Searching for New Physics in B decays at BaBar

The study of CP violation at the B factories allows us to perform
quantitative tests of the CP sector of the Standard Model.
Accurate measurements of the sides and angles of the Unitarity Triangle
determine the parameters rho and eta of the theory, while redundant
measurements of the same quantities allow us to probe physics Beyond the
Standard Model.

The recent measurements of the B_s mixing frequency at the Tevatron have
dramatically improved our knowledge of |V_td/V_ts|, the right side of the
Unitarity Triangle. This opens up a new opportunity for probing New
Physics through an independent determination of the same quantity. In this
talk, I will discuss how such a measurement can be made using decays of
B->rho gamma and B->K* gamma, and show our recent results.