Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1994. / On t.p., "[yields]" appears as a rightward arrow. Vita. / Includes bibliographical references (p. 317-327). / by Vincent Cianciolo. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1996. / Includes bibliographical references (p. 217-224). / by Bernard B. Beard. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (pages 193-201). / This thesis concerns the observation of a new particle and the measurements of its properties, from the search of the Higgs boson through its decay into two photons at the CMS experiment at CERN's Large Hadron Collider (LHC), on the full LHC "Run I" data collected by the CMS detector during 2011 and 2012, consisting of proton-proton collision events at [square root of] s = 7 TeV with L = 5.1 fb-1 and at [square root of] s = 8 TeV with L = 19.7 fb-1, with the final calibration. In particular, an excess of events above the background expectation is observed, with a local significance of 5.7 standard deviations at a mass of 124.7 GeV, which constitutes the observation of a new particle through the two photon decay channel. A further measurement provides the precise mass of this new particle as 124.72+0.35 -0.36 GeV = 124.72+0.31 -0.32(stat)+0.16 -0.16(syst) GeV. Its total production cross section times two photon decay branching ratio relative to that of the Standard Model Higgs boson is determined as 1.12+0.26 -0.23 = 1.12+0.21 -0.21(stat)+0.15 -0.09(syst), compatible with the Higgs boson expectation. Further extractions of its properties relative to the Higgs boson, including the production cross section times decay branching ratios for separate Higgs production processes, couplings to bosons and to fermions, and effective couplings to the photon and to the gluon, are all compatible with the expectations for the Standard Model Higgs boson. / by Mingming Yang. / Ph. D.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2009. / Includes bibliographical references (p. 63-65). / We use a sample of 53 elliptical galaxies which are lensing background emission-line galaxies and have been observed by the SLACS collaboration using HST and SDSS to place constraints on the post-Newtonian parameter 7 and the cosmological parameter A. We find y = 1.00 ± 0.04 on kiloparsec scales, consistent with the predictions of general relativity. Assuming a flat universe, we constrain QA = 0.72 ± 0.15, in agreement with results from other independent techniques and strongly excluding h = 0. We also use these lenses as a probe of galactic dynamics, finding constraints which are consistent with those obtained via other methods. / by Josiah Schwab. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1993. / Includes bibliographical references (p. 201-206). / by William Michael Schmitt. / Ph.D.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2005. / Includes bibliographical references (leaf 55). / Using canonical quantization we show that the spectrum of the scalar cosmological fluctuations as calculated until now is not correct. We derive the correct expression for the spectrum, and show that our correct treatment alleviates the fine-tuning problem in inflation. / by Svetlin Valentinov Tassev. / S.B.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 99-105). / We first demonstrate theoretically and experimentally that electromagnetic resonators with high quality factors (Q) can be used to transfer power efficiently over distances substantially larger than the characteristic dimensions of the resonators by operating in a so-called "strongly coupled" regime. We next generalize the notion of strongly coupled resonances to a system comprising one power source and multiple receivers in a regime of broad practical applicability and show that, by appropriately tuning the parameters of the system, it is possible to significantly improve the overall efficiency of the wireless power transfer relative to the single-source and single-receiver configuration. We experimentally verify the predicted improvement in efficiency for a system consisting of one large source (area ~ 1 m2 ) coupling to two much smaller receivers of dimensions comparable to those of many portable electronic devices (area ~ 0.07 m2 ). Next, we present a novel design for an electrical conductor whose structure is optimized to have the lowest achievable resistance in the 2-20 MHz frequency range, where it can offer performance an order of magnitude better than the best currently available conductors. The two following chapters deal with energy transport in photonic crystals. We first investigate numerically how a square lattice of dielectric rods may be used to collimate a laser beam and the feasibility of using this system as a chemical sensor. Finally, we present and demonstrate through specific examples a systematic and general procedure, which is both computationally inexpensive and straightforward to implement, for coupling strongly dissimilar waveguides with 100% transmission. / by André B. Kurs. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 193-203). / Introduction: Over the centuries we have been studying the world around us, discovering new physics at new length scales. Starting from our everyday experience which ranges from scales of about 10[superscript 3] to 10[superscript -3] meters (m), we encounter phenomena like gravity, contact forces, fluid dynamics and light. When we move on to the smaller scales of cells at 10[superscript -5] m or molecules and atoms around 10[superscript -10] m, we pass entire fields of science such as biology and chemistry. It is surprising that the underlying physics that leads to this rich variety of phenomena is simply (quantum) electrodynamics. The nucleus of the atom at scales of 10[superscript -15] m is made of protons and neutrons and is held together by the nuclear force. This is a residual force coming from the strong force, also known as Quantum Chromodynamics (QCD). QCD is responsible for confining the quarks to protons and neutrons. The remaining force that is part of the well established Standard Model of particle physics is the weak force, which for example plays a role in some hadron decays. With the Large Hadron Collider (LHC) at CERN starting to take data, we will be probing nature at smaller length scales than before and hope to discover new physics. In order to reconstruct new short distance physics from the measured leptons and QCD radiation, one typically looks for a signal with a certain number of jets of energetic hadrons. This thesis explores the effect of such restrictions on the hadronic final state in theoretical calculations, with an emphasis on the 0-jet case which allows us to study initial-state radiation. An introduction to the work in this thesis can be found in the next section ... / by Wouter J. Waalewijn. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 118-128). / AMS-02 is a precision particle physics experiment in space aiming to study dark matter, antimatter, and properties of cosmic rays to the TeV energy scale. This thesis presents a study of the cosmic ray positron fraction in AMS-02 data covering an energy range of 0.5 GeV to 500 GeV, and identifies 10.3 x 106 electron and 650 x 101 positron events. The results show that the positron fraction increases with energy and reaches a maximum at 275 ± 32 GeV. / by Matthew Scott Krafczyk. / Ph. D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2005. / Includes bibliographical references (leaves 189-198). / We study strong interaction effects in nonleptonic decays of ... mesons with energetic particles in the final state. An introduction to Soft Collinear Effective Theory (SCET), the appropriate effective field theory of QCD for such decays, is given. We focus on decays of the type ... where M is a light energetic meson of energy E. The SCET formulates the problem as an expansion in powers of where Q [approx.] ... . A factorization theorem is proven at leading order that separates the physics of the scales ... . In addition, the factorization theorem decouples energetic degrees of freedom associated with the light meson allowing us to derive heavy quark symmetry relations between the ... type amplitudes. A new mechanism for the generation of non-perturbative strong phases is shown within the framework of factorization. Heavy quark symmetry relations are shown to apply for these strong phases as well. Furthermore, the strong phases for certain light mesons in the final state are shown to be universal. The analysis is extended to ... type decays with isosinglet light mesons and excited charmed mesons in the final state respectively. A host of other phenomenological relations are derived and found to be in good agreement with available data. / by Gautam Mantry. / Ph.D.