No description available.

The purpose of this study reported in these pages was to ascertain how well the educational system as practiced in the public high schools of New Mexico was complying, 1948-1949, with the provision of the state Constitution, included in Article XII, which stipulates that "a uniform system of free public schools sufficient for the education of, and open to, all the children of school age in the state shall be established and maintained."

This thesis describes a measurement of the Standard Model Higgs boson coupling to fermions in decays to two τ-leptons, a search for charged Higgs bosons in decays to a τ-lepton and a neutrino, as well as the reconstruction, identification and triggering of hadronically decaying τ-leptons. The data considered are collected by the ATLAS experiment at the Large Hadron Collider. The reconstruction and identification of hadronically decaying τ-leptons in the ATLAS experiment during Run 2 of the Large Hadron Collider are described, and the performance of the τ trigger is measured in events with top–antitop-quark pairs using data from 13 TeV proton–proton collisions, corresponding to an integrated luminosity of 3.2 fb-1, collected in 2015, and 11.5 fb-1, collected in 2016. Hadronically decaying τ-leptons are of importance to many physical processes involving Higgs bosons. The coupling of the Standard Model Higgs boson to fermions is measured in decays to two τ-leptons using 7 TeV data corresponding to an integrated luminosity of 4.5 fb-1, collected in 2011, and 8 TeV data corresponding to an integrated luminosity of 20.3 fb-1, collected in 2012. The signal strength is measured to be μ = 1.4, corresponding to an excess over the background-only model of 4.5σ. Charged Higgs bosons are searched for in decays to a τ-lepton and a neutrino, where the τ-lepton decays hadronically. 13 TeV data corresponding to an integrated luminosity of 14.7 fb-1, collected in 2015 and 2016, are used. No excess over the Standard Model background is observed, and the 95 % confidence-level exclusion limits on σ(pp → [b]tH+) × (H+ → τν) are set to 2.0 pb–8 fb in the range 200–2000 GeV.

This project involved designing and building a radiochromic film (RCF) densitometer using a still digital camera as the light detector and light emitting diode, LED, as the light source. The behaviour of the LED and charged coupled device (CCD) in the still digital camera, under different light exposure settings (by changing LED current and camera shutter speed) were measured and an optimal setting was determined. Additionally, methods were devised and tests were carried out in order to spread the illumination area of the single light source. Uniform spreading of the LED illumination area was possible by the use of two diffusers placed at an optimum separation distance that was determined in this work. The usefulness of this custom-made RCF densitometer was demonstrated by using this device to image exposed RCF and using the film analysis software, Image J, to determine the film absorbed dose. Two clinical situations were examined: open and virtual wedge radiation beams. It was concluded that still digital cameras can be used in RCF densitometers provided they can capture and store raw images, a single diffused LED can illumination an area large enough for RCF densitometry and appropriate film analysis software is needed to extract and handle the large volume of greyscale data from the RCF.

