# D-meson duos in p-p and p-Pb collisions

- Institution: CERN
- Department: Conferences
- Speaker: Hannu Paukkunen
- Year: 2021
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3018069)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

The LHCb collaboration has recently measured cross sections for the simultaneous production of two charmed-particles in p-p \[1\] and p-Pb \[2\] collisions. These include opposite-sign and same-sign D-meson pairs offering, for the first time, a chance to study the interplay of single-parton (SPS) and double-parton scattering (DPS) across different collision systems.

In this talk, we discuss our NLO QCD framework \[3\] used to calculate the double D-meson cross sections. The setup is based on factorized PDFs and D-meson fragmentation functions, taking into into account both the SPS and DPS contributions. The DPS contributions are estimated with an effective cross section approach neglecting the partonic correlations. We find a nice agreement with the LHCb p-p and p-Pb data when using values for the effective cross section consistent with other measurements. In particular, we conclude that the same-sign D-meson data provide the first quantitative confirmation of DPS at work in p-Pb collisions.

We also compare our results to Pythia Monte Carlo simulations and discuss the implications of DPS on the two-particle azimuthal correlations and possibilities to resolve signatures of saturation phenomena.

\[1\] LHCb Collaboration, JHEP 06 (2012) 141. \[2\] LHCb Collaboration, arXiv:2007.06945 \[hep-ex\]. \[3\] Helenius, Paukkunen, Phys.Lett.B 800 (2020) 135084..

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## Lectures

1. [D-meson duos in p-p and p-Pb collisions](https://invisiblenetwork.ai/learn/cern/3018069/a205bc459933), 21 min (CERN's player)