2,416 research outputs found
Is There a Significant Difference Between the Results of the Coulomb Dissociation of 8B and the Direct Capture 7Be(p,g)8B Reaction?
Recent claims of the Seattle group of evidence of "slope difference between
CD [Coulomb Dissociation] and direct [capture] results" are based on wrong and
selective data. When the RIKEN2 data are included correctly, and previously
published Direct Capture (DC) data are also included, we observe only a 1.9
sigma difference in the extracted so called "scale independent slope (b)",
considerably smaller than claimed by the Seattle group. The very
parameterization used by the Seattle group to extract the so called b-slope
parameter has no physical foundation. Considering the physical slope (S' =
dS/dE), we observe a 1.0 sigma agreement between slopes (S') measured in CD and
DC, refuting the need for new theoretical investigation. The claim that S17(0)
values extracted from CD data are approximately 10% lower than DC results, is
based on misunderstanding of the CD method. Considering all of the published CD
S17(0) results, with adding back an unconfirmed E2 correction of the MSU data,
yields very consistent S17(0) results that agree with recent DC measurements of
the Seattle and Weizmann groups. The recent correction of the b-slope parameter
(0.25 1/MeV) suggested by Esbensen, Bertsch and Snover was applied to the wrong
b-slope parameter calculated by the Seattle group. When considering the correct
slope of the RIKEN2 data, this correction in fact leads to a very small b-slope
parameter (0.14 1/MeV), less than half the central value observed for DC data,
refuting the need to correct the RIKEN2 data. In particular it confirms that
the E2 contribution in the RIKEN2 data is negligible. The dispersion of
measured S17(0) is mostly due to disagreement among individual DC experiments
and not due to either experimental or theoretical aspects of CD.Comment: Reference 12 amended with an important communication from Dr. Bertsc
Do bond yields follow the hierarchy of risk post BRRD?
With a sample of 4,065 bonds issued by 63 banks from 12 euro area countries during 2013â2017, this study investigates how introducing bailâin regulation has influenced bond yields in secondary markets, by distinguishing between nonâbailâinable and different classes of bailâinable bonds. The bailâin risk premium does not follow the hierarchy of risk; it is stronger for less risky bonds. The effect on the spread between senior unsecured and nonâbailâinable bonds is much higher than for subordinated bonds. Regarding subordinated bonds, the impact is higher for securities excluded from regulatory capital than for those included
How Well Do We Know the Beta-Decay of 16N and Oxygen Formation in Helium Burning
We review the status of the 12C(a,g)16O reaction rate, of importance for
stellar processes in a progenitor star prior to a super-nova collapse. Several
attempts to constrain the p-wave S-factor of the 12C(a,g)16O reaction at Helium
burning temperatures (200 MK) using the beta-delayed alpha-particle emission of
16N have been made, and it is claimed that this S-factor is known, as quoted by
the TRIUMF collaboration. In contrast reanalyses (by G.M. hale) of all thus far
available data (including the 16N data) does not rule out a small S-factor
solution. Furthermore, we improved our previous Yale-UConn study of the beta-
delayed alpha-particle emission of \n16 by improving our statistical sample (by
more than a factor of 5), improving the energy resolution of the experiment (by
20%), and in understanding our line shape, deduced from measured quantities.
Our newly measured spectrum of the beta-delayed alpha-particle emission of 16N
is not consistent with the TRIUMF('94) data, but is consistent with the
Seattle('95) data, as well as the earlier (unaltered !) data of Mainz('71). The
implication of this discrepancies for the extracted astrophysical p-wave
s-factor is briefly discussed.Comment: 6 pages, 4 figures, Invited Talk, Physics With Radioactive Beams,
Puri, India, Jan. 12-17, 1998, Work Supported by USDOE Grant No.
DE-FG02-94ER4087
- âŠ