Gavin Salam's web
A BFKL alien

This page contains material intended to supplement hep-ph/0204287, written in collaboration with Ciafaloni, Colferai and Stasto. It provides mpeg movies showing the evolution of BFKL "cigars" as one varies the total rapidity Y of a high energy collision. These cigars indicate the regions in rapidity and (log) transverse momentum space which contribute significantly to the BFKL evolution.

The movies illustrate the transition to the non-perturbative region, which in certain situations occurs through an abrupt tunneling transition.

They are given for three values of t=lnQ2, where Q2 is the scale of the colliding objects. The evolution used is leading-log BFKL with a coupling which runs as a function of the emitted transverse momenta. The non-perturbative region is modeled by a cutoff at t=4 (except in the last set of movies). The values used are not intended to be phenomenologically relevant, but rather have been chosen to illustrate the dynamics at play.

The links labeled "ducks" show vertical cross sections through the centers of the movie frames, as a function of Y.

The picture on the left (a BFKL "alien") is a frame from one of the movies (t=20) illustrating a transition (tunneling) stage.

t=30 (as in hep-ph/0204287) small mpeg (288k) large mpeg (528k) duck (png)
t=20 small mpeg (472k) large mpeg (800k) duck (png)
t=10 (showing a mixture of diffusion and tunneling) small mpeg (320k) large mpeg (560k) duck (png)
t=10, tcutoff=2 small mpeg (328k) large mpeg (568k) duck (png)

Gavin Salam

Last modified: Mon Sep 6 14:48:28 CEST 2004