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First Search for the Standard Model Higgs Boson Using the Semileptonic Decay Channel: H --> WW --> mu bar nu jj

Description: This dissertation presents the first search for the standard model Higgs boson (H) in decay topologies containing a muon, an imbalance in transverse momentum (E{sub T}) and jets, using p{bar p} collisions at {radical}s = 1.96 TeV with an integrated luminosity of 4.3 fb{sup -1} recorded with the D0 detector at the Fermilab Tevatron Collider. This analysis is sensitive primary to contributions from Higgs bosons produced through gluon fusion, with subsequent decay H {yields} WW {yields} {mu}{nu}jj… more
Date: September 1, 2010
Creator: Zelitch, Shannon Maura & U., /Virginia
Partner: UNT Libraries Government Documents Department
open access

Search for vector-like quark production in the lepton+jets and dilepton+jets final states using 5.4 fb-1 of Run II data

Description: The Standard Model of particle physics provides an excellent description of particle interactions at energies up to {approx}1 TeV, but it is expected to fail above that scale. Multiple models developed to describe phenomena above the TeV scale predict the existence of very massive, vector-like quarks. A search for single electroweak production of such particles in p{anti p} collisions at a center-of-mass energy of 1.96 TeV is performed in the W+jets and Z+jets channels. The data were collected … more
Date: October 1, 2010
Creator: Caughron, Seth
Partner: UNT Libraries Government Documents Department
open access

A Sterile-Neutrino Search with the MINOS Experiment

Description: The MINOS experiment is a long-baseline neutrino oscillation experiment in the the NuMI beamline at Fermilab, USA. Using a near detector at 1 km distance from the neutrino production target, and a far detector at 735 km from the target, it is designed primarily to measure the disappearance of muon neutrinos. This thesis presents an analysis using MINOS data of the possibility of oscil- lation of the neutrinos in the NuMI beam to a hypothetical sterile flavour, which would have no Standard Model… more
Date: September 1, 2010
Creator: Rodrigues, Philip
Partner: UNT Libraries Government Documents Department
open access

Dark matter limits froma 15 kg windowless bubble chamber

Description: The COUPP collaboration has successfully used bubble chambers, a technology previously applied only to high-energy physics experiments, as direct dark matter detectors. It has produced the world's most stringent spin-dependent WIMP limits, and increasingly competitive spin-independent limits. These limits were achieved by capitalizing on an intrinsic rejection of the gamma background that all other direct detection experiments must address through high-density shielding and empirically-determin… more
Date: December 1, 2010
Creator: Szydagis, Matthew Mark
Partner: UNT Libraries Government Documents Department
open access

Search for associated production of z and Higgs bosons in proton-antiproton collisions at 1.96 TeV

Description: We present a search for associated production of Z and Higgs bosons in 4.2 fb{sup -1} of {bar p}p collisions at {radical}s = 1.96 TeV, produced in RunII of the Tevatron and recorded by the D0 detector. The search is performed in events containing at least two muons and at least two jets. The ZH signal is distinguished from the expected backgrounds by means of multivariate classifiers known as random forests. Binned random forest output distributions are used in comparing the data to background-… more
Date: December 1, 2010
Creator: BackusMayes, John Alexander & /Washington U., Seattle
Partner: UNT Libraries Government Documents Department
open access

A Search for Neutrino Induced Coherent NC($\pi^{0}$) Production in the MINOS Near Detector

Description: The production of single, highly forward {pi}{sup 0} mesons by NC coherent neutrino-nucleus interactions ({nu}{sub {mu}} + N {yields} {nu}{sub {mu}} + N + {pi}{sup 0}) is a process which probes fundamental aspects of the weak interaction. This reaction may also pose as a limiting background for long baseline searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations if the neutrino mixing angle {theta}{sub 13} is very small. The high-statistics sample of neutrino interactions recorded by the… more
Date: November 1, 2010
Creator: Cherdack, Daniel David & U., /Tufts
Partner: UNT Libraries Government Documents Department
open access

