Conveners
Nuclear, Particle and Radiation Physics: Nuclear, Particle and Radiation Physics
- Manny Mathuthu (North West University- Mafikeng)
Nuclear, Particle and Radiation Physics: Nuclear, Particle and Radiation Physics
- Thomas Dietel (University of Cape Town)
- Zinhle Buthelezi (iThemba LABS)
Nuclear, Particle and Radiation Physics: Nuclear, Particle and Radiation Physics
- Edward Nkadimeng (University of the Witwatersrand)
Nuclear, Particle and Radiation Physics: Nuclear, Particle and Radiation Physics
- Armand Bahini (School of Physics, Wits)
Nuclear, Particle and Radiation Physics
- Mukesh Kumar (University of the Witwatersrand)
Nuclear, Particle and Radiation Physics
- JAMES KEAVENEY (University of Cape Town)
Nuclear, Particle and Radiation Physics
- There are no conveners in this block
Mining and processing of naturally occurring radioactive materials could result in elevated levels of natural radionuclides in the environment. The aim of this study was to evaluate the radioactivity levels on a large scale in the West Rand District in South Africa, which is dominated by abandoned gold mine tailings and the consequential radiological exposures to members of the public. The...
The issues of an increased water quality and deterioration due to mining activities are if major concern. The river systems have deteriorated noticeably due to mining effluent and other industrial effluents.Mining activities are the major sources of the radio toxic and heavy metals pollutants.These pollutants are naturally found everywhere in the environment, and accumulate easily in the soil...
The Republic of South Africa in 1991 signed the non-proliferation treaty (NPT) which regulates nuclear states in terms of usage of nuclear technology and materials. However, the implementation of nuclear safeguards requires nuclear material accounting and control (NMAC). These safeguarded nuclear material include uranium, thorium and plutonium. There are nuclear material of unreacted waste,...
Nuclear forensic science seeks to to aid attribution process of nuclear or radioactive materials found outside regulatory control. It is progressively seen as fundamental part of a strong nuclear security program. Having abundant deposits of uranium ore in Africa portends potential nuclear insecurity thereby the need to generate fingerprints becomes inevitable task. Isotopic ratios such as...
One of the key requirements of materials operating in high radiation environments is that they are radiation hard. That is, they endure low to no-radiation induced damage when exposed to high radiation fields, and that is important in that such materials do not lose their performance levels. Displacement per atom (dpa) which relates the number of displaced atoms in materials by exposure to...
Abstract
Heavy quarks (charm and beauty) are produced at an early stage of the collision via hard parton scatterings. In ALICE, heavy quarks are measured in the central barrel (|η|<0.9) which is optimized for the reconstruction ofη|η|<0.9) which is optimized for the reconstruction of<0.9) which is optimized for the reconstruction of) which is optimized for the reconstruction of hadrons,...
Measurements of heavy-flavour (charm and beauty quark) production in proton-proton (pp) collisions as a function of the charged-particle multiplicity are important in order to gain more insight on which processes are involved in the collision at a partonic level. These measurements also provide information on the interplay between hard and soft mechanisms during particle production.
We...
A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider (LHC) at CERN is undergoing a major upgrade during which some of its sub-detectors are replaced with new ones, while others are equipped with new electronics to handle the expected higher collision rates in the next running period (Run 3), which is foreseen to start in 2022. As part of the upgrade, certain sub-detectors such...
The start of the operation of the High Luminosity LHC (HL-LHC) is planned
for the year 2029. The associated increase in luminosity provides an opportunity for further scientific discoveries as well as many technical challenges. The HL-LHC environment has necessitated the Phase-II upgrade of the ATLAS hadronic Tile-Calorimeter. The upgrade will take place during the long shutdown from December...
