Glueballs are particles whose valence degrees of freedom are gluons and therefore in their description the gauge field plays a dominant role. We review recent results in the physics of glueballs with the aim set on phenomenology and discuss the possibility of finding them in conventional hadronic experiments and in the Quark Gluon Plasma. In order to describe their properties we resort to a variety of theoretical treatments which include, lattice QCD, constituent models, AdS/QCD methods, and QCD sum rules. The review is supposed to be an informed guide to the literature. Therefore, we do not discuss in detail technical developments but refer the reader to the appropriate references.

The graviton solutions for the glueball spectrum of ref.[1] interpreted in a different manner lead to very interesting results which we describe in this comment.

Two-parton correlations in the pion are investigated in terms of double parton distribution functions. A Poincaré covariant Light-Front framework has been adopted. As non perturbative input, the pion wave function obtained within the so-called soft-wall AdS/QCD model has been used. Results show how novel dynamical information on the structure of the pion, not accessible through one-body parton distribution, are encoded in double parton distribution functions.

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Methods Monte Carlo simulation of the MoEDAL experimentThe MM simulation code is developed in Gauss 40 , which is the LHCb simulation framework that uses Geant4 as the simulation engine. MoE-DAL simulations use a dedicated Geant4 class that describes production and propagation of MMs 41 . The MM ionization energy losses, geometry and material content of the MoEDAL detector and its vicinity are modeled in the simulation. The MMTs are described in Geant4 as sensitive detectors and produce hits when MMs are trapped in them. These hits are recorded in simulation and analysed for calculating efficiency and the expected rate of MMs detection. A custom-made momentum distribution of MMs derived from Schwinger kinematics (equation ( 3)) is implemented and propagated through the MoEDAL geometry.