Prof.
John Carter
(University of Witwatersrand)
11/02/2015, 09:20
Alan Cornell,
Bruce Mellado Garcia
(University of the Witwatersrand)
11/02/2015, 09:35
Razieh Morad
(University of Cape Town)
11/02/2015, 13:30
The spectacular measurements from the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) provide compelling evidence that the matter produced in heavy ion collision is a deconfined state of QCD, Quark-Gluon Plasma (QGP), at temperatures above ~160 MeV which appears to be nearly perfect, with an extremely low viscosity-to-entropy ratio η/s ~ 1/4π.
Within this expanding...
R McConnel
(University of Cape Town)
11/02/2015, 13:50
Using a classical gluon cascade, we study the thermalisation of a gluon-plasma in a homogeneous box by considering the time evolution of the entropy, and in particular how the thermalisation time depends on the strong coupling constant. We then partition the volume into cells with a linearly increasing temperature gradient in one direction, and homogeneous/isotropic in the other two...
Isobel Kolbe
(University of Cape Town)
11/02/2015, 14:10
In the heavy ion experiments at RHIC and the LHC, a state of matter known as the quark-gluon plasma (QGP) has been produced. The so-called ‘hard particles’, or particles with very high momentum that are produced as a consequence of the asymptotic freedom of QCD, can be used as tomographic probes of the QGP. We will study the way in which energy is dissipated in this QGP by calculating, in...
Ben Meiring
(University of Cape Town)
11/02/2015, 14:30
AdS/CFT computations have been used to describe the energy loss of QCD-like particles moving through a strongly coupled plasma, but little is understood regarding the initial conditions of these jets.
We use the Schwinger-Keldysh finite-time formalism applied to an interacting scalar field theory to derive a perturbative expression for the energy momentum tensor associated with hard...
Mr
Warren Anthony Carlson
(University of the Witwatersrand)
11/02/2015, 15:40
Modern theories suggest that microscopic black-hole might form as particle collision remnants in modern particle colliders. A remarkable consequence of quantum mechanics is that these black-holes should decay rapidly into a shower of particles. While it is clear that the particle and energy signatures of such a shower should be distinguishable from other processes of particles collisions, the...
Gerhard Harmsen
(University of Witwatersrand)
11/02/2015, 16:00
This paper aims to calculate the quasi normal modes for spin-3/2 fields of black holes, since spin-3/2 fields can be thought of as vector fields whose components are spinors we can use Camporesi and Higuchi’s results as a starting point. This project will then determine the stability of micro ultra-spinning black holes. We will then use this information to calculate the emission spectrum of a...
Mukesh Kumar
(University of the Witwatersrand (ZA))
11/02/2015, 16:20
In this talk I am going to present some studies on the prospects of single top quark production at the LHeC and double-Higgs production at the FCC-he. In particular we are investigating the tbW couplings via single top quark production with the introduction of possible anomalous Lorentz structure and the sensitivity of Higgs-self-coupling (λ) through double Higgs production. The studies are...
Jonathan Esteves
(University of Witwatersrand)
11/02/2015, 16:40
The Large Hadron Electron Collider (LHeC) at the European Laboratory, CERN, is expected to collide electrons and protons at high energy. Studies pertaining to the feasibility of observing the Higgs boson in this environment were reported in the Conceptual Design Report. Here the effect of decreasing the electron energy in an ep collision to find the optimal, economic electron energy for the...
Xolisile Octavia Thusini
(University of Cape Town)
12/02/2015, 11:00
The observation of the Higgs boson with the ATLAS detector in 2012 was a major achievement for science. This essay is aimed at understanding the relevance of the Higgs boson in the Standard Model and analysing the experimental observation of the particle. The dataset used in the experiment had an integrated luminosity of about 25 fb−1 at the centre-of-mass energy of s = 8 TeV. To understand...
Xifeng Ruan
(University of the Witwatersrand (ZA))
12/02/2015, 11:20
The measurements of the Higgs bosonproperties are performed in Higgs decaying into two photons channel after the discovery. The gluon-gluon fusion, the vector boson fusion, the Higgs production in association with a $W$ or $Z$ boson or a top-quark pair are measured in this final state. The multivariate analysis (MVA) method is applied to extract the Higgs boson in the vector boson fusion...
