ABSTRACT

Abstract
CAREER: Spectral Properties of Hot and Dense QCD Matter (Ralf Rapp)

More than 99% of the mass of matter around us is concentrated in atomic
nuclei, which are made of protons and neutrons. The elementary building
blocks of these (and other ``hadrons") are believed to be (almost)
massless ``quarks" and ``gluons". However, quarks and gluons have never
been observed in isolation, and their strong interaction is responsible
for generating the masses of the hadrons. The origin of these phenomena
is among the main questions in modern nuclear physics. Under extreme
conditions of temperature and density, hadrons are expected to dissolve
into a new state of matter, the ``Quark-Gluon Plasma", which probably
existed in the early universe a few microseconds after its birth. One of
the key objectives in Dr. Rapp's research plan is to investigate how
hadrons change their spectral properties (such as masses and decay
widths) in hot and dense matter, and how this relates to phase changes
into a Quark-Gluon Plasma. His calculations will be applied to
experiments at the Relativistic Heavy-Ion Collider at Brookhaven
National Laboratory, where gold nuclei are collided at high energy to
recreate, for a short moment, the Quark-Gluon Plasma. To meet the
challenge of identifying signatures of this transient state, Dr. Rapp
will evaluate decay products of unstable particles allowing access to
modifications of their spectral properties. He will pursue similar
approaches to electron scattering experiments off nuclei at Jefferson
Laboratory, as well as to cold dense quark matter which could prevail in
compact stellar objects, so-called neutrons stars. In addition, Dr.
Rapp will build a vigorous educational program for graduate and
undergraduate students, including continued engagement in the NSF-funded
REU site at the Cyclotron Institute. He will endeavor to broaden the
general interest and education in modern nuclear science via a
``Saturday Morning Physics" program at Texas A&M University for high
school students from a greater area around College Station, which is
particularly suitable to enhance the involvement of minority groups, and
to improve prospective undergraduate enrollment in physics.

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