Study Predicts Charmed-Strange Molecular Tetraquarks with -doublet and Identifies Resonance in Coupled Channel

The search for exotic particles continues to reshape our understanding of the strong force, and recent investigations focus on the possibility of tetraquarks, particles composed of four quarks. Fu-Lai Wang, Si-Qiang Luo, and Xiang Liu, all from Lanzhou University, systematically explore the potential for charmed-strange molecular tetraquarks, specifically those formed from a meson and an anti-charmed meson pair. Their work identifies a resonance previously observed by the LHCb experiment as a genuine molecular state with specific quantum properties, confirming its structure through detailed theoretical modelling. Importantly, this research not only validates the existence of this particle but also predicts a series of related tetraquark candidates, offering a comprehensive picture of this exotic spectrum and providing testable predictions for future experiments.

Exotic Hadrons, Molecules, and Heavy Quarks

This extensive collection of research papers focuses on hadron physics, particularly the study of exotic hadrons, molecular states, and particles containing heavy quarks. The compilation highlights a vibrant area of modern particle physics, investigating particles beyond traditionally understood quark combinations. Key themes include the search for tetraquarks and pentaquarks, and the exploration of hadrons that may be bound states of other hadrons, known as molecular hadrons. A significant portion of the research concentrates on hadrons containing charm and bottom quarks, examining their properties, decays, and interactions.

The list demonstrates a strong focus on theoretical investigations, aiming to understand the underlying physics of these unusual particles and connect them to experimental observations. Several researchers consistently appear throughout the compilation, indicating key figures actively contributing to the field. Many papers attempt to explain experimental results obtained from facilities such as LHCb and BESIII, suggesting a close connection between theory and experiment. Specific studies investigate the nature of resonances and the possibility of tetraquarks containing charm quarks, while others re-examine charmed mesons, predicting the existence of new ones.

Charmed Tetraquark Structure via Meson Exchange Analysis

Scientists systematically investigated the molecular structure of charmed-strange tetraquarks, focusing on combinations of mesons and their anti-partners. They employed the one-boson-exchange model to analyze the composition of these exotic hadrons, identifying a resonance observed by the LHCb experiment as a molecular state formed by a K-meson and a D1-meson with consistent quantum numbers. This state exhibits a significant contribution from the K-star-D1 channel, indicating a complex internal structure. The team extended this analysis to predict the existence of additional partner states within the K-star-D1 and K-D-star-2 systems, providing testable predictions for future experiments.

This involved a detailed examination of interactions between particles, considering the exchange of various bosons, and incorporating coupled-channel effects. The inclusion of the sigma exchange, crucial for potentially binding the K-D1 system, alongside pion exchange, further refined the model. This comprehensive approach allows researchers to systematically investigate the molecular spectrum of charmed-strange particles and interpret experimental observations.

Molecular Structure of the X1(2900) Tetraquark

Scientists have achieved a comprehensive understanding of exotic tetraquark states, specifically focusing on the composition and properties of charmed-strange molecular tetraquarks. Their work investigates the interactions between mesons to reveal the underlying structure of these complex particles, providing crucial insights into the strong force that governs their behavior. The research team identified the X1(2900) resonance as a molecular state formed by the coupling of a K-meson and a D1-meson, possessing quantum numbers of 0(1−). Detailed analysis demonstrates that while the X1(2900) state is primarily composed of a K-D1 combination, it also exhibits a significant contribution from a K-D1 arrangement, indicating a complex internal structure. The team’s calculations predict the existence of additional partner states in the K-D1 and K(∗)-D∗2 systems, extending the observed spectrum of these exotic particles and offering testable hypotheses for future experiments. The research confirms that interactions between these particles are governed by the exchange of various mesons, including pions, sigmas, rhos, and omegas, and that coupled-channel effects play a crucial role in binding these states.

Charmed-Strange Tetraquark Structure and Partner States

This research presents a comprehensive investigation into the nature of charmed-strange molecular tetraquarks, specifically those composed of a meson and an anticharmed meson. Through a detailed analysis using the one-boson-exchange model, the team identified a resonance observed in earlier experiments as a molecular state with specific quantum numbers, confirming its composition and internal structure. This state is primarily formed by one component but also exhibits a significant contribution from another, revealing a complex interplay of forces within the particle. Furthermore, the study predicts the existence of several partner states to this resonance, expanding the potential spectrum of these exotic tetraquarks in different configurations and suggesting a series of candidate molecular tetraquarks for future experimental searches. While acknowledging the inherent limitations of theoretical models, the team’s work provides valuable insights into the strong force interactions governing these particles and establishes a foundation for further exploration of the charmed-strange sector of hadron physics.