JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)...JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)θ_(13) oscillation parameters using reactor antineutrinos,which is one of the primary physics goals of the experiment.The sensitivities are obtained using the best knowledge available to date on the location and overburden of the experimental site,the nuclear reactors in the surrounding area and beyond,the detector response uncertainties,and the reactor antineutrino spectral shape constraints expected from the TAO satellite detector.It is found that the △m_(21)^(2) and sin^(2)θ_(12) oscillation parameters will be determined to 0.5%precision or better in six years of data collection.In the same period,the △m_(31)^(2) parameter will be determined to about 0.2%precision for each mass ordering hypothesis.The new precision represents approximately an order of magnitude improvement over existing constraints for these three parameters.展开更多
This paper presents the results of a study that compares CTOM, a microscopic optical model potential(OMP), which is an optical model co-created by the China Nuclear Data Center & Tuebingen University, to CH89, whi...This paper presents the results of a study that compares CTOM, a microscopic optical model potential(OMP), which is an optical model co-created by the China Nuclear Data Center & Tuebingen University, to CH89, which is a typical phenomenological OMP.The respective OMPs were tested by applying them to the modelling of nucleon elastic scattering and(d,p) transfer reactions involving14C,36S, and58Ni targets at both low and relatively high energies. The results demonstrated that although both potentials successfully accounted for the angular distributions of both the elastic scattering and transfer cross sections, the absolute values of the transfer cross sections calculated using CTOM were approximately 25% larger than those calculated using CH89. This increased transfer cross sections allowed CTOM to produce single particle strength reduction factors for the three reactions that were consistent with those extracted from(e,e′p) reactions as well as with more recent(p,2p) and(p,pn) reactions. Notch tests suggested that nucleon elastic scattering and transfer reactions are sensitive to different regions of the OMP;accordingly,phenomenological OMPs, which are constrained only by elastic scattering cross sections, may not be sufficient for nucleon transfer reactions. Therefore, we suggest that microscopic OMPs, which reflect more theoretical considerations, should be preferred over phenomenological ones in calculations of direct nuclear reactions.展开更多
The level structure of the double-magic nucleus ^(34)Si(Z=14,N=20)was investigated by evaluating the available data.On the basis of experimental results from the beta-decay and fusion-evaporation reactions,we establis...The level structure of the double-magic nucleus ^(34)Si(Z=14,N=20)was investigated by evaluating the available data.On the basis of experimental results from the beta-decay and fusion-evaporation reactions,we established the level scheme by assigning spin-parities up to 6_(1)^(+)at 6233 keV.The high energy positions of the excited states are consistent with the magicity at ^(34)Si,such as the 2_(2)^(+)state of the spherical ground band at 4.519 MeV and the 3^(-),4^(-),and 5^(-)states of the one-particle one-hole cross-shell states at approximately 4.5 MeV.This nucleus,for a long time,has attracted much attention because of,on one side,a proton bubble structure in the ground state and,on the other side,a deformation in the second 0^(+)state,0_(2)^(+).By a comparison of the constructed level scheme with the shell model calculations,we describe the emerging structures in the ground and second 0+states and the negative-parity 3^(-)states within the framework of the shell model context.We propose a deformed rotational band with the cascading 6_(2)^(+)−4_(1)^(+)−2_(1)^(+)transitions built on the 0_(2)^(+)state.展开更多
