Speaker
Description
We analyse the high precision HERA $F_2$ data in the low-$x$, $x<0,01$, and very-low-$x$, $x<0.001$, regions using $\lambda$-fits. $\lambda$ is a measure of the rate of rise of $F_2$ defined by $F_2 \propto (1/x)^{\lambda}$. We show that $\lambda$ determined in these two regions, at various $Q^2$ values, is systematically smaller in the very-low-$x$ region as compared to the low-$x$ region. We discuss some possible physical interpretations of this effect.
Our observation that the value of the exponent $\lambda$ decreases at small values of $x$, indicates that measurements at the future ep colliders, like VHEeP or LHeC will become exciting, as they will approach the high energy limit of the virtual photon-hadron cross sections, where DGLAP and BFKL meets and the confinement effects should become simple.
The analysis is based on Phys.Lett. B802 (2020) 135199.
