The CSS Hamiltonian: high energy evolution of rapidity dependent observables

by Alexander Kovner (UConn)

Tuesday 13 Aug 2024, 11:00 → 13:00 US/Eastern

Small Seminar Room ( https://bnl.zoomgov.com/j/1618286847?pwd=N20xUlNMYjhJVThoQkp5TktJdmQ5dz09)

We consider evolution of observables which depend on a small but fixed value of longitudinal momentum fraction 

x, to high rapidity, such that η>ln1/x. We show that this evolution is not given by the JIMWLK (or BK) equation. We derive the evolution Hamiltonian - HCSS−JIMWLK​ which generates this evolution in the cases of dilute and dense projectile wave function. The two limits yield identical results for HCSS−JIMWLK​. We show that the resulting evolution for the gluon TMD is identical to the (double logarithmic) perturbative Collins-Soper-Sterman evolution equation in the longitudinal resolution parameter at a fixed and very large transverse resolution.