Z(c)(4430) and Z(c)(4200) as triangle singularities

Autor(es)

Nakamura, S. X. ; Tsushima, K.

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW D; v. 100, n. 5, p. 6-pg., 2019-09-09.

Resumo

Z(c)(4430) discovered by the Belle Collaboration and confirmed by the LHCb Collaboration in (B) over bar (0) -> psi(2S)K-pi(+) is generally considered to be a charged charmoniumlike state that includes minimally two quarks and two antiquarks. Z(c)(4200) found in (B) over bar (0) -> J/psi K-pi(+) by Belle is also a good candidate of a charged charmoniumlike state. In this work, we propose a compelling alternative to the tetraquark-based interpretations of Z(c)(4430) and Z(c)(4200). We demonstrate that kinematical singularities in triangle loop diagrams induce a resonancelike behavior that can consistently explain the properties (spin parity, mass, width, and Argand plot) of Z(c)(4430) and Z(c)(4200) from the experimental analyses. Applying this idea to Lambda(0)( )(b)-> J/psi p pi(-),we also identify triangle singularities that behave like Z(c)(4200), but no triangle diagram is available for Z(c)(4430). This is consistent with LHCb's finding that their description of the Lambda(0)(b) -> J/psi p pi(-) data is significantly improved by including a Z(c)(4200) contribution while Z(c)(4430) seems to hardly contribute. Even though the proposed mechanisms have uncertainty in the absolute strengths which are currently difficult to estimate, otherwise the results are essentially determined by the kinematical effects and, thus, robust. (AU)

• Processo FAPESP: 17/05660-0 - Estudos teóricos da estrutura e reações de núcleos exóticos e sistemas de muitos corpos
• Beneficiário: Brett Vern Carlson
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 16/15618-8 - Análise de Tau e pesados méson hadrônicas decaimentos e neutrino-núcleo interações, para estruturas e interações hadron, e física além do modelo padrão
• Beneficiário: Kazuo Tsushima
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional