Production of light anti-nuclei in high-energy pp and ep collisions: a coalescence-based approach

This thesis presents a study of light (anti)nucleus production in high-energy collisions, focusing on the interplay between coalescence and nucleon--nucleon (N--N) interactions. The formation of loosely bound states such as (anti)deuterons and (anti)helium nuclei is a rare process that requires correlated (anti)nucleons in the final state. A consistent modelling of this process must therefore account for both bound-state formation and final-state interactions, which modify two-particle distributions and influence the probability of clustering. A model is developed and coupled through an afterburner to the Monte Carlo event generator \textsc{PYTHIA8} to simulate proton--proton and electron--proton collisions. Two complementary implementations of the coalescence mechanism are presented: a wave-function-based formalism and a Wigner-function approach, where in both cases the coalescence probability is computed. Within the same framework, N--N interactions are incorporated through a semiclassical energy-conservation prescription, and the model is extended iteratively to describe nuclei and antinuclei up to $A=4$. The model is applied to pp collisions at $\sqrt{s}=13.6$~TeV, where transverse-momentum spectra and the coalescence parameters $B_{2}$ and $B_{3}$ are compared to ALICE measurements. A grid-based $\chi^{2}$ minimisation is performed to constrain the source and deuteron size parameters. The result of the model is further compared to ZEUS data in ep collisions and used to provide predictions for the future Electron--Ion Collider, including yields and $B_{2}$ distributions within the ePIC dRICH acceptance.