Anti-collinear resummation in JIMWLK evolution in the linear regime

A bstract The recently-proposed resummation procedure for anti-collinear logarithms in the JIMWLK kernel [1] is studied in the linear (BFKL) regime in the fixed-coupling approximation. Simple closed form expressions for the resummed momentum space kernel and characteristic function χ ( n, γ ) are found. We find that the anti-collinear pole in the leading order characteristic function at γ = 1 disappears, and instead $$ \chi \left(\gamma =1\right)=\frac{12}{11}\frac{\pi }{\alpha_s{N}_c} $$ χ γ = 1 = 12 11 π α s N c for n F = 0. Comparison with the known NLO BFKL eigenvalue, with the target-Bjorken limit ( Q T ≫ Q P ) of the γ * ( Q P ) + γ * ( Q T )-scattering amplitude and with the “all-poles” resummation prescription are presented.