Precise measurements of analyzing powers in p-d
elastic scattering show evidence for the presence of
three-nucleon forces. Present theories can not explain
our results and our data spurs active theoretical
efforts on many fronts. Our very high precision
cross-section and analyzing-power measurements provide
rigorous test of such theories.
Big Bang Nucleosynthesis (BBN) is well described by a small
number of reactions at energies easily obtained in the
lab. The outcome of Standard BBN is determined almost
entirely by the nuclear reaction rates and the baryon to
photon ratio, η, of the universe. By measuring key
cross sections, one can adjust η to reproduce the
current measured values of primordial elemental abundances
With present error bars, the D(d,p)T and D(d,n)3He cross
sections at energies in the range of a few hundred keV make
large contributions to the uncertainties in deuterium
abundances predicted by BBN network calculations (for η
= 5.1 × 10-10. We plan to to measure
total cross sections for both of these reactions at lab
energies ranging from 100 to about 700 keV. We predict
error bars of less than two percent. The mini-tandem and
high voltage chamber at TUNL are ideally suited for this
purpose. Presently we have collected angular distributions
at incident deuteron energies of 480, 570, and 660 keV.
