Theoretical group with internationally recognised expertise in the physics and phenomenology of elementary particles and their fundamental interactions at large colliders (high-energy frontier) and flavour factories (high-intensity frontier). Pioneering group in the application of effective field theories and perturbative methods to higher orders in quantum field theories for the analysis and interprest of experimental data. The group has expertise in the physics of the scalar sector of electroweak theory, electroweak symmetry breaking and Higgs boson physics, strong interactions, heavy quark physics (top and bottom quarks), and the flavour physics of leptons and hadrons.

The group is also notable for its coordination of national and European research networks, and for its involvement in outreach and knowledge transfer activities. The Standard Model (SM) of particle physics is the quantum field theory that describes the strong, weak and electromagnetic interactions of the three families of quarks and leptons. It has been very successful in describing all experimental observations over a wide range of energy scales, from the electron mass to beyond the top quark mass. The recent discovery of the Higgs boson is a major achievement that also opens up new questions in the scalar sector of the theory: is it solely responsible for the spontaneous electroweak symmetry breaking (EWSB) mechanism, what fundamental dynamics explains the hierarchy between the masses of the three families? This is the most important flavour sector, which in the SM includes 20 of the 25 free parameters of the model.

Another question of interest is to explore whether or not there is structure in the current gap between the known states and the Planck scale. In order to discover new phenomena, the possible existence and properties of an extended spectrum of states beyond those included in the SM must be investigated. Recent, ongoing and future experiments such as the Tevatron, the LHC or the Linear Collider (LC) at the high-energy boundary, or the flavour factories (K, D and B) capable of measuring with high precision observables at low energies at the high-intensity boundary, complement each other very well in the search for deviations from the SM predictions that may be able to reveal underlying dynamics. This goal will only be possible if the tremendous experimental effort is matched by a corresponding theoretical work able to match the experimental accuracy. This is a difficult task because theoretical predictions often involve strong interaction effects that are not easy to quantify. Very complex higher-order perturbative calculations are needed to provide accurate theoretical predictions of hard scattering processes at the LHC, while non-perturbative methods are needed to predict low-energy observables in the flavour factories. Not only the quark sector, but also the area of lepton flavour is a field of enormous interest, boosted by the discovery of neutrino masses. The search for lepton flavour violation in flavour factories (LHCb, MEG, SuperBelle) must be complemented with a solid theoretical framework to resolve a possible structure of the theory beyond the SM. Our research goals include current trends integrating LHC physics and present and future flavour factories, with a strong interest towards phenomenology in a future LC.

The aim of the project is to study functions with smooth properties defined in Banach spaces as well as the existence of equivalent norms with "better" properties than the initial one (renormings). This study refers both to the influence that the geometric characteristics, or topological properties, of the space have on the differentiability of the norm or the existence of renormings with certain properties, and to the study of various classes of smooth functions, whether analytic, differentiable or polynomial, as Banach spaces or algebras and the operators that can be defined between them.

Using effective field theories, constructed from symmetries of the fundamental interactions, and many-body quantum physics techniques, we study a broad spectrum of problems concerning the properties and interactions of light and heavy hadrons in vacuum and dense media, the dynamical generation of resonances and exotic states, nuclear response functions, and neutrino interactions with matter. Special emphasis is given to the scientific programme of the European FAIR laboratory (PANDA and CBM experiments), the LHCb experiment and the needs and opportunities offered by the neutrino physics experimental programme (T2K experiments, SBN programme, MINERvA, DUNE).

The study of the properties of hadrons based on their structure described by quarks, antiquarks and gluons and their strong, electromagnetic and weak interactions. The theory describing the structure of hadrons is Quantum Chromodynamics (QCD), a theory whose exact solution has not yet been possible since its formulation in 1973. 

There are currently two main lines of research in the study of the structure of hadrons, on the one hand effective models or theories that incorporate mechanisms that describe approximately the properties and symmetries of QCD. Another line of action is the numerical solution of the theory by means of complex computer calculations called QCD on the lattice, since the spacetime is discretised on a lattice, and an attempt is made to find a solution of the theory on this lattice. 

