Rinaldi, M., & Vento, V. (2023). Phase transition in the holographic hard-wall model. Phys. Rev. D, 108(11), 114020–10pp.
Abstract: A Hawking-Page phase transition between anti-de Sitter (AdS) thermal and AdS black hole was presented as a mechanism for explaining the QCD deconfinement phase transition within holographic models. In order to implement temperature dependence in the confined phase we use a hard-wall AdS/QCD model, where the geometry at low temperatures is described also by a black hole metric. We then investigate the temperature dependence of glueball states described as gravitons propagating in deformed background spaces. Finally, we use potential models to physically describe the implications of our study.
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Rinaldi, M., Scopetta, S., & Vento, V. (2013). Double parton correlations in constituent quark models. Phys. Rev. D, 87(11), 114021–9pp.
Abstract: Double parton correlations, having effects on the double parton scattering processes occurring in high-energy hadron-hadron collisions, for example at the LHC, are studied in the valence quark region by means of constituent quark models. In this framework, two particle correlations are present without any additional prescription, at variance with what happens, for example, in independent particle models, such as the MIT bag model in its simplest version. From the present analysis, conclusions similar to the ones obtained recently in a modified version of the bag model can be drawn: correlations in the longitudinal momenta of the active quarks are found to be sizable, while those in transverse momentum are much smaller. However, the framework used allows us to understand clearly the dynamical origin of the correlations. In particular, it is shown that the small size of the correlations in transverse momentum is a model-dependent result, which would not occur if models with sizable quark orbital angular momentum were used to describe the proton. Our analysis permits us, therefore, to clarify the dynamical origin of the double parton correlations and to establish which, among the features of the results, are model independent. The possibility of testing the studied effects experimentally is discussed.
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Richard, J. M., Valcarce, A., & Vijande, J. (2017). String dynamics and metastability of all-heavy tetraquarks. Phys. Rev. D, 95(5), 054019–7pp.
Abstract: Multiquark states have been advocated to explain recent experimental data in the heavy-light sector, and there are already speculations about multiquarks containing only heavy quarks and antiquarks. With a rigorous treatment of the four-body problem in current quark models, full-charm (cc (c) over bar(c) over bar) and full-beauty(bb (b) over bar(b) over bar) tetraquarks are found to be unbound. Thus their stability should rely on more subtle effects that are not included in the simple picture of constituent quarks. The case of (bc (b) over bar(c) over bar) might be more favorable if the naive color-additive model of confinement is replaced by a string-inspired interaction.
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Richard, J. M., Valcarce, A., & Vijande, J. (2021). Effect of relativistic kinematics on the stability of multiquarks. Phys. Rev. D, 103(5), 054020–8pp.
Abstract: We discuss whether the bound nature of multiquark states in quark models could benefit from relativistic effects on the kinetic energy operator. For mesons and baryons, relativistic corrections to the kinetic energy lead to lower energies, and thus call for a retuning of the parameters of the model. For multiquark states, as well as their respective thresholds, a comparison is made of the results obtained with nonrelativistic and relativistic kinetic energy. It is found that the binding energy is lower in the relativistic case. In particular, QQ (q) over bar(q) over bar tetraquarks with double heavy flavor become stable for a larger ratio of the heavy to light quark masses; the all-heavy tetraquarks QQ (Q) over bar(Q) over bar that are not stable in standard nonrelativistic quark models remain unstable when a relativistic form of kinetic energy is adopted.
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Restrepo, D., Taoso, M., Valle, J. W. F., & Zapata, O. (2012). Gravitino dark matter and neutrino masses with bilinear R-parity violation. Phys. Rev. D, 85(2), 023523–7pp.
Abstract: Bilinear R-parity violation provides an attractive origin for neutrino masses and mixings. In such schemes the gravitino is a viable decaying dark matter particle whose R-parity violating decays lead to monochromatic photons with rates accessible to astrophysical observations. We determine the parameter region allowed by gamma-ray line searches, dark matter relic abundance, and neutrino oscillation data, obtaining a limit on the gravitino mass m((G) over tilde) less than or similar to 1-10 GeV corresponding to a relatively low reheat temperature T-R less than or similar to few x 10(7)-10(8) GeV. Neutrino mass and mixing parameters may be reconstructed at accelerator experiments like the Large Hadron Collider.
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