Neutrino signals in electron-capture storage-ring experiments

Neutrino signals in electron-capture decays of hydrogen-like parent ions P in storage-ring experiments at GSI are reconsidered, with special emphasis placed on the storage-ring quasi-circular motion of the daughter ions D in two-body decays P --> D + e-neutrino. It is argued that to the extent that daughter ions are detected, these detection rates might exhibit modulations with periods of order seconds, similar to those reported in the GSI storage-ring experiments for two-body decay rates [1,2]. New dedicated experiments in storage rings, or using traps, could explore these modulations.Comment: Presented first at the EMMI-RRTF Workshop, Jena/Dornburg, July 6-9 2014, and revised substantially since then; this final arXiv version includes footnotes that were excluded from the published versio

MESON2016 -- Concluding Remarks

Several topics presented and discussed at MESON2016 are highlighted, including pentaquarks, dibaryons and meson-nuclear bound states.Comment: concluding plenary talk given at MESON2016 -- the 14th International Workshop on Meson Production, Properties and Interaction, 2nd-7th June 2016, Krak\'ow, Poland, to appear in the EPJ Web of Conferences, v2 -- references update

Physics of Antiproton Nuclear Interactions near Threshold

Antiproton-nucleus optical potentials fitted to $\bar p$-atom level shifts and widths are used to calculate the recently reported very low energy ($p_{L}<100$ MeV/c) $\bar p$ cross sections for annihilation on light nuclei. The apparent suppression of annihilation upon increasing the atomic charge $Z$ and mass number $A$ is resolved as due to the strong effective repulsion produced by the very absorptive optical potential which keeps the $\bar p$-nucleus wavefunction substantially outside the nuclear surface, so that the resulting reaction cross section saturates as function of the strength of Im $V_{{\rm opt}}$. This feature, for $E >0$, parallels the recent prediction, for $E < 0$, that the level widths of $\bar p$ atoms saturate and, hence, that $\bar p$ deeply bound atomic states are relatively narrow. Predictions are made for $\bar p$ annihilation cross sections over the entire periodic table at these very low energies and the systematics of the calculated cross sections as function of $A$, $Z$ and $E$ are discussed and explained in terms of a Coulomb-modified strong-absorption model. Finally, optical potentials which fit simultaneously low-energy $\bar p - ^4$He observables for $E < 0$ as well as for $E > 0$ are used to assess the reliability of extracting Coulomb modified $\bar p$ nuclear scattering lengths directly from the data.Comment: 8 pages including 4 figures; invited talk at the Third International Conference on Perspectives in Hadronic Physics, Trieste, May 2001. To be published in Nucl. Phys.

Overview of Antikaon-Nuclear Theory and Phenomenology

Experimental evidence for antikaon-nuclear quasibound states is briefly reviewed. Theoretical and phenomenological arguments for and against deep antikaon-nucleus potentials which might allow for narrow quasibound states are reviewed, with recent calculations suggesting widths larger than 100 MeV for binding energy smaller than 100 MeV. Results of RMF calculations that provide a lower limit of 50+/-10 MeV for the width of deeply bound states are discussed.Comment: Invited talk at the Yukawa International Symposium on New Frontiers in QCD, Kyoto University, December 2006. To be published in Progress of Theoretical Physics Supplemen