physics detector, which successfully recorded its first Au + Au collision data at 200 GeV at the Relativistic Heavy Ion Collider (RHIC). sPHENIX will provide heavy flavor physics measurements at RHIC, covering an [...] Read more.
The sPHENIX experiment is a state-of-the-art jet and heavy flavor physics detector, which successfully recorded its first Au + Au collision data at 200 GeV at the Relativistic Heavy Ion Collider (RHIC). sPHENIX will provide heavy flavor physics measurements at RHIC, covering an unexplored kinematic region and unprecedented precision, to probe the parton energy loss mechanism, parton transport coefficients in quark–gluon plasma, and the hadronization process under various medium conditions. At the center of sPHENIX, the monolithic active pixel sensor (MAPS)-based VerTeX detector (MVTX) is a high-precision silicon pixel detector. The MVTX provides excellent position resolution and the capability of operating in continuous streaming readout mode, allowing precise vertex determination and recording a large data sample, both of which are particularly crucial for heavy flavor physics measurements. In this work, we will show the general performance of heavy-flavor hadron reconstruction. In addition, we will discuss the commissioning experience with sPHENIX. Finally, we will provide the projection of b-hadron and jet observables and discuss the estimated constraints on theoretical models. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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9 pages, 1323 KiB  
Article
First-Order Event Plane Correlated Directed and Triangular Flow from Fixed-Target Energies at RHIC-STAR
by Sharang Rav Sharma
Universe 2024, 10(3), 118; https://doi.org/10.3390/universe10030118 - 1 Mar 2024
Viewed by 964
Abstract
We report the measurement of first-order event plane-correlated directed flow (v1) and triangular flow (v3) for identified hadrons (π±, K±, and p), net particle (net-K, net-p), and light nuclei (d [...] Read more.
We report the measurement of first-order event plane-correlated directed flow (v1) and triangular flow (v3) for identified hadrons (π±, K±, and p), net particle (net-K, net-p), and light nuclei (d and t) in Au + Au collisions at sNN = 3.2, 3.5, and 3.9 GeV in the fixed-target mode from the second phase of the beam energy scan (BES-II) program at RHIC-STAR. The v1 slopes at mid-rapidity for identified hadrons and net particles except π+ are found to be positive, implying the effect of dominant repulsive baryonic interactions. The slope of v1 for net-kaon undergoes a sign change from negative to positive at a lower collision energy compared to net-proton. An approximate atomic mass number scaling is observed in the measured v1 slopes of light nuclei at mid-rapidity, which favors the nucleon coalescence mechanism for the production of light nuclei. The v3 slope for all particles decreases in magnitude with increasing collision energy, suggesting a notable integrated impact of the mean-field, baryon stopping, and collision geometry at lower collision energies. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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5 pages, 225 KiB  
Article
Understanding the Effect of Conserved Charges on the Coalescence Sum Rule of Directed Flow
by Kishora Nayak, Shu-Su Shi and Zi-Wei Lin
Universe 2024, 10(3), 112; https://doi.org/10.3390/universe10030112 - 1 Mar 2024
Viewed by 973
Abstract
Recently, the rapidity-odd directed flow (v1) of produced hadrons (K, ϕ, p¯, Λ¯, Ξ¯+, Ω, and Ω¯+) has been studied. Several combinations of these [...] Read more.
Recently, the rapidity-odd directed flow (v1) of produced hadrons (K, ϕ, p¯, Λ¯, Ξ¯+, Ω, and Ω¯+) has been studied. Several combinations of these produced hadrons, with very small mass differences but differences in the net electric charge (Δq) and net strangeness (ΔS) on the two sides, have been considered. A difference in v1 between the two sides of these combinations (Δv1) has been proposed as a consequence of the electromagnetic field produced in relativistic heavy-ion collisions, especially if Δv1 increases with Δq. Our study is performed to understand the effect of the coalescence sum rule (CSR) on Δv1. We point out that the CSR leads to Δv1=cqΔq+cSΔS, where the coefficients cq and cS reflect the Δv1 of produced quarks. Equivalently, one can write Δv1=cqΔq+cBΔB, involving the difference in the net baryon number ΔB, where the CSR gives cB=3cS. We then propose two methods to extract the coefficients for the Δq and ΔS dependences of Δv1. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
12 pages, 733 KiB  
Article
Two-Pomeron Interaction
by Luis Cancino Arancibia and Carlos Contreras
Universe 2024, 10(3), 103; https://doi.org/10.3390/universe10030103 - 20 Feb 2024
Viewed by 1016
Abstract
We study the interaction of two discrete pomeron fields while considering mass mixing and the general structure of the interaction potential for pomerons within the framework for a functional renormalization group analysis of Reggeon field theory. We find fixed points from the zeros [...] Read more.
