The 76Cu conundrum remains unsolved
Abstract
Near the doubly-magic nucleus \nuc{Ni}{78} (, ), there has been a decades-long debate on the existence of a long-lived isomer in \nuc{Cu}{76}. A recent mass measurement claimed to have settled the debate, by measuring the energy of the isomer and shedding light on the structure of the nucleus. In this work, we present new, more accurate, and precise values of the half-lives of the isomeric and ground states in \nuc{Cu}{76}. Our findings suggest that both states have very similar half-lives, in the 600-700 ms range, in disagreement with the literature values, implying that they cannot be differentiated by their decay curves. These results raise more questions than they answer, reopening the debate and showing that the structures in \nuc{Cu}{76} are still not fully understood.
Cite
@article{arxiv.2505.06400,
title = {The 76Cu conundrum remains unsolved},
author = {B. Olaizola and A. Illana and J. Benito and D. P. Suárez-Bustamante and G. Del Piccolo and A. Algora and B. Andel and A. N. Andreyev and M. Araszkiewicz and Y. Ayyad and R. A. Bark and T. Berry and M. J. G. Borge and K. Chrysalidis and T. E. Cocolios and C. Costache and J. G. Cubiss and P. Van Duppen and Z. Favier and L. M. Fraile and H. O. U. Fynbo and F. Galtarossa and G. Georgiev and P. T. Greenless and R. Grzywacz and L. J. Harkness-Brennan and R. Heinke and M. Huyse and P. Ibañez and K. Johnston and P. M. Jones and D. S. Judson and J. Konki and A. Korgul and U. Köster and J. Kurcewicz and M. Labiche and I. Lazarus and R. Lică and M. Llanos-Expósito and M. Madurga and N. Marginean and R. Marginean and B. A. Marsh and C. Mihai and R. E. Mihai and J. R. Murias and E. Nácher and C. Neacsu and A. Negret and V. M. Nouvilas and J. Ojala and J. N. Orce and C. A. A. Page and R. D. Page and J. Pakarinen and J. Papadakis and S. Pascu and A. Perea and M. Piersa-Siłkowska and A. M. Plaza and Zs. Podolyák and W. Poklepa and V. Pucknell and P. Rahkila and C. Raison and E. Rapisarda and K. Rezynkina and F. Rotaru and K. Schomacker and M. Siciliano and C. Sotty and M. Stryjczyk and O. Tengblad and J. M. Udías and V. Vedia and S. Viñals and R. Wadsworth and N. Warr and H. De Witte and D. Yates and Z. Yue and the IDS collaboration},
journal= {arXiv preprint arXiv:2505.06400},
year = {2025}
}