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Particles
Number of Followers: 0  Open Access journalISSN (Online) 2571-712X Published by MDPI  [249 journals]
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- Particles, Vol. 6, Pages 30-56: Constraints on Nuclear Symmetry Energy
Parameters
Authors: James M. Lattimer
First page: 30
Abstract: A review is made of constraints on the nuclear symmetry energy parameters arising from nuclear binding energy measurements, theoretical chiral effective field predictions of neutron matter properties, the unitary gas conjecture, and measurements of neutron skin thicknesses and dipole polarizabilities. While most studies have been confined to the parameters SV and L, the important roles played by, and constraints on Ksym, or, equivalently, the neutron matter incompressibility KN, are discussed. Strong correlations among SV,L, and KN are found from both nuclear binding energies and neutron matter theory. However, these correlations somewhat differ in the two cases, and those from neutron matter theory have smaller uncertainties. To 68% confidence, it is found from neutron matter theory that SV=32.0±1.1 MeV, L=51.9±7.9 MeV and KN=152.2±38.1 MeV. Theoretical predictions for neutron skin thickness and dipole polarizability measurements of the neutron-rich nuclei 48Ca, 120Sn, and 208Pb are compared to recent experimental measurements, most notably the CREX and PREX neutron skin experiments from Jefferson Laboratory. By themselves, PREX I+II measurements of 208Pb and CREX measurement of 48Ca suggest L=121±47 MeV and L=−5±40 MeV, respectively, to 68% confidence. However, we show that nuclear interactions optimally satisfying both measurements imply L=53±13 MeV, nearly the range suggested by either nuclear mass measurements or neutron matter theory, and is also consistent with nuclear dipole polarizability measurements. This small parameter range implies R1.4=11.6±1.0 km and Λ1.4=228−90+148, which are consistent with NICER X-ray and LIGO/Virgo gravitational wave observations of neutron stars.
Citation: Particles
PubDate: 2023-01-04
DOI: 10.3390/particles6010003
Issue No: Vol. 6, No. 1 (2023)
- Particles, Vol. 6, Pages 57-120: Emergence of Hadron Mass and Structure
Authors: Minghui Ding, Craig D. Roberts, Sebastian M. Schmidt
First page: 57
Abstract: Visible matter is characterised by a single mass scale; namely, the proton mass. The proton’s existence and structure are supposed to be described by quantum chromodynamics (QCD); yet, absent Higgs boson couplings, chromodynamics is scale-invariant. Thus, if the Standard Model is truly a part of the theory of Nature, then the proton mass is an emergent feature of QCD; and emergent hadron mass (EHM) must provide the basic link between theory and observation. Nonperturbative tools are necessary if such connections are to be made; and in this context, we sketch recent progress in the application of continuum Schwinger function methods to an array of related problems in hadron and particle physics. Special emphasis is given to the three pillars of EHM—namely, the running gluon mass, process-independent effective charge, and running quark mass; their role in stabilising QCD; and their measurable expressions in a diverse array of observables.
Citation: Particles
PubDate: 2023-01-11
DOI: 10.3390/particles6010004
Issue No: Vol. 6, No. 1 (2023)
- Particles, Vol. 6, Pages 121-133: Interference with Non-Interacting Free
Particles and a Special Type of Detector
Authors: Ioannis Contopoulos, Athanasios C. Tzemos, Foivos Zanias, George Contopoulos
First page: 121
Abstract: This paper demonstrates how a classical detector that collects non-interacting individual classical massive free particles can generate a quantum interference pattern. The proposed classical picture requires that particles carry the information of a phase equal to an action integral along their trajectory. At the point of their detection, a special type of detector collects the phases from all individual particles reaching it, adds them up over time as complex numbers, and divides them by the square root of their number. The detector announces a number of detections equal to the square of the amplitude of the resulting complex number. An interference pattern is gradually built from the collection of particle phases in the detection bins of the detector after several repetitions of the experiment. We obtain perfect agreement with three solutions of the Schrödinger equation for free particles: a Gaussian wavepacket, two Gaussian wavepackets approaching each other, and a Gaussian wavepacket reflecting off a wall. The main conclusion of the present work is that the interference of quantum mechanics is basically due to the detectors that collect the particles when there are macroscopic detectors operating as proposed. Finally, a simple physical experiment with a single-photon detector is proposed that will be able to test our theory.
Citation: Particles
PubDate: 2023-01-17
DOI: 10.3390/particles6010005
Issue No: Vol. 6, No. 1 (2023)
- Particles, Vol. 6, Pages 134-135: Acknowledgment to the Reviewers of
Particles in 2022
Authors: Particles Editorial Office Particles Editorial Office
First page: 134
Abstract: High-quality academic publishing is built on rigorous peer review [...]
Citation: Particles
PubDate: 2023-01-18
DOI: 10.3390/particles6010006
Issue No: Vol. 6, No. 1 (2023)
- Particles, Vol. 6, Pages 136-143: Coulomb Force from Non-Local
Self-Assembly of Multi-Peak Densities in a Charged Space Continuum
Authors: Igor É. Bulyzhenkov
First page: 136
Abstract: Maxwell’s electrodynamics admits radial charge densities of the elementary organization with one vertex of the spherical symmetry. A multi-vertex distribution of sharply inhomogeneous charge densities can also be described by monistic field solutions to Maxwell’s equations–equalities. Coulomb–Lorentz forces are exerted locally to correlated electric densities in their volume organization with the fixed self-energy integral. The long-range Coulomb interaction between the dense peaks of the charged space continuum can be described quantitatively through bulk integrals of local tensions within observable bodies in favor of the monistic all-unity in the material space physics of Descartes and Russian cosmists.
