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Helmut Satz

Publications and source records attributed to Helmut Satz.

At least 37 records · Page 2Linked to original sources
arXiv2008

On the Kertész line: Thermodynamic versus Geometric Criticality

The critical behaviour of the Ising model in the absence of an external magnetic field can be specified either through spontaneous symmetry breaking (thermal criticality) or through cluster percolation (geometric criticality). We extend this to finite external fields for the case of the Potts' model, showing that a geometric analysis leads to the same first order/second order structure as found in thermodynamic studies. We calculate the Kertész line, separating percolating and non-percolating regimes, both analytically and numerically for the Potts model in presence of an external magnetic field.

cond-mat.stat-mech↗
arXiv2008

The Thermodynamics of Quarks and Gluons

This is an introduction to the study of strongly interacting matter. We survey its different possible states and discuss the transition from hadronic matter to a plasma of deconfined quarks and gluons. Following this, we summarize the results provided by lattice QCD finite temperature and density, and then investigate the nature of the deconfinement transition. Finally we give a schematic overview of possible ways to study the properties of the quark-gluon plasma.

hep-ph↗
arXiv2006

Thermal Hadron Production by QCD Hawking Radiation

The QCD counterpart of Hawking radiation from black holes leads to thermal hadron production in high energy collisions, from $e^+e^-$ annihilation to heavy ion interactions. This hadronic radiation is formed by tunnelling through the event horizon of colour confinement and is emitted at a universal temperature $T_H \simeq (σ/2 π)^{1/2}$, where $σ$ denotes the string tension. Since the event horizon does not allow information transfer, the radiation is thermal ``at birth''.

hep-ph↗
arXiv2006

Quarkonium Binding and Dissociation: The Spectral Analysis of the QGP

In statistical QCD, the thermal properties of the quark-gluon plasma can be determined by studying the in-medium behaviour of heavy quark bound states. The results can be applied to quarkonium production in high energy nuclear collisions, if these indeed form a fully equilibrated QGP. Modifications could arise if an initial charm excess persists in the collision evolution and causes quarkonium regeneration at hadronization.

hep-ph↗
arXiv2006

Colour Deconfinement and Quarkonium Binding

At high temperatures, strongly interacting matter becomes a plasma of deconfined quarks and gluons. In statistical QCD, deconfinement and the properties of the resulting quark-gluon plasma can be investigated by studying the in-medium behaviour of heavy quark bound states. In high energy nuclear interactions, quarkonia probe different aspects of the medium formed in the collision. We survey the results of recent charmonium production studies in SPS and RHIC experiments.

hep-ph↗
arXiv2006

Charm and Beauty in a Hot Environment

We discuss the spectral analysis of quarkonium states in a hot medium of deconfined quarks and gluons, and we show that such an analysis provides a way to determine the thermal properties of the quark-gluon plasma.

hep-ph↗
arXiv2004

The SPS Heavy Ion Programme

Statistical QCD predicts with increasing temperature a transition from hadronic matter to a plasma of deconfined quarks and gluons. The SPS Heavy Ion Programme was initiated to study this transition and the resulting quark-gluon plasma. After summarizing the different probes for the collision evolution, I survey the experimental results obtained so far and assess the conclusions that can be drawn.

hep-ph↗
arXiv2004

The Hagedorn Temperature and Partition Thermodynamics

We review the resonance gas formalism of hadron thermodynamics and recall that an exponential increase of the resonance spectrum leads to a limiting temperature of hadronic matter. We then show that the number p(n) of ordered partitions of an integer n grows exponentially with n and satisfies the integer counterpart of the statistical bootstrap equation. Considering the set of all partitions as a Gibbs ensemble provides a partition thermodynamics which is also governed by a limiting temperature, determined by the combinatorial structure of the problem. Further associating intrinsic quantum numbers to integers results in a phase diagram equivalent to that found in QCD for hadronic matter as function of temperature and baryochemical potential.

hep-ph↗
arXiv2001

Cluster Percolation and Explicit Symmetry Breaking in Spin Models

Many features of spin models can be interpreted in geometrical terms by means of the properties of well defined clusters of spins. In case of spontaneous symmetry breaking, the phase transition of models like the q-state Potts model, O(n), etc., can be equivalently described as a percolation transition of clusters. We study here the behaviour of such clusters when the presence of an external field H breaks explicitly the global symmetry of the Hamiltonian of the theory. We find that these clusters have still some interesting relationships with thermal features of the model.

