Engineering topics
Publications and source records attributed to Rogers, Ted.
This talk summarized work done recently to organize the steps for implementing TMD phenomenology in a way optimized for contexts where the extraction and interpretation of hadronic structures and nonperturbative effects is the primary driving motivation.
The strong force which binds hadrons is described by the theory of quantum chromodynamics (QCD). Determining the character and manifestations of QCD is one of the most important and challenging outstanding issues necessary for a comprehensive understanding of the structure of hadrons. Within the context of the QCD parton picture, the parton distribution functions (PDFs) have been remarkably successful in describing a wide variety of processes. However, these PDFs have generally been confined to the description of collinear partons within the hadron. New experiments and facilities provide the opportunity to additionally explore the transverse structure of hadrons which is described by generalized parton distributions (GPDs) and transverse-momentum-dependent parton distribution functions (TMD PDFs). In our previous report Lin et al. (2018), we compared and contrasted the two main approaches used to determine the collinear PDFs: the first based on perturbative QCD factorization theorems, and the second based on lattice-QCD calculations. In the present report, we provide an update of recent progress on the collinear PDFs, and also expand the scope to encompass the generalized PDFs (GPDs and TMD PDFs). We review the current state of the various calculations, and consider what new data might be available in the near future. We also examine how a shared effort can foster dialog between the PDF and lattice-QCD communities, and yield improvements for these generalized PDFs.
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We investigate the so-called Lorentz invariance relations from the standpoint of the proper definitions of partonic correlations functions resulting from factorization; that is in light the proper treatment of ultraviolet divergences. We show that there are corrections to the naive Lorentz invariance relations are nontrivial even in very simple renormalizable quantum field theories. We also discuss the implications for phenomenological applications.
The research reports on the development of a whole-field, system-level interferometry technique having phase-synchronized data acquisition and adjustable phase triggering. The technique utilizes a Fizeau interferometer, arbitrary function generator, oscilloscope, trigger filter, and CCD camera to determine the out-of-plane modal frequencies of a thin, highly reflective membrane. The technique generates phase-adjustable CCD camera trigger signals that are synchronized to the audio frequency excitation signal. The surface figures from the resulting interferograms were evaluated with fringe-following software and compared against that of an ideal membrane vibrating at resonance.
A full-aperture, interferometric method for measuring the modal characteristics of the Advanced Mirror System Demonstrators (AMSDs) will be presented. The method involves stroboscopic surface figure measurement using an interferometer capable of simultaneous phase-shift measurements. Results of bread-board experiments will be presented as well as the plan for cryo measurements of the AMSDs.