 |
Norwegian
University of Science and Technology NTNU |
Institute of physics |
Research in the Astroparticle-Physics Group at NTNU
Phase Diagram of QCD:
The Fig. shows the phase diagram of QCD as function of the temperature
T and the chemical potential mu.
Strongly interacting matter which is confined and where chiral symmetry
is broken correponds to low temperatures and small chemical potentials.
If hadronic matter is heated, it is expected to undergo a phase transition
to a new state of matter called a quark-gluon plasma.
In the quark-gluon plasma, the quarks are no longer confined in hadrons, but
can move freely around much in the same way as in ordinary plasmas.
The chiral symmetry, which was broken at low temperatures, is restored
in the high-temperature quark-gluon phase. In cosmological models, the
quark-gluon plasma existed
in the early universe
until a time approximately 10^(-5) seconds after the Big
Bang. Knowing the properties of this phase of QCD is therefore essential
to understanding the evolution of the early universe.
In order to examine these properties, there is currently a large
experimental activity aiming at creating a quark-gluon plasma
in heavy-ion collisions.
The various heavy-ion collision experiments can be characterized by
a temperature and a chemical potential. In the Fig. some of the
ongoing
and planned
experiments at CERN (SPS and ALICE) and
Brookhaven National Lab (RHIC)
are marked by crosses.
One of the primary goals of the
experimental programs at Brookhaven National
Lab (RHIC) and CERN
(LHC starting in 2007) is to produce and study the quark-gluon plasma.
Similarly, one can ask what happens to strongly interacting matter as
one increases the density.
In this case, one expects that QCD undergoes
a phase transitions to a state called quark matter
in which
quarks are no longer confined
If the temperature is sufficiently low, quark matter might also be
a color superconductor. Color superconductivity is analogous to ordinary
superconductivity, but there can be various color-superconducting phases.
The phase diagram at high density is very relevant to astrophysics since
astrophysical objects such as neutron stars might have a core
whose density is several times the density of ordinary nuclear matter.
Preprints:
hep-ph/0504177
Color Superconductivity VS. Pseudoscalar Condensation in a Three-flavor
NJL model.
astro-ph/0510188
Reconciling the Ultra-high Energy Cosmic Ray Spectrum with Fermi Shock
Acceleration.
astro-ph/0510444
The Galactic Magnetic Field as Spectrograph for Ultrahigh Energy Cosmic Rays.
hep-ph/0504264
Derivation of Neutrino Matter Potentials Induced by Earth.
hep-ph/0505079
Analytic Formulas for Neutrino-electron Scattering Cross Sections.
hep-ph/0505115
Exploiting Non-adiabatic Density Shifts in Neutrino Interactions.
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Phase Diagram of QCD:
The Fig. shows the phase diagram of QCD as function of the temperature T and the chemical potential mu. Strongly interacting matter which is confined and where chiral symmetry is broken correponds to low temperatures and small chemical potentials. If hadronic matter is heated, it is expected to undergo a phase transition to a new state of matter called a quark-gluon plasma. In the quark-gluon plasma, the quarks are no longer confined in hadrons, but can move freely around much in the same way as in ordinary plasmas. The chiral symmetry, which was broken at low temperatures, is restored in the high-temperature quark-gluon phase. In cosmological models, the quark-gluon plasma existed in the early universe until a time approximately 10^(-5) seconds after the Big Bang. Knowing the properties of this phase of QCD is therefore essential to understanding the evolution of the early universe. In order to examine these properties, there is currently a large experimental activity aiming at creating a quark-gluon plasma in heavy-ion collisions. The various heavy-ion collision experiments can be characterized by a temperature and a chemical potential. In the Fig. some of the ongoing and planned experiments at CERN (SPS and ALICE) and Brookhaven National Lab (RHIC) |
hep-ph/0504177 Color Superconductivity VS. Pseudoscalar Condensation in a Three-flavor NJL model.
astro-ph/0510188 Reconciling the Ultra-high Energy Cosmic Ray Spectrum with Fermi Shock Acceleration.
astro-ph/0510444 The Galactic Magnetic Field as Spectrograph for Ultrahigh Energy Cosmic Rays.
hep-ph/0504264 Derivation of Neutrino Matter Potentials Induced by Earth.
hep-ph/0505079 Analytic Formulas for Neutrino-electron Scattering Cross Sections.
hep-ph/0505115 Exploiting Non-adiabatic Density Shifts in Neutrino Interactions.