Conveners
Nuclear, Particle and Radiation Physics
- Edward Nkadimeng (University of the Witwatersrand)
Nuclear, Particle and Radiation Physics
- Retief Neveling (SSC Laboratory, iThemba LABS, Faure, 7100, South Africa.)
Nuclear, Particle and Radiation Physics
- Mukesh Kumar (University of the Witwatersrand)
Nuclear, Particle and Radiation Physics
- Lindsay Donaldson (SSC Laboratory, iThemba LABS, Faure, 7100, South Africa.)
Nuclear, Particle and Radiation Physics
- Retief Neveling (SSC Laboratory, iThemba LABS, Faure, 7100, South Africa.)
Nuclear, Particle and Radiation Physics
- John Sharpey-Schafer (UniZulu)
Nuclear, Particle and Radiation Physics
- Edward Nkadimeng (University of the Witwatersrand)
Nuclear, Particle and Radiation Physics
- Peane Maleka (iThemba LABS)
Nuclear, Particle and Radiation Physics
- Pete Jones (SSC Laboratory, iThemba LABS, Faure, 7100, South Africa.)
Nuclear, Particle and Radiation Physics
- Salah-eddine Dahbi (University of Wits)
Nuclear, Particle and Radiation Physics
- Suzan Bvumbi (National Radioactive Waste Disposal Institute)
Nuclear, Particle and Radiation Physics
- Edward Nkadimeng (University of the Witwatersrand)
In this talk we explore the scale invariant (SI) scotogenic model in the context of anomalies observed in various multi-leptonic final states at the Large Hadron Collider (LHC). This model is vary well known to accommodate dark matter (DM) requirements in association with scalar sector. In a classically SI framework this model is also motivated by neutrino mass and DM. This model is an...
After the discovery of a Higgs boson at the Large Hadron Collider (LHC) by the ATLAS and CMS experiments, a number of multi-lepton anomalies that represent a significant experimental evidence for a new physics have been identified. These anomalies are consistent with the decay of a heavy boson $H$ with a mass around $270 \,$GeV, into a Higgs like boson $S$ of a mass around $150 \,$GeV. The...
Accurate nuclear data is a key factor in determining the suitability and reliabil-
ity of many theoretical nuclear models and large scale calculations. This is especially true for cases where the systematic calculations are challenging such as light and deformed nuclei.The photoabsorption cross section and the relative branching ratios for these nuclei are of particular interests to...
High energy-resolution proton inelastic scattering experiments with Ep = 200 MeV were performed on the even-even Nd isotope chain and 152Sm. The experiments focussed on the excitation-energy region of the Isovector Giant Dipole Resonance (IVGDR) and made use of the zero-degree mode of the K600 magnetic spectrometer at iThemba LABS. A goal of the highlighted study was to...
Background: Inelastic $\alpha$-particle scattering at energies of a few hundred MeV and very-forward scattering angles including $0^\circ$ has been established as a tool for the study of the isoscalar giant monopole (IS0) strength distributions in nuclei. This compressional mode of nuclear excitation can be used to derive the incompressibility of nuclear matter.
Objective: An independent...
The concept of clustering - that nuclei can contain sub-groups of correlated nucleons combining into larger structures rather than consisting simply of individual nucleons - has become extremely important in understanding the structure of light nuclei. The Hoyle state, the second 0+ state at 7.654 MeV in 12C, is considered the archetype of alpha cluster states in nuclei, and its existence is...
This study aims to test and develop the (p,p'γ) detection capabilities of the K600 magnetic spectrometer when positioned at zero degrees and coupled to the Ball of Germanium and Lanthanum bromide detectors (BaGeL) at iThemba LABS. This is done hrough an investigation into the low-lying dipole strength of 58Ni with a proton beam of Ep = 80 MeV. The use of proton inelastic scattering at forward...
The production of a single top quark in association with a W boson and a Z boson ($tWZ$) is a rare Standard Model process which has never before been measured. This process will be a useful input into global Standard Model Effective Field Theory (SMEFT) fits due to its sensitivity to top-electroweak SMEFT coefficients in regions of high W boson and Z boson transverse momenta. It is also a...
In Beyond Standard Model (BSM) theories, Axion-Like Particles (ALPs) are hypothesized to be Pseudo-Nambu-Goldstone bosons that have spontaneously broken the global Peccei-Quinn (PQ) symmetries at very high energies. Due to the approximated symmetry shifts, the ALPs are naturally lighter compared to the electroweak or QCD particles. Future high-precision experiments may be able to find ALPs...
Elemental abundances are excellent probes of classical novae (CN). Sensitivity studies show that $^{38}$K($p$,$\gamma$)$^{39}$Ca reaction rate uncertainties modify the abundance of Ca by a factor of 60 in CN ejecta. Direct measurements of the $^{38}$K($p$,$\gamma$)$^{39}$Ca reaction have reduced the uncertainties but discrepancies in resonance energies between different experiments persist. To...