Robert Graham Reed
(University of the Witwatersrand (ZA))
12/02/2015, 11:40
The Standard Model (SM) of particle physics, with the discovery of the Higgs boson, is a complete model of the known fundamental particles and their interactions. The data taken in the 2012 run was then compared to the Monte Carlo and an excess has been found in the Higgs transverse momentum in the di-photon and ZZ decay channels. A possible explanation is a beyond the SM pseudo scalar boson...
David Gossman
(University of the Witwatersrand)
12/02/2015, 12:00
Using the Standard Model of particle physics (SM) to model the interactions between fundamental particles, simulations of processes resulting in the production of Higgs bosons were done for different centre of mass energies of the CERN Large Hadron Collider (LHC). The results from these simulations were then compared to actual data obtained at the ATLAS and CMS experiments and it was found...
Stefan Erich Von Buddenbrock
(University of the Witwatersrand (ZA))
12/02/2015, 12:20
The Standard Model of particle physics is, so far, the best description of elementary particle dynamics and interactions. However, while it explains many of the phenomena we observe in experiment, there are shortcomings. It is therefore essential for particle physicists to have a clear understanding of the theory which makes up the Standard Model, as well as possible additions to the Standard...
Claire Lee
(University of Johannesburg (ZA))
12/02/2015, 14:00
Luis March Ruiz
(University of the Witwatersrand (ZA))
12/02/2015, 14:20
The missing transverse energy plays a really important role in reconstructing events produced at hadron colliders. Undetectable particles, such as neutrinos, pass through the matter with a negligible probability of interaction. Hence, no direct evidence of them can be measured in a general purpose detector, as ATLAS. However, the total momenta in the transverse plane to the beam axis has to be...
Ammar Abdalgabar
(University of Witwatersrand)
12/02/2015, 14:40
Even if the unification and supersymmetry breaking scales are around 10^6 to 10^{9} TeV, a large A_t coupling may be entirely generated at low energies through RGE evolution in the 5D MSSM. Independent of the precise details of supersymmetry breaking, we take advantage of power law running in five dimensions and a compactification scale in the 10-10^3 TeV range to show how the gluino mass may...
Guillermo Nicolas Hamity
(University of the Witwatersrand (ZA))
12/02/2015, 15:00
The neutral CP-dd boson A is predicted by many models with an extended Higgs sector. Searching for the A boson in the sensitive Zh decay, where h is assumed to be the LHC discovered Higgs boson, within the mass range of 220-1000 GeV offers a gateway to find physics beyond the Standard Model. A search for a gluon-fusion-produced A in the decay to Zh, with a final state of two light leptons and...
Ferdinand Wilhelm Schenck
(University of Cape Town (ZA))
12/02/2015, 15:20
measurement was made of the exclusive production of muon pairs in 4.5 fb−1 of ATLAS data collected at a centre of mass energy of 7 TeV. Exclusive interactions in this context occur when two charged hadrons interact via photon exchange and escape the interaction intact while at the same time creating particle anti-particle pair. This work will search for exclusive interactions in proton-proton...
Harshna Jivan
(University of the Witwatersrand (ZA))
12/02/2015, 16:10
The Tile Calorimeter of the ATLAS detector, is a hadronic calorimeter responsible for detecting hadrons as well as accommodating for the missing transverse energy that result from the p-p collisions within the LHC. Plastic scintillators form an integral component of this calorimeter due to their ability to undergo prompt fluorescence when exposed to ionising particles. The scintillators...
Chad Dean Pelwan
(University of the Witwatersrand (ZA))
12/02/2015, 16:30
In an attempt to understand the effects of ionizing radiation on various scintillation plastics, a number of studies are currently under way with a hope that favourable properties of scintillator plastics, such as high light output and fast decay time, can be optimized. In this investigation, MBTS irradiated plastics that were situated on the TileCal of the ATLAS detector at CERN were sent to...
