ITMP Seminar "Scattering from production in 2d"

Dear Colleagues,

We are pleased to announce that the next ITMP seminar will be held on Wednesday, Feb 3, at 18:00 (Moscow time). The seminar will be arranged via Zoom.

Speaker: Piotr Tourkine, Paris LPTHE, CERN

Title: Scattering from production in 2d

Abstract: In this seminar, I will talk about recent results about a numerical method to find unitary S-matrices. The method, based on works of Atkinson, was invented in the late 60s and was used as a proof of existence of functions that satisfy all of the S-matrix axioms in 4d. However, it was not put in practical use.

Our recent results concern the implementation of those methods for S-matrices in two dimensions, using two different iterative schemes: a fixed-point iteration and Newton's method. Those schemes iterate the unitarity and dispersion relations, and converge to solutions to the S-matrix axioms. This numerical strategy provides a solution to the problem of reconstructing the scattering amplitude starting from a given particle production probability. 

After a general introduction, the talk will be focused on how we implemented the algorithms, what they converge to, and the conditions under which they converge. We will see that the question of convergence naturally connects to the recent study of the coupling maximization in the two-dimensional S-matrix bootstrap. If time allows, I'll also comment on a fractal structure which we observed to be related to the so-called CDD-ambiguities.

I'll conclude with possible future directions.

If you want to join the seminar please register here before 15:00, February 3.

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