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Grönqvist, Hanna. "Fluctuations in High-Energy Particle Collisions." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS155/document.
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Nous étudions des fluctuations qui sont omniprésentes dans des collisions entre particules aux hautes énergies. Ces fluctuations peuvent être de nature classique ou quantique et nous allons considérer ces deux cas. D'abord, nous étudions les fluctuations quantiques qui sont présentes dans des collisions entre protons. Celles-ci sont calculables en théorie quantique des champs, et nous allons nous concentrer sur une certaine classe de diagrammes dans ce cadre. Dans un second temps nous allons étudier des fluctuations qui sont présentes dans des collisions entre particules plus lourdes que le proton. Celles-ci sont décrites par les lois quantiques de la nature qui donnent les positions des nucléons dans le noyau, ou bien des fluctuations classiques, d'origine thermique, qui affectent l'évolution hydrodynamique du milieu produit dans une collision. Les fluctuations dans des collisions entre protons peuvent être calculées analytiquement jusqu'à un certain ordre en théorie quantique des champs. Nous allons nous concentrer sur des diagrammes à une boucle, d'une topologie donnée. Ces diagrammes aux boucles donnent des intégrales, qui typiquement sont difficiles à calculer. Nous allons démontrer comment des outils des mathématiques modernes peuvent être utilisés pour faciliter leur évaluation. En particulier, nous allons étudier des relations entre des coupures d'un diagramme, la discontinuité à travers d'un branchement et le coproduit. Nous allons démontrer comment l'intégrale originale peut être reconstruit à partir de l'information contenue dans le coproduit. Nous nous attendons à ce que ces méthodes seront utiles pour le calcul des diagrammes avec des topologies plus difficiles et ainsi aident au calcul des nouvelles amplitudes de diffusion. A la fin, nous étudions les deux types de fluctuations qui ont lieu dans des collisions entre ions lourds. Celles-ci sont liées soit à l'état initial de la matière, soit à l'état intermédiaire produit dans une telle collision. Les fluctuations de l'état initial ont été mesurées expérimentalement, et on voit qu'elles donnent lieu à des non-Gaussianités dans le spectre final de particules. Nous allons démontrer comment ces non-Gaussianités peuvent être comprises comme des positions et des énergies d'interaction aléatoires des 'sources' dans les noyaux entrant en collision. En plus, nous étudions le bruit hydrodynamique dans le milieu produit juste après une collision. Le comportement de ce milieu est celui d'un fluide à basse viscositéWe study fluctuations that are omnipresent in high-energy particle collisions. These fluctuations can be either of either classical or quantum origin and we will study both. Firstly, we consider the type of quantum fluctuations that arise in proton-proton collisions. These are computable perturbatively in quantum field theory and we will focus on a specific class of diagrams in this set-up. Secondly, we will consider the fluctuations that are present in collisions between nuclei that can be heavier than protons. These are the quantum laws of nature that describe the positions of nucleons within a nucleus, but also the hydrodynamic fluctuations of classical, thermal origin that affect the evolution of the medium produced in heavy-ion collisions. The fluctuations arising in proton-proton collisions can be computed analytically up to a certain order in perturbative quantum field theory. We will focus on one-loop diagrams of a fixed topology. Loop diagrams give rise to integrals that typically are hard to evaluate. We show how modern mathematical methods can be used to ease their computation. We will study the relations among unitarity cuts of a diagram, the discontinuity across the corresponding branch cut and the coproduct. We show how the original integral corresponding to a given diagram can be reconstructed from the information contained in the coproduct. We expect that these methods can be applied to solve more complicated topologies and help in the computation of new amplitudes in the future. Finally, we study the two types of fluctuations arising in heavy-ion collisions. These are related either to the initial state or the intermediate state of matter produced in such collisions. The initial state fluctuations are experimentally observed to give rise to non-Gaussianities in the final-state spectra. We show how these non-Gaussianities can be explained by the random position and interaction energy of `sources' in the colliding nuclei. Furthermore, we investigate the effect of hydrodynamical noise in the evolution of the medium produced just after a collision. This medium behaves like a fluid with a very low viscosity, and so the corresponding evolution is hydrodynamical
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Droubi, Mohamad Ghazi. "Monitoring particle impact energy using acoustic emission technique." Thesis, Heriot-Watt University, 2013. http://hdl.handle.net/10399/2661.
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The estimation of energy dissipated during multiple particle impact is a key aspect in evaluating the abrasive potential of particle-laden streams. A systematic investigation of particle impact energy using acoustic emission (AE) measurements is presented in this thesis with experiments carried out over a range of particle sizes, particle densities and configurations. A model of the AE impact time series is developed and validated on sparse streams where there are few particle overlaps and good control over particle kinetic energies. The approach is shown to be robust and extensible to cases where the individual particle energies cannot be distinguished. For airborne particles, a series of impact tests was carried out over a wide range of particle sizes (from 125 microns to 1500 microns) and incident velocities (from 0.9 ms-1 to 16 ms-1). Two parameters, particle diameter and particle impact speed, both of which affect the energy dissipated into the material, were investigated and correlated with AE energy. The results show that AE increases with the third power of particle diameter, i.e. the mass, and with the second power of the velocity, as would be expected. The diameter exponent was only valid up to particle sizes of around 1.5mm, an observation which was attributed to different energy dissipation mechanisms with the higher associated momentum. The velocity exponent, and the general level of the energy were lower for multiple impacts than for single impacts, and this was attributed to particle interactions in the guide tube and/or near the surface leading to an underestimate of the actual impact velocity in magnitude and direction. In order to develop a model of the stream as the cumulation of individual particle arrival events, the probability distribution of particle impact energy was obtained for a range of particle sizes and impact velocities. Two methods of time series processing were investigated to isolate the individual particles arrivals from the background noise and from particle noise associated with contact of the particles with the target after their first arrival. For the conditions where it was possible to resolve individual impacts, the probability distribution of particle arrival AE energy was determined by the best-fit lognormal probability distribution function. The mean and variance of this function was then calibrated against the known nominal mass and impact speed. A pulse shape function was devised for the target plate by inspection of the records, backed up by pencil lead tests and this, coupled with the energy distribution functions allowed the iv records to be simulated knowing the arrival rate and the nominal mass and velocity of the particles. A comparison of the AE energy between the recorded and simulated records showed that the principle of accumulating individual particle impact signatures could be applied to records even when the individual impacts could not be resolved. For particle-laden liquid, a second series of experiments was carried out to investigate the influence of particle size, free stream velocity, particle impact angle, and nominal particle concentration on the amount of energy dissipated in the target using both a slurry impingement erosion test rig and a flow loop test rig. As with airborne particles, the measured AE energy was found overall to be proportional to the incident kinetic energy of the particles. The high arrival rate involved in a slurry jet or real industrial flows poses challenges in resolving individual particle impact signatures in the AE record, hence, and so the model has been further developed and modified (extended) to account for different particle carrier-fluids and to situations where arrivals cannot necessarily be resolved. In combining the fluid mechanics of particles suspended in liquid and the model, this model of AE energy can be used as a semi-quantitative diagnostic indicator for particle impingement in industrial equipments such as pipe bends.