Citation: Particles
PubDate: 2023-01-20
DOI: 10.3390/particles6010007
Issue No: Vol. 6, No. 1 (2023)
- Particles, Vol. 6, Pages 144-172: Beyond the Standard Model with
Six-Dimensional Spinors
Authors: David Chester, Alessio Marrani, Michael Rios
First page: 144
Abstract: Six-dimensional spinors with Spin(3,3) symmetry are utilized to efficiently encode three generations of matter. E8(−24) is shown to contain physically relevant subgroups with representations for GUT groups, spacetime symmetries, three generations of the standard model fermions, and Higgs bosons. Pati–Salam, SU(5), and Spin(10) grand unified theories are found when a single generation is isolated. For spacetime symmetries, Spin(4,2) may be used for conformal symmetry, AdS5→dS4, or simply broken to Spin(3,1) of a Minkowski space. Another class of representations finds Spin(2,2) and can give AdS3 with various GUTs. An action for three generations of fermions in the Majorana–Weyl spinor 128 of Spin(4,12) is found with Spin(3) flavor symmetry inside E8(−24). The 128 of Spin(12,4) can be regarded as the tangent space to a particular pseudo-Riemannian form of the octo-octonionic Rosenfeld projective plane E8(−24)/Spin(12,4)=(OsxO)P2.
Citation: Particles
PubDate: 2023-01-28
DOI: 10.3390/particles6010008
Issue No: Vol. 6, No. 1 (2023)
- Particles, Vol. 6, Pages 1-16: Consistent Theories of Free Dirac Particle
without Singular Predictions
Authors: Giuseppe Nisticò
First page: 1
Abstract: Dirac’s theory is not a unique theory consistent with the physical principles specific of a free spin-one-half particle. In fact, we derive classes of theories of an elementary free particle from the principle of Poincaré’s invariance and from the principle of the covariance of the position. The theory of Dirac is just one of these theories, characterized by singular predictions, namely, the zitterbewegung. Yet, the class here derived contains families of consistent theories without singular predictions. For the time being, the experimental verifiability of these alternative theories is restricted to the predictions of free-particle theories for ideal experiments.
Citation: Particles
PubDate: 2022-12-20
DOI: 10.3390/particles6010001
Issue No: Vol. 6, No. 1 (2022)
- Particles, Vol. 6, Pages 17-29: Elliptic Flow and Its Fluctuations from
Transport Models for Au + Au Collisions at sNN = 7.7 and 11.5 GeV
Authors: Vinh Ba Luong, Dim Idrisov, Petr Parfenov, Arkadiy Taranenko
First page: 17
Abstract: The elliptic flow v2 is one of the key observables sensitive to the transport properties of the strongly interacting matter formed in relativistic heavy-ion collisions. In this work, we report on the calculations of v2 and its fluctuations of charged hadrons produced in Au+Au collisions at center-of-mass energy per nucleon pair sNN = 7.7 and 11.5 GeV from several transport models and provide a direct comparison with published results from the STAR experiment. This study motivates further experimental investigations of v2 and its fluctuations with the Multi-Purpose Detector (MPD) at the NICA Collider.
Citation: Particles
PubDate: 2022-12-30
DOI: 10.3390/particles6010002
Issue No: Vol. 6, No. 1 (2022)
- Particles, Vol. 5, Pages 426-441: Quantum States for a Minimum-Length
Spacetime
Authors: Alessandro Pesci
First page: 426
Abstract: Starting from some results regarding the form of the Ricci scalar at a point P in a (particle-like) spacetime endowed with a minimum distance, we investigate how they might be accommodated, specifically for the case of null separations, in a as-simple-as-possible quantum structure for spacetime at P, and we try to accomplish this in terms of potentially operationally defined concepts. In so doing, we provide a possible explicit form for the operator expressing the Ricci scalar as a quantum observable, and give quantum-informational support, thus regardless of or before field equations, to associating with a patch of horizon an entropy proportional to its area.
Citation: Particles
PubDate: 2022-09-23
DOI: 10.3390/particles5040033
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 442-450: Electromagnetic Response in an Expanding
Quark–Gluon Plasma
Authors: Igor A. Shovkovy
First page: 442
Abstract: The validity of conventional Ohm’s law is tested in the context of a rapidly evolving quark–gluon plasma produced in heavy-ion collisions. Here, we discuss the electromagnetic response using an analytical solution in kinetic theory. As conjectured previously, after switching on an electric field in a nonexpanding plasma, the time-dependent current is given by J(t)=(1−e−t/τ0)σ0E, where τ0 is the transport relaxation time and σ0 is the steady-state electrical conductivity. Such an incomplete electromagnetic response reduces the efficiency of the magnetic flux trapping in the quark–gluon plasma, and may prevent the observation of the chiral magnetic effect. Here, we extend the study to the case of a rapidly expanding plasma. We find that the decreasing temperature and the increasing transport relaxation time have opposite effects on the electromagnetic response. While the former suppresses the time-dependent conductivity, the latter enhances it.
Citation: Particles
PubDate: 2022-10-22
DOI: 10.3390/particles5040034
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 451-487: Analysis of Overlapping Resonances with
Unitary Breit–Wigner and K-Matrix Approaches
Authors: Victor Henner, Tatyana Belozerova
First page: 451
Abstract: We compare two methods for obtaining the parameters of overlapping resonances. The convenience of the Breit–Wigner (BW) approach is based on the fact that it operates with the masses and widths of the states. For several resonances with the same quantum numbers, a sum of BW functions violates the unitarity of the S-matrix. However, unitarity can be maintained by introducing interference phases to a BW implementation of scattering matrix formalism. A background can be added to the BW amplitudes in the standard way by using background phases. The K-matrix method is often used to analyze data related to several resonances with the same quantum numbers. It guarantees the unitarity of the S-matrix, but its parameters can be considered as resonance masses and widths only for well-spaced states. It also does not allow the separation of the resonant and background contributions in scattering amplitudes, which is critically important for determining parameters of wide resonances. To demonstrate the features of these methods, we consider several examples using simulated data.
Citation: Particles
PubDate: 2022-10-27
DOI: 10.3390/particles5040035
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 488-492: The Number of Elementary Fermions and
the Electromagnetic Coupling
Authors: Liberato De De Caro
First page: 488
Abstract: Electric charges and masses of elementary fermions of the Standard Model and fundamental physical constants (speed of light in vacuum, Planck constant, gravitational constant, vacuum permittivity, electron charge) are related through a simple equation. This new relation links 10 of the free parameters of the Standard Model—the masses of the three charged leptons and six quarks, and the electromagnetic coupling—in a compact formula, leaving strong constraints for allowing further elementary charged fermions beyond the Standard Model’s physics. The formula is not derived by theoretical calculations, but it is based on the empirically measured values of the electric charges and proper masses of the known elementary fermions.
