Search

The production of fully-heavy tetraquark states in proton–proton (pp) and proton–nucleus (pA) collisions at the center-of-mass energies of the Large Hadron Collider (LHC) and at the Future Circular Collider (FCC) is investigated considering that these states are produced through the double parton scattering mechanism. We estimate the cross sections for the T 4 c , T 4 b and T 2 b 2 c states and present predictions for pp, pCa and pPb collisions considering the rapidity ranges covered by central and forward detectors. We demonstrate that the cross sections for pA collisions are enhanced in comparison to the pp predictions scaled by the atomic number. Moreover, our results indicate that a search of these exotic states is, in principle, feasible in the future runs of the LHC and FCC. [ABSTRACT FROM AUTHOR]

We perform a fit to the LHCb data on the T cc (3875) state in order to determine its nature. We use a general framework that allows to have the D 0 D ∗ + , D + D ∗ 0 components forming a molecular state, as well as a possible nonmolecular state or contributions from missing coupled channels. From the fits to the data we conclude that the state observed is clearly of molecular nature from the D 0 D ∗ + , D + D ∗ 0 components and the possible contribution of a nonmolecular state or missing channels is smaller than 3%, compatible with zero. We also determine that the state has isospin I = 0 with a minor isospin breaking from the different masses of the channels involved, and the probabilities of the D 0 D ∗ + , D + D ∗ 0 channels are of the order of 69% and 29% with uncertainties of 1%. The differences between these probabilities should not be interpreted as a measure of the isospin violation. Due to the short range of the strong interaction where the isospin is manifested, the isospin nature is provided by the couplings of the state found to the D 0 D ∗ + , D + D ∗ 0 components, and our results for these couplings indicate that we have an I = 0 state with a very small isospin breaking. We also find that the potential obtained provides a repulsive interaction in I = 1 , preventing the formation of an I = 1 state, in agreement with what is observed in the experiment. [ABSTRACT FROM AUTHOR]

We calculate the cross sections of the processes T cc + π , T cc + ρ → D (∗) D (∗) and of the corresponding inverse reactions. We use effective Lagrangians to account for the couplings between light and heavy mesons, and give special attention to the form factors in the vertices. Using QCD sum rules we calculate here for the first time the T cc + - D - D ∗ form factor. The T cc + absorption cross sections are found to be larger than the production ones. We compare our results with the only other existing estimate of these quantities, presented in a work by J. Hong, S. Cho, T. Song and S. H. Lee, in which the authors employed the quasi-free approximation. We find cross sections which are one order of magnitude smaller. [ABSTRACT FROM AUTHOR]

Deals with a study on gauge fluctuations in superconducting films. Ways by which spatial boundaries can be modeled; Application of the functional approach of the Gaussian Effective Potential formalism to the Ginzburg-Landau model; Critical behaviour of the confined Ginzburg-Landau model.

In this work, we investigate the interaction between spin-zero and spin-one monopoles by making use of an effective field theory based on two-body and four-body interaction parts. In particular, we analyze the formation of bound state of monopole–antimonopole (i.e., monopolium). The magnetic-charge conjugation symmetry is studied in analogy to the usual-charge conjugation to define a particle basis, for which we find bound-state solutions with relatively small binding energies and which allows us to identify the bounds on the parameters in the effective Lagrangians. Estimations of their masses, binding energies and scattering lengths are performed as functions of monopole masses and interaction strength in a specific renormalization scheme. We also examine the general validity of the approach and the feasibility of detecting the monopolium. [ABSTRACT FROM AUTHOR]

In this work we investigate the Zb(10610) (called simply Zb) abundance in the hot hadron gas produced in heavy ion collisions after the quark-gluon plasma phase. We use effective Lagrangians to calculate the thermally averaged cross sections of Zb production in processes such as B(∗)+B¯(∗)→π+Zb(10610) and also of its absorption in the corresponding inverse processes. We then solve the rate equation to follow the time evolution of the Zb multiplicity. We find that, if we neglect the Zb decay, the number of Zb’s produced at the end of the quark-gluon plasma phase remains almost constant during the hadron phase. The introduction of the decay in the rate equation leads to a suppression in the final yield by a factor two. [ABSTRACT FROM AUTHOR]