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Schimann, Hubert C. R. "Force and Energy Measurement of Bubble-Particle Detachment." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9963.
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Possibilities for increasing the upper limit of floatable particle sizs in the froth flotation process have been examined since the early beginnings of mineral flotation. The economic implications of such an incresae are far ranging; from decreased grinding costs and increased recoveries to simplified flow-sheet design and increased throughput, all leading to increased revenue. Bubble-particle detachment has been studied to better understand the factors influencing the strength of attachment and the energies involved. Direct measurements of bubble particle detachment were performed using a hanging balance apparatus (KSV Sigma 70 tensiometer) and using a submerged hydrophobic plate in water. Three experiments were used; direct force measurement of bubble-particle detachment, detachment force and energy of a bubble from a submerged hydrophobic plate, and detachment force and energy of a cetyltrimethylammonium bromide coated silica sphere from a flat bubble. Octadecyltrichlorosilane was used as a hydrophobic coating in the first two experimental methods. These experiments were recorded with a CCD camera to identify the detachment processes involved. Energies for both methods were calculated and divided into the two main steps of the detachment process: Three-Phase-Contact pinning and three phase contact line sliding. The first step represents the energy barrier which must be overcome before detachment can begin. It is directly related to contact angle hysteresis. Detachment occurs during the second step, where the solid-vapor interface is replaced by solid-liquid and liquid-vapor. This step corresponds to the work of adhesion. The effects of surface tension, contact angle and hysteresis were well demonstrated with the three experimental methods. Good correlation was found between theoretical work of adhesion and measured energies.Master of Science
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Olvegård, Maja. "Emittance and Energy Diagnostics for Electron Beams with Large Momentum Spread." Doctoral thesis, Uppsala universitet, Högenergifysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198080.
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Following the discovery of the Higgs-like boson at the Large Hadron Collider, there is demand for precision measurements on recent findings. The Compact Linear Collider, CLIC, is a candidate for a future linear electron-positron collider for such precision measurements. In CLIC, the beams will be brought to collisions in the multi-TeV regime through high gradient acceleration with high frequency RF power. A high intensity electron beam, the so-called drive beam, will serve as the power source for the main beam, as the drive beam is decelerated in special structures, from which power is extracted and transfered to the main beam. When the drive beam is decelerated the beam quality deteriorates and the momentum spread increases, which makes the beam transport challenging. Dedicated diagnostics to monitor the momentum profile along each bunch train and transverse profile diagnostics will be needed to guarantee the reliability of the decelerator and consequently the power source of the main beam acceleration. A test facility, CTF3, has been constructed at CERN to validate key technical aspects of the CLIC concept. The beam quality in the decelerator will be investigated in the test beam line, TBL, where several power extraction structures reduce the drive beam energy by up to 55%. At the same time, the single-bunch rms energy spread grows from the initial value of 1% to almost 6%. To monitor the parameters of such a beam is challenging but crucial for the optimization of the beamline. In this thesis we report on progress made on adapting generally used methods for beam profile measurements to the demanding conditions of a wide momentum profile. Two detector technologies are used for measuring transverse profile and momentum profile and we discuss the performance of these instruments, in the view of the large momentum spread and with the outlook towards equivalent beam profile monitors in the CLIC decelerator.
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Ding, Ailin. "Particle Assisted Wetting." Doctoral thesis, Universitätsbibliothek Chemnitz, 2007. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200701494.
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Die Benetzbarkeit und Nichtbenetzbarkeit von Oberflächen durch eine Flüssigkeit sind faszinierende und wichtige Phänomene in Wissenschaft und Technologie. Jüngst wurde entdeckt, dass Partikel die Benetzung einer Wasseroberfläche durch ein Öl unterstützen können. Es wurde eine Theorie entwickelt, das Prinzip der zu beschreiben. In der vorliegenden Doktorarbeit wurde diese Theorie im Experiment sowohl qualitativ als auch quantitativ untersucht, wobei zwei Arten von Kieselgelpartikeln Verwendung fanden. Mit Hilfe einer Reihe unregelmäßig geformter Partikel mit variierender Hydrophobie wurde der Einfluss der Oberflächenhydrophobie der Partikel auf die partikel-assistierte Benetzung untersucht. Es wurde herausgefunden, dass die Partikel mit höchster Hydrophilie Linsen aus reinem Öl bilden, während die Partikel in die Wasserphase abtauchen. Die Partikel mit größter Hydrophobie hingegen bewirken die Ausbildung von kleinen Bereichen, in denen Öl und Partikel eine stabile homogene Schicht formen. Für Partikel mit mittlerer Hydrophobie wurden beide Phänomene beobachtet. Diese drei verschiedenen Beobachtungen bestätigen, dass die Oberflächenhydrophobie der Partikel das Benetzungsverhalten des Öls auf der Wasseroberfläche bestimmen. Für die unregelmäßig geformten Partikel war aufgrund des unbekannten Kontaktwinkels ein direkter Vergleich zur Theorie nicht möglich. Um die Theorie quantitativ zu prüfen, wurden sphärische Partikel synthetisiert und ihre Oberflächen mit Hilfe von zehn Silanisierungsmittel modifiziert. Anschließend wurde ein Vergleich der experimentellen Ergebnisse mit dem entsprechenden theoretischen Phasendiagramm durchgeführt. Die Untersuchungen zeigten, dass die theoretischen Vorhersagen zum Großteil mit den experimentellen Ergebnissen übereinstimmen. Es wurden alle Fälle der Benetzung beobachtet, die auch in der theoretischen Beschreibung berücksichtigt wurden. Darüber hinaus wurden auch Abweichungen von der Theorie festgestellt. Haben die Partikel ähnliche Affinitäten zur Luft/Öl- und Öl/Wasser-Grenzfläche, hängt die Beschaffenheit der Benetzungsfilme zusätzlich vom Oberflächendruck ab. Deshalb könnte es notwendig sein, die einfache Theorie zu erweitern um den beschriebenen Beobachtungen Rechnung zu tragenWetting and de-wetting of surfaces by a liquid are fascinating and important phenomena in science and technology. Recently, it was discovered that particles can assist the wetting of a water surface by an oil, and a theory describing the principle behind particle assisted wetting was developed. In this thesis, the theory was experimentally investigated qualitatively and quantitatively by using two series of silica particles. The influence of the surface hydrophobicity of the particles on particle assisted wetting was investigated by a series of irregular shaped particles with varying hydrophobicity. By applying mixtures of particles and oil to a water surface, it was found that for the most hydrophilic particles, only lenses of pure oil formed, with the particles being submerged into the aqueous phase. The most hydrophobic particles helped to form patches of stable homogenous mixed layers composed of oil and particles. For particles with intermediate hydrophobicity, lenses and patches of mixed layers were observed. These three different observations verified that the hydrophobicity of the particle surface determines the wetting behaviour of the oil at the water surface. For the irregular shaped particles with unknown contact angles with liquid interfaces, no direct comparison to the theory was possible. To test the theory quantitatively, a series of spherical particles was synthesized and their surfaces were modified by ten kinds of silane coupling agents; then the experimental results were compared with the corresponding theoretical phase diagram. It indicated that the theory agrees at large with the experimental results. All scenarios of wetting layers taken into account in the theoretical description were observed. In the fine print, deviations from the theory were also observed. If the particles have similar affinities to air/oil and oil/water interfaces, the experimentally observed morphology of the wetting layers depends in addition on the surface pressure. It might therefore be necessary to extend the simple theoretical picture to take these observations into accounts
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Webb, S. "Unusual effects in particle diffraction." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234226.
