Higgs boson production in high energy proton-nucleus collisions

We study Higgs boson production from gluon-gluon fusion at midrapidity in high energy proton-nucleus collisions. For this process the presently still little known gluon distribution function h₁^⊥g(x,k_⊥) might give a numerically relevant contribution. We show by explicit calculation that using color glass condensate model input the result obtained in the naive kₜ factorization approach matches the result obtained in the transverse momentum dependent factorization framework for a dilute medium. We also verify the earlier finding [P. Sun, B.-W. Xiao, and F. Yuan, Phys. Rev. D 84, 094005 (2011)] that the kₜ factorization formalism for Higgs production breaks down in a dense medium. In doing so, we formulate a hybrid model which allows one to treat such reactions theoretically.