Speaker: Anna Stasto (Penn State)

Title:  Gluon and Dipole Cascades on the Light-Front

Abstract: 
The problem of kinematic effects in the gluon and color dipole 
cascades is addressed in the large N_c limit of SU(N_c) Yang--Mills 
theory. We investigate the tree level multi-gluon components of the 
gluon light cone wave functions in the light cone gauge keeping the 
exact kinematics of the gluon emissions. We focus on the components 
with all helicities identical to the helicity of the incoming gluon. 
The recurrence relations for the gluon wave functions are derived. 
In the case when the virtuality of the incoming gluon is neglected 
the exact form of the multi-gluon wave function is obtained. 
Furthermore, we propose an approximate scheme to treat the kinematic 
effects in the color dipole evolution kernel. The new kernel 
entangles longitudinal and transverse degrees of freedom and leads 
to a reduced diffusion in the impact parameter. When evaluated in the 
next-to-leading logarithmic (NLL) accuracy, the kernel reproduces the 
correct form of the double logarithmic terms of the dipole size ratios 
present in the exact NLL dipole kernel. Finally, we analyze the 
scattering of the incoming gluon light cone components off a gluon 
target and the fragmentation of the scattered state into the final 
state. The equivalence of the resulting amplitudes and the 
maximally-helicity-violating amplitudes is demonstrated in the special 
case when the target gluon is far in rapidity from the evolved gluon 
wave function.