Speaker
Description
We investigate improvements on models of dipole cross-section, one of which was originally proposed by Golec-Biernat and W\"usthoff (GBW), and the other is a DGLAP improved model proposed by Bartels, Golec-Biernar and Kowalski (BGK), which has improved small dipole behaviour.
Both models have been very successful in describing saturation phenomenon in small $x$ DIS.
In this study, we incorporate Sudakov factor which makes the dipole cross-section hard scale $Q^2$ (photon virtuality) dependent.
The parameters are fitted to HERA data and $\chi^2$ value are obtained for each model.
The GBW model, which showed strong deviation from the data with $Q^2$ above $\sim50 \mathrm{GeV}^2$, improves noticeably at large $Q^2$ due to the hard scale dependence. For the data $Q^2<100 \mathrm{GeV}^2$, the $\chi^2$ value is reduced by $\sim10\%$. The $\chi^2$ value of the BGK model improves by $\sim15\%$, for the data $Q^2<650 \mathrm{GeV}^2$.
