On Monday, Feb. 19, at 1 p.m., André Baião Raposo of the University of Edinburgh will present "Two Troubled Hadrons in a Box: Solving Left-Hand Cut Issues in the Lüscher Scattering Formalism" via Zoom.
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Abstract: The Lüscher formalism is a widely used method in the study of scattering processes through lattice QCD. It allows one to relate finite-volume spectrum information obtained in lattice calculations to scattering amplitudes. Recent lattice results for systems where a lighter particle can couple to heavier scattering particles (nucleon-nucleon or DD* scattering) have highlighted the limitations of the standard formalism below the two-particle threshold. Due to the presence of left-hand cuts in the angular-momentum-projected scattering amplitudes, the method leads to inconsistencies if applied far enough below threshold that one hits these cuts. In this talk, I describe an extension of the existing formalism that circumvents this issue for the nearest left-hand cut and present the full workflow to hence obtain the scattering amplitude.