Coupled-channel effects in hadron–hadron correlation functions

Abstract

Two-particle momentum correlation functions as measured in heavy ion collisions or in high-energetic proton-proton collisions are studied. Special emphasis is put on systems like ΛΛ or K − p where effects from the coupling to other channels could be relevant. In both cases other channels open at relatively low momenta or are already open at the reaction threshold. To have a solid basis, realistic coupled-channel interactions for ΛΛ − ΞN − ΛΣ − ΣΣ and πΛ − πΣ −KN are utilized in the actual calculations. It is found that the opening of the ΞN channel leaves a trace in the ΛΛ correlation function that could be detectable in experiments. Should the proposed H-dibaryon be located close to or below the ΞN it will have a very pronounced effect. The presence of open channels in systems like Ξ − p or K − p does influence the correlation functions significantly at low momenta and will certainly complicate any dedicated analysis.

Scattering Studies with Low-Energy Kaon-Proton Femtoscopy in Proton-Proton Collisions at the LHC

“…The introduction of coupled-channel contributions in the correlation function has been shown to result in additional attractive terms enhancing the signal, in particular in the low k à region [34]. As expected, the Kyoto results clearly underestimate the data at low momenta where the Σπ channel is particularly relevant.…”

“…Contrary to the scattering, in femtoscopy only the final state is measured and different initial states are allowed. In the K − p system, this translates into an extreme sensitivity of the correlation function to the introduction of the different coupledchannels, which affect both shape and magnitude of the femtoscopic signal [34].…”

K−p Correlation Function from High-Energy Nuclear Collisions and Chiral SU(3) Dynamics

“…Let this two-particle state be fed by a set of coupled channels, each denoted by j. In the center-of-mass frame of the two measured particles (a, b), their correlation function C(q) is given as [18,23]:…”

Probing ΩΩ and pΩ dibaryons with femtoscopic correlations in relativistic heavy-ion collisions

“…In reality, the correlation at small q originates not only from the single-channel FSI but also from the quantum statistics in the case of identical pairs (HBT effect), from the Coulomb interaction, and from the coupled channel effect [26]. Furthermore, the correlation from the HBT effect is affected by the collective flow through the modification of the source geometry.…”

“…As discussed in the Appendix A, the J = 1 contribution causes visible uncertainties in the pΩ correlation function. While the coupling effects to octet-octet channels with J = 1 in the pΩ correlation function have been assumed to be described by the absorption, the coupled channel formula [26] shows that creation processes such as ΛΞ → pΩ also contribute to the correlation function of pΩ. Then we need to evaluate the transition potentials and the source function of Λ and Σ. Refs.…”