## Theoretical Particle Physics

### Brent Nelson

Associate Professor

PhD University of California, Berkeley, 2001

(617)373-2956

b.nelson@neu.edu

### Research Summary:

My research interests lie in the area of high energy particle physics beyond the Standard Model. In particular, I am interested in theoretical considerations and phenomenology that may be indicative of string theory in low-energy observations. This field of research is still developing and is very likely to grow significantly in importance with the advent of the LHC and other forthcoming experiments. The wide variety of my investigations are all geared towards answering one fundamental question: what observational evidence can be marshalled to bolster the proposition that some particular string theory construction is a strong candidate for an underlying theory of all interactions?

To truly make contact with the observable world a candidate string model must succeed on three fronts: (1) it must produce the Standard Model gauge group, particle content and superpotential couplings; (2) it must allow for moduli stabilization and supersymmetry breaking that produces a realistic phenomenology; and (3) it must be capable of explaining any new physics signals found at the LHC and other upcoming experiments. My research seeks avenues of attack on each of these challenges.

With the LHC era nearly here, it has become particularly important to focus on the the issue of how observations made at hadron colliders will shape theoretical model-building for the next decade. There are two (related) problems to consider. First, how well do standard search and measurement techniques fare in situations slightly different from the standard supersymmetric benchmark models of the MSSM? Second, how can multiple observations be brought together to produce a unique and accurate picture of the underlying Lagrangian for the new physics we hope to discover at the LHC? I have devoted much recent thought on these topics, and plan to continue to do so over the next two to three years.

### Recent Publications:

Mary K. Gaillard and B.D. Nelson, “Kahler Stabilized, Modular Invariant Heterotic String Models”, **International Journal of Modern Physics** A22 (2007) 1451.

J. Gray, Y.H. He, V. Jejjala and B.D. Nelson, “Vacuum Geometry and the Search for New Physics” **Physics Letters** B638 (2006) 253.

B. Altunkaynak, P. Grajek, M. Holmes, G. Kane and B. D. Nelson, “Studying Gaugino Mass Unification at the LHC,” **Journal of High Energy Physics**, 0904 (2009) 114.

Baris Altunkaynak, Michael Holmes and Brent D. Nelson, “Solving the LHC Inverse Problem with Dark Matter Observations,” **Journal of High Energy Physics**, 0810 (2008) 013.

Junhai Kang, Paul Langacker and Brent D. Nelson, “Theory and Phenomenology of Exotic Isosinglet Quarks and Squarks,” **Physical Review** D77 (2008) 035003.