We study the interaction of two discrete pomeron fields while considering mass mixing and the general structure of the interaction potential for pomerons within the framework for a functional renormalization group analysis of Reggeon field theory. We find fixed points from the zeros of the beta function establishing the existence of three groups of solutions: the first corresponds to two uncoupled pomerons, the second is a solution known as a “pomeron–odderon” interaction, and the final is a real general solution with an interaction potential. We also study its universal properties around this fixed point. This analysis allows for a discussion for the first time on the mixing of two pomerons through renormalization flow paths from the ultraviolet to the non-perturbative infrared regions. Finally, we comment on its role in high-energy scattering. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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9 pages, 384 KiB  
Communication
Pion Interferometry with Lévy-Stable Sources in sNN = 200 GeV Au + Au Collisions at STAR
by Dániel Kincses
Universe 2024, 10(3), 102; https://doi.org/10.3390/universe10030102 - 20 Feb 2024
Cited by 2 | Viewed by 1082
Abstract
Measurements of femtoscopic correlations in high-energy heavy-ion collisions are used 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 [...] Read more.
Measurements of femtoscopic correlations in high-energy heavy-ion collisions are used 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 applied to the measured one-dimensional two-pion correlation functions in Au + Au collisions at sNN = 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, mT, and on centrality. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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12 pages, 337 KiB  
Article
Proposal for an Electromagnetic Mass Formula for the X17 Particle
by Sándor Varró
Universe 2024, 10(2), 86; https://doi.org/10.3390/universe10020086 - 12 Feb 2024
Viewed by 1122
Abstract
Recent observations of anomalous angular correlations of electron–positron pairs in several nuclear reactions have indicated the existence of a hypothetical neutral boson of rest mass ~17 MeV/c2, called the X17 particle. Similarly, one has interpreted an independent set of experiments [...] Read more.
Recent observations of anomalous angular correlations of electron–positron pairs in several nuclear reactions have indicated the existence of a hypothetical neutral boson of rest mass ~17 MeV/c2, called the X17 particle. Similarly, one has interpreted an independent set of experiments on photon pair spectra around the invariant mass ~38 MeV/c2, by assuming the existence of the so-called E38 particle. In the present paper, we derive analytical mass formulas for the X17 particle and the E38 particle, on the basis of quantum electrodynamics. We shall use the exact solutions of the Dirac equation of the joint system of a charged particle and plane waves of the quantized electromagnetic radiation. When these solutions are applied to a proton, they lead to dressed radiation quanta with a rest mass of 17.0087 MeV/c2, which may be identified with the X17 vector bosons. A similar consideration, applied to the udd quarks of the neutron, yields dressed quanta, whose mass equals 37.9938 MeV/c2, corresponding to the E38 particle. These formulas, besides the Sommerfeld fine structure constant and the masses of the nucleons, do not contain any adjustable parameters. The present analysis also delivers the value 0.846299 fm for the proton radius. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
9 pages, 423 KiB  
Communication
Coulomb-Nuclear Interference in Polarized pA Scattering
by Boris Kopeliovich, Michal Krelina and Irina Potashnikova
Universe 2024, 10(2), 63; https://doi.org/10.3390/universe10020063 - 31 Jan 2024
Cited by 1 | Viewed by 801
Abstract
We made the first attempt to understand the observed unusual t dependence of single-spin asymmetry observed in the HJET experiment at RHIC. Usually, the interaction of hadrons is presented as a long-range Coulomb interaction and a short-range strong interaction with Coulomb corrections. Such [...] Read more.