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Jiang, Min. "Energy based dissolution simulation using smoothed particle hydrodynamic sampling." Thesis, Bournemouth University, 2016. http://eprints.bournemouth.ac.uk/24744/.
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Fluid simulation plays an important role in Computer Graphics and has wide applications in film and games. The desire for an improved physically-based fluid simulation solver has grown hand in hand with the advances made in Computer Graphics. Interesting fluid behaviours emerge when solid objects are added to a simulation: when fluid and solid make contact, they do not only have a physical interaction (e.g., buoyancy), but also a chemical reaction (e.g., dissolution) under the right conditions. Dissolution is one of the most common natural phenomena which is an important visual effect in fluid simulation. However this phe- nomenon is difficult to simulate due to the complexity of the behaviour and there are only few techniques available. A novel unified particle-based method for approximating chemical dis- solution is introduced in this thesis which is fast, predictable and visually plausible. The dissolution algorithm is derived using chemical Collision Theory and integrated into a Smoothed Particle Hydrodynamics (SPH) framework. The Collision Theory of chemistry is used as an analogy to the dissolution process modelling. Dissolution occurs when solute submerges into solvent. Physical laws govern the local excitation of so- lute particles based on the relative motion with solvent particles. When the local excitation energy exceeds a user specified threshold (activation energy), the particle will be dislodged from the solid. Unlike previous methods, this dissolution model ensures that the dissolution result is in- dependent of solute sampling resolution. A mathematical relationship is also established between the activation energy, the interfacial surface area, and the total dissolution time — allowing for intuitive artistic con- trol over the global dissolution rate. Applications of this method are demonstrated using a number of practical examples, including antacid pills dissolving in water and hydraulic erosion of non-homogeneous ter- rains. Both solutes and solvents are represented by particles, and the dis- tribution of the solute particles greatly affects the plausibility of the dissolution simulation. An even but stochastic distribution of particles on both the surface and within the volume of the solute is essential for a good visual simulation of the dynamic process of dissolution. A new iterative particle-based sampling method derived from SPH is introduced in this thesis which can generate a range of blue noise pat- terns and is computationally efficient, controllable and has a variety of applications. This approach resolves many of the limitations of classic blue noise methods, such as the lack of controllability or varying the dis- tribution properties of the generated samples. Fast sampling is achieved in general dimensions for curves, surfaces and volumes. By varying a sin- gle parameter, the proposed method can generate a range of controllable blue noise samples with different distribution properties which are suit- able for various applications such as adaptive sampling and multi-class sampling. The SPH sampling approach is used for solute particle distribution which guarantees a predictable and smooth dissolution process thanks to the evenly distributed density and also gives the user control of the volume change during the phase transition. The proposed SPH sampling method achieves better visual effects compared with simple grid sampling and other blue noise sampling methods. Our energy based dissolution simulation with SPH sampled solute and solvent ensures that the dissolution behaviour is physically and chemi- cally plausible, while supporting features such as object separation and sharp feature rounding. The simulation is parallelized per particle on a GPU to enhance the performance.
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Wilkason, Thomas Frederick Jr. "Exclusive cone jet algorithms for high energy particle colliders." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100326.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 59-62).
In this thesis, I develop an exclusive cone jet algorithm based on the principles of jet substructure and demonstrate its use for physics analyses at the Large Hadron Collider. Based on the event shape N-jettiness, this algorithm, called "XCone," partitions the event into a fixed number of conical jets of size RO in the rapidity-azimuth plane. This algorithm is designed to locate substructure independent of momentum, allowing accurate resolution of jets at both low and high energy scales. I present three potential analyses using XCone to search for heavy resonances, Higgs bosons, and top quarks at various momenta and show that it reconstructs these particles with efficiencies between 60% and 80% without any additional substructure techniques, and maintains this efficiency over a wide kinematic range. This algorithm provides many key advantages over traditional jet algorithms that make it appealing for use at the LHC and other high energy particle colliders.
by Thomas Frederick Wilkason, Jr.
S.B.
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Bylin, Johan. "Analysis of a spin-particle tunnelling junction." Thesis, Uppsala universitet, Materialteori, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-254984.
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This project is to analyse the energy spectrum of a spin-molecular tunnelling junction which is composed of molecules confined between two conducting metallic leads. By letting a continuous stream of electrons flow across the junction the molecules can interact with each other with an indirect force called exchange interaction, and those exchange interactions which are of interest in this project are described by models called the Heisenberg, the Ising and the Dzyaloshinski-Moriya models. The molecules may also interact with themselves anisotropically and if there is an external magnetic field there will be yet another kind of interaction. The goal of this project is to see the contribution of all these spin interactions and how they affect the resulting energy spectrum under the variation of the junction's chemical potential and the voltage bias between the leads. This project is of a theoretical nature where the models are analytically adapted for a restricted scenario and is later on numerically calculated to be graphed and analysed. The models are restricted to only consider molecules of same spin and approximated to only consider interactions between closest neighbouring molecules. The results are composed of both analytically derived energy values and numerical computed values which show that there exists certain critical values of the variation parameters which naturally splits the ground state of the system and that the self-interaction may further split the degenerate ground state. A possible outcome of these result could be the possibility to control the magnetic order of the molecules to either be locked in an anti-ferromagnetic configuration or be easily mixed by manipulating the chemical potential or the voltage bias.Detta projekt handlar om att analysera energispektrumet från en spinn-molekyl-tunnelkor-sning som består av molekyler instängda mellan två ledande metaller. När en kontinuerlig elektronström korsar tunnelkorsningen så kan molekylerna växelverka med varandra via en indirekt kraft kallad utbytesinteraktion, och de utbytesinteraktioner som är relevanta i denna uppställning beskrivs av de så kallade Heisenberg-, Ising- och Dzyaloshinski-Moriya-modellerna. Molekylerna kan också växelverka med sig själva anisotropt och om det finns ett externt magnetfält så tillkommer ytterligare en interaktionsterm. Målet för detta projekt är att se hur alla dessa spinnbidrag påverkar det slutliga energispektrumet under variation av korsningens kemiska potential och spänningen mellan metalledarna. Projektet är teoretiskt lagt på så sätt att modellerna är analytiskt anpassade för ett begränsat scenario samt att de är numeriskt beräknade så att energispektrumet kan plottas i grafer och analyseras. Modellerna är begränsade för molekyler av samma spinn och är approximerade så att endast närmsta-granne-interaktioner är beaktade. Resultaten är uppdelade i både analytiskt framtagna energivärden samt numeriskt beräknande energinivåer och båda visar att det finns kritiska värden på variationsparametrarna som automatiskt delar grundtillståndet för systemet samt att självinteraktionerna ytterligare kan dela det degenererade grundtillståndet. Ett möjligt utfall av dessa resultat är att de kan användas till att kontrollera systemets magnetiska ordning på så sätt att det antingen är låst i en antiferromagnetisk konfiguration eller med enkelhet kan mixas genom att ändra den kemiska potentialen eller spänningen mellan metalledarna.
