Speaker
Description
We derive a new one-parameter family of manifestly crossing-symmetric dispersion relations for 2→2 scattering amplitudes in quantum field theories. We demonstrate that this parametric crossing-symmetric dispersion relation (PCSDR) both enlarges the convergence domain and improves the convergence rate relative to conventional fixed-t dispersion relations in many cases. For tree-level string-theory amplitudes, using the PCSDR, we obtain new series representations that exhibit poles in all the channels and converge in the full kinematic domain. We then apply this framework to bootstrap weakly coupled gravitational effective field theories and derive nontrivial bounds on their low-energy Wilson coefficients.
Based on arXiv: 2506.03862 [hep-th].