# About the Particle Theory Group

Current Members of the Group:

Peter Freund (Emeritus)

Yoichiro Nambu (Emeritus, Nobel Laureate)

Research Focus:

The theory group investigates the most fundamental constituents of matter and their interactions. The aim is the development of a fundamental theory of particle interactions, consistent with the principles of quantum mechanics and relativity, which could lead to the explanation of phenomena as diverse as (1) chemistry, (2) radioactive decays, (3) nuclear structure, and (4) planetary motion and the behavior of black holes. Each of these first four types of process is governed by a different interaction : Electromagnetism, Weak interactions, Strong interactions and Gravitation. The behavior of black holes represents an open problem: The proper marriage of quantum mechanics with gravity (general relativity).

Important progress has been made in recent decades towards the fulfillment of the above goals. All experiments which not include gravity can be explained by a quantum field theory known as the Standard Model. Explaining the scale of the weak interactions requires some extension of the Standard Model; supersymmetry is a promising candidate for the principle underlying that extension. The incorporation of quantum gravity requires us to go beyond the Standard Model. The best known candidate is based on String Theory.

Areas of recent and ongoing research include:

- Gauge theory/gravity duality
- Brane dynamics and QCD
- Spontaneous supersymmetry breaking
- Geometry of compactification in string models
- Effective field theory in strong interaction dynamics
- Collider signatures of supersymmetry
- Dark matter models and signatures
- Electroweak baryogenesis
- Flavor physics and CP asymmetry
- String Cosmology