We thank the RIKEN Nishina Center accelerator staff and the BigRIPS team for the stable operation of the high-intensity Zn beam and for the preparation of the secondary beam setting. This work has been supported by the JSPS Grant-in-Aid for Scientific Research JP16K05352, JP18K03639, JP16H02179, and JP18H05404, the RIKEN Special Postdoctoral Researcher Program, Colciencias–Convocatoria 617 Becas Doctorados Nacionales, the Ministry of Science and Technology of Vietnam through the Physics Development Program Grant No. ĐTĐLCN.25/18, HIC for FAIR, the Croatian Science Foundation under Projects No. 1257 and No. 7194, the European Regional Development Fund GINOP-2.3.3-15- 2016-00034 and the National Research, Development and Innovation Fund K128947 projects, the NKFIH (128072), the Spanish Ministerio de Economía y Competitividad under Contract No. FPA2017-84756-C4-2-P, the NRF Grants No. 2018R1A5A1025563 and No. 2019M7A1A1033186 funded by the Korean government, the MEXT as “Priority issue on post-K computer” (Elucidation of the fundamental laws and evolution of the universe), the Joint Institute for Computational Fundamental Science (JICFuS), the Ramón y Cajal program RYC-2017-22781 of the Spanish Ministry of Science, Innovation and Universities, the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Project-ID 279384907–SFB 1245 and Grant No. BL 1513/1-1, the PRISMA Cluster of Excellence, and the BMBF under Contracts No. 05P15RDFN1, No. 05P18RDFN1, and No. 05P19RDFN1. TRIUMF receives funding via a contribution through the National Research Council Canada. Computations were performed with an allocation of computing resources on Cedar at WestGrid and Compute Canada, and on the Oak Cluster at TRIUMF managed by the University of British Columbia, Department of Advanced Research Computing (ARC). The development of MINOS was supported by the European Research Council (ERC) through Grant No. MINOS-258567.

Low-lying excited states in the N=32 isotope Ar50 were investigated by in-beam γ-ray spectroscopy following proton- and neutron-knockout, multinucleon removal, and proton inelastic scattering at the RIKEN Radioactive Isotope Beam Factory. The energies of the two previously reported transitions have been confirmed, and five additional states are presented for the first time, including a candidate for a 3- state. The level scheme built using γγ coincidences was compared to shell-model calculations in the sd-pf model space and to ab initio predictions based on chiral two- and three-nucleon interactions. Theoretical proton- and neutron-knockout cross sections suggest that two of the new transitions correspond to 2+ states, while the previously proposed 41+ state could also correspond to a 2+ state.

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