The Efimov(Thomas) trimers in excited 12 C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64)Zn(64 Ni)+ 70(64)Zn(64 Ni) reactions at the beam energy of E/A...The Efimov(Thomas) trimers in excited 12 C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64)Zn(64 Ni)+ 70(64)Zn(64 Ni) reactions at the beam energy of E/A = 35 MeV/nucleon. In heavy ion collisions, a-particles interact with each other and can form complex systems such as 8 Be and 12 C. For the 3 a-particle systems,multi-resonance processes give rise to excited levels of 12 C. The interaction between any two of the 3 a-particles provides events with one, two or three 8 Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events with the three a-particle relative energies consistent with the ground state of 8 Be are observed with the decrease of the instrumental error for the reconstructed 7.458 MeV excitation level in 12 C, which was suggested as the Efimov(Thomas) state.展开更多
The behavior of relativistic hadron multiplicity for 4He-nucleus interactions is investigated. The experi- ment is carried out at 2.1 A and 3.7 A GeV （Dubna energy） to search for the incident energy effect on the in...The behavior of relativistic hadron multiplicity for 4He-nucleus interactions is investigated. The experi- ment is carried out at 2.1 A and 3.7 A GeV （Dubna energy） to search for the incident energy effect on the interactions inside different emulsion target nuclei. Data are presented in terms of the number of emitted relativistic hadrons in both forward and backward angular zones. The dependence on the target size is presented. For this purpose the statistical events are discriminated into groups according to the interactions with H, CNO, Em, and AgBr target nuclei. The separation of events, into the mentioned groups, is executed based on Glauber＇s multiple scattering theory approach. Features suggestive of a decay mechanism seem to be a characteristic of the backward emission of relativistic hadrons. The results strongly support the assumption that the relativistic hadrons may already be emitted during the de-excitation of the excited target nucleus, in a behavior like that of compound-nucleus disintegration. Regarding the limiting fragmentation hypothesis beyond 1 A GeV, the target size is the main parameter affecting the backward production of the relativistic hadron. The incident energy is a principal factor responsible for the forward relativistic hadron production, implying that this system of particle production is a creation system. However, the target size is an effective parameter as well as the projectile size considering the geometrical concept regarded in the nuclear fireball model. The data are analyzed in the framework of the FRITIOF model.展开更多
Theα-particle preformation factors of nuclei above doubly magic nuclei ^(100)Sn and ^(208)Pb are investigated within the generalized liquid drop model.The results show that theα-particle preformation factors of nucl...Theα-particle preformation factors of nuclei above doubly magic nuclei ^(100)Sn and ^(208)Pb are investigated within the generalized liquid drop model.The results show that theα-particle preformation factors of nuclei near self-conjugate doubly magic ^(100)Sn are significantly larger than those of analogous nuclei just above ^(208)Pb,and they will be enhanced as the nuclei move towards the N=Z line.The proton-neutron correlation energy E_(p-n) and two protons-two neutrons correlation energy E_(2p-2n) of nuclei near ^(100)Sn also exhibit a similar situation,indicating that the interactions between protons and neutrons occupying similar single-particle orbitals could enhance theα-particle preformation factors and result in superallowed a decay.This also provides evidence of the significant role of the proton-neutron interaction onα-particle preformation.Also,the linear relationship betweenα-particle preformation factors and the product of valence protons and valence neutrons for nuclei around ^(208)Pb is broken in the100 Sn region because theα-particle preformation factor is enhanced when a nucleus near 100 Sn moves towards the N=Z line.Furthermore,the calculatedαdecay half-lives fit well with the experimental data,including the recent observed self-conjugate nuclei ^(104)Te and ^(108)Xe[Phys.Rev.Lett.121,182501(2018)].展开更多
