Mon·Jan 12, 2015Monday·January 12, 2015

1. 01*

   Neutrino-nucleus interactions and the short-range structure of nuclei

   F. Cavanna🇺🇸 · O. Palamara🇺🇸 · R. Schiavilla🇺🇸 · M. Soderberg🇺🇸 · R.B. Wiringa🇺🇸

   Improvements in theoretical modeling of Short Range structures and phenomena, and comparisons with data, will require sustained collaboration between nuclear theorists and neutrino experimentalists. The extensive history of studying this area of nuclear physics in electron- and hadron-scattering experiments, coupled with the transformative capabilities of LArTPCs to identify neutrinos, will provide a ripe opportunity for new discoveries that will further our understanding of the nucleus.

   nucl-exnucl-th7 citations
2. 02*

   Interference phenomena in the $J^P=1/2^{-}$-wave in $\eta$ photoproduction

   A.V. Anisovich🇩🇪 · E. Klempt🇩🇪 · B. Krusche🇨🇭 · V.A. Nikonov🇩🇪 · A.V. Sarantsev🇩🇪 · U. Thoma🇩🇪 · D. Werthmüller🇨🇭

   The recent precise experimental results for the photoproduction of $\eta$-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina coupled channel model. The main result is that the narrow structure observed in the excitation function of $\gamma n\to n\eta$ can be reproduced fully with a particular interference pattern in the $J^P=1/2^{-}$ partial wave. Introduction of the narrow resonance $N(1685)$ with the properties reported in earlier publications deteriorates the quality of the fit.

   nucl-exEPJA(2015)·43 citations
3. 03*

   Three-body nature of $N^{\ast }$ and ${\Delta }^{\ast }$ resonances from sequential decay chains

   The CBELSA/TAPS Collaboration

   The $N{\pi }^0{\pi }^0$ decays of positive-parity $N^{\ast }$ and ${\Delta }^{\ast }$ resonances at about 2\,GeV are studied at ELSA by photoproduction of two neutral pions off protons. The data reveal clear evidence for several intermediate resonances: $\Delta (1232)$, $N(1520)3/2^{-}$, and $N(1680)5/2^{+}$, with spin-parities $J^P=3/2^{+}$, $3/2^{-}$, and $5/2^{+}$. The partial wave analysis (within the Bonn-Gatchina approach) identifies $N(1440)1/2^{+}$ and the $N(\pi \pi {)}_{\mathrm{S}-\mathrm{wave}}$ (abbreviated as $N\sigma$ here) as further isobars, and assigns the final states to the formation of nucleon and $\Delta$ resonances and to non-resonant contributions. We observe the known $\Delta (1232)\pi$ decays of $\Delta (1910)1/2^{+}$, $\Delta (1920)3/2^{+}$, $\Delta (1905)5/2^{+}$, $\Delta (1950)7/2^{+}$, and of the corresponding spin-parity series in the nucleon sector, $N(1880)1/2^{+}$, $N(1900)3/2^{+}$, $N(2000)5/2^{+}$, and $N(1990)7/2^{+}$. For the nucleon resonances, these decay modes are reported here for the first time. Further new decay modes proceed via $N(1440)1/2^{+}\pi$, $N(1520)3/2^{-}\pi$, $N(1680)5/2^{+}\pi$, and $N\sigma$. The latter decay modes are observed in the decay of $N^{\ast }$ resonances and at most weakly in ${\Delta }^{\ast }$ decays. It is argued that these decay modes provide evidence for a 3-quark nature of $N^{\ast }$ resonances rather than a quark-diquark structure.

   nucl-exPRL(2015)·41 citations
4. 04*

   Imperfect World of $\beta \beta$-decay Nuclear Data Sets?

   B. Pritychenko🇺🇸

   The precision of double-beta ($\beta \beta$) decay experimental half-lives and their uncertainties is reevaluated. A complementary analysis of the decay uncertainties indicates deficiencies due to small size of statistical samples, and incomplete collection of experimental information. Further experimental and theoretical efforts would lead toward more precise values of $\beta \beta$-decay half-lives and nuclear matrix elements.

   nucl-exJ.Phys.G(2015)·2 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.