Super-allowed beta decay of nuclei at the drip-line

We have investigated the continuous particle spectra following the beta decay of the neutron-rich nuclei that terminate the mass 6, 8, 9 and 11 isobaric chains. Strong beta transitions feeding the very top of the spectrum are found systematically. The favoured states are within a few MeV of the energy of the initial state. This phenomenon seems to be linked to the occurrence of a di-neutron structure or neutron halo in the drip-line nuclei.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday     

Study of neutron rich neon isotopes

The half-lives andP _n -values of the neutron rich isotopes^26–29Ne have been determined. The results are compared to shell-model calculations and good agreement is found except for²⁹Ne, where the half-life exceeds the predictions by more than an order of magnitude. This unexpectedly long half-life can be explained as due to a fp intruder configuration.     

Precise determination of the unperturbed 8B neutrino spectrum

A measurement of the final state distribution of the (8)B β decay, obtained by implanting a (8)B beam in a double-sided silicon strip detector, is reported here. The present spectrum is consistent with a recent independent precise measurement performed by our collaboration at the IGISOL facility, Jyv?skyl? [O. S. Kirsebom et al., Phys. Rev. C 83, 065802 (2011)]. It shows discrepancies with previously measured spectra, leading to differences in the derived neutrino spectrum. Thanks to a low detection threshold, the neutrino spectrum is for the first time directly extracted from the measured final state distribution, thus avoiding the uncertainties related to the extrapolation of R-matrix fits. Combined with the IGISOL data, this leads to an improvement of the overall errors and the extension of the neutrino spectrum at high energy. The new unperturbed neutrino spectrum represents a benchmark for future measurements of the solar neutrino flux as a function of energy.     

Signature of a strong coupling with the continuum in 11Be + 120Sn scattering at the Coulomb barrier

The angular distribution for ¹¹Be + ¹²⁰Sn quasielastic scattering at E _lab = 32 MeV was measured at REX-ISOLDE, CERN. The interpretation of the data in terms of coupled-channel calculations suggests a strong coupling with the p -states lying in the continuum.     

Conversational Implicatures and Cancellability

In this paper I argue against a criticism by Matthew Weiner to Grice’s thesis that cancellability is a necessary condition for conversational implicature. I argue that the purported counterexamples fail because the supposed failed cancellation in the cases Weiner presents is not meant as a cancellation but as a reinforcement of the implicature. I moreover point out that there are special situations in which the supposed cancellation may really work as a cancellation.

Shell structure of the near-dripline nucleus 23O

Breakup reactions were used to study the ground-state configuration of the neutron-rich isotope 23O. The 22O fragments produced in one-nucleon removal from 23O at 938 MeV/nucleon in a carbon target were detected in coincidence with deexciting gamma rays. The widths of the longitudinal momentum distributions of the 22O fragments and the one-neutron removal cross sections were interpreted in the framework of a simple theoretical model which favors the assignment of Ipi = 1/2+ to the 23O ground state.     

Multiple particle break-up study of low excited states in <Superscript>9</Superscript>Be: The ghost peak in the <Superscript>8</Superscript>Be excitation energy spectrum visited

The aim of this work is to find out the origin of the anomalous resonance in ⁸Be seen in the reactions through excited states in ⁹Be. We have populated the ⁹Be excited states by β-decay of ⁹Li. Energy and direction of the two α particles has been detected and the neutron spectra reconstructed. In our work we identified the “anomalous resonance" in ⁸Be observed in several reaction studies as coming from the decay of the 2.43 and 2.78 MeV states in ⁹Be. This anomalous resonance appears when the two detected α particles are assumed to form a resonance in ⁸Be. We argued that the main decaying channels for these two levels in ⁹Be do not involve ⁸Be.