Citation: Particles
PubDate: 2022-11-10
DOI: 10.3390/particles5040036
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 493-513: Formation, Possible Detection and
Consequences of Highly Magnetized Compact Stars
Authors: Banibrata Mukhopadhyay, Mukul Bhattacharya
First page: 493
Abstract: Over the past several years, there has been enormous interest in massive neutron stars and white dwarfs due to either their direct or indirect evidence. The recent detection of gravitational wave event GW190814 has confirmed the existence of compact stars with masses as high as ∼2.5–2.67 M⊙ within the so-called mass gap, indicating the existence of highly massive neutron stars. One of the primary goals to invoke massive compact objects was to explain the recent detections of over a dozen Type Ia supernovae, whose peculiarity lies with their unusual light curve, in particular the high luminosity and low ejecta velocity. In a series of recent papers, our group has proposed that highly magnetised white dwarfs with super-Chandrasekhar masses can be promising candidates for the progenitors of these peculiar supernovae. The mass-radius relations of these magnetised stars are significantly different from those of their non-magnetised counterparts, which leads to a revised super-Chandrasekhar mass-limit. These compact stars have wider ranging implications, including those for soft gamma-ray repeaters, anomalous X-ray pulsars, white dwarf pulsars and gravitational radiation. Here we review the development of the subject over the last decade or so, describing the overall state of the art of the subject as it stands now. We mainly touch upon the possible formation channels of these intriguing stars as well as the effectiveness of direct detection methods. These magnetised stars can have many interesting consequences, including reconsideration of them as possible standard candles.
Citation: Particles
PubDate: 2022-11-17
DOI: 10.3390/particles5040037
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 514-534: Recovering the Conformal Limit of Color
Superconducting Quark Matter within a Confining Density Functional
Approach
Authors: Oleksii Ivanytskyi, David B. Blaschke
First page: 514
Abstract: We generalize a recently proposed confining relativistic density-functional approach to the case of density-dependent vector and diquark couplings. The particular behavior of these couplings is motivated by the non-perturbative gluon exchange in dense quark matter and provides the conformal limit at asymptotically high densities. We demonstrate that this feature of the quark matter EoS is consistent with a significant stiffness in the density range typical for the interiors of neutron stars. In order to model these astrophysical objects, we construct a family of hybrid quark-hadron EoSs of cold stellar matter. We also confront our approach with the observational constraints on the mass–radius relation of neutron stars and their tidal deformabilities and argue in favor of a quark matter onset at masses below 1.0M⊙.
Citation: Particles
PubDate: 2022-11-28
DOI: 10.3390/particles5040038
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 535-560: Parametrizations of Collinear and
kT-Dependent Parton Densities in Proton
Authors: Nizami A. Abdulov, Anatoly V. Kotikov, Artem Lipatov
First page: 535
Abstract: A new type of parametrization for parton distribution functions in the proton, based on their Q2-evolution at large and small x values, is constructed. In our analysis, the valence and nonsinglet parts obey the Gross–Llewellyn–Smith and Gottfried sum rules, respectively. For the singlet quark and gluon densities, momentum conservation is taken into account. Then, using the Kimber–Martin–Ryskin prescription, we extend the consideration to Transverse Momentum Dependent (TMD, or unintegrated) gluon and quark distributions in the proton, which currently plays an important role in a the number of phenomenological applications. The analytical expressions for the latter, valid for both low and large x, are derived for the first time.
Citation: Particles
PubDate: 2022-11-28
DOI: 10.3390/particles5040039
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 561-579: Model Study of the Energy Dependence of
Anisotropic Flow in Heavy-Ion Collisions at \({\sqrt{s_{\text{NN}}}}\) =
2–4.5 GeV
Authors: Petr Parfenov
First page: 561
Abstract: The anisotropic flow is one of the important observables sensitive to the equation of state (EOS) and transport properties of the strongly interacting matter created in relativistic heavy-ion collisions. In this work, we report a detailed multi-differential study of the directed (v1), elliptic (v2), triangular (v3), and quadrangular (v4) flow coefficients of protons in relativistic heavy-ion collisions at sNN=2.2-4.5 GeV using several hadronic transport models. Recent published results for Au + Au collisions at sNN=2.4 GeV from HADES experiment and at sNN=3.0 GeV from the STAR experiment have been used for comparison. The study motivates further experimental investigations of the anisotropic collective flow of protons and neutrons in a high baryon density region.
Citation: Particles
PubDate: 2022-12-09
DOI: 10.3390/particles5040040
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 580-588: Dynamical Pair Production at Sub-Barrier
Energies for Light Nuclei
Authors: Thomas Settlemyre, Hua Zheng, Aldo Bonasera
First page: 580
Abstract: In the collision of two heavy ions, the strong repulsion coming from the Coulomb field is enough to produce e+e− pair(s) from vacuum fluctuations. The energy is provided by the kinetic energy of the ions and the Coulomb interaction at the production point. If, for instance, the electron is located at the center of mass (C.M.) of the two ions moving along the z-axis, and the positron is at a distance x from the electron, the ions can be accelerated towards each other since the Coulomb barrier is lowered by the presence of the electron. This screening results in an increase in the kinetic energy of the colliding ions and may result in an increase in the fusion probability of light ions above the adiabatic limit.
Citation: Particles
PubDate: 2022-12-17
DOI: 10.3390/particles5040041
Issue No: Vol. 5, No. 4 (2022)
- Particles, Vol. 5, Pages 210-224: Coupled-Channel Analysis of the Process
γγ→π0π0
Authors: Yury S. Surovtsev, Petr Bydžovský, Thomas Gutsche, Robert Kamiński, Valery E. Lyubovitskij, Miroslav Nagy
First page: 210
Abstract: We study the process γγ→π0π0 involving the principal mechanisms, the structure of its cross section and the role of individual isoscalar-tensor resonances in the saturation of its energy spectrum.
