Física de Partículas
http://hdl.handle.net/10347/2921
2021-10-23T11:22:20ZHolographic entanglement entropy for perturbative higher-curvature gravities
http://hdl.handle.net/10347/26812
Holographic entanglement entropy for perturbative higher-curvature gravities
Bueno, Pablo; Camps, Joan; Vilar López, Alejandro
The holographic entanglement entropy functional for higher-curvature gravities involves a weighted sum whose evaluation, beyond quadratic order, requires a complicated theory-dependent splitting of the Riemann tensor components. Using the splittings of general relativity one can obtain unambiguous formulas perturbatively valid for general higher-curvature gravities. Within this setup, we perform a novel rewriting of the functional which gets rid of the weighted sum. The formula is particularly neat for general cubic and quartic theories, and we use it to explicitly evaluate the corresponding functionals. In the case of Lovelock theories, we find that the anomaly term can be written in terms of the exponential of a differential operator. We also show that order-n densities involving nR Riemann tensors (combined with n − nR Ricci’s) give rise to terms with up to 2nR − 2 extrinsic curvatures. In particular, densities built from arbitrary Ricci curvatures combined with zero or one Riemann tensors have no anomaly term in their functionals. Finally, we apply our results for cubic gravities to the evaluation of universal terms coming from various symmetric regions in general dimensions. In particular, we show that the universal function characteristic of corner regions in d = 3 gets modified in its functional dependence on the opening angle with respect to the Einstein gravity result
2021-01-01T00:00:00ZThe nature of X(3872) from high-multiplicity pp collisions
http://hdl.handle.net/10347/26786
The nature of X(3872) from high-multiplicity pp collisions
Esposito, Angelo; González Ferreiro, Elena; Pilloni, Alessandro; Polosa, Antonio Davide; Salgado López, Carlos Alberto
The structure of exotic resonances that do not trivially fit the usual quark model expectations has been a matter of intense scientific debate during the last two decades. A possible way of estimating the size of these states is to study their behavior when immersed in QCD matter. Recently, LHCb has measured the relative abundance of the exotic X(3872) over the ordinary ψ(2S). We use the comover interaction model to study the yield of a compact X(3872). To confirm the reliability of the model in high-multiplicity pp collisions, we describe the suppression of excited over ground Υ states. With this at hand, we show that the size of the compact X(3872) would be slightly larger than that of the ψ(2S). If the X(3872) is instead assumed to be a meson molecule of large size, we argue that its evolution in QCD matter should be described via a coalescence model, as suggested by data on deuteron production. We show that the predictions of this model for the X(3872) are in contrast with data
2021-01-01T00:00:00ZEntanglement entropy in cubic gravitational theories
http://hdl.handle.net/10347/26757
Entanglement entropy in cubic gravitational theories
Cáceres, Elena; Castillo Vásquez, Rodrigo; Vilar López, Alejandro
We derive the holographic entanglement entropy functional for a generic gravitational theory whose action contains terms up to cubic order in the Riemann tensor, and in any dimension. This is the simplest case for which the so-called splitting problem manifests itself, and we explicitly show that the two common splittings present in the literature — minimal and non-minimal — produce different functionals. We apply our results to the particular examples of a boundary disk and a boundary strip in a state dual to 4- dimensional Poincaré AdS in Einsteinian Cubic Gravity, obtaining the bulk entanglement surface for both functionals and finding that causal wedge inclusion is respected for both splittings and a wide range of values of the cubic coupling
2021-01-01T00:00:00ZInteracting color strings as the origin of the liquid behavior of the quark-gluon plasma
http://hdl.handle.net/10347/26753
Interacting color strings as the origin of the liquid behavior of the quark-gluon plasma
Ramírez, Jhony; Díaz, Bogar; Pajares Vales, Carlos
We study the radial distribution function of the color sources (strings) formed in hadronic collisions and the requirements to obtain a liquid. As a repulsive interaction is needed, we incorporate a concentric core in the strings as well as the probability that a string allows core-core overlaps. We find systems where the difference between the gas-liquid and confined-deconfined phase transition temperatures is small. This explains the experimentally observed liquid behavior of the quark-gluon plasma above the confined-deconfined transition temperature
2021-01-01T00:00:00Z