In an experiment at the SISSI-LISE3 facility of GANIL, the decay of the proton drip line nucleus ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ has been studied. Fragment-implantation events have been correlated with radioactive decay events in a $16\times 16$ pixel silicon-strip detector. The decay-energy spectrum of ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ implants shows a distinct peak at $(1.14\pm 0.04)\mathrm{M}\mathrm{e}\mathrm{V}$ with a half-life of $T_{1/2}=({4.7}_{-1.4}^{+3.4})\mathrm{m}\mathrm{s}$. None of the events in this peak is in coincidence with $\beta$ particles. For a longer correlation interval, daughter decays of the two-proton daughter ${}^{\mathrm{43}}\mathrm{C}\mathrm{r}$ can be observed after ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ implantation. The decay energy for ${}^{\mathrm{45}}\mathrm{F}\mathrm{e}$ agrees nicely with several theoretical predictions for two-proton radioactivity.

The root-mean-square (rms) nuclear charge radius of ${}^8\mathrm{He}$, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms charge radius of ${}^6\mathrm{He}$ was measured to be 2.068(11) fm, in excellent agreement with a previous result. The significant reduction in charge radius from ${}^6\mathrm{He}$ to ${}^8\mathrm{He}$ is an indication of the change in the correlations of the excess neutrons and is consistent with the ${}^8\mathrm{He}$ neutron halo structure. The experiment was based on laser spectroscopy of individual helium atoms cooled and confined in a magneto-optical trap. Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations.

The possibility to probe new physics scenarios of light Majorana neutrino exchange and right-handed currents at the planned next generation neutrinoless double βdecay experiment SuperNEMO is...

The NEMO 3 detector, which has been operating in the Fréjus underground laboratory since February 2003, is devoted to the search for neutrinoless double-beta decay ($\beta \beta 0\nu$). The half-lives of the two neutrino double-beta decay ($\beta \beta 2\nu$) have been measured for ${}^{100}\mathrm{Mo}$ and ${}^{82}\mathrm{Se}$. After 389 effective days of data collection from February 2003 until September 2004 (phase I), no evidence for neutrinoless double-beta decay was found from $\sim 7\mathrm{kg}$ of ${}^{100}\mathrm{Mo}$ and $\sim 1\mathrm{kg}$ of ${}^{82}\mathrm{Se}$. The corresponding limits are $T_{1/2}(\beta \beta 0\nu )>4.6\times {10}^{23}\mathrm{yr}$ for ${}^{100}\mathrm{Mo}$ and $T_{1/2}(\beta \beta 0\nu )>1.0\times {10}^{23}\mathrm{yr}$ for ${}^{82}\mathrm{Se}$ (90% C.L.). Depending on the nuclear matrix element calculation, the limits for the effective Majorana neutrino mass are $⟨m_{\nu }⟩<0.7–2.8\mathrm{eV}$ for ${}^{100}\mathrm{Mo}$ and $⟨m_{\nu }⟩<1.7–4.9\mathrm{eV}$ for ${}^{82}\mathrm{Se}$.

The nucleus ${}^{54}\mathrm{Zn}$ has been observed for the first time in an experiment at the SISSI/LISE3 facility of GANIL in the quasifragmentation of a ${}^{58}\mathrm{Ni}$ beam at $74.5\mathrm{MeV}/\mathrm{\text{nucleon}}$ in a ${}^{\mathrm{nat}}\mathrm{Ni}$ target. The fragments were analyzed by means of the ALPHA-LISE3 separator and implanted in a silicon-strip detector where correlations in space and time between implantation and subsequent decay events allowed us to generate almost background free decay spectra for about 25 different nuclei at the same time. Eight ${}^{54}\mathrm{Zn}$ implantation events were observed. From the correlated decay events, the half-life of ${}^{54}\mathrm{Zn}$ is determined to be ${3.2}_{-0.8}^{+1.8}\mathrm{ms}$. Seven of the eight implantations are followed by two-proton emission with a decay energy of 1.48(2) MeV. The decay energy and the partial half-life are compared to model predictions and allow for a test of these two-proton decay models.