We made the first attempt to understand the observed unusual t dependence of single-spin asymmetry observed in the HJET experiment at RHIC. Usually, the interaction of hadrons is presented as a long-range Coulomb interaction and a short-range strong interaction with Coulomb corrections. Such a division gives rise to a Coulomb phase of the hadronic term. Conversely, here we consider short-range hadronic interaction as a correction to the long-range electromagnetic term, i.e., we treat it as an absorptive correction. This significantly affects the Coulomb-nuclear interference, which is a source of single-spin azimuthal asymmetry at small angles. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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12 pages, 441 KiB  
Article
Femtoscopy with Lévy Sources from SPS through RHIC to LHC
by Máté Csanád and Dániel Kincses
Universe 2024, 10(2), 54; https://doi.org/10.3390/universe10020054 - 23 Jan 2024
Cited by 4 | Viewed by 1047
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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8 pages, 7536 KiB  
Communication
Pacific Ocean Neutrino Experiment
by Paweł Malecki
Universe 2024, 10(2), 53; https://doi.org/10.3390/universe10020053 - 23 Jan 2024
Viewed by 1195
Abstract
Following the breakthrough discoveries of very-high-energy neutrinos of astrophysical origin by IceCube, a new field of research, neutrino astronomy, was established in the previous decade. Even though two extragalactic point sources of such neutrinos have been identified by now, TXS 0506+056 and NGC [...] Read more.
Following the breakthrough discoveries of very-high-energy neutrinos of astrophysical origin by IceCube, a new field of research, neutrino astronomy, was established in the previous decade. Even though two extragalactic point sources of such neutrinos have been identified by now, TXS 0506+056 and NGC 1068, the origin and processes of the creation of astrophysical neutrinos are still mostly unexplored. To advance quickly in this new field, more neutrino telescopes are needed. This article describes the current status and plans for the development of the Pacific Ocean Neutrino Experiment (P-ONE), which is under construction in the Pacific Ocean near Vancouver Island. The deployment of P-ONE is expected to start in 2025, exploiting the already available deep-sea infrastructure provided by Ocean Networks Canada. P-ONE will complement the existing IceCube, Baikal-GVD, and KM3NeT neutrino telescopes not only with its large detection volume, but also by providing insight into the southern celestial hemisphere, where the central region of the Galactic Plane is located. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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37 pages, 436 KiB  
Article
On the Implications of |Uμi| = |Uτi| in the Canonical Seesaw Mechanism
by Jianlong Lu, Aik Hui Chan and Choo Hiap Oh
Universe 2024, 10(1), 50; https://doi.org/10.3390/universe10010050 - 21 Jan 2024
Cited by 1 | Viewed by 1127
Abstract
In the PMNS matrix, the relation |Uμi| = |Uτi| (with i=1,2,3) is experimentally favored at the present stage. The possible implications of this relation on some [...] Read more.
In the PMNS matrix, the relation |Uμi| = |Uτi| (with i=1,2,3) is experimentally favored at the present stage. The possible implications of this relation on some hidden flavor symmetry has attracted a lot of interest in the neutrino community. In this paper, we analyze the implications of |Uμi| = |Uτi| (with i=1,2,3) in the context of the canonical seesaw mechanism. We also show that the minimal μτ symmetry proposed in JHEP 06 (2022) 034 is a possible but not necessary reason for the above-mentioned relation. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
12 pages, 2703 KiB  
Communication
Conserved Charge Fluctuations from RHIC BES and FXT
by Toshihiro Nonaka
Universe 2024, 10(1), 49; https://doi.org/10.3390/universe10010049 - 19 Jan 2024
Viewed by 1042
Abstract
Cumulants up to the sixth-order of the net-particle multiplicity distributions were measured at RHIC for the Beam Energy Scan and fixed-target program, from which we obtained some interesting hints on the phase structure of the QCD matter. In this article, we present recent [...] Read more.
