Comment on "ηc\eta_c production in photon-induced interactions at the LHC"

In "$\eta_c$ production in photon-induced interactions at the LHC," \cite{Goncalves:2018yxc} Goncalves and Moreira discuss inclusive and exclusive $\eta_c$ production at $pp$ and $pA$ collisions at LHC energies. The exclusive channels are via two-photon and photon-Odderon interactions. This comment points out that there is a large additional source of almost-exclusive $\eta_c$ in ultra-peripheral collisions: from the radiative decay of $J/\psi$ that are produced in photon-nucleon interactions. Although the $J/\psi\rightarrow\gamma\eta_c$ branching ratio is small, the $J/\psi$ production cross-section is large enough that it dominates over the exclusive channels considered in \cite{Goncalves:2018yxc}, and is comparable to the non-exclusive production. In $J/\psi\rightarrow\gamma\eta_c$, the photon is very soft and therefore easy to miss, and the $\eta_c$ will have very similar kinematics to the $J/\psi$.Comment: 2 page

Prompt J/psi production from Tevatron to LHC

Models with essential non-perturbative QCD dynamics and describing Tevatron data on high-$p_\perp$ charmonium are extrapolated to give predictions of prompt J/psi production at the LHC. Differences of up to an order of magnitude occurs. An important point is here the treatment of higher order perturbative QCD effects.Comment: Presented at the VIII International Workshop on Hadron Physics (Hadrons 2002), Bento Goncalves, Brazil, 14 - 19 April 200

Deconfinement to Quark Matter in Neutron Stars - The Influence of Strong Magnetic Fields

We use an extended version of the hadronic SU(3) non-linear realization of the sigma model that also includes quarks to study hybrid stars. Within this approach, the degrees of freedom change naturally as the temperature/density increases. Different prescriptions of charge neutrality, local and global, are tested and the influence of strong magnetic fields and the anomalous magnetic moment on the particle population is discussed.Comment: To appear in the proceedings of conference XII HADRON PHYSICS April, 22-27, 2012, Bento Goncalves, Wineyards Valley Region, Rio Grande do Sul, Brazil Revised version with corrections made to the text in page