The ＂island of inversion＂ has been known for over a quar- ter century, since Warburton et al. [1] proposed that nuclei with intruder ground states would constitute a 3x3 square with Z=10-12, N=20-22 in 1990. Uncover...The ＂island of inversion＂ has been known for over a quar- ter century, since Warburton et al. [1] proposed that nuclei with intruder ground states would constitute a 3x3 square with Z=10-12, N=20-22 in 1990. Uncovering the underlying inversion mechanism and exploring the scope of the island have attracted significant theoretical and experimental efforts in the following years. Now it is well known that the reduction of N=20 shell gap, which is likely caused by the strong nucleon-nucleon tensor interaction [2-5], allows the intrusion of neutron orbits from the pf shell into the sd shell and results in the inversion of the 2p-2h intruder and 0p-0h normal con- figurations of the nuclear ground states in this region. Mean- while, the original border of the ＂island of inversion＂ has been extended greatly [6-14].展开更多
With the help of the gas-filled recoil spectrometer SHANS and a digital data acquisition system,the fine structure of the α decay for^(222)Pa was studied.The nuclides were produced through the 1p3n evaporation channe...With the help of the gas-filled recoil spectrometer SHANS and a digital data acquisition system,the fine structure of the α decay for^(222)Pa was studied.The nuclides were produced through the 1p3n evaporation channel via the heavy-ion induced fusion evaporation reaction ^(40)Ar+^(186)W.Based on the ER-α1-α2-α3 andα-γcorrelation measurement,three new α decays were observed in addition to the three branches known previously.The one with the largestαdecay energy was regarded as the ground state to ground state transition.The newly measuredαdecay properties of ^(222)Pa were examined in a framework of reduced width.展开更多
基金Supported by the Chinese Academy of Sciencesthe National Key R&D Program of China+18 种基金the CAS Center for Excellence in Particle Physics,Wuyi Universitythe Tsung-Dao Lee Institute of Shanghai Jiao Tong University in Chinathe Institut National de Physique Nucléaire et de Physique de Particules(IN2P3)in Francethe Istituto Nazionale di Fisica Nucleare(INFN)in Italythe Italian-Chinese collaborative research program MAECI-NSFCthe Fond de la Recherche Scientifique(F.R.S-FNRS)FWO under the“Excellence of Science-EOS in Belgium”the Conselho Nacional de Desenvolvimento Científico e Tecnològico in Brazilthe Agencia Nacional de Investigacion y Desarrollo and ANID-Millennium Science Initiative Program-ICN2019_044 in Chilethe Charles University Research Centre and the Ministry of Education,Youth,and Sports in Czech Republicthe Deutsche Forschungsgemeinschaft(DFG)the Helmholtz Associationthe Cluster of Excellence PRISMA+in Germanythe Joint Institute of Nuclear Research(JINR)and Lomonosov Moscow State University in Russiathe joint Russian Science Foundation(RSF)National Natural Science Foundation of China(NSFC)research programthe MOST and MOE in Taiwanthe Chulalongkorn University and Suranaree University of Technology in Thailand,University of California at Irvinethe National Science Foundation in USA。
文摘JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)θ_(13) oscillation parameters using reactor antineutrinos,which is one of the primary physics goals of the experiment.The sensitivities are obtained using the best knowledge available to date on the location and overburden of the experimental site,the nuclear reactors in the surrounding area and beyond,the detector response uncertainties,and the reactor antineutrino spectral shape constraints expected from the TAO satellite detector.It is found that the △m_(21)^(2) and sin^(2)θ_(12) oscillation parameters will be determined to 0.5%precision or better in six years of data collection.In the same period,the △m_(31)^(2) parameter will be determined to about 0.2%precision for each mass ordering hypothesis.The new precision represents approximately an order of magnitude improvement over existing constraints for these three parameters.
