The Masses of the $T_z=-3/2$ Nuclei ${}^{27}$P and ${}^{29}$S

Abstract

Isochronous mass spectrometry has been applied in the storage ring CSRe to measure the masses of the $T_z=-3/2$ nuclei ${}^{27}$P and ${}^{29}$S. The new mass excess value $ME$(${}^{29}$S) $=-3094(13)$~keV is 66(52)~keV larger than the result of the previous ${}^{32}$S(${}^3$He,${}^6$He)${}^{29}$S reaction measurement in 1973 and a factor of 3.8 more precise. The new result for ${}^{29}$S, together with those of the $T=3/2$ isobaric analog states (IAS) in ${}^{29}$P, ${}^{29}$Si, and ${}^{29}$Al, fit well into the quadratic form of the Isobaric Multiplet Mass Equation IMME. The mass excess of ${}^{27}$P has been remeasured to be $ME{(}^{27}$P$)=-685(42)$ keV. By analyzing the linear and quadratic coefficients of the IMME in the $T_z=-3/2$ $sd$-shell nuclei, it was found that the ratio of the Coulomb radius parameters is $R\approx 0.96$ and is nearly the same for all $T=3/2$ isospin multiplets. Such a nearly constant $R$-value, apparently valid for the entire light mass region with $A>9$, can be used to set stringent constraints on the isovector and isotensor components of the isospin non-conserving forces in theoretical calculations.

arXiv comment7 pages, 4 figures

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Cited by in corpus (8)

• Beta-decay spectroscopy of ${}^{27}$S
• Particle identification and revolution time corrections for the isochronous mass spectrometry in storage rings
• Characterization of a double Time-Of-Flight detector system for accurate velocity measurement in a storage ring using laser beams
• Charge resolution in the isochronous mass spectrometry and the mass of ${}^{51}$Co
• Experimentally well-constrained masses of ${}^{27}$P and ${}^{27}$S: Implications for studies of explosive binary systems
• Mass measurements for $T_z=-2$ $fp$-shell nuclei ${}^{40}$Ti, ${}^{44}$Cr, ${}^{46}$Mn, ${}^{48}$Fe, ${}^{50}$Co and ${}^{52}$Ni
• Beyond Wigner's isobaric multiplet mass equation: Effect of charge-symmetry-breaking interaction and Coulomb polarization
• Improving the resolving power of Isochronous Mass Spectrometry by employing an in-ring mechanical slit