The study of statistical nuclear properties is of importance not only in nuclear waste transmutation [Colonna2010] and nuclear fuel cycles [Report2006] but also in nuclear structure and nuclear astrophysics studies [Arnould2003]. These statistical properties - the nuclear level density (NLD), which describes the number of available energy levels in a nucleus for a given excitation energy, and...
Abstract. A substantial number of experimental studies over the years have shown that many light-to-medium-sized and some rare-earth nuclei exhibit a Low-Energy Enhancement (LEE) in the Gamma Strength Function (GSF) [1,2,3,4 and references therein]. Within the Hauser-Feshbach formalism, the GSF and the Nuclear Level Density (NLD) play crucial roles in the estimates of nuclear reaction...
iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) is a national facility of the National Research Foundation (NRF) in the Republic of South Africa. Activities at iThemba LABS are based around a number of sub-atomic particle accelerators located at the Cape Town and Johannesburg campuses. The largest of these, a K=200 separated sector cyclotron (SSC), accelerates protons to...
Determination of reaction activities on Au and Tm targets using the quasi-monoenergetic neutron beams at approximately 90 MeV
Ndevu L1,2, Lethole NL1, and Maleka PP2
1Department of Physics, University of Fort Hare, South Africa, 2Separated Sector Cyclotron Laboratory, NRF-iThemba LABS, South Africa
Email address: 201614604@ufh.ac.za
The International Atomic Energy Agency (IAEA) has...
The fast neutron beam facility at iThemba LABS (D-line) offers ns-pulsed neutron fields in the range 5-200 MeV, typically produced via the 7Li(p,xn) or 9Be(p,xn) reactions [1-3], using proton beams from the separated sector cyclotron (SSC). The D-line is currently undergoing a major upgrade and redevelopment towards ISO/IEC 17025 accreditation, including physical modifications of the vault,...
The UCT POLARIS system, a solid-state CZT detector for prompt gamma-ray imaging, has shown potential for improving range verification techniques in proton therapy [1]. However, its limitations in timing resolution and energy range impede its clinical applicability. In this project, we aim to overcome these limitations by combining the POLARIS detector with a fast-timing 2" x 2" LaBr3$_3$(Ce)...
Positron Emission Particle Tracking (PEPT) is a non-invasive particle tracking technique used to study particle and fluid transport in a range of applications, including medicine and chemical engineering. PEPT produces time-series 3D location data, however the output rate of locations is limited by the timing resolution of the equipment used. At PEPT Cape Town at the University of Cape Town,...
Motivated by an excess around 95 GeV in the LEP data, we evaluate several ex-
cesses around that mass that have emerged in recent years at the Large Hadron
Collider (LHC). Results from the CMS and ATLAS collaborations have shown
that there is a scalar at around that mass, we combine the results from both
collaborations for when the scalar decays into γγ, ττ, and WW to analyze...
In searches for physics beyond the Standard Model, BSM, machine learning classifiers are used to extract signal from background processes. The use of semi-supervised classifiers allows unlabelled signal events to be classified from labelled background events. This method minimises biases caused by preconceived understanding of the signal. During the training of machine learning classifiers,...
In recent years, multi-lepton anomalies have been accumulated by analyzing Large Hadron Collider (LHC) data, pointing towards the existence of beyond the Standard Model (SM) bosons. The data is consistent with a scalar particle $S$ within a mass range between 130 GeV and 160 GeV. A simplified model, the Two-Higgs Doublet plus an additional Scalar (2HDM$+S$) is used to predict the decay of a...
We presents a full simulation study of the production of a scalar ($M_{S}$) using $e^+ e^- \rightarrow Z S$ at the future $e^+ e^-$ colliders. We consider the events in which a Scalar recoils against a $Z$ boson decaying into a pair of muons or electrons at $\sqrt{s} = 250$~GeV. We evaluate the statistical precisions of the Scalar mass $m_{S}$ measurement at the future $e^+e^-$ colliders in...
The Brout Englert-Higgs boson, discovered at the LHC, provided the final piece of the puzzle for the Standard Model (SM) of particle physics, which has undergone extensive testing and verification both at the precision and at the high energy frontier. However, this does not exclude the existence of additional scalar bosons as long as their role in the breaking of the SM electroweak gauge...
Deterioration of pavement condition near and on the speed, bumps is observed throughout South Africa, mainly in rural and townships area. The material used to construct those speed bumps is found to be radioactive with a considerable dose rate of 0.9μSv/h compared to the 1000μSv annual limit for radiation exposure for a public member. The hazard posed by skin exposure from Ra-226 is,...
Carbonatite-peralkaline complexes represent the major type of host rock for phosphate in South Africa. It is well known that this rock also contains small amounts of naturally occurring uranium and its decay products. The spillage of polluted process water during December 2013 at the Bosveld Phosphates mine in Phalaborwa, South Africa, lead to the run-off of this water into the adjacent Selati...
