Particles

12 pages, 12298 KiB

Open AccessArticle

Track Reconstruction in a High-Density Environment with ALICE

by Mesut Arslandok, Ernst Hellbär, Marian Ivanov, Robert Helmut Münzer and Jens Wiechula

Particles 2022, 5(1), 84-95; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010008 - 10 Mar 2022

Cited by 3 | Viewed by 9968

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Selected Papers from "New Horizons in Time Projection Chambers")

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10 pages, 2989 KiB

Open AccessArticle

Techniques for TPC Calibration: Application to Liquid Ar-TPCs

by José Maneira

Particles 2022, 5(1), 74-83; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010007 - 23 Feb 2022

Cited by 1 | Viewed by 2484

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 [...] Read more.

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

^{39} A r

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. Full article

(This article belongs to the Special Issue Selected Papers from "New Horizons in Time Projection Chambers")

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21 pages, 836 KiB

Open AccessReview

High-Precision Calculations of the Higgs Boson Mass

by Edilson Reyes and Raffaele Fazio

Particles 2022, 5(1), 53-73; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010006 - 17 Feb 2022

Cited by 5 | Viewed by 5591

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, [...] Read more.

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. Full article

(This article belongs to the Special Issue Higgs Physics)

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1 pages, 201 KiB

Open AccessEditorial

Acknowledgment to Reviewers of Particles in 2021

by Particles Editorial Office

Particles 2022, 5(1), 52; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010005 - 07 Feb 2022

Viewed by 1524

Abstract

Rigorous peer-reviews are the basis of high-quality academic publishing [...] Full article

12 pages, 1294 KiB

Open AccessArticle

Pre-Equilibrium Clustering in Production of Spectator Fragments in Collisions of Relativistic Nuclei

by Roman Nepeivoda, Aleksandr Svetlichnyi, Nikita Kozyrev and Igor Pshenichnov

Particles 2022, 5(1), 40-51; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010004 - 29 Jan 2022

Cited by 6 | Viewed by 2335

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 [...] Read more.

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

^{208}

Pb–

^{208}

Pb 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

^{197}

Au nuclei in nuclear photoemulsion. Comparison of the yields of spectator nuclei calculated for

^{16}

O–

^{16}

O collisions with the yields measured in interactions of

^{16}

O with light nuclei of photoemulsion made it possible to estimate the effect of MST-clustering in small nuclear systems. Full article

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19 pages, 6065 KiB

Open AccessArticle

Pioneering the Equation of State of Dense Nuclear Matter with Strange Particles Emitted in Heavy-Ion Collisions: The KaoS Experiment at GSI

by Peter Senger

Particles 2022, 5(1), 21-39; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010003 - 17 Jan 2022

Cited by 3 | Viewed by 2404

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 [...] Read more.

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. Full article

(This article belongs to the Collection High Energy Physics)

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9 pages, 305 KiB

Open AccessArticle

Implications of the Conformal Higgs Model

by R. K. Nesbet

Particles 2022, 5(1), 12-20; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010002 - 13 Jan 2022

Viewed by 1800

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 \leq 1

(7.33 Gyr) accurately [...] Read more.

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 \leq 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

W_{2}

with mass 125 GeV. Full article

(This article belongs to the Special Issue Higgs Physics)

11 pages, 281 KiB

Open AccessArticle

Generic Three-Parameter Wormhole Solution in Einstein-Scalar Field Theory

by Bobur Turimov, Ahmadjon Abdujabbarov, Bobomurat Ahmedov and Zdeněk Stuchlík

Particles 2022, 5(1), 1-11; https://0-doi-org.brum.beds.ac.uk/10.3390/particles5010001 - 22 Dec 2021

Cited by 3 | Viewed by 2798

Abstract

An exact analytical, spherically symmetric, three-parametric wormhole solution has been found in the Einstein-scalar field theory, which covers the several well-known wormhole solutions. It is assumed that the scalar field is massless and depends on the radial coordinate only. The relation between the [...] Read more.

An exact analytical, spherically symmetric, three-parametric wormhole solution has been found in the Einstein-scalar field theory, which covers the several well-known wormhole solutions. It is assumed that the scalar field is massless and depends on the radial coordinate only. The relation between the full contraction of the Ricci tensor and Ricci scalar has been found as

R_{α β} R^{α β} = R^{2}

. The derivation of the Einstein field equations have been explicitly shown, and the exact analytical solution has been found in terms of the three constants of integration. The several wormhole solutions have been extracted for the specific values of the parameters. In order to explore the physical meaning of the integration constants, the solution has been compared with the previously obtained results. The curvature scalar has been determined for all particular solutions. Finally, it is shown that the general solution describes naked singularity characterized by the mass, the scalar quantity and the throat. Full article

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Particles, Volume 5, Issue 1 (March 2022) – 8 articles

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