Charged-current neutrino-208Pb reactions

We present theoretical results on the non flux-averaged $^{208}Pb(\nu_{e},e^-)^{208}Bi$ and $^{208}Pb(\nu_{\mu},\mu^-)^{208}Bi$ reaction cross sections, obtained within the charge-exchange Random-Phase-Approximation. A detailed knowledge of these cross sections is important in different contexts. In particular, it is necessary to assess the possibility of using lead as a detector in future experiments on supernova neutrinos, such as OMNIS and LAND, and eventually detect neutrino oscillation signals by exploiting the spectroscopic properties of $^{208}Bi$. We discuss the present status on the theoretical predictions of the reaction cross sections.Comment: 5 pages, latex, 3 figures. added discussion on present status, Submitted to Phys.Rev.

Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis

Masses, widths and photocouplings of baryon resonances are determined in a coupled-channel partial wave analysis of a large variety of data. The Bonn-Gatchina partial wave formalism is extended to include a decomposition of t- and u-exchange amplitudes into individual partial waves. The multipole transition amplitudes for $\gamma p\to p\pi^0$ and $\gamma p\to n\pi^+$ are given and compared to results from other analyses.Comment: 18 pages, 14 figure

P-wave excited baryons from pion- and photo-induced hyperon production

We report evidence for $N(1710)P_{11}$, $N(1875)P_{11}$, $N(1900)P_{13}$, $\Delta(1600)P_{33}$, $\Delta(1910)P_{31}$, and $\Delta(1920)P_{33}$, and find indications that $N(1900)P_{13}$ might have a companion state at 1970\,MeV. The controversial $\Delta(1750)P_{31}$ is not seen. The evidence is derived from a study of data on pion- and photo-induced hyperon production, but other data are included as well. Most of the resonances reported here were found in the Karlsruhe-Helsinki (KH84) and the Carnegie-Mellon (CM) analyses but were challenged recently by the Data Analysis Center at GWU. Our analysis is constrained by the energy independent $\pi N$ scattering amplitudes from either KH84 or GWU. The two $\pi N$ amplitudes from KH84 or GWU, respectively, lead to slightly different $\pi N$ branching ratios of contributing resonances but the debated resonances are required in both series of fits.Comment: 22 pages, 28 figures. Some additional sets of data are adde

Properties of baryon resonances from a multichannel partial wave analysis

Properties of nucleon and $\Delta$ resonances are derived from a multichannel partial wave analysis. The statistical significance of pion and photo-induced inelastic reactions off protons are studied in a multichannel partial-wave analysis.Comment: 12 pages, 8 Table

Development of a secondary triton beam from primary 16,18O beams for (t,3He) experiments at intermediate energies

The in-flight heavy-ion fragmentation technique has been used to produce a secondary beam of tritons (3H) at intermediate energies (Et > 100 MeV / nucleon) from primary 16,18O beams of 150 and 120 MeV/nucleon, respectively. The best results are obtained with a 16O beam of 150 MeV/nucleon, producing a 115 MeV/nucleon triton beam. The triton beam will be used in (t,3He) charge-exchange experiments at the S800 spectrometer at the NSCL. At the target of the S800, a triton rate of 5 × 106 particles per second is achieved, for a primary 16O beam of 100 pnA. The (t,3He) reaction using this beam was tested with a 24Mg target. An excitation-energy resolution of 190 ± 15 keV is achieved

Hexadecapole strength in the rare isotopes 74,76Kr

In the Ge-Sr mass region, isotopes with neutron number N≤40 are known to feature rapid shape changes with both nucleon number and angular momentum. To gain new insights into their structure, inelastic proton scattering experiments in inverse kinematics were performed on the rare isotopes 74,76Kr. This work focuses on observables related to the Jπ=41+ states of the Kr isotopes and, in particular, on the hexadecapole degree of freedom. By performing coupled-channels calculations, hexadecapole deformation parameters β4 were determined for the Jπ=41+ states of 74,76Kr from inelastic proton scattering cross sections. Two possible coupled-channels solutions were found. A comparison to predictions from nuclear energy density functional theory, employing both non-relativistic and relativistic functionals, clearly favors the large, positive β4 solutions. These β4 values are unambiguously linked to the well deformed prolate configuration. Given the β2−β4 trend, established in this work, it appears that β4 values could provide a sensitive measure of the nuclear shell structure

Gamow-Teller strengths in 24 Na using the 24 Mg( t , 3 He) reaction at 115 A MeV

Gamow-Teller transitions from Mg24 to Na24 were studied via the (t,3He) reaction at 115A MeV using a secondary triton beam produced via fast fragmentation of 150A MeV O16 ions. Compared to previous (t,3He) experiments at this energy that employed a primary α beam, the secondary beam intensity is improved by about a factor of five. Despite the large emittance of the secondary beam, an excitation-energy resolution of ∼200 keV is achieved. A good correspondence is found between the extracted Gamow-Teller strength distribution and those available from other charge-exchange probes. Theoretical calculations using the newly developed USDA and USDB sd-shell model interactions reproduce the data well

Nucleosynthesis of proton-rich nuclei. Experimental results on the rp-process

Experience NSCLInternational audienceWe report in this study the nuclear properties of proton-rich isotopes located along the rp-process path. The experiments have recently been performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The level properties above the proton separation energy of the nuclei 30S, 36K and 37Ca were measured with precision of < 10 keV. This will allow a reduction in the determination of the astrophysical (p, ) reaction rate under rp-process conditions

β-Delayed Proton Emission in the 100Sn Region

β-delayed proton emission from nuclides in the neighborhood of 100 Sn was studied at the National Superconducting Cyclotron Laboratory (NSCL). The nuclei were produced by fragmentation of a 120 MeV/nucleon 112 Sn primary beam on a Be target. Beam purification was provided by the A1900 Fragment Separator and the Radio Frequency Fragment Separator. The fragments of interest were identified and their decay was studied with the NSCL Beta Counting System in conjunction with the Segmented Germanium Array. The nuclei 96 Cd, 98 In g , 98 Inm , and 99 In were identified as β-delayed proton emitters, with branching ratios bβp = 5.5(40)%, 5.5 +3 −2%, 19(2)%, and 0.9(4)%, respectively. The branching ratios for 89 Ru, 91,92 Rh, 93 Pd, and 95 Ag were deduced for the first time with bβp = 3 +1.9 −1.7%, 1.3(5)%, 1.9(1)%, 7.5(5)%, and 2.5(3)%, respectively. The bβp = 22(1)% value for 101 Sn was deduced with higher precision than previously reported. The impact of the newly measured bβp values on the composition of the type I x-ray burst ashes was studied