Studying exotic hadrons of three-body nature

• Grant number: 25/24811-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2026
• End date: December 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Nuclear Physics
• Principal Investigator: Alberto Martinez Torres
• Grantee: Ryan Issa Sabha de Oliveira
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Collaborations such as LHCb, through the observation of Pc states (nucleons with hidden charm), in the invariant mass of J/¿N, or BESIII, with discoveries such as the ¿1(1855) state in the invariant mass of ¿¿¿, have shown the existence of baryons and mesons with quantum numbers that cannot be obtained via three-quark or quark-antiquark combinations. These hadrons are known as exotics. Occasionally, these states have masses close to the thresholds of two hadrons, with their quantum numbers obtained through s-wave interactions, suggesting a possible molecular interpretation: two hadrons, with low linear momentum in the center-of-mass frame, interacting through meson exchange and forming a new, spatially larger hadron. But on other occasions,the quantum numbers obtained are not compatible with two hadrons interacting in the s-wave and/or the states obtained may be close to three-hadron thresholds. In recent years, the study of the strong interaction between three-hadron systems has shown the generation of states such as ¿(2170), N(1710), K(1460), reproducing experimental data, and predicted the existence of exotic hadrons, such as kaons and nucleons with hidden charm and masses around 4300 MeV. In this project, we intend to introduce the student to the use of effective Lagrangians in order to study the dynamical generation of hadrons in two-body systems and the use of the two-body t-matrices obtained to investigate three-meson systems with hidden strangeness. As an application, we will study the possibility of generating the state ¿1(1855) through the interaction between two pseudo-scalar mesons and a vector meson. (AU)