QCD matter

Summary

Quark matter or QCD matter (quantum chromodynamic) refers to any of a number of hypothetical phases of matter whose degrees of freedom include quarks and gluons, of which the prominent example is quark-gluon plasma. Several series of conferences in 2019, 2020, and 2021 were devoted to this topic. Quarks are liberated into quark matter at extremely high temperatures and/or densities, and some of them are still only theoretical as they require conditions so extreme that they cannot be produced in any laboratory, especially not at equilibrium conditions. Under these extreme conditions, the familiar structure of matter, where the basic constituents are nuclei (consisting of nucleons which are bound states of quarks) and electrons, is disrupted. In quark matter it is more appropriate to treat the quarks themselves as the basic degrees of freedom. In the standard model of particle physics, the strong force is described by the theory of QCD. At ordinary temperatures or densities this force

Official source

https://en.wikipedia.org/wiki/QCD_matter

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related publications (5)

Related publications

Related people

Related units

Related concepts (40)

Related concepts

Related courses (2)

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.

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.

Related courses

Related lectures (3)

Related lectures

We study the effects of the CP-breaking topological theta-term in the large N-c QCD model by Witten, Sakai and Sugimoto with N-f degenerate light flavors. We first compute the ground state energy density, the topological susceptibility and the masses of the lowest lying mesons, finding agreement with expectations from the QCD chiral effective action. Then, focusing on the N (f) = 2 case, we consider the baryonic sector and determine, to leading order in the small theta regime, the related holographic instantonic soliton solutions. We find that while the baryon spectrum does not receive Omicron(theta) corrections, this is not the case for observables like the electromagnetic form factor of the nucleons. In particular, it exhibits a dipole term, which turns out to be vector-meson dominated. The resulting neutron electric dipole moment, which is exactly the opposite as that of the proton, is of the same order of magnitude of previous estimates in the literature. Finally, we compute the CP-violating pion-nucleon coupling constant g ($) over bar (pi NN,) finding that it is zero to leading order in the large N (c) limit.

Springer Nature2017

Neutron Electric Dipole Moment from Gauge-String Duality

Andrea Manenti

We compute the electric dipole moment of nucleons in the large N-c QCD model by Witten, Sakai, and Sugimoto with N-f = 2 degenerate massive flavors. Baryons in the model are instantonic solitons of an effective five-dimensional action describing the whole tower of mesonic fields. We find that the dipole electromagnetic form factor of the nucleons, induced by a finite topological. angle, exhibits complete vector meson dominance. We are able to evaluate the contribution of each vector meson to the final result a small number of modes are relevant to obtain an accurate estimate. Extrapolating the model parameters to real QCD data, the neutron electric dipole moment is evaluated to be d(n) = 1.8 x 10(-16)theta e cm. The electric dipole moment of the proton is exactly the opposite.

Amer Physical Soc2017

The nature of X(3872) from high-multiplicity pp collisions

Angelo Esposito

The structure of exotic resonances that do not trivially fit the usual quark model expectations has been a matter of intense scientific debate during the last two decades. A possible way of estimating the size of these states is to study their behavior when immersed in QCD matter. Recently, LHCb has measured the relative abundance of the exotic X(3872) over the ordinary psi (2S). We use the comover interaction model to study the yield of a compact X(3872). To confirm the reliability of the model in high-multiplicity pp collisions, we describe the suppression of excited over ground Upsilon states. With this at hand, we show that the size of the compact X(3872) would be slightly larger than that of the psi (2S). If the X(3872) is instead assumed to be a meson molecule of large size, we argue that its evolution in QCD matter should be described via a coalescence model, as suggested by data on deuteron production. We show that the predictions of this model for the X(3872) are in contrast with data.

SPRINGER2021