Speaker
Yuri Kovchegov
Description
We construct small-x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the g1 structure function. These evolution equations resum powers of αs ln2(1/x) in the polarization-dependent evolution: hence our equations collect powers of the parameter excluded in the DGLAP and CSS evolutions. The full non-linear version of our equations also resums the powers of αs ln(1/x) in the unpolarized evolution which includes saturation effects. The equations are written in an operator form in terms of polarization-dependent Wilson line-like operators. While the equations do not close in general, they become closed and self-contained systems of non-linear equations in the large-Nc and large-Nc and Nf limits. The resulting x-dependence of quark helicity TMD and PDF can be obtained by solving these equations numerically.
