Particles and Gravitation

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 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].  

The quark-gluon plasma is a new state of matter that can be formed by colliding heavy ions at ultrarelativistic velocities. From all the particles formed in these collisions, heavy quarkonium is one of the most promosing probes to obtain information about this new state of matter. One of the most succesful approaches to the study of the evolution of quarkonium in a medium is to model it as a Markovian open quantum system. Recently, it has been found using this approach that regeneration is crucial to reproduce experimental data on quarkonium excited states.

We propose to study the reaction pi- p —> pi- eta p, whose data have been collected by the COMPASS collaboration. 
The goal is to develop the so-called ``finite-energy sum rules’’ for this reaction, that will allow to constraints better the production of exotic meson. 
The student will first understand these constraints on a toy model (based on Veneziano amplitudes) and will subsequently apply them to the reaction under consideration.Â