Meeting held on zoom with 22-24 participants
- News: Jacek Otwinowski
- Jacek went through the scientific topics of the group summarizing the recent and future activities of the group. Discussion: None
- J/ψ hadroproduction from color reconnection by Leszek Motyka (first part) and Piotr Kotko (based on https://arxiv.org/abs/2303.13128)
- Leszek discussed an overview of studies on the production of J/psi mesons in hadron-hadron collisions, problems and possible solutions were listed. Two models, Color-Singlet and Color-Octet, are used to considered, and their contributions to J/psi hadroproduction. In short, Color-Singlet model doesn't allow to describe double J/phi hadroproduction. Color-Octet model can do it but it failures in the estimation of the magnitude of cross section by factor of about three. Discussed perturbative and nonperturbative mechanisms of color reconnection (CR) in the Lund approach (Pythia) and its problem of breaking the factorization.
- Piotr mainly focused on showing recent results which obtained in certain realization of CR in Pythia which leads to a good description of transverse momentum spectra of J/psi from ATLAS and CMS. He described the algorithm of generating inclusively (without any cuts and turning off hadronization in Pyhtia) the ccbar singlets in Pythia, focusing on the impact of the color reconnection mechanism (on/off). Only the treatment of the ccbar singlets with an invariant mass cut between 3.0 GeV, and 3.3 GeV as the J/psi is considered.
- Q: did you try to compare your results with e.g. COM?
- A: No, the primary goal was to study CR effects on J/psi production using Pythia approach
- Q: CSM does not describe polarization of J/psi, do you consider to include it in your approach?
- A: Good point, it is to be considered
- Q: did you try to simulate three J/psi mesons? (this question is based on recent CMS work https://arxiv.org/pdf/2111.05370.pdf)
- A: No, because it was quite a difficult problem for us to get double J/psi mesons in terms of computer resources.
- Q: How many events of double J/psi were obtained?
- A: I don't remember and it is difficult to say. I can say that there were a few such events. This process requires much higher statistics and numerical resources.
- Q: Do you consider to study charm baryon production?
- A: No, much more difficult production process. Focus on single, double J/psi production and their multiplicity dependence
- Authors are open for any kind of collaboration. The presented model should be studied in different kinematical regions.
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