hep-lat↗
arXiv2001

Cluster Percolation and Pseudocritical Behaviour in Spin Models

The critical behaviour of many spin models can be equivalently formulated as percolation of specific site-bond clusters. In the presence of an external magnetic field, such clusters remain well-defined and lead to a percolation transition, even though the system no longer shows thermal critical behaviour. We investigate the 2-dimensional Ising model and the 3-dimensional O(2) model by means of Monte Carlo simulations. We find for small fields that the line of percolation critical points has the same functional form as the line of thermal pseudocritical points.

hep-lat↗
arXiv2000

Percolation and Deconfinement in SU(2) Gauge Theory

The deconfinement transition in SU(2) gauge theory and the magnetization transition in the Ising model belong to the same universality class. The critical behaviour of the Ising model can be characterized either as spontaneous breaking of the $Z_2$ symmetry of spin states or as percolation of appropriately defined spin clusters. We show that deconfinement in SU(2) gauge theory can be specified as percolation of Polyakov loop clusters with Fortuin-Kasteleyn bond weights, leading to the same critical exponents as the conventional order-disorder description based on the Polykov loop expectation value.

hep-lat↗
arXiv2000

Colour Deconfinement in Nuclear Collisions

QCD predicts that strongly interacting matter will undergo a transition from a state of hadronic constituents to a plasma of unbound quarks and gluons. We first survey the conceptual features of this transition and its description in finite temperature lattice QCD, before we address its experimental investigation through high energy nucleus-nucleus collisions. After considering the conditions achievable in such collisions, we discuss the possible probes to check if the produced medium in its early stages was indeed deconfined. We then elaborate the method that has emerged and the results which were obtained using the most extensively studied deconfinement probe, the suppression of charmonium production. In closing, we discuss possible supporting information provided through the study of soft hadronic probes.

hep-ph↗
arXiv2000

Percolation and Magnetization in the Continuous Spin Ising Model

In the strong coupling limit the partition function of SU(2) gauge theory can be reduced to that of the continuous spin Ising model with nearest neighbour pair-interactions. The random cluster representation of the continuous spin Ising model in two dimensions is derived through a Fortuin-Kasteleyn transformation, and the properties of the corresponding cluster distribution are analyzed. It is shown that for this model, the magnetic transition is equivalent to the percolation transition of Fortuin-Kasteleyn clusters, using local bond weights. These results are also illustrated by means of numerical simulations.

hep-lat↗
arXiv2000

Polyakov Loop Percolation and Deconfinement in SU(2) Gauge Theory

The deconfinement transition in SU(2) gauge theory and the magnetization transition in the Ising model belong to the same universality class. The critical behaviour of the Ising model can be characterized either as spontaneous breaking of the Z_2 symmetry of spin states or as percolation of appropriately defined spin clusters. We show that deconfinement in SU(2) gauge theory can be specified as percolation of Polyakov loop clusters with Fortuin-Kasteleyn bond weights, leading to the same (Onsager) critical exponents as the conventional order-disorder description based on the Polyakov loop expectation value.

hep-lat↗
arXiv1999

The Evolution of Dynamical Screening in the Parton Cacade Model

We determine the time evolution of the colour screening mass in high energy nuclear collisions, as provided by the parton cascade model. Using our result, we discuss the onset of deconfinement and the onset of quarkonium suppression in a general, not necessarily equilibrated environment of strongly interacting constituents.

hep-ph↗
arXiv1998

A Brief History of J/Psi Suppression

Statistical QCD predicts that strongly interacting matter will become deconfined at high temperatures and/or densities. The aim of high energy nuclear collisions is to study the onset of deconfinement and the properties of deconfined media in the laboratory. Hence it is essential to define an unambiguous and experimentally viable probe for deconfinement. Twelve years ago, T. Matsui and I proposed that \J~production should constitute such a probe \cite{M&S}, and I want to sketch here rather briefly the evolution of this idea in the light of subsequent experimental and theoretical work.

hep-ph↗
arXiv1998

Deconfinement and Percolation

Using percolation theory, we derive a conceptual definition of deconfinement in terms of cluster formation. The result is readily applicable to infinite volume equilibrium matter as well as to finite size pre-equilibrium systems in nuclear collisions.

hep-ph↗