Fully-heavy tetraquark production by γγ\gamma \gamma interactions in hadronic collisions at the LHC

We investigate the production of the fully - heavy tetraquark states $T_{4Q}$ in the $\gamma \gamma$ interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC). We focus on the $\gamma \gamma \rightarrow {\cal{Q}}{\cal{Q}}$ (${\cal{Q}} = J/\psi,\, \Upsilon$) subprocess, mediated by the $T_{4Q}$ resonance in the $s$ - channel, and present predictions for the hadronic cross sections considering the kinematical ranges probed by the ALICE and LHCb Collaborations. Our results demonstrate that the experimental study of this process is feasible and can be used to investigate the existence and properties of the $T_{4c}(6900)$ and $T_{4b}(19000)$ states.Comment: 5 pages, 2 figures, 2 tables. arXiv admin note: substantial text overlap with arXiv:1809.0812

Abaqus UGENS subroutine for nonlinear analysis of periodic panels

This report describes an Abaqus UGENS subroutine for geometric and material nonlinear analysis of periodic panels using the first-order shear deformation theory. The structure is modelled with shell elements, as one layer of equivalent mechanical properties. The subroutine modifies the stiffness matrix of each shell element of the mesh separately based on its strain state. It relies on pre-computed stiffness curves that define the ABCD stiffness matrix of a unit cell. By looking at combinations of force and strain, the code interpolates the stiffness curves to calculate equivalent nonlinear stiffness. Complex stress states with different types of nonlinearity occurring simultaneously in the structure can be described. The examples show that the subroutine can deal with nonlinearities such as global buckling, local buckling and post-yield response with good accuracy and low computational cost compared to conventional FEM. The report includes the necessary information to set up the subroutine, including selection and compatibility of software and packages and input file preparation. Web-core sandwich panels are used as example throughout the report; the same principles are valid for any periodic structure. The full implementation is given in Appendix

Exclusive J/ΨJ/\Psi plus jet associated production in ultraperipheral PbPbPbPb collisions

The study of exclusive processes in ultraperipheral collisions at the Large Hadron Collider (LHC) has allowed us to test several aspects of the Standard Model and to search for New Physics. In this letter, we investigate the possibility of using these processes to improve our understanding of the quarkonium production mechanism through the study of the exclusive $J/\Psi$ plus jet associate production in ultraperipheral $PbPb$ collisions. We estimate the transverse - momentum and rapidity distributions considering that the $\gamma \gamma \rightarrow J/\Psi + X$ ($X = \gamma, \, g$) subprocess is described by the Non - Relativistic QCD (NRQCD) formalism and present predictions for the rapidity ranges covered by central and forward detectors. The experimental separation of these events is discussed and the results indicate that a future experimental analysis is, in principle, feasible in future runs of the LHC and the Future Circular Collider (FCC).Comment: 9 pages, 4 figures, 2 table