Alexander Pushnitski King's College London A new identity in scattering theory in Hamiltonian mechanics Wednesday 2nd Sep 14:05-14:55pm, Eastern Avenue Lecture Theatre. This is a joint work with Vladimir Buslaev (St.Petersburg). In this talk, I will survey the basic notions of scattering theory in Hamiltonian mechanics and define the Poincare scattering map. I will emphasise the analogies between scattering theory in Hamiltonian mechanics and quantum scattering theory. I will also discuss a certain new identity in Hamiltonian mechanics which is analogous to the Birman-Krein formula in quantum scattering theory. This identity is stated using the language of symplectic geometry and involves the Calabi invariant of the Poincare scattering map.