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Blanco-Pillado, José Juan. "Topological defects and ultra-high energy cosmic rays /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2001.
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Thesis (Ph.D.)--Tufts University, 2001.Adviser: Alexander Vilenkin. Submitted to the Dept. of Physics. Includes bibliographical references (leaves 108-114). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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Hendricks, Khalida. "Jets + Missing Energy Signatures At The Large Hadron Collider." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563367019906869.
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Phelps, Patrick. "THE LUX DARK MATTER EXPERIMENT: DETECTOR PERFORMANCE AND ENERGY CALIBRATION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1404908222.
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Papaefstathiou, Andreas. "Phenomenological aspects of new physics at high energy hadron colliders." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/239399.
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This thesis contains studies of phenomenological aspects of new physics at hadron colliders, such as the Large Hadron Collider (LHC). After a general introduction in chapter 1, in chapter 2 we outline the main features of the Standard Model (SM) of particle physics and the theoretical motivations for going beyond it. We subsequently provide brief descriptions of a few popular models that aim to solve the issues that arise within the SM. In chapter 3 we describe the general Monte Carlo method for evaluating multidimensional integrals and show how it can be used to construct a class of computational tools called Monte Carlo event generators. We describe the main generic features of event generators and how these are implemented in the HERWIG++ event generator. By applying resummation techniques, we provide, in chapter 4, analytical calculations of two types of hadron collider observables. The first, global inclusive variables, are observables that make use of all measured particle momenta and can provide useful information on the scale of new physics. The second observable is the transverse energy of the QCD initial state radiation (ET ), associated with the either Drell-Yan gauge boson production or Higgs boson production. In both cases we provide comparisons to results obtained from Monte Carlo event generators. In chapter 5 we examine two well-motivated models for new physics: one of new heavy charged vector bosons (W prime), similar to the SM W gauge bosons, and a model motivated by strong dynamics electroweak symmetry breaking that contains new resonances, leptoquarks, that couple primarily to quarks and leptons of the third generation. In the prior model, we improve the current treatment of the W' by considering interference effects with the SM W and construct an event generator accurate to next-to-leading order which we use to conduct a phenomenological analysis. For the leptoquark model, starting from an effective Lagrangian for production and decay, we provide an implementation in the HERWIG++ event generator and use it to form a strategy for mass reconstruction. The thesis ends with some conclusions and suggestions for extensions of the work presented. Further details and useful formulæ are given in the appendices.
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Marsh, Colin. "Theoretical aspects of dissipative particle dynamics." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244720.
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Tran, Ngoc Quang. "Optimisation of indoor environmental quality and energy consumption within office buildings." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/64114/1/Ngoc%20Quang_Tran_Thesis.pdf.
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This research investigated airborne particle characteristics and their dynamics inside and around the envelope of mechanically ventilated office buildings, together with building thermal conditions and energy consumption. Based on these, a comprehensive model was developed to facilitate the optimisation of building heating, ventilation and air conditioning systems, in order to protect the health of their occupants and minimise the energy requirements of these buildings.
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Massacand, Christophe Maurice Jean-Baptiste. "Particle production by tidal forces and the energy-momentum tensor /." [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10359.
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Rodriguez, Justo. "Optically induced inter-particle forces and Inter-chromophore energy transfer." Thesis, University of East Anglia, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514320.
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Sritragool, Kunlapaporn. "Modification of Rubber Particle filled Thermoplastic with High Energy Electrons." Doctoral thesis, Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-201000954.
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In present study, high energy electrons were used to modify blends based on RP and PP under two conditions: stationary and in-stationary conditions. Modification of blend under stationary condition is a process which is established in industrial application and where required absorbed dose is applied to form parts (after molding) at room temperature and in solid state. On the contrary, the modification of blend with high energy electrons under in-stationary condition is a new process (electron induced reactive processing) where required absorbed dose is applied to a molten state during melt mixing process. The modification of blend based on RP and PP under stationary condition resulted in slightly enhancement of tensile properties while the modification of this blend under in-stationary condition resulted in deterioration of tensile properties due to degradation of the PP matrix. Thus, special grafting agent (GA) is required for improving the tensile properties. The effect of different GAs on tensile, thermal, dynamic mechanical as well as morphological properties and melt flow properties of blends based on RP and PP were determined. The optimum absorbed dose for modification of blend based on RP and PP under both conditions was evaluated. In addition, the effect of treatment parameters of electron induced reactive processing was investigated.
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Walker, W. R. "Particle and energy creation in curved space ?quantum field theory." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354407.
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Baldi, Sandro. "Energy dissipation measurements in stirred vessels with particle image velocimetry." Thesis, King's College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409634.
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Patrick, Richard J. II. "The search for supersymmetry in particle physics." Thesis, California State University, Long Beach, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1527406.
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Experimental high energy physics (HEP) techniques are applied to accurate simulated collider data in search for existence or exclusion of supersymmetric (SUSY) particles. Supersymmetry is a leading candidate to resolve the hierarchy problem in particle physics as well as offer a stable dark matter candidate. Techniques and practices are explored and applied to the leptonic decay process production followed by and where is the proton, is the chargino, , are neutralinos and , are the standard model W and Higgs Bosons respectively. Signal yields are in general agreement with other researchers and ranged from 0.5 to 62.6 events. Reduction in the background to signal ratio is demonstrated through isolating the SUSY process and applying theoretical knowledge of the signal and associated dominant backgrounds. Results from this study establish procedures for future work with actual data, offer a benchmark for this specific leptonic decay process and may motivate variable selection and cut criteria choices in future analysis of similar signal processes.
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Feige, Ilya Eric Alexander. "Factorization and Precision Calculations in Particle Physics." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467340.
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We state and prove to all orders in perturbation theory a factorization theorem in Quantum Chromodynamics that concisely describes the separation of the physics associated with jet formation from that associated with the hard-scattering in high-energy particle collisions. We show how the factorization theorem, which provides an equality between amplitudes in gauge theories, can be readily applied to precision calculations of cross-sections. In the resulting factorized cross sections, the components relevant to jet production are universal and perturbatively calculable. Their renormalization group evolution can be used to sum large logarithms of scale ratios to all orders in perturbation theory, thus enabling quantitive predictions in the regime of disparate scales relevant to many important collider-physics observables. As an application, we calculate the observable 2-subjettiness at next-to-next-to-next-to-leading-logarithmic order for the decay of boosted heavy color-singlet particles such as Electroweak bosons. Our calculation is the first analytic calculation of a jet substructure observable.Physics
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Nesbitt, Brian. "Heavy-particle collisions." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301028.
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Tremblay, Luc 1969. "Effects of a particle spontaneously breaking Lorentz invariance." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38526.
