R-process: The Astrophysical Origin Of The Heavy Elements And Related Rare Isotope Accelerator Physics (Proceedings from the Institute for Nuclear Theory)

260 Pages·2004·12.61 MB·English

by  Yong-Zhong Qian

Proceedings from the Institute for Nuclear Theory - Vol.13
editors
Yong-Zhong Qian
Ernst Rehm
Hendrik Schatz
Friedrich-Karl Thielemann
The r-Process:
The Astrophysical Origin
of the Heavy Elements
and Related Rare Isotope Accelerator Physics
^1 The r-Process:
^ T he Astrophysical Origin
of the Heavy Elements
and Related Rare Isotope Accelerator Physics
PROCEEDINGS FROM THE INSTITUTE FOR NUCLEAR THEORY
Series Editors: Wick C. Haxton (Univ. of Washington)
Ernest M. Henley (Univ. of Washington)
Published
Vol. 1: Nucleon Resonances and Nucleon Structure
ed. G. A. Miller
Vol. 2: Solar Modeling
eds. A. B. Balantekin and J. N. Bahcall
Vol. 3: Phenomenology and Lattice QCD
eds. G. Kilcup and S. Sharpe
Vol. 4: N* Physics
eds. T.-S. H. Lee and W. Roberts
Vol. 5: Tunneling in Complex Systems
ed. S. Tomsovic
Vol. 6: Nuclear Physics with Effective Field Theory
eds. M. J. Savage, R. Seki and U. van Kolck
Vol. 7: Quarkonium Production in High-Energy Nuclear Collisions
eds. B. Jacak and X.-N. Wang
Vol. 8: Quark Confinement and the Hadron Spectrum
eds. A. Radyushkin and C. Carlson
Vol. 9: Nuclear Physics with Effective Field Theory II
eds. P. F. Bedaque, M. J. Savage, R. Seki and U. van Kolck
Vol. 10: Exclusive and Semi-Exclusive Processes at High Momentum Transfer
eds. C. Carlson and A. Radyushkin
Vol. 11: Chiral Dynamics: Theory and Experiment III
eds. A. M. Bernstein, J. L. Goity and U.-G. MeiBner
Vol. 12: The Phenomenology of Large A/ QCD
c
ed. R. F. Lebed
Vol. 13: The r-Process: The Astrophysical Origin of the Heavy Elements and
Related Rare Isotope Accelerator Physics
eds. Y.-Z. Qian, E. Rehm, H. Schatz and F.-K. Thielemann
editors
National Institute for Nuclear Theory,
University of Washington, USA
Yong-Zhong Qian
8-10 January 2004
University of Minnesota
Ernst Rehm
Argonne National Laboratory
Hendrik Schatz
Michigan State University
Friedrich-Karl Thielemann
University of Basel
Proceedings of the First Argonne/MSU/JINA/INT RIA Workshop
The r-Process:
The Astrophysical Origin
of the Heavy Elements
and Related Rare Isotope Accelerator Physics
Y J5 World Scientific
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THE r-PROCESS
The Astrophysical Origin of the Heavy Elements and Related Rare Isotope Accelerator Physics
Proceedings of the First Argonne/MSU/JINA/INT RIA Workshop
Copyright © 2004 by World Scientific Publishing Co. Pte. Ltd.
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SERIES PREFACE
The National Institute for Nuclear Theory Series
The national Institute for Nuclear Theory (INT) was established by the US
Department of Energy in March, 1990. The goals of the INT include:
1. Creating a productive research environment where visiting scientists can
focus their energies and exchange ideas on key issues facing the field of
nuclear physics, including those crucial to the success of existing and
future experimental facilities;
2. Encouraging interdisciplinary research at the intersections of nuclear
physics with related subfields, including particle physics, astrophysics,
atomic physics, and condensed matter;
3. Furthering the development and advancement of physicists with recent
Ph.D.s;
4. Contributing to scientific education through graduate student research,
INT summer schools, undergraduate summer research programs, and
graduate student participation in INT workshops and programs;
5. Strengthening international cooperation in physics research through
exchanges and other interactions.
While the INT strives to achieve these goals in a variety of ways, its most
important efforts are the three-month programs, workshops, and schools
it sponsors. These typically attract 300 visitors to the INT each year. In
order to make selected INT workshops and summer schools available to a
wider audience, the INT and World Scientific established the series of books
to which this volume belongs.
In January 2004 the INT and several partners, Argonne National Lab
oratory, Michigan State University, and the Joint Institute for Nuclear
Astrophysics, began a new workshop series to explore physics questions
connected with the proposed Rare Isotope Accelerator (RIA). This volume
summarizes the inaugural workshop, which focused on the r-process, the
mechanism by which many of the heavy elements were synthesized under
explosive conditions typical of core-collapse supernovae and neutron star
collisions. Organized by Yong-Zhong Qian, Ernst Rehm, Hendrik Schatz,
and Friedrich-Karl Thielemann, the workshop sought to connect the astro
physics of this process with the new information on short-lived, neutron-rich
isotopes that will become available with RIA.
v
VI
This volume is the 13th in the INT series. Earlier series volumes include the
proceedings of the 1991 and 1993 Uehling summer schools on Nucleon Res
onances and Nucleon Structure and on Phenomenology and Lattice QCD;
the 1994 INT workshop on Solar Modeling; the 1997 Jefferson Lab/INT
workshop on Nucleon Resonance Physics; the tutorials of the spring 1997
INT program on Tunneling in Complex Systems; the 1998 and 1999 Cal-