Several water sources and their state in Africa are a major concern due to mining, industrial, and other anthropogenic sources. Water is essential to life and healthy living, and also serves as home to various species of household edible fishes. Unfortunately, its contamination has led to significant deaths resulting from diseases associated with the consumption of contaminated water....
The conjecture of Bohr and Mottelson that the lowest Kπ = 0+ and Kπ = 2+ rotational bands in deformed nuclei could be identified as “vibrations” of the quadrupole shape, turns out to be fallacious.
The vast amount of current experimental data shows that the Kπ = 0+ rotational bands are 2p-2h states and that the Kπ = 2+ rotational bands are due to the energy being lowered by the nucleus...
This project entails the development of a machine learning-based gamma detection
system with tracking and prediction capabilities. It involves integrating gamma spectroscopy via an artificial intelligence model, including a custom
neural network trained on spectra from various isotopes and a compact
detector. The model would be integrated into a compact, low-cost, micro-controller
enabled...
The National Radioactive Waste Disposal Institute (NRWDI) is mandated by both the NRWDI Act No.53 of 2008 and the South African Radioactive Waste (Radwaste) Management Policy and Strategy (RWMPS) of 2005 to nationally manage the storage and disposal of all classes of radioactive waste. The disposal of Radwaste in stable geological repositories has been recognised as the ultimate world best...
An extraction of the top quark Yukawa coupling (Y$_{t}$) from top quark pair production in the dilepton final state using proton-proton collisions recorded by the ATLAS experiment during LHC run 2 & 3 is presented. Corrections from a Higgs boson exchange between the top quark and top anti-quark can produce large modifications to differential distributions near the energy threshold of...
Searches for new resonances predicted by theories beyond the Standard Model are one of the interesting projects in the physics program of the Large Hadron Collider. This study searches for high-mass spin-0 and spin-2 resonances in the $Z(\ell\ell)\gamma$ final state where the $Z$ boson decays into a pair of oppositely charged muons or electrons. The full Run-2 dataset recorded with the ATLAS...
The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the
central region of the ATLAS detector. The TileCal provides important information
for reconstruction of hadrons, jets, hadronic decays of tau leptons, missing
transverse energy and assists in muon identification. The annual operation of the
TileCal follows that of the ATLAS detector and by extension the Large...
The Large Hadron Collider (LHC) at CERN is a cornerstone of modern particle physics research, and the ATLAS experiment is one of the largest and most complex detectors at the LHC. The upcoming Phase-II Upgrade of the ATLAS detector presents a major opportunity for advancing our understanding of the fundamental properties of matter and the universe. South African institutions are playing a key...
Medicinal plants are the most sensitive factors that show the interaction between human activities and the ecological environment.The aim of this study is developing the therapeutic trace elements and nuclear forensic signature in medicinal plants of East Gojjam using nuclear techniques as tools. The samples from medicinal plants were accurately weighed and transfered into the irradiation as...
Radio-Photoluminescence Glass Dosimeters are solid-state detectors, which use the accumulation of radiation counts technique to measure the amount of radiation dose acquired. In this study, they were applied to measure the personal dose equivalent from two gamma radiation sources, i.e Co-60 teletherapy source, and Cs-137 low-level radiation source. Two reference detectors (0.6 cc farmer...
A solenoid magnetic lens spectrometer \cite{avaa2020electron} was refurbished and upgraded to incorporate measurement of internal-pairs in addition to conversion electrons. An in-beam experiment was performed on a setup where the magnetic lens spectrometer was coupled to a gamma-ray array consisting of seven Compton suppressed HPGe clover detectors. A 1.1 mg/cm$^{2}$ thick $^{50}$Ti target was...
In this presentation we give an update of the multi-lepton (electrons and muons) anomalies at the LHC is given. These include the excess production of opposite sign leptons with and without b- quarks, including a corner of the phase-space with a full hadronic jet veto; same sign leptons with and without b-quarks; three leptons with and without b-quarks, including also the presence of a Z. The...
An exploration into machine-learning based optimisation techniques applied to the extraction of the top quark Yukawa coupling ($Y_{t}$) from top quark pair production in the dilepton final state, using proton collisions recorded by the ATLAS experiment in LHC run 2 and 3 is presented. Electroweak corrections for the exchange of the Higgs boson between the top quark and the top anti-quark for...
Despite the discovery of the Higgs boson at the Large Hadron Collider (LHC) confirming the SM's predictions, additional scalar bosons may exist as long as their mixing with the SM Higgs is minimal. The 2HDM model with a singlet scalar extension has been shown to accurately explain multi-lepton anomalies at the LHC, where the heavy scalar has a mass of $m_H \approx 270$\,GeV, and the singlet...
Following a discussion on $W$-boson mass observed at the CDF and ATLAS, we explore the parameter space allowed in 2HDM+$S$ model. Further the model parameter space are constrained through vector-like leptons via muon g-2 dataset. We show our results for additional scalar mass fixed to $m_S \approx 96$ and $150$ GeV keeping the standard Higgs-boson mass at 125 GeV in all four types of 2HDM+$S$...
