Chapter 7
Relativistic Nucleus-Nucleus Collisions
and the QCD Matter Phase Diagram
Reinhard Stock
7.1 Introduction
7.1.1 Overview
This review will be concerned with our knowledge of extended matter under the
governance of strong interaction, in short: QCD matter. Strictly speaking, the
hadrons are representing the first layer of extended QCD architecture. In fact
we encounter the characteristic phenomena of confinement as distances grow to
the scale of 1 fm (i.e. hadron size): loss of the chiral symmetry property of the
elementary QCD Lagrangian via non-perturbative generation of “massive” quark
and gluon condensates, that replace the bare QCD vacuum [1]. However, given such
first experiences of transition from short range perturbative QCD phenomena (jet
physics etc.), toward extended, non perturbative QCD hadron structure, we shall
proceed here to systems with dimensions far exceeding the force range: matter
in the interior of heavy nuclei, or in neutron stars, and primordial matter in the
cosmological era from electro-weak decoupling (10 −12 s) to hadron formation
(0.5·10 −5 s). This primordial matter, prior to hadronization, should be deconfined in
its QCD sector, forming a plasma (i.e. color conducting) state of quarks and gluons
[2]: the Quark Gluon Plasma (QGP).
In order to recreate matter at the corresponding high energy density in the
terrestrial laboratory one collides heavy nuclei (also called “heavy ions”) at ultrarelativistic energies. Quantum Chromodynamics predicts [2–4] a phase transformation
R. Stock ()
Goethe University Frankfurt, Frankfurt, Germany
Frankfurt Institute of Advanced Studies (FIAS), Frankfurt, Germany
Institut fuer Kernphysik, Goethe Universitaet, Frankfurt, Germany
e-mail: stock@ikf.uni-frankfurt.de
© The Author(s) 2020
H. Schopper (ed.), Particle Physics Reference Library,
https://doi.org/10.1007/978-3-030-38207-0_7
311
Relativistic Nucleus-Nucleus Collisions
and the QCD Matter Phase Diagram
Reinhard Stock
7.1 Introduction
7.1.1 Overview
This review will be concerned with our knowledge of extended matter under the
governance of strong interaction, in short: QCD matter. Strictly speaking, the
hadrons are representing the first layer of extended QCD architecture. In fact
we encounter the characteristic phenomena of confinement as distances grow to
the scale of 1 fm (i.e. hadron size): loss of the chiral symmetry property of the
elementary QCD Lagrangian via non-perturbative generation of “massive” quark
and gluon condensates, that replace the bare QCD vacuum [1]. However, given such
first experiences of transition from short range perturbative QCD phenomena (jet
physics etc.), toward extended, non perturbative QCD hadron structure, we shall
proceed here to systems with dimensions far exceeding the force range: matter
in the interior of heavy nuclei, or in neutron stars, and primordial matter in the
cosmological era from electro-weak decoupling (10 −12 s) to hadron formation
(0.5·10 −5 s). This primordial matter, prior to hadronization, should be deconfined in
its QCD sector, forming a plasma (i.e. color conducting) state of quarks and gluons
[2]: the Quark Gluon Plasma (QGP).
In order to recreate matter at the corresponding high energy density in the
terrestrial laboratory one collides heavy nuclei (also called “heavy ions”) at ultrarelativistic energies. Quantum Chromodynamics predicts [2–4] a phase transformation
R. Stock ()
Goethe University Frankfurt, Frankfurt, Germany
Frankfurt Institute of Advanced Studies (FIAS), Frankfurt, Germany
Institut fuer Kernphysik, Goethe Universitaet, Frankfurt, Germany
e-mail: stock@ikf.uni-frankfurt.de
© The Author(s) 2020
H. Schopper (ed.), Particle Physics Reference Library,
https://doi.org/10.1007/978-3-030-38207-0_7
311