Observation of $Z$ production in proton-lead collisions at LHCb (JHEP, 2014)

(untitled) - collaboration, L; Aaij, R; Adeva, B; Adinolfi, M; Affolder, A; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; et al.