Distribution functions of vector mesons from nonperturbative functional methods

• Grant number: 25/13317-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: December 01, 2025
• End date: November 30, 2028
• Field of knowledge: Physical Sciences and Mathematics - Physics - Elementary Particle Physics and Fields
• Principal Investigator: Gastão Inácio Krein
• Grantee: Bianca Maria Silveira de Oliveira
• Host Institution: Instituto de Física Teórica (IFT). Universidade Estadual Paulista (UNESP). Campus de São Paulo. São Paulo , SP, Brazil
• Associated research grant: 18/25225-9 - São Paulo Research and Analysis Center, AP.ESP

Abstract

This project aims to compute the Parton Distribution Functions (PDFs), Transverse Momentum Distributions (TMDs), and Generalized Parton Distributions (GPDs) for vector mesons (spin-1) composed of heavy-light (anti)quark pairs. Together, PDFs, TMDs, and GPDs provide a three-dimensional picture of the internal structure of mesons - both in position and momentum space - and represent one of the major scientific challenges in contemporary hadron physics, from both theoretical and experimental perspectives. In particular, we seek to determine these distribution functions for odd-parity vector mesons such as the $D$, $D_s$, $B$, $B_s$, and $B_c$, by combining the nonperturbative formalisms of Dyson-Schwinger Equations and Bethe-Salpeter Equations. The computation of these functions will be carried out using two complementary approaches: a covariant method and another one based on the meson's light-front wave function. Based on the results obtained through both methodologies, we aim to provide theoretical predictions that are relevant to ongoing and future experiments at the Large Hadron Collider (LHC), and may also contribute to the future physics program of the Electron-Ion Collider (EIC). Additionally, we aim to improve the calculation of $J/\Psi$ meson photoproduction, which depends on the distribution amplitude of quarkonia - an ingredient we are well positioned to provide. Our approach is nonperturbative, employing dressed quark and gluon propagators to evaluate the relevant diagrams, and our goal is to critically assess the validity of the approximations commonly used in the literature. Ultimately, we intend to extract the gluonic GPD and determine the gluon's contribution to the proton's spin and mass.