Searches for New Physics at MiniBooNE: Sterile Neutrinos and Mixing Freedom

Description: The MiniBooNE experiment was designed to perform a search for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations in a region of {Delta}m{sup 2} and sin{sup 2} 2{theta} very different from that allowed by standard, three-neutrino oscillations, as determined by solar and atmospheric neutrino experiments. This search was motivated by the LSND experimental observation of an excess of {bar {nu}}{sub e} events in a {bar {nu}}{sub {mu}} beam which was found compatible with two-neutrino oscillations at {… more
Date: July 1, 2010
Creator: Karagiorgi, Georgia S.
Partner: UNT Libraries Government Documents Department
open access

Measurement of muon neutrino and antineutrino induced single neutral pion production cross sections

Description: Elucidating the nature of neutrino oscillation continues to be a goal in the vanguard of the efforts of physics experiment. As neutrino oscillation searches seek an increasingly elusive signal, a thorough understanding of the possible backgrounds becomes ever more important. Measurements of neutrino-nucleus interaction cross sections are key to this understanding. Searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillation - a channel that may yield insight into the vanishingly small mixing pa… more
Date: December 1, 2010
Creator: Anderson, Colin & U., /Yale
Partner: UNT Libraries Government Documents Department
open access

Search for V H and Technicolor Producion in the qqbb Final State Using the RunII D0 Detector

Description: A search for dijet resonance production in a four-jet all-hadronic final state from the D0 detector at Fermilab's Tevatron is presented. The data set, acquired at a p{bar p} center-of-mass energy of {radical}s = 1.96 TeV, contains primarily multijet events and represents approximately 1 fb{sup -1} of data. The cross section limits for associated Higgs production and Technicolor processes are determined through a background subtraction method using data to estimate the background. This four-jet … more
Date: April 1, 2010
Creator: Clutter, Justace R.
Partner: UNT Libraries Government Documents Department
open access

Measurement of single-target spin asymmetries in the electroproduction of negative pions in the semi-inclusive deep inelastic reaction n{up_arrow}(e,e'{pi}{sup -})X on a transversely polarized {sup 3}He target

Description: The experiment E06010 measured the target single spin asymmetry (SSA) in the semiinclusive deep inelastic (SIDIS) n{up_arrow}(e, e'{pi}{sup -})X reaction with a transversely polarized {sup 3}He target as an e#11;ective neutron target. This is the very #12;rst independent measurement of the neutron SSA, following the measurements at HERMES and COMPASS on the proton and the deuteron. The experiment acquired data in Hall A at Je#11;erson Laboratory with a continuous electron beam of energy 5.9 GeV… more
Date: June 1, 2010
Creator: Dutta, Chiranjib
Partner: UNT Libraries Government Documents Department
open access

A search for the lightest supersymmetric partner of the top quark at D0

Description: We report the result of a search for the pair production of the lightest supersymmetric partner of the top quark ({tilde t}{sub 1}) in 5.4 {+-} 0.3 fb{sup -1} of data from the D0 detector at a p{bar p} center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. The scalar top quarks are assumed to decay into a b quark, a charged lepton and a scalar neutrino ({tilde {nu}}), and the search is performed in the electron plus muon final state. No significant excess of events above the stand… more
Date: August 1, 2010
Creator: Mackin, Dennis S., Jr. & U., /Rice
Partner: UNT Libraries Government Documents Department
open access

A Measurement of the neutron electric form factor at very large momentum transfer using polaried electrions scattering from a polarized helium-3 target

Description: Knowledge of the electric and magnetic elastic form factors of the nucleon is essential for an understanding of nucleon structure. Of the form factors, the electric form factor of the neutron has been measured over the smallest range in Q{sup 2} and with the lowest precision. Jefferson Lab experiment 02-013 used a novel new polarized {sup 3}He target to nearly double the range of momentum transfer in which the neutron form factor has been studied and to measure it with much higher precision. Po… more
Date: October 1, 2010
Creator: Kelleher, Aidan
Partner: UNT Libraries Government Documents Department
open access