Shell-May Liao
(University of the Witwatersrand)
12/02/2015, 16:50
The influence of radiation on the light transmittance of plastic scintillators was studied experimentally. The high optical transmittance property of plastic scintillators makes them essential in the effective functioning of the tile calorimeter of the ATLAS detector at CERN. This significant role played by the scintillators makes this research imperative in the movement towards the upgrade of...
Thokozani Khumalo
(University of the Witwatersrand)
12/02/2015, 17:10
Semiconductor materials, such as silicon (Si) and germanium (Ge) form an important part in modern electronics. From these materials, far—reaching electronic devices, transistors and diodes for instance have been realized. The application of these devices span a wide spectrum, from domestic to research (in particle accelerators and detectors, such as the large hadron collider (LHC) and ATLAS,...
Chamunorwa Oscar Kureba
(University of the Witwatersrand (ZA))
13/02/2015, 09:00
The Large Hadron Collider (LHC) is scheduled to be upgraded in the year 2022, in order to increase its instantaneous luminosity. The High Luminosity LHC, also referred to as upgrade Phase-II, means an inevitable complete re-design of the read-out electronics in the Tile Calorimeter of the ATLAS detector, in which the completed new read-out architecture is expected to have the front-end...
Matthew Spoor
(University of the Witwatersrand (ZA))
13/02/2015, 09:20
M. Spoor
The LHC has been undergoing its first long shut down (LS1) in preparation for the Phase–II upgrade scheduled for 2024. Once upgraded the LHC will begin its high Luminosity Phase, increasing the beam luminosity by a factor of 5 to 7. The upgrade requires a redesign of the electronics systems of the ATLAS tile hadronic calorimeter (TileCal) and thus a hybrid demonstrator system is in...
Mitchell Arij Cox
(University of the Witwatersrand (ZA))
13/02/2015, 09:40
Modern Big Science projects such as the Large Hadron Collider at CERN generate enormous amounts of raw data which presents a serious computing challenge. After planned upgrades in 2022, the data output from the ATLAS Tile Calorimeter will increase by 200 times to over 40 Tb/s! Advanced and characteristically expensive Digital Signal Processors (DSPs) and Field Programmable Gate Arrays (FPGAs)...
Daniel Ohene-Kwofie
(University of the Witwatersrand (ZA))
13/02/2015, 10:00
Advances in new technologies, high speed and more accurate instrumentation for data acquisition have given rise to the accumulation of massively large amount of data typically referred to as Big-Data. The ATLAS detector, operated at the Large Hadron Collider (LHC) records proton-proton collisions at CERN every 50ns resulting in a sustained data flow up to Pb/s.
The upgraded Tile Calorimeter...
Marc Sacks
(University of Witwatersrand)
13/02/2015, 10:50
After the 2022 upgrades, the ATLAS detector will be generating raw data at a rate of about 40 TB/s. The ATLAS triggering system thus presents an opportunity to explore the use of general-purpose computing on graphics processing units (GPGPU). GPUs could be used in both first and high level triggering (HLT) systems; in the former to reduce power consumption and increase event selection...
Joshua Wyatt Smith
(University of Cape Town (ZA))
13/02/2015, 11:10
The ATLAS software framework (ATHENA) is large and dynamic, comprised of around 6.5 million lines of code. It is built in the NICOS system which uses tools and scripts located and tuned for the LXPLUS and AFS systems. Furthermore, the constraints placed on the hardware that the software is based is limiting. A local build of ATHENA is somewhat difficult on a traditional computer and even more...
Kehinde Gbenga Tomiwa
(University of the Witwatersrand (ZA))
13/02/2015, 11:30
Today's large-scale science projects have been always encountered challenges in processing large data flow from the experiments, the ATLAS detector records proton-proton collisions provided by the LHC at CERN every 50 ns which results in a total data flow of 10 Pb/s, the SKA is a radio telescope consisting of several thousand antennae, the data rates from the individual antenna at SKA results...
Robert Graham Reed
(University of the Witwatersrand (ZA))
13/02/2015, 11:50
ATLAS is a general-purpose detector at the Large Hadron Collider at CERN, Switzerland. The current Detector Control System (DCS) consists of a highly distributed system running over many servers using the SCADA product called PVSS OA. The DCS provides multiple functionality such as automated control procedures, efficient error recognition with handling, managing communication with external...
