High energy theorists from the Ģֱ reach a magic limit as first in Finland

The Quantum Chromodynamics (QCD) theory group at the Department of Physics of the Ģֱ, led by Professor Kari J. Eskola and studying strong-interaction phenomena in high-energy nuclear collisions, has reached a significant scientific milestone: Their article, published in 2009 in a leading journal of the field, Journal of High Energy Physics, has now reached the 1000 citation limit in the Inspire high energy physics database. At the same time, this is the first Finnish article in theoretical high energy physics that has reached this magic limit.
In their work Academy research fellow Hannu Paukkunen (left) and professor Kari j. Eskola determined the quark and gluon distributions of protons and neutrons inside atomic nuclei, as well as quantified their uncertainties.
Published
4.3.2020

The article is “EPS09: A New Generation of NLO and LO Nuclear Parton Distribution Functions'' and it is authored by Kari J. Eskola and Doc. Hannu Paukkunen from the Ģֱ and Prof. Carlos A. Salgado from the University of Santiago de Compostela.

”It feels naturally very good that our work has been this useful and widely used. Generally speaking, especially at conferences in our field, the amount of publicity received by EPS09 has sometimes been even overwhelming. We of course curiously followed the approaching of the 1000 citation limit over the recent years”, say Eskola and Paukkunen.

In this work, they determined the quark and gluon distributions of protons and neutrons inside atomic nuclei, as well as quantified their uncertainties. The study is based on advanced QCD theory calculations, experimental data from various different types of collision processes, and statistical analysis.

The work became fast a standard in the field

“With these so-called EPS09 nuclear parton distribution functions one could for the first time straightforwardly compute the propagation of the nuclear quark and gluon distribution uncertainties into measured observables. Because of this the work became rather fast a standard in the field, with applications in nearly all high-energy processes in nuclear collisions measured in the LHC collider at CERN and in the RHIC collider at the Brookhaven national laboratory. Also cosmic ray physics has utilized these distributions. The EPS09 distributions have also served as one motivation for the proton-lead collisions at the LHC, where one can test our understanding of the strong interaction dynamics in a detailed manner”, writers say.

This development work – still continuing strong and in international competition between different groups – has been also among the research activities of the Theory Program of the national Helsinki Institute of Physics. The work was financed also from the research project and graduate student fundings of the Academy of Finland. Docent Hannu Paukkunen, the main paper of whose PhD thesis this article was, works currently as an Academy Research Fellow at the Department of Physics of the Ģֱ, as the internationally leading expert in the research related to nuclear parton distributions.

Link to Inspire-data base:

Link to the article in the Journal of High Energy Physics journal:

For further information:
Professor Kari. J. Eskola, kari.eskola@jyu.fi, tel. +358 40 5718175
Academy research fellow Hannu Paukkunen, hannu.paukkunen@jyu.fi, tel. +358 40 805 4073

Communications officer Tanja Heikkinen, tanja.s.heikkinen@jyu.fi, tel. 358 50 581 8351
The Faculty of Mathematics and Science:
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