https://hdl.handle.net/10481/28286 2026-04-08T10:41:47Z https://hdl.handle.net/10481/112641 Running couplings in high-temperature effective field theory Rodríguez Chala, Mikael; Dashko, Andrii; Guedes, Guilherme In this work, we study the renormalization-group evolution of parameters in the three-dimensional effective field theory (3D EFT) that describes the thermally driven electroweak phase transition of the Higgs field. We consider tree-level and radiatively generated barriers induced by beyond the Standard Model physics, enabling a first-order phase transition at and below the soft scale, respectively. For each case, we compute the two-loop running of the 3D EFT couplings, including the effects of the leading nonrenormalizable terms. We then analyze how the new contributions to the beta functions compare with those in the super-renormalizable case, highlighting their impact on perturbative computations of the scalar potential, which describes the vacuum structure of the theory. By incorporating higher-order corrections in the mass parameter evolution, as well as the running of other effective operators, we set the stage for testing their impact on phase transition dynamics in lattice simulations. https://hdl.handle.net/10481/112349 Potential blind directions at TeraZ Rodríguez Chala, Mikael; Criado, Juan Carlos The next generation of high-luminosity electron-positron colliders, such as the electron-positron Future Circular Collider and the Circular Electron-Positron Collider operating at the Z pole (TeraZ), is expected to deliver unprecedented precision in electroweak measurements. These precision observables are typically interpreted within the Standard Model effective field theory (SMEFT), offering a powerful tool to constrain new physics. However, the large number of independent SMEFT operators allows for the possibility of blind directions, parameter combinations to which electroweak precision data are largely insensitive. In this work, we demonstrate that such blind directions are not merely an artifact of agnostic effective field theory scans, but arise generically in realistic ultraviolet completions involving multiple heavy fields. We identify several concrete multifield extensions of the Standard Model whose low-energy SMEFT projections align with known blind subspaces, and show that these persist even after accounting for renormalization group evolution and finite one-loop matching effects. Our analysis shows that TeraZ will set a new benchmark in precision for indirect searches, but fully probing the space of possible ultraviolet physics requires going beyond this stage. Later electron-positron Future Circular Collider runs at higher center-of-mass energies, together with the hadron-hadron Future Circular Collider, will provide the necessary complementary probes, enabling a far more complete exploration of the SMEFT parameter space. https://hdl.handle.net/10481/111900 High resolution seismic imaging of an active fault in the eastern Guadalquivir Basin (Betic Cordillera, Southern Spain) Serrano Bermejo, Inmaculada; Torcal, Federico; Martín, José Benito We calculated the high resolution seismic velocity, Poisson's ratio, crack density and saturation ratio structures in and around the source areas of the Torreperogil seismic series (October 2012–April 2013). This seismic series, characterized by a large number of low magnitude (below Mw 3.7 or Md 3.9) and very shallow microearthquakes, took place in the Guadalquivir Basin, a large flexural foreland basin with a linear ENE–WSW trending bounded to the north by the Iberian Massif and to the south by the Betic Cordillera and filled from a middle Miocene to Plio–Quaternary sedimentary sequence. In the upper layers of the crust, strong low-velocity anomalies are extensively distributed under the central zone, which together with high Poisson's ratio and crack density values may correspond to rocks which are less likely to fracture, perhaps due to the accumulation of tectonic and seismic stress. 93% of the earthquakes occurred at depths of up to 8 km, which could indicate that the base of the seismogenic zone lies at this depth. The seismic series was concentrated in layers of strong structural heterogeneities (in the boundary area between low and high anomalies), which were likely to generate earthquakes due to differential strain accumulation beneath the region. The high velocity areas are also considered to be strong yet brittle parts of the fault zone, which may generate earthquakes (at depths of between 5 km and 9 km). By contrast, low velocity areas are less prone to fracture, allowing seismic slippage to take place (from 2 to 4 km depth). The best estimate of the depth of the main shock (mbLg 3.9) is 7.6 km, which could tend to nucleate at the base of the seismogenic zone, at the “fault end” on the boundary between a low velocity zone to the east and a high velocity zone to the west, indicating the fault plane which separates both areas laterally. Assuming that this seismic contrast is one of the main