The Tile Calorimeter of the ATLAS experiment at the Large Hadron Collider is a hadronic sampling calorimeter that is designed for the reconstruction of hadrons, jets, tau-particles and missing transverse energy. In this study, the response of the gap/crack scintillators of Tile calorimeter is measured using isolated muons from $W\rightarrow \mu\nu$ events. The response of the scintillating...
CERN has planned a series of upgrades for its Large Hadron Collider (LHC). Rearmost in this current series of planned upgrades is named the High Luminosity LHC (HL-LHC) and as the name suggests will bring the instantaneous Luminosity up to $21\times 10^{34}$ \mbox{cm}$^{-2}$\mbox{S}$^{-2}$. The ATLAS detector will be substantially changed to meet the challenges of this upgrade (termed the...
Recent studies in particle physics have shown that there are myriad possibilities for strong dark sector studies at the LHC. One signature is the case of semi-visible jets, where parton evolution includes dark sector emissions, resulting in jets overlapping with missing transverse energy. Owing to the unusual MET-along-the-jet event topology, this is mostly an unexplored domain within ATLAS....
A collider search for semi-visible jet final state arising from dark matter, using Run 2 data recorded with the ATLAS detector at the CERN LHC with a center-of-mass energy of 13 TeV is presented. For this search the hidden sector is hypothesized to couple to the standard model via a heavy leptophobic Z’ mediator. Semi-visible jets are an unusual final state, where the visible states in the...
Deep neural networks have the ability to learn from highly complex data and discover non-linear feature combinations. This makes them a suitable tool to explore the high volumes of data in HEP. This study explores the ability of semi-supervised learning in conjunction with deep neural networks to extract signal from the background in the $Z\gamma$ final state using the Monte Carlo simulated...
The Standard Model (SM) of particle physics was completed by the discovery of the Higgs boson in 2012 by the ATLAS and CMS collaborations. However, the SM is not able to explain a number of phenomena and anomalies in the data. These discrepancies to the SM motivate the search for new bosons. In this paper, searches for new bosons are completed by looking for Zgamma resonances in $Z\gamma$...
We present a search for a new spin-1 or spin-0 boson where the Standard Model Higgs boson decays into a four lepton final state ($\ell$ = $\mu$ or $e$) corresponding to the $H\rightarrow XX \rightarrow 4\ell$. In this scenario, $X$ is the new boson found in the intermediate state, having a mass range of between 15 - 60 GeV. The search is conducted using pp collision data collected with the...
Particle Physics today displays a growing number of anomalies that cannot be explained by the Standard Model. Some of these anomalies are related to New Physics via quantum corrections. Other anomalies may be connected with the decay of new particles. This is the case the multi-lepton (electrons and muons) anomalies at the LHC. These include the excess production of opposite sign leptons with...
A high-statistics Coulomb-excitation study of 12C has been carried out using the 208Pb(12C,12C)208Pb Coulomb-excitation reaction at 56 MeV using the Q3D spectrometer at the Maier-Leibnitz Laboratory (MLL) in Munich (Germany). Beam currents of approximately 10^11 pps allowed the determination of the spectroscopic quadrupole moment of the first 2+ state at 4.439 MeV with unprecedented...
The multiphonon model of surface vibrations, a foundational pillar that nuclear physics is built upon is being questioned using detailed spectroscopy. The breakdown of vibrational selection rules has been confirmed in the paradigmatic Cd isotopes. Such selection rules involve particular relations for reduced transition probabilities e.g.$ B(E2,0_{2}^{+} \rightarrow 2_{1}^{+}) = 2\times...
Measurements of nuclear reaction rates are crucial in determining isotopic abundances of elements produced within stellar interiors. This study focuses on the bottleneck reaction $^{20}$Ne$(p,\gamma)^{21}$Na of the neon-sodium (NeNa) cycle, which is an important nuclear reaction cycle in stellar environments at temperatures greater than $0.05$ GK. In particular, the $^{20}$Ne$(p,\gamma)$...