La observació de un o varis bosons de Higgs és fonamental a l'hora d'entendre el trencament espontani de simetria del Model Estàndard (SM). En aquest model, un doblet escalar és el que proporciona el trencament espontani de simetria donant un bosó de Higgs.No obstant, el Model Estàndard té alguns problemes que són difícils de solucionar. Aquest tipus de problemes troben solució en les teories Supersimètriques (SUSY). El Minimal Supersymmetric Standard Model (MSSM) és l'extensió supersimètrica més simple del Model Estàndard. El sector de Higgs del MSSM està format per 2 doblets de Higgs que donen 5 bosons de Higgs després del trencament espontani de simetria: 3 bosons neutres (h, H, A) i un parell carregat (H+ ,H-).El descobriment d'un bosó de Higgs carregat (H±) seria una senyal clara de nova física més enllà del Model Estàndard. Els bosons de Higgs carregats es podrien produir en grans quantitats al LHC (Large Hadron Collider) en el decaiment del quark top. En aquesta tesi, la sensitivitat del detector ATLAS en condicions de baixa lluminositat al descobriment del Higgs carregat és estudiada en detall fent ús del canal: amb i . Després d'aplicar talls cinemàtics a les diferents mostres (senyal i fons) d'esdeveniments, el fons més rellevant és el format per amb un bosó W desintegrant-se en tn i l'altre desintegrant-se hadrònicament donant un parell de jets lleugers. Aquest fons va poder ser reduït imposant un tall a la massa transversa i en el moment transvers del leptó t: degut a la polarizació del t, en els casos en que el t decau hadrònicament en una partícula carregada, aquells jets de t que provenen de la desintegració del H± tenen un moment més gran que els que provenen de la desintegració del W±.El potencial de descoberta del detector ATLAS per a un Higgs carregat produït en la desintegració del quark top ja va ser estudiat en ATLAS amb W± desintegrant-se leptònicament (mnm o ene). Els estudis de significància presentats en aquesta tesi completen els anàlisis efectuats en el pla del MSSM (mA, tanb) per la descoberta del Higgs carregat. En la regió fins ara no coberta al voltant de tanb 5-10, s'obté una significància superior a 5s per 10 fb-1 de dades (que correspon a un any funcionant a baixa lluminositat) amb el canal estudiat en aquest treball. Amb això, la combinació els estudis de potencial de descoberta dels detectors ATLAS i CMS pels diferents bosons de Higgs (h, H, A, H+, H-) cobreixen tot l'espai (mA, tanb) del MSSM. A més a més, una característica important d'aquest canal és permet mesurar la massa. La massa del Higgs cargado del MSSM ha sigut obtinguda a partir de la distribució de la massa transversa mitjançant un mètode de màxima versemblança. L'error associat a aquesta mesura està completament dominat pels efectes sistemàtics i la precisió relativa obtinguda amb aquest mètode per la mesura de la massa és d'un 4% per una lluminositat integrada de 10 fb-1. / La observación de uno o varios bosones de Higgs es fundamental para entender la rotura espontánea de simetría del Modelo Estándar (SM). En este modelo, un doblete escalar es el que proporciona la rotura espontánea de simetría dando lugar a un bosón de Higgs.Sin embargo, el Modelo Estándar tiene algunos problemas difíciles de solucionar. Esta clase de problemas hallan solución en teorías Supersimétricas (SUSY). El Minimal Supersymmetric Standard Model (MSSM) es la extensión supersimétrica más simple del Modelo Estándar. El sector de Higgs del MSSM está formado por dos dobletes de Higgs dando lugar a 5 bosones de Higgs después de la rotura espontánea de simetría: 3 bosones neutros (h, H, A) y un par cargado (H+, H-).El descubrimiento del bosón de Higgs cargado (H±) sería una señal clara de nueva física más allá del Modelo Estándar. Los bosones de Higgs cargados podrían producirse copiosamente en el LHC (Large Hadron Collider) en la desintegración del quark top. En esta tesis, la sensitividad del detector ATLAS en condiciones de baja luminosidad al descubrimento del Higgs cargado es estudiada en detalle mediante el canal: con y . Después de aplicar cortes cinemáticos a las distintas muestras de señal y fondo, los sucesos de fondo de tipo con un bosón W desintegrándose en tn y el otro desintegrándose hadrónicamente