A copy of this work was available on the public web and has been preserved in the Wayback Machine. The capture dates from 2019; you can also visit the original URL.
The file type is
We study the 2→2 S-matrix element of a generic, gapped and Lorentz invariant QFT in d=1+1 space time dimensions. We derive an analytical bound on the coupling of the asymptotic states to unstable particles (a.k.a. resonances) and its physical implications. This is achieved by exploiting the connection between the S-matrix phase-shift and the roots of the S-matrix in the physical sheet. We also develop a numerical framework to recover the analytical bound as a solution to a numericaldoi:10.1007/jhep09(2018)052 fatcat:byzxwbn3e5dqldnuqbh4gikz3q