Cumulants up to the sixth-order of the net-particle multiplicity distributions were measured at RHIC for the Beam Energy Scan and fixed-target program, from which we obtained some interesting hints on the phase structure of the QCD matter. In this article, we present recent experimental results on (net-)proton cumulants and discuss current interpretations on the QCD critical point and the nature of the phase transition. We will also report recent results for measurements of the bayron-strangeness correlations, which were measured with the newly developed analysis technique to remove the effect from the combinatorial backgrounds for hyperon reconstruction. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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10 pages, 586 KiB  
Article
Scaling Behaviour of dN/dy in High-Energy Collisions
by Gábor Kasza and Tamás Csörgő
Universe 2024, 10(1), 45; https://doi.org/10.3390/universe10010045 - 17 Jan 2024
Cited by 1 | Viewed by 937
Abstract
From a recently found family of analytic, finite and accelerating 1+1-dimensional solutions to perfect fluid relativistic hydrodynamics, we derive simple and powerful formulae to describe the rapidity and pseudorapidity density distributions. By introducing a new scaling function, we notice that the rapidity distribution [...] Read more.
From a recently found family of analytic, finite and accelerating 1+1-dimensional solutions to perfect fluid relativistic hydrodynamics, we derive simple and powerful formulae to describe the rapidity and pseudorapidity density distributions. By introducing a new scaling function, we notice that the rapidity distribution data of the different experiments all collapse into a single curve. This data-collapsing (or -scaling) behaviour in the rapidity distributions suggests that high-energy p+p collisions may be described as collective systems. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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0 pages, 846 KiB  
Article
Polarization Measurements of p and 3He Beams at RHIC and Future EIC Using the Polarized Atomic Hydrogen Gas Jet Target
by A. A. Poblaguev
Universe 2024, 10(1), 32; https://doi.org/10.3390/universe10010032 - 11 Jan 2024
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Abstract
At the Relativistic Heavy Ion Collider (RHIC), the Polarized Atomic Hydrogen Gas Jet Target polarimeter (HJET) is employed for the precise measurement of the absolute transverse (vertical) polarization of proton beams, achieving low systematic uncertainties of approximately [...] Read more.
At the Relativistic Heavy Ion Collider (RHIC), the Polarized Atomic Hydrogen Gas Jet Target polarimeter (HJET) is employed for the precise measurement of the absolute transverse (vertical) polarization of proton beams, achieving low systematic uncertainties of approximately σPsyst/P0.5%. The acquired experimental data not only facilitated the determination of single AN(t) and double ANN(t) spin analyzing powers for 100 and 255 GeV proton beams, but also revealed a non-zero Pomeron spin-flip contribution through a Regge fit. Preliminary results obtained for forward inelastic pp and elastic pA analyzing powers will be discussed. The success of the HJET at RHIC suggests its potential application for proton beam polarimetry at the upcoming Electron–Ion Collider (EIC), aiming for an accuracy of 1%. Moreover, the provided analysis indicates that the RHIC HJET target can serve as a tool for the precision calibration, with the required accuracy, of the 3He beam polarization at the EIC. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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13 pages, 625 KiB  
Article
Exploring Global Polarization Splitting in Au+Au Collisions at sNN=19.6 GeV Using Viscous Hydrodynamic Model CLVisc
by Shasha Ye, Xuefei Yuan and Zefang Jiang
Universe 2024, 10(1), 8; https://doi.org/10.3390/universe10010008 - 25 Dec 2023
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Abstract
We present a systematic study of the global polarization of Λ and Λ¯ hyperons in Au+Au collisions at sNN=19.6 GeV using the viscous hydrodynamic model CCNU-LBNL-Viscous hydrodynamic model (CLVisc) with a modified 3D optical Glauber model initial condition. The [...] Read more.
We present a systematic study of the global polarization of Λ and Λ¯ hyperons in Au+Au collisions at sNN=19.6 GeV using the viscous hydrodynamic model CCNU-LBNL-Viscous hydrodynamic model (CLVisc) with a modified 3D optical Glauber model initial condition. The global polarization splitting as a function of transverse momentum and rapidity is investigated. It is shown that the magnitude of the net baryon density and its longitudinal titled geometry at the initial stage both have significant effects on the global polarization splitting of Λ and Λ¯ hyperons. Specifically, an increase in the magnitude of the net baryon density leads to a corresponding minor increase in the global polarization splitting. Similarly, alterations in the tilted geometry of net baryon density results in significant changes in the splitting of the global polarization. Full article
(This article belongs to the Special Issue Multiparticle Dynamics)
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