scholarly journals THE PHYSICS OF GLUEBALLS

2009 ◽  
Vol 18 (01) ◽  
pp. 1-49 ◽  
Author(s):  
VINCENT MATHIEU ◽  
NIKOLAI KOCHELEV ◽  
VICENTE VENTO
Keyword(s):  
Lattice Qcd ◽  
Gauge Field ◽  
Quark Gluon Plasma ◽  
Degrees Of Freedom ◽  
Sum Rules ◽  
Dominant Role ◽  
Gluon Plasma ◽  
Qcd Sum Rules ◽  
Technical Developments

Glueballs are particles whose valence degrees of freedom are gluons and therefore in their description the gauge field plays a dominant role. We review recent results in the physics of glueballs with the aim set on phenomenology and discuss the possibility of finding them in conventional hadronic experiments and in the Quark Gluon Plasma. In order to describe their properties we resort to a variety of theoretical treatments which include, lattice QCD, constituent models, AdS/QCD methods, and QCD sum rules. The review is supposed to be an informed guide to the literature. Therefore, we do not discuss in detail technical developments but refer the reader to the appropriate references.

scholarly journals Quark Cluster Expansion Model for Interpreting Finite-T Lattice QCD Thermodynamics

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 514
Author(s):  
David Blaschke ◽  
Kirill A. Devyatyarov ◽  
Olaf Kaczmarek
Keyword(s):  
Lattice Qcd ◽  
Cluster Expansion ◽  
Quark Gluon Plasma ◽  
Degrees Of Freedom ◽  
Gluon Plasma ◽  
Polyakov Loop ◽  
Unified Approach ◽  
Narrow Temperature Interval ◽  
Levinson Theorem ◽  
Expansion Model

In this work, we present a unified approach to the thermodynamics of hadron–quark–gluon matter at finite temperatures on the basis of a quark cluster expansion in the form of a generalized Beth–Uhlenbeck approach with a generic ansatz for the hadronic phase shifts that fulfills the Levinson theorem. The change in the composition of the system from a hadron resonance gas to a quark–gluon plasma takes place in the narrow temperature interval of 150–190 MeV, where the Mott dissociation of hadrons is triggered by the dropping quark mass as a result of the restoration of chiral symmetry. The deconfinement of quark and gluon degrees of freedom is regulated by the Polyakov loop variable that signals the breaking of the Z(3) center symmetry of the color SU(3) group of QCD. We suggest a Polyakov-loop quark–gluon plasma model with O(αs) virial correction and solve the stationarity condition of the thermodynamic potential (gap equation) for the Polyakov loop. The resulting pressure is in excellent agreement with lattice QCD simulations up to high temperatures.

scholarly journals Electrical conductivity of the quark-gluon plasma: perspective from lattice QCD

2021 ◽  
Vol 57 (4) ◽  
Author(s):  
Gert Aarts ◽  
Aleksandr Nikolaev
Keyword(s):  
Electrical Conductivity ◽  
Lattice Qcd ◽  
Quark Gluon Plasma ◽  
Sum Rules ◽  
Gluon Plasma ◽  
Comprehensive Overview ◽  
Spectral Reconstruction ◽  
Open Questions ◽  
Reconstruction Methods ◽  
Tikhonov Regularisation

AbstractA discussion on the electrical conductivity of the quark-gluon plasma as determined by lattice QCD is given. After a reminder of basic definitions and expectations, various methods for spectral reconstruction are reviewed, including the use of Ansätze and sum rules, the Maximum Entropy and Backus-Gilbert methods, and Tikhonov regularisation. A comprehensive overview of lattice QCD results obtained so far is given, including a comparison of the different lattice formulations. A noticeable consistency for the conductivities obtained is seen, in spite of the differences in the lattice setups and spectral reconstruction methods. It is found that in the case of quenched QCD little temperature dependence of $$\sigma /T$$ σ / T is seen in the temperature range investigated, while for QCD with dynamical quarks a reduction of $$\sigma /T$$ σ / T in the vicinity of the thermal crossover is observed, compared to its value in the QGP. Several open questions are posed at the end.

scholarly journals Quark Cluster Expansion Model for Interpreting Finite-T Lattice Qcd Thermodynamics

2021 ◽  
Author(s):  
David Blaschke ◽  
Kirill Devyatyarov ◽  
Olaf Kaczmarek
Keyword(s):  
Lattice Qcd ◽  
Cluster Expansion ◽  
Quark Gluon Plasma ◽  
Degrees Of Freedom ◽  
Gluon Plasma ◽  
Polyakov Loop ◽  
Unified Approach ◽  
Narrow Temperature Interval ◽  
Levinson Theorem ◽  
Expansion Model

We present a unified approach to the thermodynamics of hadron-quark-gluon matter at finite temperatures on the basis of a quark cluster expansion in the form of a generalized Beth-Uhlenbeck approach with a generic ansatz for the hadronic phase shifts that fulfills the Levinson theorem. The change in the composition of the system from a hadron resonance gas to a quark-gluon plasma takes place in the narrow temperature interval of 150−185 MeV where the Mott dissociation of hadrons is triggered by the dropping quark mass as a result of the restoration of chiral symmetry. The deconfinement of quark and gluon degrees of freedom is regulated by the Polyakov loop variable that signals the breaking of the Z(3) center symmetry of the color SU(3) group of QCD. We suggest a Polyakov-loop quark-gluon plasma model with O(αs) virial correction and solve the stationarity condition of the thermodynamic potential (gap equation) for the Polyakov loop. The resulting pressure is in excellent agreement with lattice QCD simulations up to high temperatures.

scholarly journals Excited bottomonia in quark-gluon plasma from lattice QCD

2020 ◽  
Vol 800 ◽  
pp. 135119 ◽  
Author(s):  
Rasmus Larsen ◽  
Stefan Meinel ◽  
Swagato Mukherjee ◽  
Peter Petreczky
Keyword(s):  
Lattice Qcd ◽  
Quark Gluon Plasma ◽  
Gluon Plasma

scholarly journals Holographic Multiquarks in the Quark-Gluon Plasma: A Review

2011 ◽  
Vol 2011 ◽  
pp. 1-40 ◽  
Author(s):  
Piyabut Burikham ◽  
Ekapong Hirunsirisawat
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Magnetic Properties ◽  
Quark Gluon Plasma ◽  
Bound States ◽  
Degrees Of Freedom ◽  
Gluon Plasma ◽  
Screening Length ◽  
Holographic Approach ◽  
Multiquark States

We review the holographic multiquark states in the deconfined quark-gluon plasma. Nuclear matter can become deconfined by extremely high temperature and/or density. In the deconfined nuclear medium, bound states with colour degrees of freedom are allowed to exist. Using holographic approach, the binding energy and the screening length of the multiquarks can be calculated. Using the deconfined Sakai-Sugimoto model, the phase diagram of the multiquark phase, the vacuum phase, and the chiral-symmetric quark-gluon plasma can be obtained. Then we review the magnetic properties of the multiquarks and their phase diagrams. The multiquark phase is compared with the pure pion gradient, the magnetized vacuum, and the chiral-symmetric quark-gluon plasma phases. For moderate temperature and sufficiently large density at a fixed magnetic field, the mixed phase of multiquark and pion gradient is the most energetically preferred phase.

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