Citation: Particles
PubDate: 2022-06-30
DOI: 10.3390/particles5030019
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 225-234: Stability of Spherical Nuclei in the
Inner Crust of Neutron Stars
Authors: Nikita A. Zemlyakov, Andrey I. Chugunov
First page: 225
Abstract: Neutron stars are the densest objects in the Universe. In this paper, we consider the so-called inner crust—the layer where neutron-excess nuclei are immersed in the degenerate gas of electrons and a sea of quasi-free neutrons. It was generally believed that spherical nuclei become unstable with respect to quadrupole deformations at high densities, and here, we consider this instability. Within the perturbative approach, we show that spherical nuclei with equilibrium number density are, in fact, stable with respect to infinitesimal quadrupole deformation. This is due to the background of degenerate electrons and associated electrostatic potential, which maintain stability of spherical nuclei. However, if the number of atomic nuclei per unit volume is much less than the equilibrium value, instability can arise. To avoid confusion, we stress that our results are limited to infinitesimal deformations and do not guarantee strict thermodynamic stability of spherical nuclei. In particular, they do not exclude that substantially non-spherical nuclei (so-called pasta phase) represent a thermodynamic equilibrium state of the densest layers of the neutron star crust. Rather, our results point out that spherical nuclei can be metastable even if they are not energetically favourable, and the timescale of transformation of spherical nuclei to the pasta phases should be estimated subsequently.
Citation: Particles
PubDate: 2022-07-01
DOI: 10.3390/particles5030020
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 235-244: Defining the Underlying-Event Activity
in the Presence of Heavy-Flavour Processes in Proton-Proton Collisions at
LHC Energies
Authors: László Gyulai, Szende Sándor, Róbert Vértesi
First page: 235
Abstract: We present a systematic analysis of heavy-flavour production in the underlying event in connection to a leading hard process in pp collisions at s=13 TeV, using the PYTHIA 8 Monte Carlo event generator. We compare results from events selected by triggering on the leading hadron, as well as those triggered with reconstructed jets. We show that the kinematics of heavy-flavour fragmentation complicates the characterisation of the underlying event, and the usual method which uses the leading charged final-state hadron as a trigger may wash away the connection between the leading process and the heavy-flavour particle created in association with that. Events triggered with light or heavy-flavour jets, however, retain this connection and bring more direct information on the underlying heavy-flavour production process, but may also import unwanted sensitivity to gluon radiation. The methods outlined in the current work provide means to verify model calculations for light and heavy-flavour production in the jet and the underlying event in great details.
Citation: Particles
PubDate: 2022-07-07
DOI: 10.3390/particles5030021
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 245-264: Colliding and Fixed Target Mode in a
Single Experiment—A Novel Approach to Study the Matter under New
Extreme Conditions
Authors: Oleksandr V. Vitiuk, Valery M. Pugatch, Kyrill A. Bugaev, Nazar S. Yakovenko, Pavlo P. Panasiuk, Elizaveta S. Zherebtsova, Vasyl M. Dobishuk, Sergiy B. Chernyshenko, Borys E. Grinyuk, Violetta Sagun, Oleksii Ivanytskyi
First page: 245
Abstract: Here, we propose a novel approach to experimentally and theoretically study the properties of QCD matter under new extreme conditions, namely having an initial temperature over 300 MeV and baryonic charge density over three times the values of the normal nuclear density. According to contemporary theoretical knowledge, such conditions were not accessible during the early Universe evolution and are not accessible now in the known astrophysical phenomena. To achieve these new extreme conditions, we proposed performing high-luminosity experiments at LHC or other colliders by means of scattering the two colliding beams at the nuclei of a solid target that is fixed at their interaction region. Under plausible assumptions, we estimate the reaction rate for the p+C+p and Pb+Pb+Pb reactions and discuss the energy deposition into the target and possible types of fixed targets for such reactions. To simulate the triple nuclear collisions, we employed the well-known UrQMD 3.4 model for the beam center-of-mass collision energies sNN = 2.76 TeV. As a result of our modeling, we found that, in the most central and simultaneous triple nuclear collisions, the initial baryonic charge density is approximately three times higher than the one achieved in the ordinary binary nuclear collisions at this energy.
Citation: Particles
PubDate: 2022-07-18
DOI: 10.3390/particles5030022
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 265-272: LHC Search Strategy for Squarks in
Higgsino-LSP Scenarios with Leptons and b-Jets in the Final State
Authors: Ernesto Arganda, Antonio Delgado, Roberto A. Morales, Mariano Quirós
First page: 265
Abstract: The higgsino Lightest Supersymmetric Particle (LSP) scenario opens up the possibility of decays of strongly produced particles to an intermediate neutralino, due to the Yukawa-suppressed direct decays to the higgsino. Those decays produce multijet signals with a Higgs or a Z boson being produced in the decay of the intermediate neutralino to the LSP. In this paper, we study the discovery prospects of squarks that produce b-jets and leptons in the final state. Our collider analysis provides signal significances at the 3σ level for luminosities of 1 ab−1, and at the 5σ level if we project these results for 3 ab−1.
Citation: Particles
PubDate: 2022-07-19
DOI: 10.3390/particles5030023
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 273-286: Numerical Simulations of Dark Matter
Admixed Neutron Star Binaries
Authors: Mattia Emma, Federico Schianchi, Francesco Pannarale, Violetta Sagun, Tim Dietrich
First page: 273
Abstract: Multi-messenger observations of compact binary mergers provide a new way to constrain the nature of dark matter that may accumulate in and around neutron stars. In this article, we extend the infrastructure of our numerical-relativity code BAM to enable the simulation of neutron stars that contain an additional mirror dark matter component. We perform single star tests to verify our code and the first binary neutron star simulations of this kind. We find that the presence of dark matter reduces the lifetime of the merger remnant and favors a prompt collapse to a black hole. Furthermore, we find differences in the merger time for systems with the same total mass and mass ratio, but different amounts of dark matter. Finally, we find that electromagnetic signals produced by the merger of binary neutron stars admixed with dark matter are very unlikely to be as bright as their dark matter-free counterparts. Given the increased sensitivity of multi-messenger facilities, our analysis gives a new perspective on how to probe the presence of dark matter.
Citation: Particles
PubDate: 2022-07-22
DOI: 10.3390/particles5030024
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 287-297: Giant Dipole Multi-Resonances Excited by
High-Frequency Laser Pulses
Authors: Şerban Mişicu
First page: 287
Abstract: The worldwide advent of new laser facilities makes possible the investigation of the nuclear response to a very strong electromagnetic field. In this paper, we inquire on the excitation of one of the most conspicuous collective excitations, the giant dipole resonance, within the hydrodynamical model for a proton-neutron fluid mixture placed in a Skyrme mean-field and interacting with an external ultra-strong electromagnetic field. The variables of this approach are: proton and neutron displacement (velocity) fields, density fluctuations, and fluctuations of the electric field due to the coupling of the laser electromagnetic field to the dynamical distortions of the baryonic system (electro-magneto-hydrodynamical effect). We point out the occurrence of a multiresonance structure of the absorption cross-section.
Citation: Particles
PubDate: 2022-08-04
DOI: 10.3390/particles5030025
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 298-330: Energy-Momentum Complex in Higher Order
Curvature-Based Local Gravity
Authors: Salvatore Capozziello, Maurizio Capriolo, Gaetano Lambiase
First page: 298
Abstract: An unambiguous definition of gravitational energy remains one of the unresolved issues of physics today. This problem is related to the non-localization of gravitational energy density. In General Relativity, there have been many proposals for defining the gravitational energy density, notably those proposed by Einstein, Tolman, Landau and Lifshitz, Papapetrou, Møller, and Weinberg. In this review, we firstly explored the energy–momentum complex in an nth order gravitational Lagrangian L=Lgμν,gμν,i1,gμν,i1i2,gμν,i1i2i3,⋯,gμν,i1i2i3⋯in and then in a gravitational Lagrangian as Lg=(R¯+a0R2+∑k=1pakR□kR)−g. Its gravitational part was obtained by invariance of gravitational action under infinitesimal rigid translations using Noether’s theorem. We also showed that this tensor, in general, is not a covariant object but only an affine object, that is, a pseudo-tensor. Therefore, the pseudo-tensor ταη becomes the one introduced by Einstein if we limit ourselves to General Relativity and its extended corrections have been explicitly indicated. The same method was used to derive the energy–momentum complex in fR gravity both in Palatini and metric approaches. Moreover, in the weak field approximation the pseudo-tensor ταη to lowest order in the metric perturbation h was calculated. As a practical application, the power per unit solid angle Ω emitted by a localized source carried by a gravitational wave in a direction x^ for a fixed wave number k under a suitable gauge was obtained, through the average value of the pseudo-tensor over a suitable spacetime domain and the local conservation of the pseudo-tensor. As a cosmological application, in a flat Friedmann–Lemaître–Robertson–Walker spacetime, the gravitational and matter energy density in f(R) gravity both in Palatini and metric formalism was proposed. The gravitational energy–momentum pseudo-tensor could be a useful tool to investigate further modes of gravitational radiation beyond two standard modes required by General Relativity and to deal with non-local theories of gravity involving □−k terms.
Citation: Particles
PubDate: 2022-08-10
DOI: 10.3390/particles5030026
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 331-345: Theoretical Search for Gravitational
Bound States of Tachyons
Authors: Charles Schwartz
First page: 331
Abstract: The mission here is to see if we can find bound states for tachyons in some gravitational environment. That could provide an explanation for the phenomena called Dark Matter. Starting with the standard Schwarzschild metric in General Relativity, which is for a static and spherically symmetric source, it appears unlikely that such localized orbits exist. In this work, the usual assumption of isotropic pressure is replaced by a model that has different pressures in the radial and angular directions. This should be relevant to the study of neutrinos, especially if they are tachyons, in cosmological models. We do find an arrangement that allows bound orbits for tachyons in a galaxy. This is a qualitative breakthrough. Then we go on to estimate the numbers involved and find that we do have a fair quantitative fit to the experimental data on the Galaxy Rotation Curve. Additionally we are led to look in the neighborhood of a Black Hole and there we find novel orbits for tachyons.
Citation: Particles
PubDate: 2022-08-31
DOI: 10.3390/particles5030027
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 346-360: Quick Guides for Use of the CompOSE Data
Base
Authors: Veronica Dexheimer, Marco Mancini, Micaela Oertel, Constança Providência, Laura Tolos, Stefan Typel
First page: 346
Abstract: We present a combination of two quick guides aimed at summarizing relevant information about the CompOSE nuclear equation of state repository. The first is aimed at nuclear physicists and describes how to provide standard equation of state tables. The second quick guide is meant for users and describes the basic procedures to obtain customized tables with equation of state data. Several examples are included to help providers and users to understand and benefit from the CompOSE database.
Citation: Particles
PubDate: 2022-09-05
DOI: 10.3390/particles5030028
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 361-376: Bulk Viscosity of Relativistic npeμ
Matter in Neutron-Star Mergers
Authors: Mark Alford, Arus Harutyunyan, Armen Sedrakian
First page: 361
Abstract: We discuss the bulk viscosity of hot and dense npeμ matter arising from weak-interaction direct Urca processes. We consider two regimes of interest: (a) the neutrino-transparent regime with T≤Ttr (Ttr≃5÷10 MeV is the neutrino-trapping temperature); and (b) the neutrino-trapped regime with T≥Ttr. Nuclear matter is modeled in relativistic density functional approach with density-dependent parametrization DDME2. The maximum of the bulk viscosity is achieved at temperatures T≃5÷6 MeV in the neutrino-transparent regime, then it drops rapidly at higher temperatures where neutrino-trapping occurs. As an astrophysical application, we estimate the damping timescales of density oscillations by the bulk viscosity in neutron star mergers and find that, e.g., at the oscillation frequency f=10 kHz, the damping will be very efficient at temperatures 4≤T≤7 MeV where the bulk viscosity might affect the evolution of the post-merger object.
Citation: Particles
PubDate: 2022-09-06
DOI: 10.3390/particles5030029
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 377-389: Electron Capture on Nuclei in Stellar
Environment
Authors: Panagiota Giannaka, Theocharis Kosmas
First page: 377
Abstract: The stellar electron capture on nuclei is an essential, semi-leptonic process that is especially significant in the central environment of core-collapse supernovae and in the explosive stellar nucleosynthesis. In this article, on the basis of the original (absolute) electron-capture cross-sections under laboratory conditions that we computed in our previous work for a set of medium-weight nuclear isotopes, we extend this study and evaluate folded e−-capture rates in the stellar environment. With this aim, we assume that the parent nuclei and the projectile electrons interact when they are in the deep stellar interior during the late stages of the evolution of massive stars. Under these conditions (high matter densities and high temperatures of the pre-supernova and core-collapse supernova phases), we choose two categories of nuclei; the first includes the 48Ti and 56Fe isotopes that have A<65 and belong to the iron group of nuclei, and the second includes the heavier and more neutron-rich isotopes 66Zn and 90Zr (with A>65). In the former, the electron capture takes place mostly during the pre-supernova stage, while the latter occurs during the core-collapse supernova phase. A comparison with previous calculations, which were obtained by using various microscopic nuclear models employed for single-charge exchange nuclear reactions, is also included.