Measurement of the CP violating phase beta_s in B_s->J/psi phi decays

Description: The CP violating phase {beta}{sub s}{sup J/{psi}{phi}} is measured in decays of B{sub s}{sup 0} {yields} J/{psi}{phi}. This measurement uses 5.2 fb{sup -1} of data collected in {radical}s = 1.96 TeV p{bar p} collisions at the Fermilab Tevatron with the CDF Run-II detector. CP violation in the B{sub s}{sup 0}-{bar B}{sub s}{sup 0} system is predicted to be very small in the Standard Model. However, several theories beyond the Standard Model allow enhancements to this quantity by heavier, New Phy… more
Date: July 1, 2010
Creator: Oakes, Louise Beth
Partner: UNT Libraries Government Documents Department
open access

Search for the Higgs boson in the ZH->nunubb channel: Development of a b-tagging method based on soft muons

Description: In the Standard Model of particle physics, the Higgs boson generates elementary particle masses. Current theoretical and experimental constraints lead to a Higgs boson mass between 114.4 and 158 GeV with 95% confidence level. Moreover, Tevatron has recently excluded the mass ranges between 100 and 109 GeV, 158 and 175 GeV with 95% confidence level. These results gives a clear indication to search for a Higgs boson at low mass. The D0 detector is located near Chicago, at the Tevatron, a proton-a… more
Date: October 1, 2010
Creator: Jamin, David
Partner: UNT Libraries Government Documents Department
open access

Search for Supersymmetry Using Diphoton Events in p anti-p Collisions at a center of mass energy of 1.96-TeV

Description: This dissertation presents the results of a search for supersymmetry in proton-antiproton collisions with a center of mass energy of 1.96 TeV studied with the Collider Detector at Fermilab. Our strategy is to select collisions with two photons in the final state that have the properties of being the decays of very massive supersymmetric particles. This includes looking for large total energy from the decayed particles as well as for the presence of particles that leave the detector without inte… more
Date: May 1, 2010
Creator: Lee, Eun Sin & A-M, /Texas
Partner: UNT Libraries Government Documents Department
open access

A top quark mass measurement using a matrix element method

Description: A measurement of the mass of the top quark is presented, using top-antitop pair (t{bar t}) candidate events for the lepton+jets decay channel. The measurement makes use of Tevatron p{bar p} collision data at centre-of-mass energy {radical}s = 1.96 TeV, collected at the CDF detector. The top quark mass is measured by employing an unbinned maximum likelihood method where the event probability density functions are calculated using signal (t{bar t}) and background (W+jets) matrix elements, as well… more
Date: February 1, 2010
Creator: Linacre, Jacob Thomas
Partner: UNT Libraries Government Documents Department
open access

Measurement of the $WW+WZ$ production cross section in a semileptonic decay mode at CDF

Description: The measurement of the WW + WZ production cross section in a semileptonic decay mode is presented. The measurement is carried out with 4.6 fb{sup -1} of integrated luminosity collected by the CDF II detector in {radical}s = 1.96 TeV proton-antiproton collisions at the Tevatron. The main experimental challenge is identifying the signal in the overwhelming background from W+jets production. The modeling of the W+jets background is carefully studied and a matrix element technique is used to build … more
Date: March 1, 2010
Creator: Hurwitz, Martina
Partner: UNT Libraries Government Documents Department
open access

Top Quark Produced Through the Electroweak Force: Discovery Using the Matrix Element Analysis and Search for Heavy Gauge Bosons Using Boosted Decision Trees

Description: The top quark produced through the electroweak channel provides a direct measurement of the V{sub tb} element in the CKM matrix which can be viewed as a transition rate of a top quark to a bottom quark. This production channel of top quark is also sensitive to different theories beyond the Standard Model such as heavy charged gauged bosons termed W{prime}. This thesis measures the cross section of the electroweak produced top quark using a technique based on using the matrix elements of the pro… more
Date: February 1, 2010
Creator: Pangilinan, Monica & U., /Brown
Partner: UNT Libraries Government Documents Department
open access

