Lectures

University
of Rochester
Nuclear
Science Research Group
Research
The
University of Rochester Nuclear Chemistry group performs basic research
in nuclear science. The present focus is on explorations of the dynamics
of complex nuclear reactions and the response of nuclear matter in energetic
collisions of light and heavy ions with heavy target nuclei. The research
is sponsored by grants from the United States Department of Energy.
It has been featured on the DOE
web pages. The following explains the general scope of ongoing research
and recent accomplishments.
 Scope
of Research
The group
studies experimentally and theoretically the properties of nuclei
at their limits of stability and the response of nuclear matter in
intermediateenergy collisions, specifically:
 Critical
states and nonequilibrium behavior of nuclear matter, mechanical
and chemical instabilities of hot nuclei; conformational criticality
of nuclei,
 Correlations
and dynamical cluster formation in complex nuclear reactions,
 Nuclear transparency
and the disappearance of classical friction,
 Coherent and
stochastic modes of nonequilibrium particle emission,
 Quantal behavior
in nuclear collisions and decay,
 Isospin dependence
of reaction phenomena.
The work is significant for the development of a quantumstatistical
description of the finite Abody system in a transition from weak
to strong coupling, for the determination of an effective equation
of state of nuclear matter, for the behavior of nuclear matter under
conditions of extreme pressure and temperature, its critical states
and its phase transformations. It has consequences for our microscopic
understanding of matter, the production of exotic new nuclei, and
applications in the exploration of cosmological objects and processes.
There are also direct applications of the experimental technology,
for example in fastneutron imaging (MANDI).
Accomplishments
The most important
results from the ongoing nuclear chemistry research program include:
 The discovery
of a new critical conformational instability of finite nuclei, a breakthrough
in our understanding of nuclear cluster production and phase transformation,
 The identification
of two separate cluster production mechanisms in heavyion reactions,
 The experimental
observation of a memory of the initial isospin asymmetry in the nonequilibrium
emission of nucleons and nuclear clusters,
 Evaluations of
statistical cluster aggregation mechanisms in AA and pA reactions,
 The development
of an understanding of how and why current equilibrium statistical
models fail to explain nuclear multifragmentation
 The identification
of the curiously slow, heavy residues observed in central, as well
as in peripheral heavyion collisions, as remnants of targetlike
fragments,
 Observation of
resilience and diminution of onebody transport phenomena at intermediate
energies.
This research has
benefited from advanced research equipment such as detectors
and electronics developed by the group and its collaborators (see recent
presentation).
The discovery of a new nuclear decay mode driven by the nuclear surface
entropy of expanded nuclei, could resolve the decadeold puzzle of statistical
cluster emission from hot nuclei, which traditional statistical models
have been unable to explain. The effect is a quantum phenomenon associated
with multifermion state densities.
The questions addressed
by this research program define the leading edge of research in complex
nuclear reaction mechanisms at intermediate energies.


