Neutron-proton Interaction In Odd-odd Nuclei From Statistical Analysis

The atomic nucleus is an unique quantum many-body system comprising t-wo types of fermions,neutron and proton.It has been well established that there exists a strong pairing correlation between like particles in nuclei,which has an important influence on many properties of the nucleus,including binding energy,deformation,moment of inertia and so on.On the other hand,the properties of proton-neutron interaction in nucleus and the possible onset of proton-neutron pair correlation are of great significance to the study of nuclear force,especially to the study of tensor force components,and pairing theory.However,our knowl-edge of nuclear forces is still limited so far.In particular,the possible onset of pairing interaction between protons and neutrons is one important open ques-tion which has been studied continuously.From a general perspective,system-atic studies on nuclear binding energy have revealed rich information on nuclear structure and the underlying effective interaction,and can also be used to study pairing phenomenon in nuclei.The effectiveness of this method has been verified by the research work on pair correlation between like particles in nuclei.The proton-neutron interaction extracted by this method did exist a systematic odd even staggering(OES)behavior between odd-A and even-A nuclei,which has been discovered for a long time and is considered to be related to proton-neutron pair correlation.However,there has always been controversy about where does the OES behavior come from?odd-odd nuclei or even-even nuclei.The answer to this question has an important impact on the nature of proton-neutron pair correlation,but until now there is still no direct experimental evidence to answer this question.Using the latest mass data provided by AME2020,we extracted the proton-neutron interaction by using the well known four point formula,analyzed and studied its statistical distribution and OES behavior systematically and compre-hensively,and creatively applied the statistical analysis method to analyze the proton-neutron interaction,It is found that the correlation coefficient between adjacent nuclei centered on odd-odd nuclei is abnormally large,and it is ruled out that this phenomenon is caused by mass measurement error and random fluctuation.Through analysis,it is found that this phenomenon can be used as the direct experimental evidence to support the origin of this OES behavior related to odd-odd nuclei.A convincing and reasonable explanation is given for the problem mentioned above.Based on this method,the properties of proton-neutron pair correlation are analyzed and discussed.It is of great significance to understand and study the proton neutron pairing in nuclei.Finally,the de-scription of proton-neutron interaction predicted by various theoretical models is compared with the experimentally data.The study of proton-neutron interaction and proton-neutron pair correlation will help to improve the prediction ability and accuracy of various theoretical models.