Update on J/ψ regeneration in a hadron gas

Abstract

In heavy-ion collisions, after the quark-gluon plasma there is a hadronic gas phase. Using effective Lagrangians, we study the interactions of charmed mesons which lead to J /ψ production and absorption in this gas. We update and extend previous calculations introducing strange meson interactions and also including the interactions mediated by the recently measured exotic charmonium resonances Z(3900) and Z (4025). These resonances open new reaction channels for the J /ψ, which could potentially lead to changes in its multiplicity. We compute the J /ψ production cross section in processes such as D ( * ) (s) +D ( * ) → J /ψ + (π,ρ,K,K * ) and also the J /ψ absorption cross section in the corresponding inverse processes. Using the obtained cross sections as input to solve the appropriate rate equation, we conclude that the interactions in the hadron gas phase lead to a 20-24% reduction of the J /ψ abundance. Within the uncertainties of the calculation, this reduction is the same at the Relativistic Heavy Ion Collider and the large Hadron Collider.

On the two-body decay processes of the predicted three-body K*(4307) resonance

“…It is sometimes argued that processes involving anomalous vertices should give smaller contributions that those in which no anomalous vertices are involved. However, the importance of the anomalous vertices in different contexts, like in the determination of production and absorption cross sections of several processes, calculation of radiative decays of scalar and axial resonances and kaon photo-production, has been shown [68][69][70][71][72][73][74][75].…”

Heavy-meson chiral Lagrangians, effective flavored couplings, SU(4) flavor breaking and their consequences

“…Soon after the introduction of effective SU(4) F Lagrangians, such as the ones discussed in Section 2, the study of interactions between open-charm mesons and nuclei to explore the possibility of charmed nuclear bound states became the object of intense activity [35][36][37][38][39][40]. Their application has gone beyond that field and include the reaction D ( * ) D ( * ) → πX(3872) which involves an intermediate triangle diagram with pseudoscalar and vector mesons [12], the decay of a highly excited D meson [41], the J/ψ regeneration in the hadronic gas phase following the cooling of a quark-gluon plasma [42], the production of the ψ(3770) resonance inpp →DD [43] or the thermal properties of pseudoscalar and vector charm mesons [44], amongst others. At the same time, the effective couplings, quite naturally, have also been the object of interest [23,.…”

Heavy-meson chiral Lagrangians, effective flavored couplings, SU(4) flavor breaking and their consequences

“…Soon after the introduction of effective SU(4) 𝐹 Lagrangians, such as the ones discussed in Section 2, the study of interactions between open-charm mesons and nuclei to explore the possibility of charmed nuclear bound states became the object of intense activity [35][36][37][38][39][40]. Their application has gone beyond that field and include the reaction 𝐷 ( * ) 𝐷 ( * ) → 𝜋𝑋 (3872) which involves an intermediate triangle diagram with pseudoscalar and vector mesons [12], the decay of a highly excited 𝐷 meson [41], the 𝐽/𝜓 regeneration in the hadronic gas phase following the cooling of a quark-gluon plasma [42], the production of the 𝜓(3770) resonance in p 𝑝 → D𝐷 [43] or the thermal properties of pseudoscalar and vector charm mesons [44], amongst others. At the same time, the effective couplings, quite naturally, have also been the object of interest [23,.…”