Theory seminar: Ben Ruijl

Thursday, 29 October 2020 from to (Europe/Amsterdam)
at Nikhef
   Local Unitarity: a representation of differential cross-sections that
   is locally free of infrared singularities at any order
One of the major challenges in computing higher-order corrections of
   collider observables is the treatment of infrared singularities. Local
   Unitarity is a novel representation of differential scattering
   cross-sections that locally realises the direct cancellation of
   infrared singularities exhibited by its so-called real-emission and
   virtual degrees of freedom. We take advantage of the Loop-Tree Duality
   representation of each individual forward-scattering diagram and we
   prove that the ensuing expression is locally free of infrared
   divergences, applies at any perturbative order and for any process
   without initial-state collinear singularities. Our representation is
   especially suited for a numerical implementation and we demonstrate its
   practical potential by computing fully numerically and without any IR
   counterterm the next-to-leading order accurate differential
   cross-section for the process e+ e− -> d d. We also show first results
   beyond next-to-leading order by computing interference terms part of
   the N4LO-accurate inclusive cross-section of a 1 -> 2 + X scalar
   scattering process.