Plasma quarks-gluons

Résumé

Le plasma de quarks et de gluons, ou QGP (pour Quark-Gluon Plasma) est un état de la matière qui existe à des températures et/ou des densités extrêmement élevées. Cet état consiste en une « soupe » de quarks et de gluons (presque) libres. Elle diffère en cela des autres états de la matière, comme les solides, les liquides ou les gaz, dans lesquels les quarks et les gluons sont confinés dans les hadrons. Le était sans doute présent dans l'univers durant les microsecondes après le Big Bang. Aujourd'hui, des théories prédisent son existence au sein de certaines étoiles très denses, mais le seul moyen de l'étudier réellement est de « le fabriquer » artificiellement dans des accélérateurs de particules. Description Si on remonte dans le temps, l'univers était chaud. Si la température est suffisamment élevée, le noyau des atomes se vaporise. À ce stade, l'agitation thermique est supérieure aux forces de cohésion des noyaux, et l'on obtient un gaz de hadrons (autrement dit ce

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https://fr.wikipedia.org/wiki/Plasma_quarks-gluons

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Presentation of the electroweak and strong interaction theories that constitute the Standard Model of particle physics. The course also discusses the new theories proposed to solve the problems of the Standard Model.

This course presents the physical principles and the recent research developments on three topics of particle and nuclear physics: the physics of neutrinos, dark matter, and plasmas of quarks and gluons. An emphasis is given on experimental aspects in these three research fields.

This course will focus on the electron transport in semiconductors, with emphasis on the mesoscopic systems. The aim is to understand the transport of electrons in low dimensional systems, where even particles with statistics different than fermions and bosons will be discussed.

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Séances de cours associées (38)

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Contribution of next-to-leading order and Landau-Pomeranchuk-Migdal corrections to thermal dilepton emission in heavy-ion collisions

Yannis Burnier, Chiara Gastaldi

Recently lots of effort has been made to obtain the next-to-leading-order and Landau-Pomeranchuk-Migdal corrections to the thermal dilepton emission rate in perturbative QCD. Here we apply these results to the plasma created in heavy-ion collisions and see whether these corrections improve the comparison between theoretical calculations and experimental results for the invariant mass dependence of the dilepton emission rate. In particular, we simulate the quark-gluon plasma produced at the Relativistic Heavy Ion Collider at the Brookhaven National Laboratory and the Large Hadron Collider at CERN using 2 + 1-dimensional viscous hydrodynamical simulations. We compare our results to those of the STAR experiment and comment on the need for a nonperturbative determination of the dilepton rate at low invariant mass.

Amer Physical Soc2016

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The Bayesian reconstruction of the in-medium heavy quark potential from lattice QCD and its stability

Yannis Burnier

We report recent results of a non-perturbative determination of the static heavy-quark potential in quenched and dynamical lattice QCD at finite temperature. The real and imaginary part of this complex quantity are extracted from the spectral function of Wilson line correlators in Coulomb gauge. To obtain spectral information from Euclidean time numerical data, our study relies on a novel Bayesian prescription that differs from the Maximum Entropy Method. We perform simulations on quenched 32(3) x N-tau (beta = 7.0, xi = 3.5) lattices with N-tau = 24,...,96, which cover 839MeV >= T >= 210MeV. To investigate the potential in a quark-gluon plasma with light u, d and s quarks we utilize N-f = 2 + 1 ASQTAD lattices with m(l) = m(s)/20 by the HotQCD collaboration, giving access to temperatures between 286MeV >= T >= 148MeV. The real part of the potential exhibits a clean transition from a linear, confining behavior in the hadronic phase to a Debye screened form above deconfinement. Interestingly its values lie close to the color singlet free energies in Coulomb gauge at all temperatures. We estimate the imaginary part on quenched lattices and find that it is of the same order of magnitude as in hard-thermal loop perturbation theory. From among all the systematic checks carried out in our study, we discuss explicitly the dependence of the result on the default model and the number of datapoints.

Amer Inst Physics2016

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We present a state-of-the-art determination of the complex valued static quark-antiquark potential at phenomenologically relevant temperatures around the deconfinement phase transition. Its values are obtained from nonperturbative lattice QCD simulations using spectral functions extracted via a novel Bayesian inference prescription. We find that the real part, both in a gluonic medium, as well as in realistic QCD with light u, d, and s quarks, lies close to the color singlet free energies in Coulomb gauge and shows Debye screening above the (pseudo) critical temperature T-c. The imaginary part is estimated in the gluonic medium, where we find that it is of the same order of magnitude as in hard-thermal loop resummed perturbation theory in the deconfined phase.

American Physical Society2015

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