Spectral sum rules for the quark-gluon plasma

2009 ◽  
Vol 80 (6) ◽  
Author(s):  
P. Romatschke ◽  
D. T. Son
Keyword(s):  
Quark Gluon Plasma ◽  
Sum Rules ◽  
Gluon Plasma ◽  
Spectral Sum Rules

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 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 Top quark mixed hybrid meson and the quark–gluon plasma

2019 ◽  
Vol 35 (02) ◽  
pp. 1950353 ◽  
Author(s):  
Leonard S. Kisslinger ◽  
Debasish Das
Keyword(s):  
Top Quark ◽  
Quark Gluon Plasma ◽  
Sum Rules ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
Top Quark Mass ◽  
Hybrid Meson ◽  
Quark Masses ◽  
Ion Collisions

Using the method of QCD sum rules, we estimate the energy of lowest energy top quark meson state with a hybrid admixture. This new estimate uses the previous estimates of hybrid charmonium and upsilon states, but with the mass of the top quark mass being much greater than the charm and bottom quark masses. We discuss production of mixed hybrid top quark mesons and possible detection of the creation of the quark–gluon plasma via relativistic heavy ion collisions.

scholarly journals SLAVNOV–TAYLOR IDENTITY FOR NONEQUILIBRIUM QUARK–GLUON PLASMA

2001 ◽  
Vol 16 (08) ◽  
pp. 531-540 ◽  
Author(s):  
K. OKANO
Keyword(s):  
Quark Gluon Plasma ◽  
Gluon Plasma ◽  
Polarization Tensor ◽  
Gluon Polarization ◽  
Time Path

Within the closed-time-path formalism of nonequilibrium QCD, we derive a Slavnov–Taylor (ST) identity for the gluon polarization tensor. The ST identity takes the same form in both Coulomb and covariant gauges. Application to quasi-uniform quark–gluon plasma (QGP) near equilibrium or nonequilibrium quasistationary QGP is made.

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 Medium induced QCD cascades: broadening and rescattering during branching

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
E. Blanco ◽  
K. Kutak ◽  
W. Płaczek ◽  
M. Rohrmoser ◽  
R. Straka
Keyword(s):  
Momentum Transfer ◽  
Quark Gluon Plasma ◽  
Evolution Equations ◽  
Gaussian Approximation ◽  
Gluon Plasma ◽  
Jet Quenching ◽  
Diffusive Approximation

Abstract We study evolution equations describing jet propagation through quark-gluon plasma (QGP). In particular we investigate the contribution of momentum transfer during branching and find that such a contribution is sizeable. Furthermore, we study various approximations, such as the Gaussian approximation and the diffusive approximation to the jet-broadening term. We notice that in order to reproduce the BDIM equation (without the momentum transfer in the branching) the diffusive approximation requires a very large value of the jet-quenching parameter $$ \hat{q} $$ q ̂ .

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