SMEFT, Collider, Primordial Black Hole, Dark Matter, and Gravitational Wave Phenomenology

Sam Houston State University, Huntsville TX

Investigators

Abstract

This award funds the research of Professors James B. Dent, William Shepherd, and Joel W. Walker at Sam Houston State University. Dent, Shepherd, and Walker explore theoretical physics and its connections to experimental results in the areas of Standard Model Effective Field Theory (SMEFT), collider physics, primordial black holes, dark matter, and gravitational wave phenomenology. Effective field theory is a very general approach to organizing searches for new physics that is independent of any one specific model. The Large Hadron Collider (LHC) generates the highest energy particle collisions of any machine on Earth, looking for the existence of unknown particles and interactions. Primordial black holes (PBHs) may have been formed in the very early history of our Universe, making them an attractive candidate to explain dark matter. Although the particle properties of dark matter remain mysterious, observations related to the motion and gravitational pull of galaxies and radiation left over from the early universe suggest that roughly one-quarter of the energy density of the universe exists in this invisible, non-shining form. Gravitational waves are vibrations in the structure of spacetime which provide clues about cataclysmic cosmic events such as the merger of black holes, as first observed in the last decade. This project will advance the national interest in fundamental science by exploring and connecting each of these research areas in particle physics, contributing models, search strategies, data analysis, and software tools. Significant broader impacts will be realized through the research training of students at SHSU. This project will develop those students’ analytical, numerical, and creative skills, through participation in journal publications and conference presentations. That effort will help to create the foundation for students to thrive in a future doctoral program, or for successfully transitioning into technically demanding careers in industry. In addition, the professors are publishing a new textbook based on their “Physics Bootcamp” course at SHSU, which introduces essential first and second year mathematics in a physics context and will extend a successfully redesigned course for primary school educators to include online sections. More technically, the LHC physics program is currently transitioning into a long phase of high-luminosity data collection. Since new physics has not yet manifested in obvious ways, the community must shift concentration to processes which may be kinematically concealed, or which require large statistics for discrimination, or which are intrinsically rare. This project advances that worldwide effort by investigating collider signatures of new physics in terms of indirect effects encapsulated by the SMEFT, testing applications of a new scale-invariant jet clustering algorithm, and the development of public software tools that will facilitate such analyses, especially via machine learning. For PBHs, novel search avenues for detection and phenomenological links to BSM physics models will be explored, including connections between Hawking radiation, superradiance, and gravitational waves. For dark matter physics, direct and indirect detection efforts to characterize properties such as mass (focused in the sub-GeV mass range), spin, and non-gravitational interactions will be explored both theoretically and through interpretations of upcoming data such as that from LZ, XENON, and JWST. The connection between particle physics models and gravitational waves will be explored using current observatories such as NANOGrav and LIGO, along with upcoming observatories including LISA, in searches for gravitational waves produced in association with possible phase transitions in the early universe or from PBH formation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.