tech/INT workshops on Nuclear Physics with Effective Field Theory; the
proceedings of the 1998 RHIC Winter Workshop on Quarkonium Produc
tion in Relativistic Nuclear Collisions; and the proceeding of Confinement
III, of Exclusive and Semiexclusive Reactions at High Momentum, of Chiral
Dynamics 2000, and of the Phenomenology of Large-N QCD, all collabo
rative efforts with Jefferson Laboratory. We intend to continue publishing
those proceedings of INT workshops and schools which we judge to be of
broad interest to the physics community.
Wick C. Haxton and Ernest Henley
Seattle, Washington, August, 2004
PREFACE
The next generation of radioactive beam facilities, such as the Rare
Isotope Accelerator (RIA) in the US, promise to open up a wide range of
new and exotic nuclei for study within the coming decade.
We therefore feel that it is timely to initiate a workshop series on ex
ploring the physics that will be addressed with such a quantum leap in
experimental capability. The alternating hosts of the workshops are the
National Institute for Nuclear Theory (INT), Argonne National Labora
tory (ANL), and Michigan State University (MSU). The first workshop of
the series with the title "The r-Process: the Astrophysical Origin of the
Heavy Elements and Related Rare Isotope Accelerator Physics" was held
on January 8-10, 2004 at the INT and was cosponsored by the Joint In
stitute for Nuclear Astrophysics (JINA). This volume is the proceedings of
the workshop.
The site and mechanism of the rapid neutron capture process (r-process)
remain one of the big open questions in our understanding of the origin of
the elements in nature. This process creates about half the solar abundances
of the 60 or so elements heavier than iron and is the main source of the
elements such as silver, gold, platinum, and uranium in the universe. But
what exactly are the extreme conditions that are required for this process
and where in the universe are these conditions realized? Is there only one
site for the r-process, or are there many?
The workshop brought together over 44 nuclear experimentalists, nu
clear theorists, astronomers, and theoretical astrophysicists to assess the
status of the field and to identify the open issues. This demonstrates im
pressively the importance and the great current interest of the r-process
problem. Lively discussions and a great variety of ideas provided a very
interactive and enjoyable atmosphere for the workshop, but also made it
evident that much remains to be done in this field. In particular, a need
for new experimental data became apparent.
This is where rare isotope/radioactive beam facilities will play a critical
role. New observations of stellar abundances, in particular in very metal-
poor stars, as well as meteoritic measurements of neutron-capture elements
VII
VIII
provide critical data on the r-process. But without an understanding of
the underlying nuclear physics these data cannot serve as quantitative con
straints on the r-process. Rare isotope/radioactive beam facilities are ex
pected to finally provide the missing nuclear physics input either directly or
by guiding theorists in their quest to better describe extremely unstable nu
clei near the drip lines. This strong interplay between nuclear experiments
and theory on the one hand and astrophysical observations and theory on
the other is nicely illustrated by the cover picture of this volume kindly pro
vided by Peter Moller [see P. Moller, J. R. Nix, and K.-L. Kratz, Atomic
Data Nucl. Data Tables 66, 131 (1997) for details].
Our longer-term vision is that rare isotope/radioactive beam facilities
will put the nuclear physics of the r-process on a solid basis, such that site-
specific signatures can be extracted and in the end the r-process can be used
as a probe of some of the most extreme environments in the universe. This
can be compared to the case of the s-process, where decades of experimental
studies on neutron-capture cross sections make it possible now to use s-
process nucleosynthesis as a probe of mixing processes deep in the interiors
of asymptotic giant branch stars.
We thank the Director of INT, Wick Haxton, for his generous financial
support of this successful workshop. We are extremely grateful to the INT
staff for their hospitality and immaculate logistic support. We also thank
ANL, MSU, JINA, and INT for jointly sponsoring the workshop series.
Yong-Zhong Qian (University of Minnesota)
Ernst Rehm (Argonne National Laboratory)
Hendrik Schatz (Michigan State University)
Friedrich-Karl Thielemann (University of Basel)
CONTENTS
Series Preface v
Preface vii
The r-Process in Supernovae 1
F.-K. Thielemann et al.
Precise Mass Measurements of Nuclides Approaching
the r-Process 11
J. Clark et al.
Fission and the r-Process Path: Recent Experimental
Achievements and Future Possibilities 20
J. Benlliure
/3-Decay Studies of Neutron Rich Nickel Isotopes 30
P. Hosmer et al.
Weak Strength for Astrophysics 34
S. M. Austin and R. Zegers
Nuclear Masses and Fission Barriers 43
J. M. Pearson
Understanding Beta Decay for the r Process 53
J. Engel
Neutron Captures and the r-Process 63
T. Rauscher
Supernova Neutrino-Nucleus Physics and the r-Process 73
W. C. Haxton
Equation of State and Neutrino Opacity of Dense Stellar Matter 89
S. Reddy
IX