Universe: Feature Papers–High Energy Nuclear and Particle Physics

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 2021) | Viewed by 9306

Special Issue Editor

Department of Physics, University of Athens, Zografou Campus, GR-15784 Athens, Greece
Interests: heavy ion physics
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Special Issue Information

Dear Colleagues,

This Feature Papers Issue of Universe entitled “High Energy Nuclear and Particle Physics” gives the opportunity to scientists from around the world, who are teaming up to run experiments and develop new models to determine the physical foundations that underpin our universe, to publish their recent work on a wide number of disciplines.

While dealing with the interaction of infinitesimal fundamental particles or dark energy to hide throughout space itself, High Energy Nuclear and Particle Physics addresses some of the mysterious questions, like: What is the universe made of? How do its parts interact? What laws are responsible for phenomena, both large and small?

This Feature Papers Issue of Universe tries to answer these questions covering the following research areas in both theory and experiment: supersymmetry, hadron collider physics, dark matter physics, neutrino physics, neutrino oscillations, phase transitions, critical phenomena, heavy ion collisions, ultra-high-energy cosmic rays, and astroparticle physics.

Prof. Dr. Maria Vasileiou
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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 (5 papers)

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Research

25 pages, 2434 KiB  
Article
Multipomeron Model with Collective Effects for High-Energy Hadron Collisions
by Vladimir Kovalenko, Grigorii Feofilov, Andrei Puchkov and Farkhat Valiev
Universe 2022, 8(4), 246; https://doi.org/10.3390/universe8040246 - 16 Apr 2022
Cited by 9 | Viewed by 1807
Abstract
We propose the generalized multipomeron exchange model for multiparticle production in high-energy proton–proton, proton–nucleus and heavy-ion collisions. For all of these systems, we consider collectivity effects based on the quark–gluon string fusion concept, where new types of particle-emitting sources—strings with higher tension—are produced. [...] Read more.
We propose the generalized multipomeron exchange model for multiparticle production in high-energy proton–proton, proton–nucleus and heavy-ion collisions. For all of these systems, we consider collectivity effects based on the quark–gluon string fusion concept, where new types of particle-emitting sources—strings with higher tension—are produced. We obtained the model parameters using the data on the multiplicity dependence of the mean transverse momentum of charged particles in pp and pp¯ collisions over a wide energy range (from ISR to LHC). We calculated the yields of strange, multi-strange and charm particles as a function of multiplicity for pp, p-Pb and Pb-Pb collisions at the LHC energy and compared the results with the experimental data. Full article
(This article belongs to the Special Issue Universe: Feature Papers–High Energy Nuclear and Particle Physics)
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22 pages, 1035 KiB  
Article
CP Violation for the Heavens and the Earth
by George Wei-Shu Hou
Universe 2022, 8(4), 234; https://doi.org/10.3390/universe8040234 - 11 Apr 2022
Viewed by 1373
Abstract
Electroweak baryogenesis can be driven by the top quark in a general two Higgs doublet model with extra Yukawa couplings. Higgs quartics provide the first order phase transition, while extra top Yukawa coupling ρtt can fuel the cosmic baryon asymmetry through [...] Read more.
Electroweak baryogenesis can be driven by the top quark in a general two Higgs doublet model with extra Yukawa couplings. Higgs quartics provide the first order phase transition, while extra top Yukawa coupling ρtt can fuel the cosmic baryon asymmetry through the λtImρtt product, with flavor-changing ρtc coupling as backup. The impressive ACME 2018 bound on the electron electric dipole moment calls for an extra electron coupling ρee for exquisite cancellation among dangerous diagrams, broadening the baryogenesis solution space. The mechanism suggests that extra Yukawa couplings echo the hierarchical structure of standard Yukawa couplings. Phenomenological consequences in the Higgs search and flavor physics are discussed, with μ and τ EDM touched upon. Full article
(This article belongs to the Special Issue Universe: Feature Papers–High Energy Nuclear and Particle Physics)
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19 pages, 1648 KiB  
Article
Multiplicity Dependencies of Midrapidity Transverse Momentum Distributions of Identified Charged Particles in Proton-Proton Collisions at (s)1/2 = 7 TeV at the LHC
by Khusniddin K. Olimov, Fu-Hu Liu, Kobil A. Musaev and Maratbek Z. Shodmonov
Universe 2022, 8(3), 174; https://doi.org/10.3390/universe8030174 - 10 Mar 2022
Cited by 9 | Viewed by 1667
Abstract
Dependencies of midrapidity pt distributions of the charged pions and kaons, protons and antiprotons on charged-particle multiplicity density (<dNch/>) in inelastic proton-proton collisions at (s)1/2 = 7 TeV at the LHC, measured by ALICE [...] Read more.
