Evidence for enhanced neutron-proton correlations from the level structure of the $N=Z+1$ nucleus $_{43}^{87}\mathrm{Tc}_{44}$

X. Liu , B. Cederwall , C. Qi , R.A. Wyss , Ö. Aktas , A. Ertoprak , W. Zhang , E. Clément (1) , G. de France (1) , D. Ralet (2) , A. Gadea , A. Goasduff , G. Jaworski , I. Kuti , B.M. Nyakó , J. Nyberg , M. Palacz , R. Wadsworth , J.J. Valiente-Dobón , H. Al-Azri , A. Ataç Nyberg , T. Bäck , G. de Angelis , M. Doncel , J. Dudouet (3) , A. Gottardo (2) , M. Jurado , J. Ljungvall (2) , D. Mengoni , D.R. Napoli , C.M. Petrache (4) , D. Sohler , J. Timár , D. Barrientos , P. Bednarczyk , G. Benzoni , B. Birkenbach , A.J. Boston , H.C. Boston , I. Burrows , L. Charles (5) , M. Ciemala , F.C.L. Crespi , D.M. Cullen , P. Désesquelles (2) , C. Domingo-Pardo , J. Eberth , N. Erduran , S. Ertürk , V. González , J. Goupil (1) , H. Hess , T. Huyuk , A. Jungclaus , W. Korten (6) , A. Lemasson (1) , S. Leoni , A. Maj , R. Menegazzo , B. Million , R.M. Perez-Vidal , Zs. Podolyàk , A. Pullia , F. Recchia , P. Reiter , F. Saillant (1) , M.D. Salsac (6) , E. Sanchis , J. Simpson , O. Stezowski (3) , C. Theisen (6) , M. Zielińska (6)

1 GANIL - Grand Accélérateur National d'Ions Lourds
2 CSNSM - Centre de Sciences Nucléaires et de Sciences de la Matière
3 IPNL - Institut de Physique Nucléaire de Lyon
4 IJCLab - Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
5 IPHC - Institut Pluridisciplinaire Hubert Curien
6 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers

The low-lying excited states in the neutron-deficient $N = Z + 1$  nucleus  $^{87}_{43}$Tc$_{44}$  have been studied via the fusion-evaporation reaction $^{54}$Fe $(^{36}Ar, 2n1p)$ $^{87}$Tc at the Grand Accélérateur National d'Ions Lourds (GANIL), France. The AGATA spectrometer was used in conjunction with the auxiliary NEDA, Neutron Wall, and DIAMANT detector arrays to measure coincident prompt  γ  rays, neutrons, and charged particles emitted in the reaction. A level scheme of $^{87}$Tc from the $(9/2^+_{g.s})$ state to the $( 33 / 2^+_1$) state was established based on six mutually coincident  γ -ray transitions. The constructed level structure exhibits a rotational behavior with a sharp backbending at $ℏω ≈ 0.50$ MeV. A decrease in alignment frequency and increase in alignment sharpness in the odd-mass isotonic chains around $N=44$ is proposed as an effect of the enhanced isoscalar neutron-proton interactions in odd-mass nuclei when approaching the $N=Z$ line.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

X. Liu, B. Cederwall, C. Qi, R.A. Wyss, Ö. Aktas, et al.. Evidence for enhanced neutron-proton correlations from the level structure of the $N=Z+1$ nucleus $_{43}^{87}\mathrm{Tc}_{44}$. Phys.Rev.C, 2021, 104 (2), pp.L021302. ⟨10.1103/PhysRevC.104.L021302⟩. ⟨hal-03335724⟩