Speaker
Marton Nagy
(MTA KFKI RMKI)
Description
for the PHENIX Collaboration
The collision of energetic nuclei forms a hot and dense partonic matter.
Determining the nature of the phase transition associated with the
production of the observed hadrons is an important task. Experimental
data on direction-dependent correlation length (HBT radii) studies seem
to exclude the possibility of a strong first order phase transition in
$\sqrt{s_{NN}}=200$ GeV Au+Au collisions, while lattice QCD
calculations favorize a cross-over type of hadron formation. A novel
type of correlations, hypothesized in the late 1980's and fully highlighted
in the last decade, is sensitive to the medium effects on the produced
hadrons. This type of quantum mechanical correlations, called back-to-back
correlations, or squeezed back-to-back correlations, was predicted among
particle-antiparticle pairs, both $\pi^+\pi^-$, $K^+K^-$, or $p\bar{p}$
pairs, if their masses are modified by the medium due to hadronic
interactions or chiral dynamics. Observation and exploring the properties
of such correlation effect would thus provide a unique insight into the
freeze-out dynamics of the hot and dense partonic matter created in
heavy ion collisions. The experimental details and the latest status of
the PHENIX measurement of this type of particle-antiparticle back-to-back
correlations will be presented.
Author
Marton Nagy
(MTA KFKI RMKI)
