002734101 001__ 2734101
002734101 005__ 20210426092032.0
002734101 0248_ $$aoai:cds.cern.ch:2734101$$pcerncds:FULLTEXT$$pcerncds:CERN:FULLTEXT$$pcerncds:CERN
002734101 037__ $$aCERN-TH-2020-161
002734101 084__ $$2CERN Library$$a2020-161
002734101 100__ $$aBellazzini, Brando
002734101 245__ $$aPositive Moments for Scattering Amplitudes
002734101 260__ $$c2020
002734101 269__ $$aGeneva$$bCERN$$c28 Sep 2020
002734101 300__ $$a17
002734101 520__ $$aWe find the complete set of conditions satisfied by the forward 2-to-2 scattering amplitude in unitarity and causal theories. These are based on an infinite set of energy dependent quantities – the arcs – which are dispersively expressed as moments of a positive measure defined at (arbitrarily) higher energies. We identify optimal finite subsets of constraints, suitable to bound Effective Field Theories (EFTs), at any finite order in the energy expansion. At tree-level arcs are in one-to-one correspondence with Wilson coefficients. We establish under which conditions this approximation applies, identifying seemingly viable EFTs where it never does. In all cases, we discuss the range of validity in both couplings and energy. We also extend our results to the case of small but finite t. A consequence of our study is that EFTs in which the scattering amplitude in some regime grows in energy faster than E^6 cannot be UV-completed.
002734101 595__ $$aCERN EDS$$bTHPHREQ$$c0.1
002734101 595__ $$aCERN-TH
002734101 65017 $$2SzGeCERN$$aParticle Physics - Theory
002734101 690C_ $$aPREPRINT
002734101 690C_ $$aCERN
002734101 700__ $$aMiro, Joan Elias
002734101 700__ $$aRattazzi, Riccardo
002734101 700__ $$aRiembau, Marc
002734101 700__ $$aRiva, Francesco
002734101 859__ $$fbrando.bellazzini@cern.ch
002734101 8564_ $$82272195$$s2568996$$uhttp://cds.cern.ch/record/2734101/files/CERN-TH-2020-161.pdf
002734101 916__ $$sn$$w202101
002734101 960__ $$a11
002734101 980__ $$aPREPRINT
002734101 980__ $$aCERN