6533b7dbfe1ef96bd127083b

RESEARCH PRODUCT

Mass measurements in the vicinity of the doubly magic waiting pointNi56

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Masses of $^{56,57}\mathrm{Fe}$, $^{53}\mathrm{Co}$${}^{m}$, $^{53,56}\mathrm{Co}$, $^{55,56,57}\mathrm{Ni}$, $^{57,58}\mathrm{Cu}$, and $^{59,60}\mathrm{Zn}$ have been determined with the JYFLTRAP Penning trap mass spectrometer at the Ion-Guide Isotope Separator On-Line facility with a precision of $\ensuremath{\delta}m/m\ensuremath{\leqslant}3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$. The ${Q}_{\mathrm{EC}}$ values for $^{53}\mathrm{Co}$, $^{55}\mathrm{Ni}$, $^{56}\mathrm{Ni}$, $^{57}\mathrm{Cu}$, $^{58}\mathrm{Cu}$, and $^{59}\mathrm{Zn}$ have been measured directly with a typical precision of better than $0.7 \mathrm{keV}$ and Coulomb displacement energies have been determined. The $Q$ values for proton captures on $^{55}\mathrm{Co}$, $^{56}\mathrm{Ni}$, $^{58}\mathrm{Cu}$, and $^{59}\mathrm{Cu}$ have been measured directly. The precision of the proton-capture $Q$ value for $^{56}\mathrm{Ni}$$(p,\ensuremath{\gamma})$$^{57}\mathrm{Cu}$, ${Q}_{(p,\ensuremath{\gamma})}=689.69(51) \mathrm{keV}$, crucial for astrophysical $\mathit{rp}$-process calculations, has been improved by a factor of 37. The excitation energy of the proton-emitting spin-gap isomer $^{53}\mathrm{Co}$${}^{m}$ has been measured precisely, ${E}_{x}=3 174.3(10) \mathrm{keV}$, and a Coulomb energy difference of $133.9(10) \mathrm{keV}$ for the $19/{2}^{\ensuremath{-}}$ state has been obtained. Except for $^{53}\mathrm{Co}$, the mass values have been adjusted within a network of 17 frequency ratio measurements between 13 nuclides, which allowed also a determination of the reference masses $^{55}\mathrm{Co}$, $^{58}\mathrm{Ni}$, and $^{59}\mathrm{Cu}$.