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In this thesis, we add a new vectorial particle to the standard model, a new particle that has the special property of having a vacuum state breaking Lorentz invariance and, therefore, CPT invariance. At the level of energy of the world we live in, this particle is expected to be in this vacuum state and we therefore should see around us some phenomenon that do not respect Lorentz invariance that comes from the interaction of this vectorial particle with ordinary matter. This thesis is presented in two parts. In the first part, we write every possible term involving our new vectorial field with ordinary matter while, in the second part, we calculate the effects of some of those terms and look at any experimental evidence for the calculated effects.
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Allport, P. P. "High energy neutrino scattering at low Q'2." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376865.
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Kistler, Matthew David. "The Theory and Phenomenology of the High-Energy and Transient Universe." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274474065.
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Liu, Hongqin 1956. "Simulation of a plasma particle generator." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31571.
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The goal of this research was to simulate the nucleation and particle growth in a tubular plasma particle generator and investigate the effects of various entrance and boundary conditions on the particle size distribution and production rate.The fluid flow is laminar and its domain is two-dimensional axi-symmetric and a radial quench gas injection is introduced. The method of moments was used to model the particle generation and growth starting with the dynamic aerosol equation and the assumption of a log-normal distribution function. The governing equations are solved numerically and the velocity, concentration, temperature, particle size and density profiles are obtained for various entrance and boundary conditions.
The following conclusions were reached: increasing the length of the generator tube or metal concentration gives more product, larger particle size and narrower size distribution; higher quench gas injection rates or entrance flow rate produces finer particles with a broader size distribution; increasing entrance temperature leads to smaller particles with narrower size distribution.
In addition, for a quick prediction, an artificial neural network (ANN) model was used. The ANN was trained with the data from the numerical simulations. Within the ranges of conditions examined, the output can be obtained in few seconds rather than several hours needed in the original simulations.
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Martineau, Patrick. "On particle production and brane cosmology." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80328.
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Particle production is examined within the context of brane cosmology. Non-perturbative formalisms are reviewed and employed to calculate particle number (or the energy density associated with such particles) produced in dynamical spacetimes arising from various brane configurations. Specifically, reheating from tachyon condensation, the quantum instability of a class of S-brane spacetimes, and particle production on an orbiting brane-antibrane system are investigated.
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Barbot, Cyrille. "Super-heavy X-particle decay and ultra-high energy cosmic rays." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969379846.
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Kavanagh, Andrew John. "Energy deposition in the lower auroral ionosphere through energetic particle precipitation." Thesis, Lancaster University, 2002. http://eprints.lancs.ac.uk/6758/.
Full textAbstract:
Ground-based imaging and broad beam riometers are used in conjunction with ionospheric radars and satellite instruments to investigate high-energy precipitation in the auroral zone. There are two dominant precipitation regimes in the auroral zone which lead to enhanced high frequency radio absorption; high energy electrons (> keV) from closed field lines, and protons (> MeV) penetrating from the solar wind following solar flares. Much of the work in this thesis uses data from riometers in Fennoscandia to measure the extent and movement of energetic precipitation from both sources. A case study of dayside absorption combines data from the imaging riometer with radar and satellite observations leading to an estimation of the energy of precipitation based on the riometer data. Two separate precipitation mechanisms were identified in the case study through the use of satellite particle measurements and ground-based observations of geomagnetic pulsations. The riometer showed varying movements of the absorption patches through the case study and a determination of different dominating particle drift regimes was possible through comparison with coherent HF radar. A statistical analysis of absorption in the imaging riometer field of view is carried out. The absorption is linked to both Kp and solar wind velocity using linear and quadratic fits of the data. The daily variation and distribution of absorption is investigated along with seasonal effects which are shown to be reliant on geomagnetic activity. A study of the large number of solar proton events from 1995 to 2001 inclusive is carried out with particular reference to those that produce significant absorption in the northern hemisphere polar cap (polar cap absorption –PCA). The occurrence of the absorption events is investigated and a simple empirical relationship between the integral proton flux and the absorption observed during geomagnetically undisturbed PCA conditions is developed.
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Forty, R. W. "Charmed particle production and decay in a high energy photoproduction experiment." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47064.
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Crivelli, Dawid Wiesław. "Particle and energy transport in strongly driven one-dimensional quantum systems." Doctoral thesis, Katowice: Uniwersytet Śląski, 2016. http://hdl.handle.net/20.500.12128/5879.
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This Dissertation concerns the transport properties of a strongly–correlated one–dimensional system
of spinless fermions, driven by an external electric field which induces the flow of charges and energy
through the system. Since the system does not exchange information with the environment, the
evolution can be accurately followed to arbitrarily long times by solving numerically the time–dependent
Schrödinger equation, going beyond Kubo’s linear response theory.
The thermoelectric response of the system is here characterized, using the ratio of the induced
energy and particle currents, in the nonequilibrium state under the steady applied electric field. Even
though the equilibrium response can be reached for vanishingly small driving, strong fields produce
quantum–mechanical Bloch oscillations in the currents, which disrupt the proportionality of the currents.
The effects of the driving on the local state of the ring are analyzed via the reduced density matrix of
small subsystems. The local entropy density can be defined and shown to be consistent with the laws of
thermodynamics for quasistationary evolution. Even integrable systems are shown to thermalize under
driving, with heat being produced via the Joule effect by the flow of currents. The spectrum of the
reduced density matrix is shown to be distributed according the Gaussian unitary ensemble predicted by
random–matrix theory, both during driving and a subsequent relaxation.
The first fully–quantum model of a thermoelectric couple is realized by connecting two correlated
quantum wires. The field is shown to produce heating and cooling at the junctions according to the
Peltier effect, by mapping the changes in the local entropy density. In the quasiequilibrium regime, a
local temperature can be defined, at the same time verifying that the subsystems are in a Gibbs thermal
state. The gradient of temperatures, established by the external field, is shown to counterbalance the
flow of energy in the system, terminating the operation of the thermocouple. Strong applied fields lead
to new nonequilibrium phenomena. At the junctions, observable Bloch oscillations of the density of
charge and energy develop at the junctions. Moreover, in a thermocouple built out of Mott insulators, a
sufficiently strong field leads to a dynamical transition reversing the sign of the charge carriers and the
Peltier effect.
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Panella, Comellas J. "Measurement of some charm particle decay branching ratios." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382501.
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Sayeed, Kazi Abu. "Measurement of the Branching Fractions for B0s Resonance Energy." Cincinnati, Ohio : University of Cincinnati, 2008. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1218577440.
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Thesis (Ph. D. )--University of Cincinnati, 2008.Advisors: Alan Schwartz (Committee Chair), Alexander Kagan (Committee Member), Brian Meadows (Committee Member), Michael Sitko (Committee Member), Michael Sokoloff (Committee Member) Title from electronic thesis title page (viewed Oct. 5, 2008). Includes abstract. Keywords: Particle Physics Includes bibliographical references.
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Kohani, Shahab. "3D Trench Detectors for Charged Particle Tracking and Photon Science Applications." Thesis, New York University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10928035.
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Silicon tracking detectors are frequently used in particle collider experiments, as they can provide excellent spatial precision with little material in order to cause minimal track disruption. Due to a progressive increase in collider luminosities, a common trend in these experiments is the need for higher levels of radiation damage resistance. One proposed class of designs for pixel trackers in high luminosity colliders is the Silicon 3D trench detector. The same design can be scaled up for photon science applications.