Interest in the evolution of the isoscalar giant monopole resonance (ISGMR) within the calcium isotope chain follows from a 2017 study which suggests that the monopole resonance energy, and thus the incompressibility of the nucleus KA, increase with mass. In 2020 a different group reported a weak decreasing trend of the energy moments, resulting in a generally accepted negative value for Kτ,...
During proton therapy (PT), excited-nuclei decay via emission of characteristic prompt gamma rays along the beam path within the target. These gamma rays are detectable via a Compton camera and can be used for in vivo proton beam range verification using a technique called prompt gamma imaging (PGI). The detection efficiency of a PGI device can be negatively affected by additional secondary...
Motivated by the multi-lepton anomalies, a search for narrow resonances with S → γγ, Zγ in association with light jets, b-jets, or missing transverse energy was reported in arXiv:2109.02650. The global significance of the excess at 151.5 GeV is 4σ, where the combination with the multi-lepton anomalies gives a significance much larger than 5σ. In this paper, the final states that are considered...
The measurements related to the different properties of the newly discovered Higgs boson ($h$) at the LHC by ATLAS and CMS indicate that this 125 GeV boson is compatible with the Standard Model (SM). However, this does not exclude the existence of additional scalar bosons as long as their possible mixing with the SM Higgs is sufficiently small. In a recent phenomenological analysis, a search...
The shortfall of the Standard Model (SM) has led the particle physics community to search for a plethora of physics models beyond the SM (BSM). Owing to many recent studies on multi-lepton final states in proton-proton collisions at the LHC, it has become evident that several anomalous features of the LHC data can be explained through the addition of new scalar bosons to the 2HDM model. The...
After the discovery of the Higgs boson at the Large Hadron Collider (LHC), the ATLAS and CMS Collaborations have concentrated to confirm its properties via measurements of different couplings, decay width, and differential distributions of relevant observables. In this context, recent studies on multi-lepton final states in poton-proton collisions unfold some deviations from the Standard Model...
In resonance searches for new physics, machine learning techniques are used to classify signal from background events. When using machine learning classifiers it is necessary to measure the amount of background events being incorrectly labelled as signal events. In this research the Zγ→(ℓ+ℓ−)γ final state dataset focusing around 150GeV centre of mass is used. A Wasserstein Generative...
A measurement of the leptonic charge asymmetry (A$_{C}^{\ell}$) in top quark pair production in association with a, W boson ($t\bar{t}W^{\pm}$) is presented using the trilepton final state. The A$_{C}^{\ell}$ is sensitive to new physics beyond the standard model, such as the axigluon and as a result, a measurement of the A$_{C}^{\ell}$ could prove useful in searches for new physics. The data...
The production of a single top quark with an associated $W$ and $Z$ boson ($tWZ$) is a rare Standard Model process which has never before been measured. This process is sensitive to the top quark electroweak coupling found in some Beyond Standard Model theories such as Standard Model Effective Field theory and may hold information for constraining these theories. A previous search has been...
Our group is conducting a search for physics beyond the Standard Model via non-standard decays of the Higgs boson at the ATLAS detector. A hidden or dark sector can be introduced with an additional U(1) gauge symmetry. These exotic decays are an attractive way to search for new physics as current measurements still allow for a significant branching ratio to exotic states, given even a small...
Geant4 simulation of plastic scintillator was performed to study some properties of the scintillator for possible use as a detector in SPECT/CT and PET/CT scans. The study was concentrated on the stopping power and light output of the scintillator. Different geometries such as squares, triangles, polygons, and circles were studied. The length of the different geometries varied from 5 cm to 15...
In an effort to contribute towards a better understanding of the dynamics of three-body weakly-bound systems, we present a detailed analysis of the role of nucleon-nucleon ($nn$) and three-body interactions on the three-body ground-state structure, considering the $^{22}{\rm C}\to{}^{20}{\rm C}+n+n$ system. It is found that even in the absence of the $nn$ interaction, this system remains...