són todavía importantes. Este fondo pudo ser reducido imponiendo cortes en la masa transversa del H± y en el momento transverso del leptón t: debido a la polarización del t, cuando éste se desintegra hadrónicamente en una partícula cargada, los jets de t que provienen de la desintegración del H± tienen un momento superior a los que provienen de la desintegración del W±.El potencial de descubrimiento del detector ATLAS para un Higgs cargado producido en la desintegración del quark top ya fue estudiado en ATLAS con W± desintegrándose leptónicamente (mnm o ene). Los estudios de significancia presentados en esta tesis completan los análisis efectuados en el plano del MSSM (mA, tanb) para el descubrimiento del Higgs cargado. En la región no cubierta hasta ahora alrededor de tanb 5-10, se obtiene una significancia superior a 5s para 10 fb-1 de datos (que corresponde a un año funcionando a baja luminosidad) con el canal estudiado en esta tesis. Es por eso que la combinación de los estudios de potencial de descubrimiento de los detectores ATLAS y CMS para los distintos bosones de Higgs (h, H, A, H+, H-) cubren todo el espacio (mA, tanb) del MSSM.Además, una característica importante de este canal es que permite medir la masa. La masa del Higgs cargado del MSSM se ha obtenido a partir de la distribución de la masa transversa utilizando un método de máxima verosimilitud. El error asociado a esta medida está completamente dominado por los efectos sistemáticos y la precisión relativa para la medida de la masa que se obtiene con este método es de un 4% para una luminosidad integrada de 10 fb-1. / The observation of one or several Higgs bosons will be of capital importance in order to understand the electroweak symmetry breaking mechanism. In the Standard Model (SM), one scalar doublet is responsible for the electroweak symmetry breaking giving as a result only one Higgs boson.However, the SM has serious drawbacks which are difficult to solve within the theory itself. This problems find a solution in Supersymmetric (SUSY) models. The Minimal Supersymmetric Standard Model (MSSM) is the simplest SUSY extension of the SM. The MSSM Higgs sector is made of two Higgs doublets which lead to five Higgs particles after electroweak symmetry breaking: three neutral (h, H, A) and a charged pair (H+ ,H-).The discovery of the MSSM charged Higgs (H±) would be a clear sign of new physics beyond the SM. MSSM charged Higgs could be copiously produced at the LHC (large Hadron Collider) in top decays. In the present thesis, the sensitivity of the ATLAS detector to the discovery of the charged Higgs in the low luminosity running conditions is studied in detail in the channel with and .After event selection, the most relevant remaining background is with one W boson decaying into tn and the other decaying hadronically in two light jets. That background was further reduced by imposing a cut on the transverse mass and a harder cut on the t jet transverse momentum: due to t polarization effects, in one-prong t hadronic decays, t jets from H± decay are harder than the ones produced in W± decay.The discovery potential of the ATLAS detector for a charged Higgs produced in top decays was already studied in ATLAS with the W± decaying leptonically (mnm or ene). The significance studies presented in this thesis complete the (mA, tanb) survey for the MSSM charged Higgs. Furthermore, in the so far uncovered 5-10 tanb region a significance greater than 5s is obtained for 10 fb-1 of data (corresponding to one year of running at low luminosity) with the channel studied in this work. Therefore, the discovery potential studies of ATLAS standalone and ATLAS+CMS combined for any of the different MSSM Higgs bosons (h, H, A, H+, H-) cover the whole MSSM (mA, tanb) space.Moreover, an important aspect of this channel is that it gives the possibility to measure the mass. The light MSSM charged Higgs mass was obtained from the transverse mass distribution (since in the channel there is no resonance peak) by means of a maximum likelihood method and the expected precision on this mass was also given. The error was completely dominated by systematics and a precision close to 4% could be achieved for an integrated luminosity of 10 fb-1.

