Clustering effects of nucleons in nuclei and quarks in multi-quark states

Date :From 2016-03-28 To 2016-04-22
Advisory committee :
Local coordinators :Qiang Zhao (Institute of High Energy Physics, CAS), Shan-Gui Zhou (Institute of Theoretical Physics, CAS), Chang Xu (Nanjing University),Feng-Kun Guo(Institute of Theoretical Physics, CAS)
International coordinators :Zhongzhou Ren (Chair, Nanjing University), Ulf-G. Meiβner (University of Bonn, Germany), Bing-Song Zou (Institute of Theoretical Physics, CAS), Hisashi Horiuchi (Osaka Univeristy, Japan), Peter Schuck (IN2P3-CNRS, France)

 

1. Description
         Clustering has played an important role in understanding many properties of light nuclei and exotic hadrons beyond the conventional quark model. In the sector of light nuclei, cluster structures of light nuclei such as 8Be, 12C, 16O, 20Ne etc are typically observed in their excited states close to the corresponding decay thresholds. For instance, the existence of famous Hoyle state in 12C (the second 0+ state) is essential in the synthesis of the elements, in which the dominant degrees of freedom are the alpha-particle clusters. Clustering also manifests itself in the spontaneous cluster emission of many medium and heavy radioactive nuclei, such as alpha decay and heavy cluster radioactivity. The quark clustering inside hadrons which is in principle allowed by the non-Abelian QCD theory has also huge impact on our knowledge about the nature of strong QCD and predicts the existence of exotic hadrons beyond the simple quark model scenarios. During the past several decades, the studies of clustering phenomenon in nuclei and hadrons have attracted much interest from both the theoretical and experimental sides. Cluster phenomenon has been experimentally found throughout the periodic table, and from quarks to super-heavy nuclei. Modern theoretical studies using state-of-art approaches have been performed to reproduce the clustering properties of nucleons and quarks. For instance, the microscopic model using the THSR wave function, proposed as a speci?c form of the wave function for alpha-cluster-gas-like states, naturally describes the ground states as well as other cluster-model states of light nuclei. Another example is the nuclear lattice effective field theory (NLEFT), which has been successfully applied to the Hoyle state of 12C and the ground-state properties of many light nuclei. In the study of hadron spectroscopy, recent developments in Lattice QCD and effective field theory approaches have made significant progress in the description of many newly observed exotic hadron candidates in which quark clustering effects have to be introduced. While significant progress on clustering has been made in recent years, the mechanism of cluster formation has not yet been fully understood and much more work needs to be done to pursue a quantitative description of clustering in nuclei and in hadrons. 
          
2. Subjects
The objective of this program is to achieve more comprehensive understanding of clustering phenomenon of nucleons and quarks. As there are a growing number of research groups worldwide interested in this fast developing field, the subjects of this program will include as many subtopics of clustering effects of nucleons and quarks as possible.
 
·         Cluster structure of stable and unstable nuclei
·         Clustering in quarks and hadrons
·         Clustering in nuclear reactions, nuclear matter and neutron stars
·         Alpha decay, cluster radioactivity, nuclear fission, double-beta decay
·         Clustering in hypernuclei and atomic systems