31st International Workshop on Deep Inelastic Scattering

Confronting Next-to-Leading Order CGC/Saturation Approach with HERA Data

Non programmé

20m

Maison MINATEC, Grenoble, FRANCE

Regular parallel talk WG2: Small-x, Diffraction and Vector Mesons

Orateur

Jose Garrido (Universidad Técnica Federico Santa María)

Description

We present the results obtained by confronting the next-to-leading order (NLO) CGC/saturation approach, as outlined in Ref. [Eur. Phys. J. C 80, 1029 (2020)], with the experimental combined HERA data. The model includes two features that are in accordance with our theoretical knowledge of deep inelastic scattering: the use of analytical solution for the non-linear Balitsky-Kovchegov (BK) evolution equation and the exponential behavior of the saturation momentum on the impact parameter $b$-dependence, which reproduce the correct behaviour of the scattering amplitude at large $b$ in accord with Froissart theorem. The model results are then compared to data at small-x for the structure function of the proton $F_2$, the longitudinal structure function $F_L$, the charm structure function $F_2^{c\overline{c}}$, the exclusive vector meson ($J/\psi ,\varphi ,\rho$) production and Deeply Virtual Compton Scattering (DVCS). We obtained a good agreement for the processes in a wide kinematic range of $Q^2$ at small $x$. These results provide a strong guide for finding an approach, based on Color Glass Condensate/saturation effective theory for high energy QCD, to make reliable predictions from first principles as well as for forthcoming experiments like the Electron-Ion Collider (EIC) and the LHeC.