The work discussed in this dissertation was performed as part of a collaboration between BNL, NYU, CNM and SUNY Stony Brook. The central aim of the work presented here was to evaluate the manufactured 3D trench detector prototypes and study their behavior in detail by performing a series of experimental measurements and TCAD simulations.
An experiment to measure the detector response to an Americium radioactive source was designed and used to study the noise level and charge collection efficiency of detector prototypes. An experimental system which measured the detector response to an infrared laser with computer controlled precision positioning was developed. This system was used to obtain laser pulse response maps of detectors, which in turn were utilized to investigate the dependence of charge collection efficiency of detectors on position, collection time and bias voltage. The same mapping technique was also used to study the change in irradiated detector response.
Detector response was simulated using the Silvaco TCAD Suite. These simulations were used to study depletion in large photon detectors and charge collection in response to laser hits. Approximate simulations of radiation damage were also performed to investigate the behavior of irradiated detectors. Leakage current and capacitance simulations before and after irradiation were also performed and compared to the experimental measurements. While significant variations in detector response between different prototypes were observed during the experiments, simulation results are still capable of explaining the general properties of the detectors. The combination of the simulation and the experimental results provides an understanding of the signal generation process in these detectors.
One observed problem is the large bias currents due to manufacturing surface defects. A double-sided version of the trench detector is proposed to mitigate this problem. Electric fields, depletion region shape and formation, bias voltage and transient current response of these detectors are simulated and compared with those of the standard trench detectors. Computer simulations show that the double-sided detectors also have some performance advantages over the original designs including larger more uniform spatial charge collection efficiency and higher radiation damage resistance. These simulation results and the general insensitivity of the proposed detectors to surface defects make the double-sided detectors worthy of further study.
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Old, Rob. "Asymptotic safety and high-energy scattering at the Large Hadron Collider." Thesis, University of Sussex, 2015. http://sro.sussex.ac.uk/id/eprint/61482/.
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The fascinating idea that in higher-dimensional models the fundamental scale of gravity, the Planck scale, could be as low as the electroweak scale has stimulated a substantial body of work in the past decade. In addition to solving the hierarchy problem, a low quantum gravity scale also o↵ers the exciting prospect that collider experiments become sensitive to the quantum nature of gravity. Quantum gravity signatures include missing energy due to graviton emission, enhancement of standard model reference processes via virtual graviton exchange, or the production and decay of mini black holes. Dedicated searches for all of these are presently under way at the Large Hadron Collider. Previous predictions for colliders have been encumbered by the absence of a complete theory of quantum gravity. However, the recent years have also seen important progress in the understanding of gravity as an asymptotically safe quantum field theory, in which the high-energy behaviour is controlled by an interacting fixed point. The notorious divergences of perturbation theory are thus avoided, and the theory remains predictive at arbitrarily high energies. In this thesis, we investigate the effects of asymptotic safety upon predictions for graviton-mediated processes in higher-dimensions at colliders. We consider single-graviton mediated effects in the Born approximation as well as the multi-graviton exchanges which dominate the forward scattering region at transplanckian energies, as described by the eikonal approximation. Cross sections are derived and a detailed comparison with findings from effective theory is made. Using the PYTHIA event generator we find that for some regions in parameter space quantum gravity effects are enhanced over the semiclassical predictions, as well as over standard model backgrounds. The use of our results to constrain our theory parameters is discussed.
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Wang, Gang 1958 Nov 28. "Transverse energy and charged particle multiplicity in 14.6 GeVc proton-nucleus collisions." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28956.
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Transverse energy and charged particle multiplicity produced in 14.6 GeV/c p + Al and p + Pb collisions have been studied using the E814 set-up at the BNL-AGS. Measurements of d$ sigma$/d$E sb{T}$, d$E sb{T}$/d$ eta$,d$ sigma$/d$N sb{c}$, and d$N sb{c}$/d$ eta$ are presented. From the present data the mean transverse energy per particle is obtained and it is compared to values observed in Si induced collisions at the same energy. In contrast to what is observed in nucleus-nucleus collisions, a very weak correlation is found between the transverse energy and the charged particle multiplicity. These results are compared to the predictions of various theoretical models used to describe heavy-ion collisions. The event generators RQMD and HIJET reproduce well the pseudorapidity distribution of both the transverse energy and charged particle multiplicity, whereas FRITIOF fails to reproduce the measured distributions. Contrary to what had been suggested previously in a Si + A study, the present study shows that the pseudorapidity dependence of charged particle multiplicity distributions do not follow KNO scaling.
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Azizi, Azizollah. "On monopoles in low energy string theory and non-abelian particle trajectories." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4800/.
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This thesis is mainly concerned with monopoles. First, the existence of monopoles and their behaviour in the Yang-Mills-Higgs theories, and in parallel, the instanton solutions of the Yang-Mills fields are explained. One part of this work is about monopoles and instantons in low-energy string theory. A general instanton solution for the heterotic string theory is obtained by using the ADHM construction for the classical subgroups of the string gauge group. In this direction, the embedding of subgroups and a general formula for the dilaton are explained. In the next topic of this part, the i/-monopole and its generalisation to different subgroups of the string gauge group are discussed. In the second part, the motion of the Yang-Mills particles in the Yang-Mills- Higgs fields are studied. Planar orbits are observed for a particle in a monopole field when the Higgs field contribution is neglected. The planar orbits are studied further with some numerical analysis of the equations of motion. By regarding the Higgs field contribution, a complete set of equations are worked out for the particle and fields. In this scenario, the planar motions as well as three-dimensional bounded motions are studied. At the end, the force exerted by the non-abelian Yang-Mills-Higgs fields on a particle with non-abelian charge is explored.
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Kemp, Dayne Hilton. "A compact high-energy particle detector for low-cost deep space missions." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/20046.
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Over the last few decades particle physics has led to many new discoveries, laying the foundation for modern science. However, there are still many unanswered questions which the next generation of particle detectors could address, potentially expanding our knowledge and understanding of the Universe. Owing to recent technological advancements, electronic sensors are now able to acquire measurements previously unobtainable, creating opportunities for new deep-space high-energy particle missions. Consequently, a new compact instrument was developed capable of detecting gamma rays, neutrons and charged particles. This instrument combines the latest in FPGA System-on-Chip technology as the central processor and a 3x3 array of silicon photomultipliers coupled with an organic plastic scintillator as the detector. Using modern digital pulse shape discrimination and signal processing techniques, the scintillator and photomultiplier combination has been shown to accurately discriminate between the di_erent particle types and provide information such as total energy and incident direction. The instrument demonstrated the ability to capture 30,000 particle events per second across 9 channels - around 15 times that of the U.S. based CLAS detector. Furthermore, the input signals are simultaneously sampled at a maximum rate of 5 GSPS across all channels with 14-bit resolution. Future developments will include FPGA-implemented digital signal processing as well as hardware design for small satellite based deep-space missions that can overcome radiation vulnerability.
