The study of short-range correlations between particles offers insights into the strong force and the properties of the quark-gluon plasma, a state of matter thought to have existed shortly after the Big Bang. Barbat, Torres-Rincon, Ramos, and Tolos investigate these correlations specifically for charmed mesons – particles containing charm quarks – and baryons, such as protons and neutrons. They employ the Koonin-Pratt formalism, a method used to relate two-particle correlations to the scattering amplitude of those particles, alongside the TROY formalism, which accounts for off-shell effects and coupled channel interactions. Their theoretical calculations, utilising an effective Lagrangian to model interactions, predict correlation functions for various charmed meson-baryon pairs, incorporating both Coulomb interactions and thermal effects. These predictions are intended for comparison with data collected by the ALICE and STAR experiments at the Large Hadron Collider and the Relativistic Heavy Ion Collider, respectively, offering a means to probe the strong force in both small and large collision systems.
Charmed meson interactions receive detailed scrutiny through femtoscopic analysis and established scattering theory. The ALICE and STAR collaborations have recently enabled femtoscopic measurements of open-charm mesons in both small and large collision systems, prompting theoretical investigations into hadron interactions involving charmed mesons and extending previous studies of light hadron correlations. Specifically, research focuses on understanding the interactions between D mesons and nucleons, building upon established frameworks for meson-baryon scattering. Prior work successfully applied femtoscopy to explore interactions involving exotic hidden charmed mesons and open-charm mesons with light mesons, utilising theoretical models, such as vector meson exchange, to describe the strong interaction between hadrons. The current research extends this approach to the D-nucleon system, aiming for a comprehensive understanding of charmed hadron interactions. The theoretical framework relies on established techniques for describing meson-baryon scattering, including effective Lagrangians and vector meson exchange models, providing a foundation for calculating scattering amplitudes and understanding the underlying dynamics. This work builds upon these models, incorporating recent experimental data and refining theoretical predictions.
Femtoscopy, a technique examining correlations between identical or similar hadrons, has emerged as a valuable tool for investigating strong interaction dynamics at low energies. Recent experiments at the ALICE and STAR collaborations have extended this approach to the charm sector, measuring correlations involving D mesons. This work presents a theoretical calculation of correlation functions for D and anti-D mesons with nucleons, aiming to provide predictions testable against experimental data. The research begins with an effective model describing the strong interaction between charmed mesons and baryons, based on vector meson exchange and focusing on the lowest-order, s-wave interactions, acknowledging that higher-order contributions may become relevant at higher energies. The core of the calculation involves determining the scattering matrix, or T-matrix, which describes the probability amplitude for particles to scatter. Two distinct approaches are employed: the Lednický-Lyuboshitz (LL) approximation, simplifying the calculation by utilising the effective-range expansion of the on-shell scattering amplitudes, and the TROY formalism, calculating the off-shell T-matrix and reconstructing the full wave function. Both approaches incorporate the Coulomb interaction between charged particles and account for thermal effects in coupled channels, arising from the finite temperature of the collision environment. The calculated T-matrices and wave functions are then incorporated into the Koonin-Pratt formula, a standard equation used in femtoscopy to calculate correlation functions. By comparing the results obtained from the LL approximation and the TROY formalism, the researchers assess the accuracy and limitations of each method and provide robust predictions for experimental verification.
The study focuses on D+p, D−p, D0p, and anti-D0p systems, utilising interactions derived from a vector meson-exchange model. The researchers employ two primary approaches to calculate the correlation functions: the Lednický-Lyuboshitz (LL) approximation, relying on an effective-range expansion of on-shell scattering amplitudes, and the TROY formalism, calculating off-shell T-matrices and reconstructing the full wave function. The study begins with an effective interaction model between charmed mesons and nucleons, based on vector meson exchange, and uses this to calculate the T-matrix using both the LL approximation and the TROY formalism. Finally, these results are incorporated into the Koonin-Pratt formula to calculate the femtoscopic correlation functions, providing predictions that can be compared with experimental data from the ALICE and STAR collaborations. The goal is to provide a theoretical framework for interpreting experimental measurements of D-nucleon interactions in high-energy collisions.
By comparing the results obtained from these two approaches, the study assesses the validity and limitations of the LL approximation. The calculations incorporate the effects of the Coulomb interaction and thermal weights, crucial for accurately modelling the experimental conditions. The theoretical predictions generated can be directly compared with experimental data from the ALICE and STAR collaborations, offering a means to validate the underlying interaction models and refine our understanding of strong interactions in the charm sector. Future work could extend this analysis to include additional charmed meson-baryon channels and explore the influence of different interaction models. Investigating the impact of finite-size effects and incorporating more sophisticated descriptions of the thermal environment would further enhance the accuracy and predictive power of the theoretical framework. Ultimately, this research contributes to a more comprehensive understanding of hadron interactions at high energies, providing valuable insights into the complex dynamics of the strong force.
More information: Femtoscopy of DN and D¯N systems
