Speaker: Prof.  Johanna Stachel
Title of Talk: Experimental Test of Quark Deconfinement – Hadrons with Charm Quarks

A quark-gluon plasma (QGP) is a state where chiral symmetry, a fundamental symmetry of quantum chromo dynamics (QCD), is restored and the basic degrees are unbound quarks and gluons and not hadroncs. This means the confinement that is observed in our ‘normal world’ is lifted in a QGP. Collisions of heavy nuclei at the Large Hadron Collider (LHC) are an ideal environment, to study this effect. In a nuclear collision at the LHC a QGP is formed shortly after the collision. The QGP then expands and cools until it reaches a low enough temperature to form hadrons with confined quarks and gluons, i.e. normal (hadronic) matter.

Heavy quarks are produced by hard binary collisions of (mostly) gluons very early in the nuclear collision even before the QGP forms. In our current understanding, charm quarks thermalize in the QGP which, according to what we have learned from experiments, is a strongly coupled medium. If the thermalized, deconfined charm quarks hadronize simultaneously with the other QGP constituents, there is a unique set of predictions concerning their yields and spectra that can be tested in the LHC experiments. It will be shown that data gained from the first 10 year of operation of the LHC quantitatively fulfill these expectations, based on thermally equilibrated deconfined heavy quarks. There is also a unique set of predictions for the future concerning the formation of many more and even rather exotic states containing charm quarks.

Venue (HYBRID-EVENT): Goldene Box, Physikalisches Institut, INF 226, 69120 Heidelberg AND all talks will also be streamed via the permanent Zoom-link:

Meeting ID: 946 0240 1603
Passcode: 386993

13:00 – 13:45  talk
13:45-14:00   questions & discussion
14:00 pizza



The main idea of the CRC 1225 Lunch Seminars is to bring together all scientists involved in our collaboration on a regular basis to allow exchange and discussion even outside one’s own research topics. We therefore invite all PIs and working group members of the CRC 1225 ISOQUANT to participate in the Lunch Seminars and to use this opportunity for getting to know each other, fruitful discussions and valuable exchange.

The seminar will take place in presence in accordance with the current COVID-19 regulations for on-site events (Please wear a FFP2 mask or surgical mask if the minimum distance of 1.5m can not be guaranteed).