In this work we investigate the exclusive photoproduction of J=c and the radially excited c ð2SÞ state off nucleons in proton-proton collisions. The theoretical framework considered in the analysis is the light-cone dipole formalism and predictions are done for proton-proton collisions at the CERN-LHC energy of 7 TeV. The theoretical uncertainties are investigated and a comparison is made to the recent LHCb Collaboration data for the exclusive charmonium production.

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In this work we investigate the photoproduction of radially excited vector mesons off nuclei in heavy ion relativistic collisions. In particular, we analyze the exclusive photoproduction of ψ(2S) off nuclei, evaluating the coherent and the incoherent contributions to that process. The theoretical framework used in the present analysis is the light-cone dipole formalism and predictions are done for PbPb collisions at the CERN-LHC energy of 2.76 TeV. The theoretical uncertainties are analyzed and comparison is also done to the recent ALICE Collaboration data for the ψ(1S) state photoproduction.

We present results for the low mass Drell-Yan production in proton-proton collisions at the LHC in the color dipole formalism. The DY differential cross sections at √ s = 7 TeV as a function of dilepton rapidity, transverse momentum and invariant mass are discussed. We have imposed kinematical cuts related to the low mass DY production investigated by ATLAS and LHCb collaborations.

The photonuclear production of vector mesons in ultraperipheral heavy ion collisions is investigated within the collinear approach using different parameterizations for the nuclear gluon distribution. The integrated cross section and the rapidity distribution for the AA → V AA (V = J/Ψ, Υ) process are computed for energies of RHIC and LHC. A comparison with the recent PHENIX data on coherent production of J/Ψ mesons is also presented. We demonstrate that the study of the exclusive quarkonium photoproduction can be used to constrain the nuclear effects in the gluon distribution. 13.60.Le A systematic measurement of the nuclear gluon distribution is of fundamental interest in understanding the parton structure of nuclei and to determine the initial conditions of the quark gluon plasma (QGP) predicted to be formed in central heavy ion collisions (See e.g. [1]). Another important motivation for the determination of the nuclear gluon distribution is that the high density effects expected to occur in the high energy limit of QCD should be manifest in the modification of the gluon dynamics [2]. At the moment the behavior of this distribution is completely undetermined by the fixed target experiments, with a possible improvement in the future electron-nucleus colliders (See e.g. [3,4]). However, as the date of construction and start of operation of these colliders is still in debate, we need to obtain alternative searches to estimate the medium effects in the nuclear gluon distribution. It has motivated several authors to propose the study of different observables in distinct processes to constrain the nuclear gluon distribution (For a recent review see Ref.[5]). In particular, in Ref. [6] it was proposed to study the vector meson production in ultraperipheral heavy ion collisions at RHIC and LHC in order to constrain the nuclear medium effects present in the nuclear gluon distribution. The basic idea is that in these collisions the high flux of quasi-real photons from one of the nucleus provides a copious source of photoproduced reactions [7,8,9,10]. A photon stemming from the electromagnetic field of one of the two colliding nuclei can penetrate into the other nucleus and interact with one or more of its hadrons, giving rise to photon-nucleus collisions to an energy region hitherto unexplored experimentally. For example, the interaction of quasi-real photons with protons has been studied extensively at the electron-proton collider at HERA (For a recent review see Ref.[11]). The obtained γp center of mass energies extends up to W γp ≈ 300 GeV, an order of magnitude larger than those reached by fixed target experiments. Due to the larger number of photons coming from one of the colliding nuclei in heavy ion collisions, a similar and more detailed study will be possible in these collisions, with W γN reaching 950 GeV for the Large Hadron Collider (LHC) operating in its heavy ion mode [7,8,9,10]. As the cross section for the diffractive vector meson production depends (quadratically) on the gluon distribution, it gives...