Particles and Gravitation

In this project we ask if it is possible to deduce the number of QCD colors (Nc) directly from low energy experiments with photons, pions, eta/eta’ mesons and kaons. Contrary to the common lore, it is impossible to see the Nc with just pions and photons and are the decays of the eta/eta’ meson, η/η'→γγ and η/η'→ππγ that are proportional to Nc and should replace the textbook process π→γγ lending support to Nc=3.

Axions are hypothetical particles that appear in well-motivated extensions of the Standard Model and are very attractive for being able to explain some of the open questions in particle physics, such as the strong CP-problem or the origin of dark matter in the universe. We will perform a thorough theoretical investigation of the phenomenological impact of axion interactions with SM particles, with special emphasis on hadronic particles at low energies.

In this thesis, you will make predictions for the forthcoming measurements of baryon form factors by the HADES collaboration [1]. The project can be carried in Barcelona and/or remotely with weekly Zoom meetings with the supervisor.

The sensitivity of the rare decays η/η'→π0γγ to signatures of Beyond the Standard particles in the MeV-GeV mass range will be analyzed in this work.

A neutron star merger is a highly dynamical system in which the four fundamental forces of nature—electromagnetic, weak, strong, and gravitational—play significant roles. This makes it an intriguing laboratory for studying fundamental physics, which can be explored experimentally through both gravitational and electromagnetic waves. To model this system, instead of solving quantum chromo

In this thesis, you’ll develop a model describing the photoproduction of tensor mesons based on the model from Ref. [1] and the data from Refs. [2-4]. You will learn some standard techniques and theories used in particle physics such as the helicity formalism, the decomposition into partial waves, the S-matrix (or scattering) theory and Regge theory. 

In this thesis, you will develop a model for a strange cascade, that is, a reaction in which several baryons containing strange quarks are produced. The GlueX collaboration (Hall D at the Thomas Jefferson Lab) is exploring the possibilities of setting up a polarized proton target [1]. A polarized target could potentially help in the determination of the quantum numbers of the produced strange baryon.

When the densest stars in the universe (neutron star or neutron star-black hole pairs) orbit each other, they get closer due to emitted gravitational radiation. Neutron stars have a solid exterior crust that may shatter in this extreme encounters. In this project, you will explore whether the star can shatter like a glass does when a singer hits its resonant note. This depends on the properties of dense matter and, in particular, on the symmetry energy parameter that is predicted from nuclear physics.

The Standard Model of Cosmology, the so-called ΛCDM model [1], is afflicted by

The solution of quantum field theories is one of the most challenging topics in modern theoretical physics. Recently, promising advances have relied on the use of variational approaches that exploit machine learning techniques [1]. These approaches encode the gauge symmetries in the architecture of neural networks [2], which provides advantages with respect to other sampling techniques [3]. Variational solutions to quantum field theories can be then exploited to find numerical solutions to these problems [4].