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Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/189881
Effective-theory description of heavy-flavored hadrons and their properties in a hot medium
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[eng] For many decades after the conception of the quark model in 1964, and the development of quantum chromodynamics (QCD) a few years later as the theory governing the strong interaction between quarks and gluons, there was no experimental evidence of the existence of hadronic states beyond the quark-antiquark mesons and the three-quark baryons. In the last two decades, however, with the explosion of data in electron–positron and hadron colliders, many states have
been observed that do not fit in this picture, especially in the heavy-flavor sector. Evidence of the existence of the so-called exotic hadrons has recently prompted a lot of activity in the field of hadron physics, with experimental programs in ongoing and upcoming facilities dedicated to the search for new exotic mesons and baryons, and many theoretical efforts trying to disentangle, for instance, compact multiquark structures from hadronic molecules.
In this dissertation, we focus on recently seen exotic hadrons with heavy-quark content that may be understood as being generated dynamically from the hadron–hadron interaction. This interaction is derived from a suitable effective Lagrangian and properly unitarized in a full coupled-channel basis. In particular, we discuss the possible interpretation of some of the Ωc* excited states recently discovered at LHCb as being meson–baryon molecular states. We also discuss the dynamical generation of excited open-charm mesons from the scattering of pseudoscalar and vector charmed mesons off light mesons. We show that a double-pole structure is predicted for the D0*(2300) state, as well as for the D1(2430), within the molecular picture, while the Ds0*(2317) and the Ds1(2460) may be interpreted as molecular bound states. Extensions of these calculations to the bottom sector are also presented.
Moreover, charmed hadrons are a promising probe of the quark-gluon plasma (QGP) phase that is expected to be created in heavy-ion collision experimental facilities. Charm and anticharm quarks are produced in the early stages of the collision and experience the whole evolution of the QGP, before hadronizing predominantly into open-charm mesons. To describe the experimental data, it is necessary to understand, from the theoretical side, the propagation of the D mesons in the hadronic phase and their interaction with the surrounding medium of light mesons. The approach that we employ in this thesis to study the thermal modification of open
heavy-flavor mesons in a hot medium is based on the use of effective theories. By means of an extension to finite temperature of the unitarized effective interactions with the light mesons, we obtain the in-medium spectral properties of the D, D*, Ds, and Ds* ground-state mesons. We also analyze the temperature dependence of the masses and the decay widths of the dynamically generated states. Additionally, we provide results for the bottomed mesons by exploiting the heavy-quark flavor symmetry of the Lagrangian.
In order to test the results of the thermal effective theory against lattice QCD calculations, we further employ the temperature-dependent scattering amplitudes and spectral functions to compute charm Euclidean correlators. The spectral properties of charmed mesons at finite temperature can be extracted from lattice QCD data of meson Euclidean correlators, yet relying on a priori assumptions about the shape of the spectral function. Hence, we compare both approaches at the level of Euclidean correlators and find that they compare reasonably well at temperatures below the QCD phase transition temperature. We also present calculations of off-shell transport coefficients in the hadronic phase, such as the drag force and the diffusion coefficients. Contrary to previous approaches in the literature, we implement in-medium scattering amplitudes and the thermal dependence of the heavy-meson spectral properties. The transport coefficients in the QGP phase have been recently computed with lattice QCD and extracted from Bayesian analyses of heavy-ion collision data. We observe a smooth matching with our results at the QCD phase transition temperature
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MONTAÑA FAIGET, Glòria. Effective-theory description of heavy-flavored hadrons and their properties in a hot medium. [consulta: 2 de desembre de 2025]. [Disponible a: https://hdl.handle.net/2445/189881]