# High-precision mass measurements for the isobaric multiplet mass equation at A = 52

## TL;DR

This study measured the masses of specific isotopes at A=52 with high precision, tested the isobaric multiplet mass equation, and provided new data crucial for nuclear physics and astrophysics, including proton decay and separation energies.

## Contribution

First experimental determination of masses for $^{52}$Co and $^{52}$Co$^m$, and analysis of the IMME at A=52 with no significant breakdown observed.

## Key findings

- $^{52}$Co and $^{52}$Co$^m$ are more bound than predicted.
- No significant deviation from quadratic IMME form at A=52.
- Precise $Q$ value for proton decay in $^{53}$Co obtained.

## Abstract

Masses of $^{52}$Co, $^{52}$Co$^m$, $^{52}$Fe, $^{52}$Fe$^m$, and $^{52}$Mn have been measured with the JYFLTRAP double Penning trap mass spectrometer. Of these, $^{52}$Co and $^{52}$Co$^m$ have been experimentally determined for the first time and found to be more bound than predicted by extrapolations. The isobaric multiplet mass equation for the $T=2$ quintet at $A=52$ has been studied employing the new mass values. No significant breakdown (beyond the $3\sigma$ level) of the quadratic form of the IMME was observed ($\chi^2/n=2.4$). The cubic coefficient was 6.0(32) keV ($\chi^2/n=1.1$). The excitation energies for the isomer and the $T=2$ isobaric analogue state in $^{52}$Co have been determined to be 374(13) keV and 2922(13) keV, respectively. The $Q$ value for the proton decay from the $19/2^-$ isomer in $^{53}$Co has been determined with an unprecedented precision, $Q_{p} = 1558.8(17)$ keV. The proton separation energies of $^{52}$Co and $^{53}$Ni relevant for the astrophysical rapid proton capture process have been experimentally determined for the first time. \end{abstract}