Formulation of many real-life problems evolves when the problem is being solved. For example, a change in the environment might appear after the initial problem specification and this change must be reflected in the solution. Such changes complicate usage of a traditionally static constraint satisfaction technology that requires the problem to be fully specified before the solving process start...

We propose an all-order perturbative expression for the dressing phase of the AdS5 × S string S-matrix at strong coupling. Moreover, we are able to sum up large parts of this expression. This allows us to start the investigation of the analytic structure of the phase at finite coupling revealing a few surprising features. The phase obeys all known constraints including the crossing relation and...

We study B → φK and B → φXs decays in the heavy quark limit using perturbative QCD. The next leading order corrections introduce substantial modifications to the naive factorization results (more than 50%). The branching ratio Br(B → φK) is predicted to be in the range (FB→K 1 (mφ)/0.33)(3.8 ∼ 4.0)× 10−6 which is within the one σ allowed region from the central value of 6.2×10−6 measured by CLE...

The problem of bound states in effective field theories is studied. A rescaled version of nonrelativistic effective field theory is formulated which makes the velocity power counting of operators manifest. Results obtained using the rescaled theory are compared with known results from NRQCD. The same ideas are then applied to study Yukawa bound states in 1 + 1 and 3 + 1 dimensions, and to analy...

The potential between a heavy quark and antiquark has been one of the first quantities to be studied in QCD: it is a privileged object for exploring the interplay of perturbative and non-perturbative QCD and the set in of confinement, and it plays a central role in quarkonium physics [1]. Nowadays, the progress of perturbative and lattice calculations requires an accurate and rigorous definitio...