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Zeng, Houdun, Yuliang Xin, Siming Liu, J. R. Jokipii, Li Zhang, and Shuinai Zhang. "EVOLUTION OF HIGH-ENERGY PARTICLE DISTRIBUTION IN MATURE SHELL-TYPE SUPERNOVA REMNANTS." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/623101.
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Multi-wavelength observations of mature supernova remnants (SNRs), especially with recent advances in gamma-ray astronomy, make it possible to constrain energy distribution of energetic particles within these remnants. In consideration of the SNR origin of Galactic cosmic rays and physics related to particle acceleration and radiative processes, we use a simple one-zone model to fit the nonthermal emission spectra of three shell-type SNRs located within 2 degrees on the sky: RX J1713.7-3946, CTB 37B, and CTB 37A. Although radio images of these three sources all show a shell (or half-shell) structure, their radio, X-ray, and gamma-ray spectra are quite different, offering an ideal case to explore evolution of energetic particle distribution in SNRs. Our spectral fitting shows that (1) the particle distribution becomes harder with aging of these SNRs, implying a continuous acceleration process, and the particle distributions of CTB 37A and CTB 37B in the GeV range are harder than the hardest distribution that can be produced at a shock via the linear diffusive shock particle acceleration process, so spatial transport may play a role; (2) the energy loss timescale of electrons at the high-energy cutoff due to synchrotron radiation appears to be always a bit (within a factor of a few) shorter than the age of the corresponding remnant, which also requires continuous particle acceleration; (3) double power-law distributions are needed to fit the spectra of CTB 37B and CTB 37A, which may be attributed to shock interaction with molecular clouds.
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Akhtar, Jahanzeb. "Particle tracking using the unscented Kalman filter in high energy physics experiments." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/11482.
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The extended Kalman lter (EKF) has a long history in the field of non-linear tracking. More recently, statistically-based estimators have emerged that avoid the need for a deterministic linearisation process. The Unscented Kalman filter (UKF) is one such technique that has been shown to perform favourably for some non-linear systems when compared to an EKF implementation, both in terms of accuracy and robustness. In this Thesis, the UKF is applied to a high energy physics particle tracking problem where currently the EKF is being implemented. The effects of measurement redundancy are investigated to determine improvements in accuracy of particle track reconstruction. The relationship between measurement redundancy and relative observability is also investigated through an experimental and theoretical analysis. Smoothing (backward filtering), in the high energy physics experiments, is implementedusing the Rauch Tung Striebel (RTS) smoother with the EKF , however, in Unscented Kalman filter algorithms, the Jacobian matrices required by the RTS method, are not available. The Unscented Rauch Tung Striebel (URTS) smoother addresses this problem by avoiding the use of Jacobian matrices but is not effi cient for large dimensional systems such as high energy physics experiments. A technique is implemented in the RTS smoother to make it suitable for the UKF. The method is given the name the Jacobian Equivalent Rauch Tung Striebel (JE-RTS) smoother. The implementation of this method is quite straight forward when the UKF is used as an estimator.
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Nodari, Benedetta. "Intelligent systems for particle detectors in environmental applications and High-Energy Physics." Doctoral thesis, Università degli studi di Bergamo, 2017. http://hdl.handle.net/10446/77221.
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Over the last decades, improvements in microelectronics technology have
fostered signicant progress in all fields of engineering, science and also in
radiation detection. The main challenge in designing radiation detectors is
to develop systems based on front-end electronics that is able to cope with
high radioactive environment, satisfy very high resolution requirements and
comply with high particle rates. This thesis work focuses on the analysis and
development of novel and intelligent solutions for electronics system, especially
suited for radiation detectors. In particular, two different applications are
considered here.
The first one concerns the design of a portable and affordable detector
system for continuous indoor Radon detection, based on SiPM technology. A
simple analog front-end with optimized low-noise performances and reduced
power consumption has been designed for counting each alpha particle that
occurs in the detector after Radon decay. The readout electronics is integrated
with a suite of environmental sensors on a full-custom Printed Circuit Board.
Compared to all the commercial Radon detector nowadays available, the developed system is able to detect reliable value of indoor Radon concentration
within few hours. The system also exploits the recent capabilities of microelectronic devices by including advanced functions such as Bluetooth data
transmission and energy harvesting.
In high-energy physics experiments, with particular emphasis on the HL-LHC environment, pixel detectors have to satisfy aggressive requirements
concerning high granularity, high rate capability and low power consumption.
With the advent of accessible modern technology such as 65 nm CMOS, the
processing speed and reduced power consumption can be achieved. In order
to meet such specications, a new pixel mixed signal ASIC has been designed
as a prototype front-end for the HL-HLC pixel readout system, within the
framework of RD53 collaboration. The ASIC front-end includes signal processing and synchronous analog-to-digital conversion within one Bunch Crossing
period. Thus, the emphasis of the work is on the feasibility of a synchronous
ADC within the HL-LHC environment, able to ensure high performances in
terms of low noise, power dissipation and high speed. Finally, a novel and
intelligent digital architecture has been proposed, in order to focus the eorts
of the front-end on the implementations of three main features: a novel data
sparsication method, a clusterization scheme at the hardware level itself and
fast Region-Of-Interest (ROI) trigger capability.
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Rosser, Karen Elizabeth. "Measurement of absorbed dose to water for medium energy x-rays." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338897.
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LaHurd, Danielle V. "Searching for Quark Gluon Plasma Signatures in Ultra High Energy Cosmic Rays." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1479298851843212.
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Bäckebo, Markus. "The influence of particle size distribution on bio-coal gasification rate as related to packed beds of particles." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79084.
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This thesis is a part of a collaboration between Höganäs AB and Luleå University of Technology, aiming at replacing fossil process coal with bio-coal in their sponge iron process. The difference in gasification reactivity, i.e. reaction rate, between fossil coals and bio-coals is the major challenge in the endeavor to decrease the climate impact of the existing process. The goal of this thesis is to develop a model of reaction rate for bio-coals in relation to particle size distribution. Different particle size distributions were combined and tested to see how that affects the effective reaction rate. Within the scope of this work, gasification reactivities of different materials, including coal, cokes, and bio-coals, were determined. Three bio-coals were selected to study the effect of particle size distribution on reactivity. Kinetic parameters were determined by using thermogravimetric analysis in the temperature range of 770-850 °C while varying CO2 partial pressure between 0.1-0.4 atm. The effect of particle size on the reaction rate was investigated by using particles with diameter between 0.18 and 6.3 mm. The effect of particle size distribution on the reactivity of bio-coal in a packed bed was carried out in a macro thermogravimetric reactor with a constant bed volume of 6.5 cm3 at 980 °C and 40% (vol.) of CO2. The experimental investigation in three different rate-limiting steps was done for one bio-coal sample, i.e. Cortus Bark bio-coal. The activation energy of the bio-coal was 187 kJ mol-1, and the reaction order was 0.365. For the internal diffusion control regime, an increase in particle size resulted in low reaction rate. The effective diffusivity calculated from the Thiele modulus model was 1.41*10-5 m2 s-1. For the external diffusion control regime, an increase in particle size increased the reaction rate up to a certain point where it plateaued at >1 mm. By choosing two discrete particle size distributions, where a smaller average distribution can fit into a larger average distribution the reaction rate was lowered by 30% compared to only using a single narrow particle size distribution. This solution decreased the difference of apparent reaction rate in a packed bed between the bio-coal and anthracite from 6.5 times to 4.5 times. At the moment the model is not generalized for all bio-coals. However, the developed methodology can be routinely applied to assess the different bio-coal samples. One possible error can be that pyrolysis influences the gasification rate for bio-coal that is pyrolyzed below the temperature of the gasification test. There is a clear correlation between particle size distributions, bulk density, and apparent reactivity. By mixing two distributions the reaction rate of Cortus Bark was reduced from 6.5 times the reaction rate of anthracite to 4.5.
