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Establishing the Mirage Mediation Model at the Large Hadron ColliderWang, Kechen 2011 August 1900 (has links)
This thesis describes the research I did during my Master's study. I investigated the stau-neutralino coannihilation region of the Mirage Mediation Model at the Large Hadron Collider (LHC). By constructing five kinematic observables at the LHC, the masses of supersymmetric particles (sparticles) were determined. The Mirage Mediation
Model parameters were determined from the sparticles' masses. This is the first time to establish the Mirage Mediation Model at the LHC. All these techniques can be applied to other coannihilation regions of the Mirage Mediation Model and other supersymmetry (SUSY) models.
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Determination of Dose From Light Charged Ions Relevant to Hadron Therapy Using the Particle and Heavy Ion Transport System (PHITS)Butkus, Michael Patrick 2011 August 1900 (has links)
In conventional radiotherapy for tumor treatment, photons are used to impart an energetic dose inside a tumor with the goal of killing the cancerous cells. This process is intrinsically inefficient due to the fact that photons lose their energy exponentially with depth causing the highest dose to occur in overlying healthy tissue. However, charged particles with a mass of 1 amu or greater lose their energy in a manner that allows for a high dose to be localized at significant depth. The area of high dose localization is known as the Bragg Peak. Exploitation of the Bragg Peak could lead to more efficient non-invasive treatment plans by reducing the dose in healthy tissues.
Using the Particle and Heavy Ion Transport System (PHITS), the dose and fragmentation particles from ions of 1H, 4He, 7Li, 12C, 16O, and 20Ne were found at varying depths in a water phantom. A water filled cylindrical phantom with a radius of 10 cm was used to mimic a human body. The energy of each ion was selected so that the Bragg Peak would occur approximately 10 cm into the depth of the water phantom where a 1 cm radius water sphere was placed to simulate a solid tumor.
Dose equivalent localization rates within the tumor were found to be 14.5, 36.5, 45.7, 49.5, 41.3, and 34.1 percent for 1H, 4He, 7Li, 12C, 16O, and 20Ne, respectively. The percentage of dose within the tumor increased with increasing atomic number up to 12C, decreasing thereafter. The total dose distal from the tumor ranged from 0.1, 0.9, 2.8, 0.9, 0.5, and 0.6 percent for the ions ordered by their masses. Complementing its high dose in the tumor, carbon was seen to experience the lowest amount of dose escaping due to fragmentation and scattering, on a dose normalized basis.
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Robust track based alignment of the ATLAS silicon detectors and assessing patron distribution uncertainties in Drell-Yan processesHeinemann, Florian January 2007 (has links)
The ATLAS Experiment is one of the four large detectors located at the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland. In summer 2008, ATLAS is expected to start collecting data from proton-proton collisions at 14 TeV centre-of-mass energy. In the centre of the detector, the reconstruction of charged particle tracks is performed by silicon and drift tube based sub-detectors. In order to achieve the ATLAS physics goals the resolutions of the measured track parameters should not be degraded by more than 20% due to misalignment. Thus, the relative positions of the silicon detector elements have to be known to an accuracy of about 10 micrometers in the coordinate with the best measurement precision. This requirement can be achieved by track based alignment algorithms combined with measurements from hardware based alignment techniques. A robust track based alignment method based on track residual and overlap residual optimisation has been developed and implemented into the ATLAS offline software framework. The alignment algorithm has been used to align a test beam setup and also part of the final ATLAS detector using cosmic ray muons. Several simulation studies showed that the algorithm will be able to align the full detector with collision data. In addition to detector misalignments, limitations in the knowledge of the proton structure are going to affect physics discoveries at the LHC. Therefore, parton distribution uncertainties in high-mass Drell-Yan processes have been determined. This study includes the analysis of the forward-backward asymmetry. It has been performed on the level of next-to-leading order in both, Monte Carlo simulation using k-factors and parton distribution functions. This analysis is crucial for new physics searches with the ATLAS detector.
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Searching for weakly produced supersymmetric particles using the ATLAS detector at the LHCWilliams, Sarah Louise January 2014 (has links)
No description available.
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Phenomenology of the standard model and beyond at hadron collidersVryonidou, Eleni January 2013 (has links)
No description available.
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Measurements of charmonia production and a study of the X (3872) at LHCbMangiafave, Nicola January 2012 (has links)
No description available.
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A measurement of the B⁰s -> K⁺K⁻ lifetime at the LHCb experimentCliff, Harry Victor January 2012 (has links)
No description available.
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Measurement of the effective lifetime of the B0 s meson using the flavour specific decay Bs → D-s π + at the LHCb experimentFardell, Gemma Claire January 2013 (has links)
This thesis presents a measurement of the effective B0s decay width, ΓFS, from a single exponential fit to the flavour-specific decay channel B0s → D-s π +. This measurement is based on an integrated luminosity of 340 pb-1 recorded by LHCb in 2011 at a center of mass energy of 7TeV. The dataset is divided into two exclusive selections. B0s → D-s (( ϕ →K-K+) π-)π + only has a significant background contribution arising from combinatorial background, and the modelling of this is determined entirely by the data. B0s → D-s ((K-K* (892)0 → K+ π-))π + has a larger contribution from combinatoric and mis-identified background and provides an alternative measurement. A simultaneous fit for the effective B0s decay width is performed to both the datasets leading to the result: ΓFS = 0:668 ± 0:017 ± 0:031 ps-1 The result is then combined with information from the LHCb B0s → J/ψØ analysis leading to an improved measurement of the average B0 s decay width: Γs = 0:666 ± 0:010 ± 0:031 ps-1
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Pion energy reconstruction methods for the ATLAS electromagnetic and hadronic endcap calorimetersHughes, Tamara Michelle 13 November 2009 (has links)
In preparations for the ATLAS experiment at the Large Hadron Collider at CERN, sections of the ATLAS Electromagnetic Endcap Calorimeter (EMEC) and Hadronic Endcap Calorimeter (HEC) were subjected to particle beams in the summer of 2002. The EMEC and HEC are non-compensating calorimeters with e/h > I: electromag¬netic showers will, on average; have a higher energy response than hadronic showers initiated by particles of the same energy. To reconstruct the energy of pions, the method of software compensation is investigated. Several beam energy dependent weighting schemes are studied, using calorimeter depth weights and cluster energy density weights. Finally, a beam energy independent cluster energy density weighting scheme is studied. Partial software compensation is achieved for pion energy recon¬struction, improving the energy resolution and response linearity of the calorimeters.
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Calibration and response of the high pseudorapidity region of the ATLAS liquid argon end-cap calorimetersShaw, Warren Darrell 03 February 2010 (has links)
In preparation for the ATLAS experiment at the LHC at CERN. the high pseudorapidity region (|n| > 2.5) of the ATLAS end-cap liquid argon calorimeters underwent particle beam testing in 2004. One of the main goals of these tests is to study energy reconstruction in the complex interface region between the electromagnetic. hadronic, and forward calorimeters at. 1 - 3.2. These detectors were exposed to beams of electrons and pions with energies ranging from 6 GeV to 200 GeV. Three methods of calibration in the electromagnetic end-cap calorimeter (EMEC) are studied and compared to the results of a previous beam test. of the EMEC. The electromagnetic scale factor (aEM) is computed and compared to the previous beam test value. Studies of the energy response and resolution of the high pseudorapidity region of the three end-cap calorimeters to the particle beam position scans are given.
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