The exclusive photoproduction of Upsilon state Υ(1S) and its radially excited states Υ(2S, 3S) is investigated in the context of ultra-peripheral collisions at the LHC energies. Predictions are presented for their production in proton-proton, proton-nucleus and nucleus-nucleus collision at the energies available at the LHC run 2. The rapidity and transverse momentum distributions are shown, and the robustness of the model is tested against the experimental results considering ψ(1S, 2S) and Υ(1S) states. The theoretical framework considered in the analysis is the light-cone color dipole formalism, which includes consistently parton saturation effects and nuclear shadowing corrections.

The field equations of the pseudo‐complex general relativity (pc‐GR) have an extra term, of repulsive character, which may halt the gravitational attractive collapse of matter distributions in the evolution process of compact stars. This additional term simulates the presence of dark energy in the Universe. In this paper, we explore the presence of this additional term and study the role of dark energy in the structure of neutron stars composed by nucleons, hyperons, mesons, and weakly interacting massive fermion dark matter particles (WIMPs) held together by the nuclear force and the gravitational interaction superimposed on the repulsive background of dark energy. To describe the hadron–lepton sector, we consider three different effective models, Zimanyi–Moszkowski, Boguta–Bodmer, and the analytic parameterized coupling model, which we extend to consider, in the baryonic sector, the presence of the whole fundamental baryon octet. By solving the Tolman‐Oppenheimer‐Volkoff (TOV) equations, we estimate the maximum gravitational mass of neutron stars.

The exclusive photoproduction of Υ(nS) states were calculated in ultra-peripheral collisions for coherent and incoherent process in PbPb at √ sNN = 5.5 TeV. Different dipole models were compared in the theoretical framework of light-cone color dipole formalism. Moreover, it was calculated the differential cross section for the Upsilon states and their total cross section for two intervals of rapidity: |y| ≤ 4 4 and 2 ≤ y ≤ 4.5. A systematic study is done on the theoretical uncertainties associated to the production and predictions are presented for the first time for the incoherent cross section of the radially excited states.

In this work we consider the QCD parton saturation models to describe soft interactions at the high energy limit. The total and elastic cross sections as well as the elastic slope parameter are obtained for proton-proton and pion-proton collisions and compared to recent experimental results. The analyses are done within the color dipole formalism taking into account saturation models which have been tested against DIS data. The main point is that the match between soft and hard interaction occurs in the saturation region which can be described by high density QCD approaches. Discussion is performed on the main theoretical uncertainties associated with calculations.

In this paper, we analyze the exclusive vector meson photoproduction in the recent run using xenon ions at energy of 5.44 TeV performed by the Large Hadron Collider. We focus on the ultraperipheral collisions and provide theoretical predictions for coherent and incoherent cross sections within the color dipole approach and gluon saturation framework. The rapidity distribution is investigated in both cases and comparison to other approaches available in the literature is completed. We show that the expected yields are enough to perform reliable cross section measurements for light mesons as ρ 0 and ϕ.