Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2010. / In title on title-page: unable to ascertain meaning of symbols used. Cataloged from PDF version of thesis. / Includes bibliographical references (49-52). / In this thesis, we estimate the sensitivity of Double Chooz, a reactor Ve --> Ve experiment, to detect "early" neutrino oscillations based on a three-active plus one-sterile, or (3 + 1), neutrino mixing model by implementing a least-squares fit to the simulated electron antineutrino reactor spectrum1 . By comparing the expected spectra from the null hypothesis and the (3 + 1) oscillation hypothesis at the Double Chooz near detector L = 200 m, we expect a modest sterile neutrino discovery potential, limited by the ~ 2% reactor flux uncertainty. This potential may be expanded by employing a Double Chooz-like detector at a very short baseline L = 6 m from the reactor. At both baselines, the p-value for the null hypothesis was extremely small p ~ 0.004, which is compelling evidence for rejecting this hypothesis. Very short baseline antineutrino oscillation reactor experiments may help to resolve the current global incompatibilities between neutrino and antineutrino data sets. / by Javier M. G. Duarte. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2002. / Includes bibliographical references (p. 167-172). / We studied the inclusive reaction e[left arrow above] p[left arrow above] [left arrow] e'X with a 2.5GeV and a 4.2GeV incident beam of polarized electrons. The virtual photon four momentum squared, Q2, varied from 0.2GeV2/c2 to 1GeV2/c2 and the center of mass total energy W ranged up to 2GeV. The measurement was performed at the CEBAF Large Acceptance Spectrometer (CLAS) of the Thomas Jefferson National Accelerator Facility during the Fall of 1998. A cryogenic NH3 target was used as a source of protons polarized in the direction of the incident electron beam. For the first time, proton spin structure functions were studied with precision in the resonance region. The data indicate that a dramatic change in the spin structure occurs between the deep inelastic high Q2 region and the region of low Q2 where photons become nearly real. / by Alexander Skabelin. / Ph.D.

Thesis: S.B. in Science, Technology and Society, Massachusetts Institute of Technology, Department of Physics, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 89-92). / This thesis is a biographical snapshot of physicist Herman Feshbach (1917-2000). Herman Feshbach was a nuclear physics that spent over three-quarters of his life at the Massachusetts Institute of Technology. His life is a window through which I analyze the changes experienced by the physics community throughout World War II and the postwar era. The events that I narrate are centered in New York, where Feshbach's early life unfolds, and in Cambridge, Massachusetts, where Feshbach matured as a scientist. There are two recurring themes throughout this work.The first theme deals with the ways in which politics, wartime, and government funding place strains and provoke change in scientific practices. The second theme pertains to how scientists accommodate to the aforementioned strains, either through open political activism or changes within scientific institutions. Herman Feshbach's life is an excellent example of how these themes weave into each other, making the boundary between science and society more permeable and porous than it is usually presented. / by Juana C. Becerra / S.B. in Science, Technology and Society

Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, June 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages [96]-[97]). / by Liam Augustus Cohen. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2008. / In title on title page, instances of "s" in "B⁰s - B⁻⁰s" and "Bs" appear subscript; and, in "B⁰s - B⁻⁰s" the "s" appears directly under the superscript "0." / Includes bibliographical references (p. 235-241). / This thesis describes the contribution of partially reconstructed hadronic decays in the world's first observation of B⁰s - B⁻⁰s oscillations. The analysis is a core member of a suite of closely related studies whose combined time-dependent measurement of the B⁰s - B⁻⁰s oscillation frequency Am, is of historic significance. Using a data sample of 1 fb-1 of pp collisions at V = 1.96 TeV collected with the CDF-II detector at the Fermilab Tevatron, we find signals of 3150 partially reconstructed hadronic B, decays from the combined decay channels ... These events are analyzed in parallel with 2000 fully reconstructed ... decays. The treatment of the data is developed in stages of progressive complexity, using high-statistics samples of hadronic Bo and B+ decays to study the attributes of partially reconstructed events. The analysis characterizes the data in mass and proper decay time, noting the potential of the partially reconstructed decays for precise measurement of B branching fractions and lifetimes, but consistently focusing on the effectiveness of the model for the oscillation measurement. We efficiently incorporate the measured quantities of each decay into a maximum likelihood fitting framework, from which we extract amplitude scans and a direct measurement of the oscillation frequency. The features of the amplitude scans are consistent with expected behavior, supporting the correctness of the calibrations for proper time uncertainty and flavor tagging dilution. The likelihood allows for the smooth combination of this analysis with results from other data samples, including 3500 fully reconstructed hadronic B, events and 61 500 partially reconstructed semileptonic B, events. The individual analyses show compelling evidence for B⁰s - B⁻⁰s oscillations, and the combination yields a clear signal. The probability that random fluctuations could produce a comparable signature is 8 x 10-8, which exceeds the 5 standard deviations threshold of significance for observation. / (cont.) The discovery threshold would not be achieved without inclusion of the partially reconstructed hadronic decays. We measure .... consistent with the Standard Model expectation. / by Jeffrey Robert Miles. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2013. / In title on title-page, "[square root of]" appears as the mathematical symbol. Cataloged from PDF version of thesis. / Includes bibliographical references (p. 153-158). / We have performed a search for the production of the standard model Higgs boson decaying to diphotons in pp collisions at the LHC at [square root of]s = 7-8 TeV with the CMS detector. Having analyzed data corresponding to 5.1 fb-1 at [square root of]s = 7 TeV (2011) and 5.3 fb-1 at [square root of]s = 8 TeV (2012), a statistically significant excess of events is observed with respect to the background prediction. Interpreted as a standard model Higgs, this excess has a local significance of 4.1 standard deviations, with the maximum significance occurring for a Higgs mass of 125 GeV. Taking into account the trials factor given the search range of 110 GeV to 150 GeV in Higgs mass, this excess has a global significance of 3.2 standard deviations. This constitutes evidence for a new particle decaying to diphotons with a mass of around 125 GeV. The rate of observed events is consistent with predictions for the standard model Higgs boson. / by Joshua Lorne Bendavid. / Ph.D.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1998. / Includes bibliographical references (leaf 56) and index. / by Anthony Rene Salas. / B.S.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1999. / Includes bibliographical references (p. 279-284). / by George A. Heintzelman. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1999. / Includes bibliographical references (leaves 209-222). / by Igor P. Bilinsky. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2014. / 127 / Title as it appears in MIT commencement exercises program, June 6, 2014: Few uses of low-dimensional gauge theory Cataloged from PDF version of thesis. / Includes bibliographical references (pages 201-209). / In this thesis we discuss aspects of strongly coupled gauge theories in two and three dimensions. In three dimensions, we present results for the scaling dimension and transformation properties of monopole operators in gauge theories with large numbers of fermions. In two dimensions, we study (0,2) gauge theories as a tool for constructing string backgrounds with non trivial H-flux. We demonstrate how chiral matter content in the gauge theory allows the construction of infrared fixed points outside of the usual Calabi-Yau framework, and further derive consistency relations for a special class of torsional models. / by Ethan Stanley Dyer. / Ph. D.