Gamma-ray and Radioactive Decay Spectroscopy of Heavy Proton Unbound Nuclei

确定可见核的极限是核物理学中的一个长期挑战。对于富质子核，理论预测表明，这些极限是由Z=82的偶核中的双质子发射和奇Z核的单质子发射决定的[1-4]。双质子放射性是一种罕见的现象，从基态得到的实验发现仅限于少数几个轻核[5-10]。然而，从测量质量表[11]的外推，结合核密度泛函理论的进展，已经能够预测出重核中两质子放射性与a衰变竞争的候选者。在大多数情况下，由于配对相互作用，从偶核-Z核的基态发射的两质子将发生在离B-稳定性远得多的地方，而不是奇-Z核的单质子滴线。已知的轻核中基态双质子发射的情况发生在比预测的双质子滴线轻的两个中子附近[3]。来自重核基态的两质子发射将只在位于两质子滴线[3]之外的十个或更多中子的核素中占主导地位，并且无法使用现有的实验设备进行访问。然而，有一种可能性是直接的两质子发射可能来自核中更接近稳定的激发态。本项目将使用衰变关联和伽马射线能谱技术从重核的长寿命激发态中寻找罕见的衰变模式。参考文献[1]V.I.Goldansky，Nucl。太棒了。19(1960)482.[2]V.I.Goldansky，Nucl.太棒了。27(1961)648.[3]E.Olsen，M.Pfutzner，N.Birge，M.Brown，W.Nazarewicz，A.Perhac，Phys.莱特牧师。[4]E.Olsen，M.Pfutzner，N.Birge，M.Brown，W.Nazarewicz，A.Perhac，Phys.莱特牧师。139903.[5]I.Mukha等人，Phys.莱特牧师。99(2007年)182501.[6]M.Pfutzner等人，欧元。太棒了。J.A 14(2002)279.[7]J.Giovinazzo等人，Phys.莱特牧师。89(2002年)102501.[8]M.Pomorski等人，Phys.C 83修订版(2011年)061303.[9]B.Blank等人，Phys.莱特牧师。94(2005年)232501.[10]T.Goigoux等人，Phys.莱特牧师。第117期(2016年)162501.[11]M·王、G·奥迪、A·H·瓦普斯特拉、F·G·孔德夫、M·麦考密克、徐X.、B·法伊弗、陈晓华。太棒了。C 36(2012)1603。

Establishing the limits of observable nuclei is a long-standing challenge in nuclear physics. For proton-rich nuclei, theoretical predictions suggest that these limits are determined by two-proton emission in even-Z nuclei up to Z=82 and by the emission of a single proton for odd-Z nuclei [1-4]. Two-proton radioactivity is a rare phenomenon and experimental discoveries from ground states has been limited to a few light nuclei [5 - 10]. However, extrapolations from the table of measured masses [11] combined with advances in nuclear density functional theory have allowed candidates where two-proton radioactivity competes with a-decay in heavy nuclei to be predicted.In most cases, two-proton emission from the ground states of even-Z nuclei would occur much further from B-stability than the one-proton drip line for odd-Z nuclei due to the pairing interaction. The known cases of ground state two-proton emission in light nuclei occur around two neutrons lighter than the predicted two-proton drip line [3]. Two-proton emission from the ground states of heavy nuclei would only dominate in nuclides that lie ten or more neutrons beyond the two-proton drip line [3] and are inaccessible using current experimental facilities. However, there is a possibility that direct two-proton emission might proceed from excited states in nuclei closer to stability.This project will use decay correlation and gamma-ray spectroscopy techniques to search for rare decay modes from long-lived excited states in heavy nuclei.References[1] V.I. Goldansky, Nucl. Phys. 19 (1960) 482.[2] V.I. Goldansky, Nucl. Phys. 27 (1961) 648.[3] E. Olsen, M. Pfutzner, N. Birge, M. Brown, W. Nazarewicz, A. Perhac, Phys. Rev. Lett. 110 (2013) 222501.[4] E. Olsen, M. Pfutzner, N. Birge, M. Brown, W. Nazarewicz, A. Perhac, Phys. Rev. Lett. 111 (2013) 139903.[5] I. Mukha, et al., Phys. Rev. Lett. 99 (2007) 182501.[6] M. Pfutzner, et al., Eur. Phys. J. A 14 (2002) 279.[7] J. Giovinazzo, et al., Phys. Rev. Lett. 89 (2002) 102501.[8] M. Pomorski, et al., Phys. Rev. C 83 (2011) 061303.[9] B. Blank, et al., Phys. Rev. Lett. 94 (2005) 232501.[10] T. Goigoux, et al., Phys. Rev. Lett. 117 (2016) 162501.[11] M. Wang, G. Audi, A.H. Wapstra, F.G. Kondev, M. MacCormick, X. Xu, B. Pfeiffer, Chin. Phys. C 36 (2012) 1603.