Citation: Particles
PubDate: 2022-09-12
DOI: 10.3390/particles5030030
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 390-406: Original e− Capture Cross Sections for
Hot Stellar Interior Energies
Authors: Panagiota Giannaka, Theocharis Kosmas, Hiroyasu Ejiri
First page: 390
Abstract: The nuclear electron capture reaction possesses a prominent position among other weak interaction processes occurring in explosive nucleosynthesis, especially at the late stages of evolution of massive stars. In this work, we perform exclusive calculations of absolute e−-capture cross sections using the proton–neutron (pn) quasi-particle random phase approximation. Thus, the results of this study can be used as predictions for experiments operating under the same conditions and in exploring the role of the e−-capture process in the stellar environment at the pre-supernova and supernova phase of a massive star. The main goal of our study is to provide detailed state-by-state calculations of original cross sections for the e−-capture on a set of isotopes around the iron group nuclei (28Si, 32S, 48Ti, 56Fe, 66Zn and 90Zr) that play a significant role in pre-supernova as well as in the core–collapse supernova phase in the energy range 0≤E≤50 MeV.
Citation: Particles
PubDate: 2022-09-12
DOI: 10.3390/particles5030031
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 407-426: Shock-Induced Mesoparticles and
Turbulence Occurrence
Authors: Tatiana A. Khantuleva, Yurii I. Meshcheryakov
First page: 407
Abstract: The development of a new approach to describe turbulent motions in condensed matter on the basis of nonlocal modeling of highly non-equilibrium processes in open systems is performed in parallel with an experiment studying the mesostructure of dynamically deformed solids. The shock-induced mesostructure formation inside the propagating waveform registered in real time allows the transient stages of non-equilibrium processes to be qualitatively and quantitatively revealed. A new nonlocal approach, developed on the basis of the nonlocal and retarded transport equations obtained within the non-equilibrium statistical physics, is used to describe the occurrence of turbulence. Within the approach, the reason for the transition to turbulence is that the non-equilibrium spatiotemporal correlation function generates the dynamic structures in the form of finite-size clusters on the mesoscale, with almost identical values of macroscopic densities moving as almost solid particles that can interact and rotate. The fragmentation of spatiotemporal correlations upon impact forms the mesoparticles that move at different speeds and transfer mass, momentum and energy-like wave packets. The movements recorded simultaneously at two scale levels indicate the energy exchange between them. Its description required a redefinition of the concept of energy far from local thermodynamic equilibrium. The experimental results show that the irreversible part of the dynamic mesostructure remains frozen into material as a new defect.
Citation: Particles
PubDate: 2022-09-16
DOI: 10.3390/particles5030032
Issue No: Vol. 5, No. 3 (2022)
- Particles, Vol. 5, Pages 96-109: Multiplicity Distribution and KNO Scaling
of Charged Particles Production from pp Collisions at Different Energies
Authors: Mohammed Attia Mahmoud
First page: 96
Abstract: The multiplicity distribution of charged particles produced from proton–proton collisions at energies s = 2.36, 2.76, 5, 7, 8, 10, 13 and 14 TeV were studied in the present work. Furthermore, multiplicity distribution was studied in different pseudorapidity regions ∣η∣ < 0.5, 1, 1.5, 2, and 2.5. KNO scaling was studied at the same pseudorapidity regions. This is valid in the pseudorapidity region ∣η∣ < 0.5, but with increasing pseudorapidity, the violation increases. The influence of MPI and color reconnection in violation of KNO scaling were studied. The relation between mean multiplicity and collisions energy was explored, noted that it increases with the increasing energy of collisions.
Citation: Particles
PubDate: 2022-03-31
DOI: 10.3390/particles5020009
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 110-127: Electrostatic Simulations for the DUNE
ND-GAr Field Cage
Authors: Christopher Hayes, Jon Urheim
First page: 110
Abstract: ND-GAr is one of three detector systems in the design of the DUNE Near Detector complex, which will be located on the Fermilab campus, sixty meters underground and 570 m from the source of an intense neutrino beam. ND-GAr will consist of a cylindrical 10-bar gaseous Argon Time Projection Chamber (TPC) and a surrounding sampling electromagnetic calorimeter embedded within a superconducting solenoid, the cryostat and yoke for which together serve as the pressure vessel. While various options for the specific configuration of ND-GAr are being explored, essential design work for the detector has moved forward in recent months. This document describes basic mechanical, electrostatic, and gas flow design features of the ND-GAr TPC and presents results of electrostatic simulations of the interior of the pressure vessel for both single and dual-anode arrangements. Simulations are implemented with the Elmer finite-element software suite and related programs.
Citation: Particles
PubDate: 2022-04-06
DOI: 10.3390/particles5020010
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 128-134: Effect of Protoneutron Star Magnetized
Envelops in Neutrino Energy Spectra
Authors: Vladimir N. Kondratyev, Tamara D. Lobanovskaya, Dimash B. Torekhan
First page: 128
Abstract: The neutrino dynamics in hot and dense magnetized matter, which corresponds with protoneutron star envelopes in the core collapse supernova explosions, is considered. The kinetic equation for a neutrino phase space distribution function is obtained, taking into account inelastic scattering by nuclear particles. The transfer component in a momentum space using transport properties is studied. The energy transfer coefficient is shown to change from positive to negative values when the neutrino energy exceeds four times the matter temperature. In the vicinity of a neutrino sphere, such effects are illustrated to lead to the energy strengthening in the neutrino spectra. As this paper demonstrates, such a property is favorable for the possibility of observing supernova neutrino fluxes using Large Volume Neutrino Telescopes.
