COST Workshop on Interplay of hard and soft QCD probes for collectivity in heavy-ion collisions

Lundmarksalen (Lund university)


Lund university

Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 27, Lund
Christian Bierlich (Lunds universitet) , Roman Pasechnik (Lunds universitet)

Since the discovery of collective, heavy-ion like phenomena in small systems, like the appearance of a near-side ridge at high multiplicity, and strangeness enhancement with a smooth transition to pA and AA collision systems, a key question for both the hadron-hadron and heavy-ion communities have been if the origin of collectivity is the same across systems. A relevant point to answering this question is to address the heretofore non-observation of jet quenching in small systems. If the above mentioned collective phenomena in small systems are indeed a sign of final-state interactions, the key to understanding the differences and similarities between small and large systems, must be to thoroughly investigate the interplay between hard and soft probes on the collective phenomena.

In this workshop, we review the state of the art theoretical approaches to modelling both the soft and hard parts of collective effects in hadron-hadron and heavy-ion collisions. This will be followed up with discussions and ideas of how to tackle the challenge of unifying the descriptions. We aim for a discussion between theoreticians working on different approaches (effective models and MC generators) from several points of view. The goal is to come to a common understanding of the advantages and disadvantages of the different approaches. We plan to produce a short document summarising the present status and the output of the discussions.

The workshop would start with an overview of small systems, recent hydro and jet quenching results results, relation between hydro and jet quenching in large and small systems and what we learn about QCD. The follow up sessions would be devoted to the topics of jet fragmentation modification in high density environments, jet chemistry aspects, multiplicity and outlook on what we learn from the collider data. There will be a few experiments talks on prospects from HL-LHC, ALICE upgrade, STAR, ALICE and ALTAS results.

The first two days of the workshop will be devoted to a mini-school, with a few lectures primarily targeted at Ph.D. students and young postdocs, reviewing some of the main theoretical microscopic and macroscopic approaches to hadron-hadron and heavy-ion collisions. The school will also include a hands-on tutorial session of the Rivet framework for comparing Monte Carlo predictions to the data, with its recent updates to including heavy-ion processes.

Confirmed invited lecturers and topics:

  • Ilkka Helenius - Nuclear PDFs
  • Leif Lönnblad - Angantyr
  • Torbjörn Sjöstrand - Pythia
  • Volodymyr Vovchenko - Statistical thermal model
  • Christian Bierlich - Rivet hand-on session
  • Klaus Werner - EPOS
  • Stefan Prestel - Jets in perturbative QCD
  • Liliana Apolinario - Jet quenching
  • Christopher Plumberg - Flow

Internet access is available through the eduroam wireless network.

Dates for the School: from 25 February 2019 13:00 to 26 February 2019 17:15 
Dates for the Workshop: from 27 February 2019 09:00 to 1 March 2019 12:00

Location: Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 27, Lund

Room: Lundmarksalen

Registration and workshop programme: Since the number of particpants has reached the room capacity limit, the registration is closed now (contact the organisers in case you really wish to attend but forgot to register). The agenda is full and almost finalised. Any requests for late changes should sent via email to

Local oraganising committee:

  • Roman Pasechnik (chair)
  • Christian Bierlich
  • Korinna Zapp
  • Peter Christiansen
  • Leif Lönnblad



  • Adam Takacs
  • Adrian Nassirpour
  • Andrew Lifson
  • Anna Önnerstad
  • Anton Motornenko
  • Antoni Szczurek
  • Asaad Dafallah
  • Atousa Pournaghi
  • Azizbek Boltabaev
  • BABBI Saint -Cyr
  • Christian Bierlich
  • Christian Holm Christensen
  • Christine Rasmussen
  • Christopher Plumberg
  • Cristiana Oprea
  • David Silvermyr
  • Elena Bratkovskaya
  • Emmanuel de Oliveira
  • Filip Krizek
  • Freja Thoresen
  • Gunnar Ingelman
  • Gösta Gustafson
  • Harsh Shah
  • Helene Ausar
  • Hristu Culetu
  • Igor Altsybeev
  • Ilkka Helenius
  • Isobel Kolbe
  • Izabela Babiarz
  • Jakub Cimerman
  • Joao Barata
  • Joerg aichelin
  • Johannès JAHAN
  • Jonatan Adolfsson
  • Jurgen Schukraft
  • Katarina Krizkova Gajdosova
  • Klaus Werner
  • Konrad Tywoniuk
  • Korinna Zapp
  • Kristjan Gulbrandsen
  • Leif Gellersen
  • Leif Lönnblad
  • Liliana Apolinário
  • Lisa Vergara
  • Lucia Oliva
  • Mahbobeh Jafarpour
  • Martin Angelsmark
  • Michal Sumbera
  • Mohammad Alem Sultani
  • Nachiketa Sarkar
  • Naghmeh Mohammadi
  • Oliver Matonoha
  • Omar Vazquez Rueda
  • OUAMBITA IKAMBA Marie -Josée Emeline
  • Pablo Guerrero Rodríguez
  • Patrick Kirchgaesser
  • Peter Christiansen
  • Premomoy Ghosh
  • Raj kumar Thapa
  • Robin Tornkvist
  • Roman Pasechnik
  • Smita Chakraborty
  • Stefan Gieseke
  • Stefan Prestel
  • Tamás Csörgő
  • Torbjörn Sjöstrand
  • Victor Goncalves
  • Vladimir Kovalenko
  • Vojtech Pacik
  • Volodymyr Vovchenko
  • Vytautas Vislavicius
  • Wolfgang Schaefer
  • Yassine SEKHMANI
  • You Zhou
  • zafar mobeen
  • Zuzana Moravcova
  • Владимир Пастушенко