B Flavour Tagging with Artificial Neural Networks for the CDF II Experiment

Description: One of the central questions arising from human curiosity has always been what matter is ultimately made of, with the idea of some kind of elementary building-block dating back to the ancient greek philosophers. Scientific activities of multiple generations have contributed to the current best knowledge about this question, the Standard Model of particle physics. According to it, the world around us is composed of a small number of stable elementary particles: Electrons and two different kinds … more
Date: January 1, 2010
Creator: Schmidt, Andreas
Partner: UNT Libraries Government Documents Department
open access

A Measurement of Neutrino-Induced Charged-Current Neutral Pion Production

Description: This work presents the first comprehensive measurement of neutrino-induced charged-current neutral pion production (CC{pi}{sup 0}) off a nuclear target. The Mini Booster Neutrino Experiment (MiniBooNE) and Booster Neutrino Beam (BNB) are discussed in detail. MiniBooNE is a high-statistics ({approx} 1,000,000 interactions) low-energy (E{sub {nu}} {element_of} 0.5-2.0 GeV) neutrino experiment located at Fermilab. The method for selecting and reconstructing CC{pi}{sup 0} events is presented. The {… more
Date: April 1, 2010
Creator: Nelson, Robert H.
Partner: UNT Libraries Government Documents Department
open access

DualTrust: A Trust Management Model for Swarm-Based Autonomic Computing Systems

Description: Trust management techniques must be adapted to the unique needs of the application architectures and problem domains to which they are applied. For autonomic computing systems that utilize mobile agents and ant colony algorithms for their sensor layer, certain characteristics of the mobile agent ant swarm -- their lightweight, ephemeral nature and indirect communication -- make this adaptation especially challenging. This thesis looks at the trust issues and opportunities in swarm-based autonom… more
Date: May 1, 2010
Creator: Maiden, Wendy M.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Top Quark Mass in the Di-lepton Channel using the Dalitz-Goldstein Method

Description: This dissertation describes a measurement of the mass of the top quark using a method developed by G. Goldstein and R.H. Dalitz. It is based on 2.0 fb{sup -1} of data collected by the Collider Detector Facility at Fermi National Accelerator Laboratories. Di-lepton events were observed from colliding protons with anti-protons with {radical}s = 1.96 TeV in the Tevatron Collider. A total of 145 candidate events were observed with 49 expected to be from background. These events include two neutrino… more
Date: October 1, 2010
Creator: Hare, Matthew Frederick & U., /Tufts
Partner: UNT Libraries Government Documents Department
open access

Measurement of the t tbar cross section at the Run II Tevatron using Support Vector Machines

Description: This dissertation measures the t{bar t} production cross section at the Run II CDF detector using data from early 2001 through March 2007. The Tevatron at Fermilab is a p{bar p} collider with center of mass energy {radical}s = 1.96 TeV. This data composes a sample with a time-integrated luminosity measured at 2.2 {+-} 0.1 fb{sup -1}. A system of learning machines is developed to recognize t{bar t} events in the 'lepton plus jets' decay channel. Support Vector Machines are described, and their a… more
Date: August 1, 2010
Creator: Whitehouse, Benjamin Eric & U., /Tufts
Partner: UNT Libraries Government Documents Department
open access

Study of the (e,e'p) quasi-elastic reaction in complex nuclei: theory and experiment

Description: Experimental coincidence cross section and transverse-longitudinal asymmetry A{sub TL} have been obtained for the quasielastic (e,e'p) reaction in {sup 16}O, {sup 12}C, and {sup 208}Pb in constant q-ω kinematics in the missing momentum range -350 < p{sub miss} < 350 MeV/c. In these experiments, performed in experimental Hall A of the Thomas Jefferson National Accelerator Facility (JLAB), the beam energy and the momentum and angle of the scattered electrons were kept fixed, while the … more
Date: March 1, 2010
Creator: Herraiz, Joaquin Lopez
Partner: UNT Libraries Government Documents Department
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