Citation: Particles
PubDate: 2022-04-12
DOI: 10.3390/particles5020011
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 135-145: Rabi Frequency Management of Collapsing
Quasi-Two-Dimensional Bose-Einstein Condensates with Pseudospin-1/2
Authors: Shukhrat N. Mardonov, Bobomurat J. Ahmedov
First page: 135
Abstract: The collapse of quasi-two-dimensional pseudospin-1/2 Bose-Einstein condensate of attracting atoms with intra- and cross-spin interaction is studied in the presence of the Rabi coupling. The condensate dynamics is presented as a function of the self-interaction and Rabi frequency. The evolution of two components of the condensate by using the Gross-Pitaevskii equations is investigated. The initial Gaussian ansatz for two-component wave functions is selected for the better interpretation of the numerical results. The intra-spin-coupling modifies the critical number of atoms causing the collapse while the collapse is observed only in a single pseudospin component. It is demonstrated that for cross-spin-coupling only double spin-components collapse can occur.
Citation: Particles
PubDate: 2022-04-28
DOI: 10.3390/particles5020012
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 146-156: The Novel Scaling of Tsallis Parameters
from the Transverse Momentum Spectra of Charged Particles in Heavy-Ion
Collisions
Authors: Junqi Tao, Weihao Wu, Meng Wang, Hua Zheng, Wenchao Zhang, Lilin Zhu, Aldo Bonasera
First page: 146
Abstract: The transverse momentum (pT) spectra of charged particles measured in Au + Au collisions from the beam energy scan (BES) program, Cu + Cu collisions at sNN=62.4, 200 GeV at the RHIC and Pb + Pb, Xe + Xe collisions at the LHC are investigated in the framework of Tsallis thermodynamics. The theory can describe the experimental data well for all the collision systems, energies and centralities investigated. The collision energy and centrality dependence of the Tsallis distribution parameters, i.e., the temperature T and the nonextensive parameter q, for the A + A collisions are also studied and discussed. A novel scaling between the temperature divided by the natural logarithm of collision energy (T/lns) and the nonextensive parameter q is presented.
Citation: Particles
PubDate: 2022-05-09
DOI: 10.3390/particles5020013
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 157-170: Unruh Effect and Information Entropy
Approach
Authors: Maksym Teslyk, Olena Teslyk, Lidiia Zadorozhna, Larisa Bravina, Evgeny Zabrodin
First page: 157
Abstract: The Unruh effect can be considered a source of particle production. The idea has been widely employed in order to explain multiparticle production in hadronic and heavy-ion collisions at ultrarelativistic energies. The attractive feature of the application of the Unruh effect as a possible mechanism of the multiparticle production is the thermalized spectra of newly produced particles. In the present paper, the total entropy generated by the Unruh effect is calculated within the framework of information theory. In contrast to previous studies, here the calculations are conducted for the finite time of existence of the non-inertial reference frame. In this case, only a finite number of particles are produced. The dependence on the mass of the emitted particles is taken into account. Analytic expression for the entropy of radiated boson and fermion spectra is derived. We study also its asymptotics corresponding to low- and high-acceleration limiting cases. The obtained results can be further generalized to other intrinsic degrees of freedom of the emitted particles, such as spin and electric charge.
Citation: Particles
PubDate: 2022-05-27
DOI: 10.3390/particles5020014
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 171-179: Experimental Determination of the QCD
Effective Charge αg1(Q)
Authors: Alexandre Deur, Volker Burkert, Jian-Ping Chen, Wolfgang Korsch
First page: 171
Abstract: The QCD effective charge αg1(Q) is an observable that characterizes the magnitude of the strong interaction. At high momentum Q, it coincides with the QCD running coupling αs(Q). At low Q, it offers a nonperturbative definition of the running coupling. We have extracted αg1(Q) from measurements carried out at Jefferson Lab that span the very low to moderately high Q domain, 0.14≤Q≤2.18 GeV. The precision of the new results is much improved over the previous extractions and the reach in Q at the lower end is significantly expanded. The data show that αg1(Q) becomes Q-independent at very low Q. They compare well with two recent predictions of the QCD effective charge based on Dyson–Schwinger equations and on the AdS/CFT duality.
Citation: Particles
PubDate: 2022-05-31
DOI: 10.3390/particles5020015
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 180-187: Diurnal Variations of the Count Rates
from Dark Photons in PHELEX
Authors: Anatoly Kopylov, Igor Orekhov, Valery Petukhov
First page: 180
Abstract: This paper reports the PHELEX experiment, i.e., PHoton–ELectron EXperiment, to search for the dark photons (DPs) of cold dark matter using a multicathode counter technique specifically developed for this purpose by the authors. The paper presents new data, a novel upper limit for the constant of kinetic mixing, and the first results of measurements of the diurnal variations in solar and stellar frames. The perspectives of this method are outlined in terms of the search for DPs.
Citation: Particles
PubDate: 2022-06-06
DOI: 10.3390/particles5020016
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 188-197: Approaches to Measuring Direct Photon
Yield in A–A Collisions
Authors: Dmitri Peresunko
First page: 188
Abstract: An overview of experimental methods for measuring direct photon spectra in pp, p–A and A–A collisions is presented. The advantages and limitations of each method are discussed and illustrated by the results of various experiments.
Citation: Particles
PubDate: 2022-06-09
DOI: 10.3390/particles5020017
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 198-209: Stripping Model for Short Gamma-Ray
Bursts in Neutron Star Mergers
Authors: Sergei Blinnikov, Andrey Yudin, Nikita Kramarev, Marat Potashov
First page: 198
Abstract: We overview the current status of the stripping model for short gamma-ray bursts. After the historical joint detection of the gravitational wave event GW170817 and the accompanying gamma-ray burst GRB170817A, the relation between short gamma-ray bursts and neutron star mergers has been reliably confirmed. Many properties of GRB170817A, which turned out to be peculiar in comparison with other short gamma-ray bursts, are naturally explained in the stripping model, suggested by one of us in 1984. We point out the role of late Dmitriy Nadyozhin (1937–2020) in predicting the GRB and kilonova properties in 1990. We also review the problems to be solved in the context of this model.
