Nov 25 – 29, 2019
University of Pavia
Europe/Rome timezone

The High-Energy Limit of 2 to 2 Partonic Scattering Amplitudes

Nov 28, 2019, 5:00 PM
Aula Foscolo (University of Pavia)

Aula Foscolo

University of Pavia

Via Strada Nuova 65, Pavia


Prof. Einan Gardi (University of Edinburgh )


Recently, there has been significant progress in computing scattering amplitudes in the high-energy limit using rapidity evolution equations. I describe the state-of-the-art and demonstrate the interplay between exponentiation of high-energy logarithms and that of infrared singularities.
The focus in this talk is the imaginary part of 2 to 2 partonic amplitudes, which can be determined by solving the BFKL equation. I demonstrate that the wavefunction is infrared finite, and that its evolution closes in the soft approximation. Within this approximation I derive a closed-form solution for the amplitude in dimensional regularization, which fixes the soft anomalous dimension to all orders at NLL accuracy.
I then turn to finite contributions of the amplitude and show that the remaining `hard’ contributions can be determined algorithmically, by iteratively solving the BFKL equation in exactly two dimensions within the class of single-valued harmonic polylogarithms.
To conclude I present numerical results and analyse large-order behaviour of the amplitude.

Primary authors

Prof. Einan Gardi (University of Edinburgh ) Dr Joscha Reichel (University of Edinburgh ) Prof. Simon Caron-Huot (McGill University) Dr Leonardo Vernazza (Nikhef)

Presentation materials