Dependencies of midrapidity pt distributions of the charged pions and kaons, protons and antiprotons on charged-particle multiplicity density (<dNch/>) in inelastic proton-proton collisions at (s)1/2 = 7 TeV at the LHC, measured by ALICE Collaboration, are investigated. The simultaneous minimum χ2 fits with the Tsallis function with thermodynamical consistence and the Hagedorn function with included transverse flow have well-described the pt spectra of the particle species in the ten studied groups of charged-particle multiplicity density. The effective temperatures, T, of the Tsallis function with thermodynamical consistence have shown a steady rise with increasing the charged-particle multiplicity in proton-proton collisions at (s)1/2 = 7 TeV, in agreement with the similar result obtained recently in proton-proton collisions at (s)1/2 = 13 TeV at the LHC. The respective T versus <dNch/> dependence in proton-proton collisions at (s)1/2 = 7 TeV is reproduced quite well by the simple power function with the same value (≈ 1/3) of the exponent parameter as that extracted in proton-proton collisions at (s)1/2 = 13 TeV. The identical power dependence T~ε1/3 between the initial energy density and effective temperature of the system has been observed in proton-proton collisions at (s)1/2 = 7 and 13 TeV. We have observed that the transverse radial flow emerges at <dNch/> ≈ 6 and then increases, becoming substantial at larger multiplicity events in proton-proton collisions at (s)1/2 = 7 TeV. We have estimated, analyzing T0 and βt versus <dNch/> dependencies, that the possible onset of deconfinement phase transition in proton-proton collisions at (s)1/2 = 7 TeV occurs at <dNch/> ≈ 6.1 ± 0.3, which is close to the corresponding recent estimate (<dNch/> ≈ 7.1 ± 0.2) in proton-proton collisions at (s)1/2 = 13 TeV. The corresponding critical energy densities for probable onset of deconfinement phase transition in proton-proton collisions at (s)1/2 = 7 and 13 TeV at the LHC have been estimated to be 0.67 ± 0.03 and 0.76 ± 0.02 GeV/fm3, respectively. Full article
(This article belongs to the Special Issue Universe: Feature Papers–High Energy Nuclear and Particle Physics)
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11 pages, 12556 KiB  
Article
Fluctuations of Initial State and Event-by-Event Pseudo-Rapidity Correlations in High Energy Nuclear Collisions
by Nassurlla Burtebayev, Anastasiya Fedosimova, Igor Lebedev, Elena Dmitriyeva, Sayora Ibraimova and Ekaterina Bondar
Universe 2022, 8(2), 67; https://doi.org/10.3390/universe8020067 - 21 Jan 2022
Cited by 4 | Viewed by 1779
Abstract
The initial state, about which there is usually very little direct experimental information, leads to significant fluctuations in the distribution of secondary particles and fragments. In this paper, to estimate the initial state the fragmentation parameters of interacting nuclei are analyzed. To investigate [...] Read more.
The initial state, about which there is usually very little direct experimental information, leads to significant fluctuations in the distribution of secondary particles and fragments. In this paper, to estimate the initial state the fragmentation parameters of interacting nuclei are analyzed. To investigate the correlations, the Hurst method is used. A detailed study of event-by-event pseudo-rapidity correlations in terms of the Hurst index, multiplicity of secondary particles and target dependence has been carried out for heavy (AgBr) and light (HCNO) targets present in the nuclear emulsion (NIKFI BR-2) using Au-197 projectiles at 10.6 A GeV. Evidences of short-range particle correlations and cluster formation in the pseudo-rapidity space are found from our analysis. The total ensemble of events has been divided into four classes depending on the behavior of Hurst index: uncorrelated, with short-range correlations, with long-range correlations and mixed. Events of various types differ significantly in the multiplicity of secondary particles, fragmentation of the projectile nucleus, and have significant differences in the pseudo-rapidity distribution of secondary particles. Full article
(This article belongs to the Special Issue Universe: Feature Papers–High Energy Nuclear and Particle Physics)
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19 pages, 1261 KiB  
Article
The Resonant Bremsstrahlung of Ultrarelativistic Electrons on a Nucleus with Radiation of Hard Gamma-Quanta in the Presence of a Pulsed Field of the X-ray Pulsar
by Alexander Dubov, Victor V. Dubov and Sergei P. Roshchupkin
Universe 2020, 6(9), 143; https://doi.org/10.3390/universe6090143 - 03 Sep 2020
Cited by 6 | Viewed by 1866
Abstract
The investigation scrutinizes the circulation of the large-scaled fluxes of ultrarelativistic electrons near the neutron stars. This work focuses on the effects that occur during the adjustment of the strong electromagnetic field near the X-ray pulsars. Particularly, this study analyzes the resonant high-energy [...] Read more.
The investigation scrutinizes the circulation of the large-scaled fluxes of ultrarelativistic electrons near the neutron stars. This work focuses on the effects that occur during the adjustment of the strong electromagnetic field near the X-ray pulsars. Particularly, this study analyzes the resonant high-energy spontaneous bremsstrahlung of ultrarelativistic electrons in the pulsed fields of a nucleus and X-ray pulsar. Specific attention is given to the pulsed character of the field model. Under the resonant conditions the intermediate virtual electron within the electromagnetic field transforms into a real particle. As a result, the initial second-order process with accordance to the fine structure constant effectively splits into two first-order effects: the stimulated Compton process and the field-assisted scattering of an electron on a nucleus. In this research we obtain the resonant differential cross-sections with registration of frequency and radiation angle of a hard gamma-quantum. To summarize, the resonant differential cross-section of the effect within the external pulsed electromagnetic field of X-ray pulsar significantly exceeds the corresponding cross-section without an external field. Full article
(This article belongs to the Special Issue Universe: Feature Papers–High Energy Nuclear and Particle Physics)
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