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Carter, Jeremy. "A measurement of charmed particle lifetime in experiment NA1 at the CERN SPS." Thesis, Royal Holloway, University of London, 1988. http://repository.royalholloway.ac.uk/items/697f1280-d01f-4bb4-aa54-6668138f54b8/1/.
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An analysis of data collected In the NA1 high energy photoproduction experiment at the CERN SPS is presented. The theoretical status of charmed particle decay is reviewed. The NA1 experimental apparatus is discussed. Experiment NA1 used an active semiconductor target exposed to a 70-225 GeV tagged photon beam and the forward spectrometer FRAMM to collect data on the decay of particles carrying the charm quantum number. FRAMM was equipped with three lever arms for charged particle momentum analysis, electromagnetic calorimeters for neutral particle reconstruction and Cerenkov detectors for charged particle identification. The active target measured the charged particle multiplicity development along the beam axis to determine the decay length of particles. The proper time resolution of the target was -0.2x10-13s. A sample of sixty-three Ac charmed baryons are isolated in the decay channel via an inclusive analysis. Twenty-four of these Acs havedecay lengths resolved in the NA1 active target which can be matched to the information in the forward spectrometer FRAMM. A study of the sixty-three reconstructed in FRAMM indicates that a large proportion decayed via the channel, a decay which is believed to proceed exclusively through W exchange.
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Lacasse, Roger. "Test of particle identification at target rapidity in the E814 experiment." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61174.
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One of the unique features of the E814 experimental setup at the BNL-AGS, is its nearly 4$ pi$ calorimetry. Calorimeters, however, do not provide information on the nature of particles and their multiplicity. Particle identification is important to understand the expansion phase of the hot nuclear matter produced in relativistic heavy ion collisions. In the present 814 experiment the charged particle multiplicity is measured at forward angles only, by a Si pad detector. The addition of a similar Si detector in the target rapidity region, overlapping the Target Calorimeter, is being considered. Initial calculations have shown a possibility of particle identification by using the signals from a silicon detector and from the highly segmented Target Calorimeter. In this thesis, the potential for particle identification of an upgraded silicon multiplicity detector at target rapidity is evaluated using a silicon surface barrier detector and part of the Target Calorimeter. The measured response is compared to the predictions of the event generator HIJET followed by complete tracking using the code GEANT.
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Merritt, Hayes. "Measurement of the Proton-Proton to ZZX Cross Section at A Center of Mass Energy of 8 TeV." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1385508302.
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Senosi, Kgotlaesele Johnson. "Vector boson production with the ALICE detector." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27310.
Full textAbstract:
The main objective of this thesis is to study and investigate the production of massive vector bosons (W+ and W−). This a priori mentioned production is not sensitive to hot nuclear matter effects because of the weak coupling nature of these vector bosons. Thus, in heavy ion collisions they provide a good reference for the medium-induced effects on other probes. The production mechanism of these vector bosons is highly isospin dependent and thus they are affected by the initial state effects. Initial state effects include isospin, Fermi motion, EMC effect, shadowing and nuclear absorption. Hence their production in lead-lead (Pb-Pb) and proton-lead (p-Pb) collisions can be used to test some of these initial state effects. In this thesis only two of these initial state effects will be considered namely, isospin and shadowing (referring to shadowing and anti-shadowing). Eke, these vector bosons can be used to provide a non-arbitrary reference to the probes affected by the medium. Traditionally, in heavy ion collisions, hard processes are expected to scale with the number of binary collision thus a precise study of these vector bosons can be used to test the factorisation assumed in models used to determine centrality. This unique property of electroweak (W) bosons makes them essential probes to study the possible inherent bias in centrality determination. In proton-proton (pp) collisions, their production can be used to obtain information on quark parton distribution functions (PDF). The data used in the analysis was collected by A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider (LHC). The ALICE detector is designed to study ultrarelativistic heavy-ion collisions, in which a hot and dense, strongly-interacting medium is created. The production of W bosons is studied in p-Pb, p-p and Pb-Pb collisions at 5.023, 8 and 5.023 TeV centre-of-mass energies, respectively. The forward muon spectrometer with the pseudorapidity acceptance −4.0 < ŋ < −2.5 is used. W bosons are studied via the inclusive single muon differential pT spectrum.
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Al-Khalili, Jameel Sadik. "Intermediate energy deuteron elastic scattering from nuclei in a three-body model." Thesis, University of Surrey, 1989. http://epubs.surrey.ac.uk/842863/.
Full textAbstract:
A study is made of polarized deuteron elastic scattering from 58Ni and 40Ca at the intermediate energies of 400 and 700 MeV. A three-body formalism, based on the Single Folding Model, is used for two sets of Dirac nucleon optical potential parameters. Both potentials are designed to fit the proton elastic scattering observables at half the incident deuteron energy. The two potentials give different predictions for the deuteron scattering observables when used in the Schrodinger equation with relativistic kinematics. Good qualitative agreement with the experimental observables is obtained in both cases for deuteron elastic cross-section, vector (Ay) and tensor (Ayy) analyzing power data of the Saclay group. Quantitative discrepancies between theory and data, particularly in Ayy, suggest mechanisms missing from the simple three-body model. To this end, two sources of spin-dependent effects, Pauli-blocking and breakup of the deuteron to spin-singlet intermediate states, are studied. The role of the spin-dependence associated with Pauli-blocking is studied quantitatively for the d-58 Ni system. The magnitude of the momentum-dependent Tp tensor interaction, is shown to pass through a local maximum in the region of 400 MeV incident deuteron energy. Comparison of numerical calculations with the available experimental data at this energy shows the Pauli mechanism not to be responsible for outstanding discrepancies between theory and data. Breakup effects on the elastic amplitude are studied within a two-step calculation, using two separate high energy methods. The first neglects distortion in the initial, final and intermediate states. Use is made of the Adiabatic approximation, which allows closure over the intermediate breakup states. The effect on the elastic amplitude due to breakup to both triplet and singlet intermediate spin states are calculated. The inclusion of spin-singlet breakup in the model has a very large effect on Ayy, compared with that of spin-triplet breakup. This is attributed to a large contribution from a TL-like tensor interaction in the case of singlet breakup, which is negligibly small in the triplet case. Second order breakup effects are also calculated in Glauber theory, using central potentials. Continuum-continuum coupling effects are found to be negligible at intermediate energies, and thus the two-step calculation is adequate. Glauber theory shows, however, that distortion effects are important at these energies, and suggests the need for a more accurate treatment of spin-singlet breakup effects in future calculations.