Speaker: Zoltán Varga (Wigner FK and BME)

Title: Exploring the underlying event through heavy-flavor production

Date: 19 May 2023, 14:00

Place: Building 2, Media room


Recent experimental results, coming from ALICE and CMS, show a low-pT enhancement of charm baryon production over model predictions, which are based on e+e- collisions. This new development challenges the assumption that the fragmentation function is universal, i.e. independent of the collision system [1,2]. Several scenarios have been proposed to explain the discrepancy between the predictions and the experimental data, including the enhanced color re-connection model [3], which is capable of describing the charm enhancement in pp collisions.

We studied the charm-baryon enhancement in collision events generated by PYTHIA 8 and applied the enhanced color-reconnection model. We proposed a measurement method based on several event-activity classifiers, to identify the origin of the charm-baryon enhancement. Our conclusion is, that within the scenario under investigation, the excess charm production is connected to the underlying event and it is independent of the jet production [4].

Our studies have been extended to higher mass baryons, and also explored the role of the isospin. [5] Finally, we made predictions for the beauty-baryon production and its modification by the underlying event. These new observables we explored, provide a unique opportunity in the upcoming measurements from the high-luminosity LHC Run 3 period to better understand the charm and beauty fragmentation mechanisms, and will help the further developments of models.

[1] CMS Coll., Phys. Lett. B 803 (2020) 135328, arXiv:1906.03322.
[2] ALICE Coll., Physicial Review Letters 127, 202301 (2021), arXiv:2011.06078.
[3] C., J.R., S., P.Z., JHEP 2015, 3 (2015), arXiv:1505.01681.
[4] Z. V., R. V., J.Phys.G 49 (2022), arXiv:2111.00060.
[5] Z.V., A.M., R.V., arXiv:2302.09740 (accepted in J.Phys.G)