基金Supported by the National Natural Science Foundation of China(1176014,11605097,11421505,11865010)the US Department of Energy(DE-FG02-93ER40773,NNSA DE-NA0003841(CENTAUR))+6 种基金the Robert A.Welch Foundation(A-1266)supported by the Chinese Academy of Sciences(CAS)President’s International Fellowship Initiative(2015VWA070)Strategic Priority Research Program of the Chinese Academy of Sciences(XDB16 and XDPB09)Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT-18-B21)Doctoral Scientific Research Foundation of Inner Mongolia University for Nationalities(BS365 and BS400)The Fundamental Research Funds for the Central Universities(GK201903022)Natural Science Foundation of Inner Mongolia(2018MS01009)
文摘The Efimov(Thomas) trimers in excited 12 C nuclei, for which no observation exists yet, are discussed by means of analyzing the experimental data of 70(64)Zn(64 Ni)+ 70(64)Zn(64 Ni) reactions at the beam energy of E/A = 35 MeV/nucleon. In heavy ion collisions, a-particles interact with each other and can form complex systems such as 8 Be and 12 C. For the 3 a-particle systems,multi-resonance processes give rise to excited levels of 12 C. The interaction between any two of the 3 a-particles provides events with one, two or three 8 Be. Their interfering levels are clearly seen in the minimum relative energy distributions. Events with the three a-particle relative energies consistent with the ground state of 8 Be are observed with the decrease of the instrumental error for the reconstructed 7.458 MeV excitation level in 12 C, which was suggested as the Efimov(Thomas) state.
文摘The behavior of relativistic hadron multiplicity for 4He-nucleus interactions is investigated. The experi- ment is carried out at 2.1 A and 3.7 A GeV （Dubna energy） to search for the incident energy effect on the interactions inside different emulsion target nuclei. Data are presented in terms of the number of emitted relativistic hadrons in both forward and backward angular zones. The dependence on the target size is presented. For this purpose the statistical events are discriminated into groups according to the interactions with H, CNO, Em, and AgBr target nuclei. The separation of events, into the mentioned groups, is executed based on Glauber＇s multiple scattering theory approach. Features suggestive of a decay mechanism seem to be a characteristic of the backward emission of relativistic hadrons. The results strongly support the assumption that the relativistic hadrons may already be emitted during the de-excitation of the excited target nucleus, in a behavior like that of compound-nucleus disintegration. Regarding the limiting fragmentation hypothesis beyond 1 A GeV, the target size is the main parameter affecting the backward production of the relativistic hadron. The incident energy is a principal factor responsible for the forward relativistic hadron production, implying that this system of particle production is a creation system. However, the target size is an effective parameter as well as the projectile size considering the geometrical concept regarded in the nuclear fireball model. The data are analyzed in the framework of the FRITIOF model.
基金Supported by the National Natural Science Foundation of China(12175170,11675066,12005303)。
文摘Theα-particle preformation factors of nuclei above doubly magic nuclei ^(100)Sn and ^(208)Pb are investigated within the generalized liquid drop model.The results show that theα-particle preformation factors of nuclei near self-conjugate doubly magic ^(100)Sn are significantly larger than those of analogous nuclei just above ^(208)Pb,and they will be enhanced as the nuclei move towards the N=Z line.The proton-neutron correlation energy E_(p-n) and two protons-two neutrons correlation energy E_(2p-2n) of nuclei near ^(100)Sn also exhibit a similar situation,indicating that the interactions between protons and neutrons occupying similar single-particle orbitals could enhance theα-particle preformation factors and result in superallowed a decay.This also provides evidence of the significant role of the proton-neutron interaction onα-particle preformation.Also,the linear relationship betweenα-particle preformation factors and the product of valence protons and valence neutrons for nuclei around ^(208)Pb is broken in the100 Sn region because theα-particle preformation factor is enhanced when a nucleus near 100 Sn moves towards the N=Z line.Furthermore,the calculatedαdecay half-lives fit well with the experimental data,including the recent observed self-conjugate nuclei ^(104)Te and ^(108)Xe[Phys.Rev.Lett.121,182501(2018)].
