LHCb is one of the four LHC experiments which started collecting pp collisions in 2010 at a centre-of-mass energy of 7 TeV. With its forward geometry, LHCb is dedicated to the study of heavy-flavor production and decay. The solid understanding of the muon triggers and identification is a crucial milestone towards the sophisticated analyses searching for new physics or CP violation in B decays. We present the study of the production of quarkonia resonances in the dimuon sample collected in the first year of data taking, corresponding to 37 pb-1. The promptly-produced J/psi and psi(2S) are separated from the b-hadron decay products using topological information.
We will discuss the measurements of the double differential production cross-section of J/psi and Upsilon states, as well as their impact on the understanding of quarkonia production. The results will be shown in the framework of different theory models.