Torreperogil faults it could imply that stress has accumulated in an existing fault zone with lateral heterogeneity in velocity. This work has been supported by the Comisión Interministerial de Ciencia y Tecnología CICYT (Spain) projects with references CGL2012-31472 (Estructura cortical y litosférica en el Sector Central de la Cordillera Bética y su transicion al Macizo Varisco. Sismotectónica del sur-sureste de la Península Ibérica), CGL2013-46368-P (Localización de la deformación en convergencia oblicua y cuencas tardiorogénicas: estudio multidisciplinar de casos (Béticas) y modelización); Proyectos de Excelencia de la Junta de Andalucía (Spain) P09-RNM-5100 (Estructura 3D del Arco de Gibraltar y modelado numérico de la propagación de ondas sísmicas de terremotos en la zona de contacto de placa Nubia-Eurasia) and RNM-451 (Evolución reciente de los contactos principales entre dominios estructurales/reológicos del Sistema del Arco de Gibraltar: estudios integrados tierra-mar); and Grupo de Investigación de la Junta de Andalucía (Spain) RNM-104, Sismología y Geofísica. https://hdl.handle.net/10481/111898 Distribution of crack density parameter in Central Betic Cordillera (Southern Spain) Serrano Bermejo, Inmaculada; Torcal, Federico; Morales Soto, José Abstract In this study we have used high-resolution P- and S-wave velocity results to estimate crack density (ε, epsilon) and saturation ratio (ξ, xi) at a depth of 2 km in an intramountain basin and surrounding regions. Detailed observations of gravity, seismic profile and geological data reveal high ε consistent with large sedimentary thickness and minimum ε coinciding with elevations arising from the basement of the basin. From the distribution of seismic measurements of ξ it is possible to identify the presence of aquifers in detrital sediments, sandstone and dolostone. However, ξ does not show significant changes for the aquifers in geological formations made up also of schists and marbles. A low ξ anomaly in the western part could be associated with Triassic evaporite and clay rocks, and high values of ξ in the southwestern part near thermal springs may be imaging the intricate system of fractures which connect at depth with aquifer rocks. This work has been supported by the Comisión Interministerial de Ciencia y Tecnología CICYT (Spain) projects with references CGL2012–31472 (Estructura cortical y litosférica en el Sector Central de la Cordillera Bética y su transicion al Macizo Varisco. Sismotectónica del sur-sureste de la Península Ibérica), CGL2009–11384 (Transpresión y reparto de la deformación en la rama norte del Arco de Gibraltar (25 m.a. -Reciente): registro estructural, evolución tectónica y modelización); Proyectos de Excelencia de la Junta de Andalucía (Spain) P09-RNM-5100 (Estructura 3D del Arco de Gibraltar y modelado numérico de la propagación de ondas sísmicas de terremotos en la zona de contacto de placa Nubia-Eurasia) and P08-RNM-03713 (Dinámica del Sistema del Arco de Gibraltar: Estudios geológicos multidisciplinares tierra-mar y evolución 4D); and Grupo de Investigación de la Junta de Andalucía (Spain) RNM-104, Sismología y Geofísica. https://hdl.handle.net/10481/111739 Determination of the mass distribution of the first stars from the 21-cm signal Gessey-Jones, Thomas; Sartorio, Nina S.; Bevins, Harry T. J.; Fialkov, Anastasia; Handley, Will J.; de Lera Acedo, Eloy; Mirouh, Giovanni Marcello; Izzard, Robert G.; Barkana, Rennan Properties of the first generation of stars [referred to as the Population III (Pop III) stars], such as their initial mass function (IMF), are poorly constrained by observations and have yet to converge between simulations. The cosmological 21-cm signal of neutral hydrogen is predicted to be sensitive to Lyman-band photons produced by these stars, thus providing a unique way to probe the first stellar population. In this paper, we investigate the impacts of the Pop III IMF on the cosmic-dawn 21-cm signal via the Wouthuysen-Field effect, Lyman-Werner feedback, Ly α heating, and cosmic microwave background heating. We calculate the emission spectra of star-forming haloes for different IMFs by integrating over individual metal-free stellar spectra, computed from a set of stellar evolution histories and stellar atmospheres, and taking into account variability of the spectra with stellar age. Through this study, we therefore relax two common assumptions: that the zero-age main-sequence emission rate of a Pop III star is representative of its lifetime mean emission rate, and that Pop III emission can be treated as instantaneous. Exploring bottom-heavy, top-heavy, and intermediate IMFs, we show that variations in the 21-cm signal are driven by stars lighter than 20 M⊙. For the explored models, we find maximum relative differences of 59 per cent in the cosmic-dawn global 21-cm signal, and 131 per cent between power spectra. Although this impact is modest, precise modelling of the first stars and their evolution is necessary for accurate prediction and interpretation of the 21-cm signal.