Citation: Particles
PubDate: 2022-06-16
DOI: 10.3390/particles5020018
Issue No: Vol. 5, No. 2 (2022)
- Particles, Vol. 5, Pages 12-20: Implications of the Conformal Higgs Model
Authors: R. K. Nesbet
First page: 12
Abstract: The postulate of universal local Weyl scaling (conformal) symmetry modifies both general relativity and the Higgs scalar field model. The conformal Higgs model (CHM) acquires a cosmological effect that fits the observed accelerating Hubble expansion for redshifts z≤1 (7.33 Gyr) accurately with only one free constant parameter. Conformal gravity (CG) has recently been fitted to anomalous rotation data for 138 galaxies. Conformal theory explains dark energy and does not require dark matter, providing a viable alternative to the standard ΛCDM paradigm. The theory precludes a massive Higgs particle but validates a composite gauge field W2 with mass 125 GeV.
Citation: Particles
PubDate: 2022-01-13
DOI: 10.3390/particles5010002
Issue No: Vol. 5, No. 1 (2022)
- Particles, Vol. 5, Pages 21-39: Pioneering the Equation of State of Dense
Nuclear Matter with Strange Particles Emitted in Heavy-Ion Collisions: The
KaoS Experiment at GSI
Authors: Peter Senger
First page: 21
Abstract: High-energy heavy-ion collisions offer the unique possibility to study fundamental properties of nuclear matter in the laboratory, which are relevant for our understanding of the structure of compact stellar objects and the dynamics of neutron star mergers. Of particular interest are the nuclear matter equation of state (EOS), the in-medium modifications of hadrons and the degrees of freedom of matter at high densities and temperatures. Pioneering experiments exploring the EOS for symmetric matter were performed at the SIS18 accelerator of GSI, measuring, as function of beam energy, the collective flow of protons and of light fragments and subthreshold strangeness production. These data were reproduced by various microscopic transport model calculations, providing, up to date, the best constraint for the EOS of symmetric matter with an incompressibility of about 200 MeV for densities up to twice the saturation density. This article reviews the experimental results on subthreshold kaon production together with the theoretical interpretation and gives a brief outlook towards future experiments at higher densities.
Citation: Particles
PubDate: 2022-01-17
DOI: 10.3390/particles5010003
Issue No: Vol. 5, No. 1 (2022)
- Particles, Vol. 5, Pages 40-51: Pre-Equilibrium Clustering in Production
of Spectator Fragments in Collisions of Relativistic Nuclei
Authors: Roman Nepeivoda, Aleksandr Svetlichnyi, Nikita Kozyrev, Igor Pshenichnov
First page: 40
Abstract: An algorithm of pre-equilibrium clustering of spectator matter based on the construction of the minimum spanning tree (MST) is presented. The algorithm was implemented in the Abrasion-Ablation Monte Carlo for Colliders (AAMCC) model designed to study the characteristics of spectator matter in collisions of relativistic nuclei. Due to accounting for the pre-equilibrium clusters in modelling 208Pb–208Pb collisions at the LHC, the agreement of simulation results with experimental data on the average multiplicities of spectator nucleons was improved. The results of the AAMCC-MST were compared with experimental data on the interactions of 197Au nuclei in nuclear photoemulsion. Comparison of the yields of spectator nuclei calculated for 16O–16O collisions with the yields measured in interactions of 16O with light nuclei of photoemulsion made it possible to estimate the effect of MST-clustering in small nuclear systems.
Citation: Particles
PubDate: 2022-01-29
DOI: 10.3390/particles5010004
Issue No: Vol. 5, No. 1 (2022)
- Particles, Vol. 5, Pages 52: Acknowledgment to Reviewers of Particles in
2021
Authors: Particles Editorial Office Particles Editorial Office
First page: 52
Abstract: Rigorous peer-reviews are the basis of high-quality academic publishing [...]
Citation: Particles
PubDate: 2022-02-07
DOI: 10.3390/particles5010005
Issue No: Vol. 5, No. 1 (2022)
- Particles, Vol. 5, Pages 53-73: High-Precision Calculations of the Higgs
Boson Mass
Authors: Edilson Reyes, Raffaele Fazio
First page: 53
Abstract: In this paper, we review the status of the computations of the perturbative quantum corrections to the Higgs boson mass in the Standard Model and in its supersymmetric extensions. In particular, supersymmetric theories require a very accurate computation of the Higgs boson mass, which includes corrections even up to the three-loop level, since their predictions are limited by theoretical uncertainties. A discussion about these uncertainties in the context of the Minimal and Next To Minimal Supersymmetric Standard Model is included.
Citation: Particles
PubDate: 2022-02-17
DOI: 10.3390/particles5010006
Issue No: Vol. 5, No. 1 (2022)
- Particles, Vol. 5, Pages 74-83: Techniques for TPC Calibration:
Application to Liquid Ar-TPCs
Authors: José Maneira
First page: 74
Abstract: Large liquid argon TPCs are playing an increasingly important role in neutrino physics, and their calibration will be an essential component of their capability to reach the required performance and precision. Natural sources are extensively used but present limitations, since natural radioactivity from 39Ar is of low energy, and the rate of cosmic ray muons is low when the detectors are placed deep underground. Argon gas TPCs have been calibrated with ionizing laser beams for several decades, and more recently the technique has been further developed for use in liquid TPCs. Other recent ideas include the use of external neutron generators creating pulses that propagate into the detector. This paper reviews the development of the laser and neutron methods for the calibration of argon TPCs and describes their planned implementation in the upcoming DUNE experiment.
Citation: Particles
PubDate: 2022-02-23
DOI: 10.3390/particles5010007
Issue No: Vol. 5, No. 1 (2022)
- Particles, Vol. 5, Pages 84-95: Track Reconstruction in a High-Density
Environment with ALICE
Authors: Mesut Arslandok, Ernst Hellbär, Marian Ivanov, Robert Helmut Münzer, Jens Wiechula
First page: 84
Abstract: ALICE is the dedicated heavy-ion experiment at the CERN Large Hadron Collider (LHC). Its main tracking and particle-identification detector is a large volume Time Projection Chamber (TPC). The TPC has been designed to perform well in the high-track density environment created in high-energy heavy-ion collisions. In this proceeding, we describe the track reconstruction procedure in ALICE. In particular, we focus on the two main challenges that were faced during the Run 2 data-taking period (2015–2018) of the LHC, which were the baseline fluctuations and the local space charge distortions in the TPC. We present the corresponding solutions in detail and describe the software tools that allowed us to circumvent these challenges.
Citation: Particles
PubDate: 2022-03-10
DOI: 10.3390/particles5010008
Issue No: Vol. 5, No. 1 (2022)