Our work follows the first line, i.e. the modelling of QCD. Within this scheme of studying hadrons and their properties, several regimes are investigated:

• Short distances: by studying deeply inelastic processes. In recent years this study has focused on the description of generalised pattern functions (GPD) and transverse momentum distributions (TMD). These quantities, which allow access to the structure of the proton and pions, are being measured experimentally and lead to observables whose theoretical analysis helps us to understand the non-perturbative properties of QCD. 
• Intermediate distances: the primary interest here is in understanding the hadronic spectrum. The number of hadrons, as can be seen in the Particle Data Group compendium, is enormous. But they all seem to consist of five valence quarks (antiquarks): u,d,s,c,b, since the t quark (antiquark) is so heavy that it does not have time to bind. Our work consists of analysing the spectrum to understand the interaction between quarks that gives rise to hadrons. From this phenomenological interaction we try to learn properties of QCD. In recent years, the possible existence of so-called exotic states, multi-quarks and glueballs, have required our special attention. Gluons are also part of the description of QCD and gluons have self-couplings, therefore they could give rise to states of only valence gluons called glueballs and in the last years we have been intensively devoted to them. Our study consists of analysing the structure and possible decays of hadrons in order, by comparing with experimental data from laboratories around the world, Belle BaBar, Bes, to draw consequences for the fundamental interaction. We are also engaged in predicting future processes to be observed in the future FAIR accelerator and its PANDA detector. The contrast of theoretical and experimental data allows us to understand the interaction of quarks and gluons with each other and their strong, electromagnetic or weak decay channels through the properties of the spectrum: masses and decay widths. 
• Large distances: hadron-hadron interaction. Nuclear physics is governed by the interaction between hadrons. Due to a property called confinement, quarks and gluons cannot appear free, they must always be bound together to form hadrons. However, they must be the cause of the observed interaction between hadrons, in particular between the proton and the neutron to form atomic nuclei. Our work consists in explaining the interaction between hadrons from the interaction between quarks.
• Hadronic matter at high temperatures and densities: interactions between heavy ions allow us to study hadronic matter outside normal conditions, which are now available in accelerators such as RHIC and LHC, and it is expected that hadronic properties different from normal ones will indicate possible QCD phase transitions.

Einstein's General Relativity (GR) theory and Minkowski's Quantum Field Theory (QFT) in space successfully describe observable physics over a wide range of length and energy scales. However, it is very difficult to understand the quantum behaviour of gravity itself. At energy scales far below the Planck energy, TQC in curved space is nevertheless remarkably successful. It predicts the quantum radiance of black holes and shows how the primordial irregularities of our universe, observed in the cosmic microwave background and in the large-scale structure, can be generated in the early universe. For lengths or energies close to the Planck scale, the absence of a well-understood theory urges a worldwide effort to build a viable quantum theory for the gravitational field. The complexity of the problem requires a multidisciplinary approach, incorporating a wide range of viewpoints, ranging from sophisticated mathematics to ambitious experiments. A deep understanding of our basic theories is required, as well as an improvement of the main approaches for a proper quantum theory of gravity. Our group pursues this research strategy in an interrelated way. In particular, our main purposes are:

1. Quantum field theory in curved space-time and its observable consequences in cosmology. Initial conditions in inflation and the observable universe: low angular multipoles in the CMB, non-Gaussianities, potential quantum gravity effects, etc. Renormalisation effects in curved space: power spectra, primordial magnetic fields, etc. Mechanism of gravitational creation of particles and its physical implications (early universe, dark matter, dark energy, etc.).
2. Quantum aspects of black holes and acoustic black holes. Especially the possibility of detecting the Hawking effect through density correlations in Bose-Einstein condensates; study of quantum effects in black holes/acoustic black holes; backreaction of the Hawking flow in BECs; applications of analogue gravity in cosmology; mini black holes at the LHC, correlations and unitarity.
3. Classical and quantum aspects of gravitation in Palatini formalism. Extensions of general relativity and astrophysical and cosmological applications, semiclassical formulation of quantum field theory, dynamics of brane-worlds and AdS/CFT correspondence in geometries with independent metric and connection (Palatini). Structure and stability of black holes in such varieties. Non-singular cosmologies and effective descriptions of quantum gravity models, problem of accelerated cosmic expansion and dark matter from a gravitational point of view.
4. Supersymmetry and spacetime deformations. Deformations of Minkowski superspace and conformal superspace in terms of super Grassmannians and quantum super flags. Field theories of these non-commutative spaces. Solutions of black holes in supergravity: universality and classification.

The group has been doing research in quantum optics, nonlinear optics, laser dynamics and other systems since 1989, with stable and uninterrupted funding through the national research plans of the Spanish government. The research is of a basic nature and seeks to describe new phenomena, both through theory and experiment. An important part of the group's activity is the training of PhDs, with 10 doctoral theses having been defended by 2019.