Theoretical physics / Elméleti fizika

Zoltán Varga (Wigner RCP and Budapest Tech. U.): Exploring the underlying event through heavy-flavor production

Europe/Budapest
Tanacsterem

Tanacsterem

Description

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)