Speaker
Description
Exclusive emissions of vector mesons in forward directions of rapidity offer us a faultless chance to probe the proton structure at small-$x$. Here, a high-energy factorization formula is established within the Balitsky-Fadin-Kuraev-Lipatov (BKFL), given as the convolution of a impact factor depicting the forward-meson emission and of an unintegrated gluon distribution (UGD) driving the gluon evolution at small-$x$. Being a nonperturbative quantity, the UGD is not well known and several models for it have been proposed so far. We present recent progresses on the study of exclusive emissions of forward $\rho$-mesons in lepto-hadronic collisions, showing how osbervables sensitive to different polarization states of the $\rho$-particle act as discriminators for the existing UGD models.
