The goal of nuclear structure research is to build a coherent framework that explains all the properties of nuclei, nuclear matter, and nuclear reactions. While extremely ambitious, this goal is no longer a dream. With the advent of new generations of exotic beam facilities, which will greatly expand the variety and intensity of rare isotopes available, new theoretical concepts, and the extreme-scale computing platforms that enable cutting-edge calculations of nuclear properties, nuclear structure physics is poised at the threshold of its most dramatic expansion of opportunities in decades.
The overarching questions guiding nuclear structure research have been expressed as two general and complementary perspectives: a microscopic view focusing on the motion of individual nucleons and their mutual interactions, and a mesoscopic one that focuses on a highly organized complex system exhibiting special symmetries, regularities, and collective behavior. Through those two perspectives, research in nuclear structure in the next decade will seek answers to a number of open questions:
New facilities and tools will help to explore the vast nuclear landscape and identify the missing ingredients in our understanding of the nucleus. A huge number of new nuclei are now available—proton rich, neutron rich, the heaviest elements, and the long chains of isotopes for many elements. Together, they comprise a vast pool from which key isotopes—designer nuclei—can be chosen because they isolate or amplify specific physics or are important for applications.
At the same time, research with intense beams of stable nuclei continues to produce innovative science, and, in the long term, discoveries at exotic beam facilities will raise new questions whose answers are accessible with stable nuclei.
Examples of the current program that offer a glimpse into future areas of inquiry are the investigation of new forms of nuclear matter such as neutron skins occurring on the surfaces of nuclei having large excesses of neutrons over protons, the ability to fabricate the superheavy elements that are predicted to exhibit unusual stability in spite of huge electrostatic repulsion, and structural studies in exotic isotopes whose properties defy current textbook paradigms.
Hand in hand with experimental developments, a qualitative change is taking