Forward Heavy Quarkonium Productions at the LHC

Understand

We investigate the low transverse momentum heavy quarkonium ($J/\psi$, $\Upsilon$) productions in the forward rapidity region of $pp$ and $pA$ collisions at the LHC as an important probe to the transverse momentum tomography of the gluons in hadrons in the Color Glass Condensate (CGC) framework.

• By implementing the Sudakov resummation consistently in the CGC formalism, we achieve an excellent agreement between the improved CGC calculations and the LHC data.
• We show that both the small-$x$ and the Sudakov effects are essential for a complete description of heavy quarkonium productions in the low transverse momentum region.
• This provides a solid foundation to study the small-$x$ gluon saturation in a big nucleus with the future $pA$ programs at the LHC.