[NT/RBRC seminar] Transverse momentum distributions of quarks and gluons inside the proton

by Prof. Cristian Pisano (U. Cagliari)

Friday 10 May 2024, 11:00 → 13:00 US/Eastern

Large seminar room (https://bnl.zoomgov.com/j/1614715193?pwd=WkwxODVWdzZzb29zQnZRVGp3VTBDQT09)

Although quarks and gluons are confined within hadrons, tests of their fundamental properties and studies of their distributions are possible through scattering processes. In this talk I will discuss how, using data obtained from the scattering of a hard virtual photon off a proton, one can map the density of quarks in three dimensions, i.e., as a function of their longitudinal momentum (along the photon’s direction) and their transverse momentum (orthogonal to the photon). If the proton is unpolarized, the distribution is cylindrically symmetric. On the other hand, if the proton is polarized in the transverse plane, the distributions of up and down quarks turn out to be distorted in opposite directions. This distortion, known as Sivers effect, is related to quark orbital angular momentum. Proposals on how to obtain analogous maps for the gluon densities will be presented as well.