In this thesis I explore the possibilities of detecting doubly charged Higgs bosons from the Higgs Triplet Model (HTM) at the Large Hadron Collider (LHC) at CERN. Higgs bosons are included into the Standard Model (SM) of particle physics in order to explain the origin of mass of the elementary particles. Even though the SM is considered to be a reliable starting point for any particle theory, no Higgs particles have to this day been found. There are therefore high expectations for the record-breaking energies of the LHC to lead to a Higgs discovery. The HTM produces seven different Higgs bosons, and among these we find the doubly charged ones. Because of their exotic charge, I focus on studying these Higgs particles in particular. To this purpose, I implement the full HTM theory as an alternative model option in standard particle physics Monte-Carlo software and then simulate LHC proton-proton collisions at a center of mass energy of 14 TeV. The investigated signal is defined as two like-signed leptons, four hard jets and missing energy in the final state. The main production mechanisms are pair-production and associated production with a singly charged Higgs. Since I choose to study a region of parameter space where the triplet vacuum expectation value is relatively large, the doubly charged Higgs decays into W's and the singly charged Higgs into WZ or tb. The results of the simulations show that the LHC could probe Higgs masses up to at least 300 GeV with an integrated luminosity of about 300 fb.1.

Anthropomorphic phantoms are commonly used for testing radiation fields without the need to expose human subjects. One of the most widely known is RANDO phantom. This phantom is used primarily for medical X-ray applications, but a similar design known as "MATROSHKA" is now being used for space research and exposed to heavy ion irradiations from the Galactic environment. Since the radiation field in the phantom should respond in a similar manner to how it would act in human tissues and organs under an irradiation, the tissue substitute chosen for soft tissue and the level of complexity of the entire phantom are crucial issues. The phantoms, and the materials used to create them, were developed mainly for photon irradiations and have not been heavily tested under the conditions of heavy ion exposures found in the space environment or external radiotherapy. The Particle and Heavy-Ion Transport code System (PHITS) was used to test the phantoms and their materials for their potential as human surrogates for heavy ion irradiation. Stopping powers and depth-dose distributions of heavy charged particles (HCPs) important to space research and medical applications were first used in the simulations to test the suitability of current soft tissue substitutes. A detailed computational anthropomorphic phantom was then developed where tissue substitutes and ICRU-44 tissue could be interchanged to verify the validation of the soft tissue substitutes and and determine the required level of complexity of the entire phantom needed to achieve a specified precision as a replacement of the human body. The materials tested were common soft tissue substitutes in use and the materials which had a potential for the soft tissue substitute. Ceric sulfate dosimeter solution was closest to ICRU-44 tissue; however, it was not appropriate as the phantom material because it was a solution. A150 plastic, ED4C (fhw), Nylon (Du Pont Elvamide 8062), RM/SR4, Temex, and RW-2 were within 1% of the mean normalized difference of mass stopping powers (or stopping powers for RW-2) when compared to the ICRU-44 tissue, and their depth-dose distributions were close; therefore, they were the most suitable among the remaining solid materials. Overall, the soft tissue substitutes which were within 1% of ICRU-44 tissue in terms of stopping power produced reasonable results with respect to organ dose in the developed phantom. RM/SR4 is the best anthropomorphic phantom soft tissue substitute because it has similar interaction properties and identical density with ICRU-44 tissue and it is a rigid solid polymer giving practical advantages in manufacture of real phantoms.

No description available.

This thesis presents searches for a charged Higgs boson (H±) in proton-proton collisions with center-of-mass energies of 7 TeV and 8 TeV, using data collected by the ATLAS experiment at the Large Hadron Collider at CERN. Multiple search channels are used with the common characteristic of at least one charged lepton (electron or muon) that effectively reduces the multi-jet background and is used for efficient triggering. Charged Higgs bosons decaying to a tau lepton and a neutrino are searched for using final states with two charged leptons, or one charged lepton and a hadronically decaying tau. A significant background originates from quark- or gluon-initiated jets that may be misidentified as hadronic tau decays. Methods to estimate this background are presented, including a largely data-driven matrix method. Signal processes with a charged Higgs boson mass below or above that of the top quark are considered. With the dataset collected at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3 fb-1, upper limits at 95% confidence level are placed on the branching fraction B(t→bH±)×B(H±→τν) in the range 1.1–0.3% for charged Higgs boson masses between 80 GeV and 160 GeV, and on the top-quark associated H± production cross section in the range 0.93 to 0.03 pb for charged Higgs boson masses between 180 GeV and 1 TeV.

Designs for future nuclear fusion power reactors rely on the ability to create a stable plasma (hot ionized gas of hydrogen isotopes) as a medium with which to sustain nuclear fusion reactions. My dissertation work involves designing, constructing, testing, installing, operating, and validating a new diagnostic for spherical tokamaks, a type of reactor test facility. Through detecting charged particles emitted from the plasma, this instrument can be used to study fusion reaction rates within the plasma and how they are affected by plasma perturbations. Quantitatively assessing nuclear fusion reaction rates at specific locations inside the plasma and as a function of time can provide valuable data that can be used to evaluate theory-based simulations related to energy transport and plasma stability. The Proton Detector (PD), installed in the Mega Amp Spherical Tokamak (MAST) at the Culham Centre for Fusion Energy (CCFE) in Abingdon, England, was the first instru- ment to experimentally detect 3 MeV Protons and 1 MeV Tritons created from deuterium- deuterium (hydrogen isotopes) nuclear fusion reactions inside a spherical tokamak’s plasma. The PD consists of an array of particle detectors with a protective housing and the neces- sary signal conditioning electronics and readout. After several years of designing (which included simulations for detector orientations), fabricating, and testing the PD, it was installed in MAST and data were collected over a period of two months in the summer of 2013. Proton and triton rates as high as 200 kHz were measured and an initial radial profile of these fusion reaction rates inside the plasma was extracted. These results will be compared to a complementary instrument at MAST as well as theory-based simulations and form the knowledge basis for developing a larger future in- strument. The design and performance of all instrument components (electrical, computa- tional, mechanical), and subsequent data analysis methods and results are described in this dissertation.