Professor Yao primarily studies quantum field theory and particle physics. His focus has been how to use quantum field theory as a tool to formulate general framework and to extract physical consequences. He and his team have been working on problems where there are various scales, such as disparate masses. He has formulated theoretical framework to deal with these problems in general.

Professor Yao is also very interested in the issue of masses, which is a window into the extension of the Standard Model. This idea correlates with the effective field theory. Anticipating new precision experimental results from b-factories and other facilities, Professor Yao and one of his research fellows have developed a general way to evaluate two-loop Feynman diagrams, which fully respects the mass structure and the kinematics of the process under consideration.

Professor Yao is a Fellow of the American Physical Society.

**Selected Publications**

NNLL QCD Corrections to the Decay B?¨X(S) L+ L-, (A. Ghinculov, T. Hurth, G. Isidori, Y.P. Yao), *SLAC-PUB-9580*, *CERN-TH-2002-263*, **8**, submitted to *Nucl. Phys.* **B** e-Print Archive: hep-ph/0211197 (November, 2002).

Exclusive Semi-Leptonic Decays of B Meson into Light Mesons, (with R. Akhoury and G. Sterman), *Phys. Rev.* **D 50**, 358 (1994).

Exact ƒ¿s Calculation of b?¨s + ƒÁ, b?¨s + g, (with K. Adel), *Phys. Rev.* **D 49**, 4945 (1994).

Modification of the Equivalence Theorem Due to Loop Corrections, (with C.P. Yuan), *Phys. Rev.* **D 38**, 2237 (1989).

Soft Breaking of Two Loop Finite N=1 Supersymmetric Gauge Theories, (with D.R.T. Jones and L. Mezincescu), *Phys. Lett.* **B 148**, 317 (1984).

Decoupling, Effective Lagrangian, and Gauge Hierarchy in Spontaneously Broken Non-Abelian Gauge Theories, (with Y. Kazama), *Phys. Rev.* **D 25**, 1605 (1982).