基金supported by the National Natural Science Foundation of China(Grant Nos.11775013,U1432247,11775316,U1630143,and 11465005)the National Key Research and Development Program(Grant No.2016YFA0400502)Science Challenge Project(Grant No.TZ2018001)
文摘This paper presents the results of a study that compares CTOM, a microscopic optical model potential(OMP), which is an optical model co-created by the China Nuclear Data Center & Tuebingen University, to CH89, which is a typical phenomenological OMP.The respective OMPs were tested by applying them to the modelling of nucleon elastic scattering and(d,p) transfer reactions involving14C,36S, and58Ni targets at both low and relatively high energies. The results demonstrated that although both potentials successfully accounted for the angular distributions of both the elastic scattering and transfer cross sections, the absolute values of the transfer cross sections calculated using CTOM were approximately 25% larger than those calculated using CH89. This increased transfer cross sections allowed CTOM to produce single particle strength reduction factors for the three reactions that were consistent with those extracted from(e,e′p) reactions as well as with more recent(p,2p) and(p,pn) reactions. Notch tests suggested that nucleon elastic scattering and transfer reactions are sensitive to different regions of the OMP;accordingly,phenomenological OMPs, which are constrained only by elastic scattering cross sections, may not be sufficient for nucleon transfer reactions. Therefore, we suggest that microscopic OMPs, which reflect more theoretical considerations, should be preferred over phenomenological ones in calculations of direct nuclear reactions.
基金Supported by the Institute for Basic Science Korea(IBS-R031-D1)Guangdong Major Project of Basic and Applied Basic Research(2021B0301030006)computational resources from Sun Yat-sen University。
文摘The level structure of the double-magic nucleus ^(34)Si(Z=14,N=20)was investigated by evaluating the available data.On the basis of experimental results from the beta-decay and fusion-evaporation reactions,we established the level scheme by assigning spin-parities up to 6_(1)^(+)at 6233 keV.The high energy positions of the excited states are consistent with the magicity at ^(34)Si,such as the 2_(2)^(+)state of the spherical ground band at 4.519 MeV and the 3^(-),4^(-),and 5^(-)states of the one-particle one-hole cross-shell states at approximately 4.5 MeV.This nucleus,for a long time,has attracted much attention because of,on one side,a proton bubble structure in the ground state and,on the other side,a deformation in the second 0^(+)state,0_(2)^(+).By a comparison of the constructed level scheme with the shell model calculations,we describe the emerging structures in the ground and second 0+states and the negative-parity 3^(-)states within the framework of the shell model context.We propose a deformed rotational band with the cascading 6_(2)^(+)−4_(1)^(+)−2_(1)^(+)transitions built on the 0_(2)^(+)state.
基金supported by the National Natural Science Foundation of China(Grant Nos.11575006,11675003,11375017,11235001,11335002, 11375015,11320101004,and 11461141002)the China Postdoctoral Science Foundation(Grant Nos.2015M580007,and 2016T90007)the Chinese Major State Basic Research Development Program(Grant No.2013CB834400)
文摘The ＂island of inversion＂ has been known for over a quar- ter century, since Warburton et al. [1] proposed that nuclei with intruder ground states would constitute a 3x3 square with Z=10-12, N=20-22 in 1990. Uncovering the underlying inversion mechanism and exploring the scope of the island have attracted significant theoretical and experimental efforts in the following years. Now it is well known that the reduction of N=20 shell gap, which is likely caused by the strong nucleon-nucleon tensor interaction [2-5], allows the intrusion of neutron orbits from the pf shell into the sd shell and results in the inversion of the 2p-2h intruder and 0p-0h normal con- figurations of the nuclear ground states in this region. Mean- while, the original border of the ＂island of inversion＂ has been extended greatly [6-14].
基金Supported by the National Natural Science Foundation of China(11805289,11775316)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34010000)the National Key R&D Program of China(2018YFA0404402)。
文摘With the help of the gas-filled recoil spectrometer SHANS and a digital data acquisition system,the fine structure of the α decay for^(222)Pa was studied.The nuclides were produced through the 1p3n evaporation channel via the heavy-ion induced fusion evaporation reaction ^(40)Ar+^(186)W.Based on the ER-α1-α2-α3 andα-γcorrelation measurement,three new α decays were observed in addition to the three branches known previously.The one with the largestαdecay energy was regarded as the ground state to ground state transition.The newly measuredαdecay properties of ^(222)Pa were examined in a framework of reduced width.
