A reflection asymmetric relativistic mean field (RAS-RMF) approach is developed by expanding the equations of motion for both the nucleons and the mesons on the eigenfunctions of the two-centre harmonic-oscillator p...A reflection asymmetric relativistic mean field (RAS-RMF) approach is developed by expanding the equations of motion for both the nucleons and the mesons on the eigenfunctions of the two-centre harmonic-oscillator potential. The efficiency and reliability of the RAS-RMF approach are demonstrated in its application to the well-known octupole deformed nucleus 226Ra and the available data, including the binding energy and the deformation parameters, are well reproduced.展开更多
In order to study the effect of tensor force,we plan to perform a(p,d)reaction with a 400–1600 Me V proton beam on the RIBLL2 at Lanzhou.Based on the experimental conditions of RIBLL2,a Monte Carlo method is used to ...In order to study the effect of tensor force,we plan to perform a(p,d)reaction with a 400–1600 Me V proton beam on the RIBLL2 at Lanzhou.Based on the experimental conditions of RIBLL2,a Monte Carlo method is used to simulate(p,d)reaction process.The distributions of primary beam and scattered deuterons are given on the target and at the F1,F2,F3,and F4 positions.Considering the yield of the deuteron,to separate the produced deuteron from the background particles,the target thickness is optimized.To obtain a clear particle identification spectrum by time of flight(TOF)and energy loss(?E),the distance between the two detectors,as well as the energy and timing resolution of detectors are simulated.As a result,the distance between F2 and F4 is fit for that of TOF.After taking into account the particle distribution at F4,both sizes of Multi-Wire Drift Chamber,namely MWDC2 and MWDC3,are selected to be 50 mm×50 mm.展开更多
Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to dire...Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of^(25)Mg(p,γ)^(26)Al,^(19)F(p,α)^(16)O,^(13)C(α,n)^(16)O and ^(12)C(α,γ)^(16)O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.展开更多
The experimental data of 100 A MeV12C +12C elastic scattering are checked by using two-body kinematic calculation and12 C + p elastic scattering. It is shown that the measured data are true and reliable. In the paper,...The experimental data of 100 A MeV12C +12C elastic scattering are checked by using two-body kinematic calculation and12 C + p elastic scattering. It is shown that the measured data are true and reliable. In the paper,the transformation between the excited energy spectra of the12 C +12C system and the ground state energy spectra of the12 C + p system is introduced. The method of subtraction of the hydrogen background in the natural carbon target used in the experiment is elaborately described and the results are discussed. It is indicated that this method of subtraction of hydrogen background is reasonable and can be used in the data analysis. Based on the elastic scattering cross section of the previous experiment of12C+p at 95.3A MeV, the hydrogen content entered into the reaction is analyzed. The final hydrogen content in the natural carbon target is(2.73 ± 0.12)%.展开更多
The continuum-discritized coupled channel method and the glauber model are applied for the description of deuteron elastic breakup and the stripping processes,respectively.Combined with the conventional two-component ...The continuum-discritized coupled channel method and the glauber model are applied for the description of deuteron elastic breakup and the stripping processes,respectively.Combined with the conventional two-component exciton model for pre-equilibrium processes and the Hauser-Feshbach theory for compound process,an approach based on models is proposed to analyze the inclusive proton energy spectra of a deuteron-induced reaction.The contributions from each process to the energy spectra of the 58Ni(d,xp)reaction are quantitatively given.The results show that this approach is able to reasonably reproduce the experimental data of the double differential cross sections,energy spectra and cross sections,although further improvements are needed.展开更多
We report on the first observation of the neutron-rich nucleus^(131)Ag.This isotope was produced via fragmentation reactions of intense secondary radioactive ion beams,including 134,135Sn.The secondary beams were prod...We report on the first observation of the neutron-rich nucleus^(131)Ag.This isotope was produced via fragmentation reactions of intense secondary radioactive ion beams,including 134,135Sn.The secondary beams were produced from induced fission reactions from a stable 238U beam at 345 MeV/nucleon.Secondary reaction residues were selected by the ZeroDegree spectrometer and identified by measuring their magnetic rigidity,time of flight,energy loss,and total kinetic energy.展开更多
A new Goldstone particle named Majoron is introduced in order to explain the origin of neutrino mass via some new physics models assuming that neutrinos are Majorana particles.By expanding the signal region and using ...A new Goldstone particle named Majoron is introduced in order to explain the origin of neutrino mass via some new physics models assuming that neutrinos are Majorana particles.By expanding the signal region and using likelihood analysis,it becomes possible to search for Majoron using experiments originally designed to search forμ-e conversion.For the COMET experiment,the sensitivity of processμ→eJ is able to reach B(μ→eJ)=2.3×10-5in Phase-I and O(10-8)in Phase-II.Meanwhile,the sensitivities to search for Majoron in future experiments are also discussed in this article.展开更多
We study multi-quark systems in lattice QCD. First, we revisit and summarize our accurate mass measurements of low-lying 5Q states with J = 1/2 and I = 0 in both positive- and negative-parity channels in anisotropic l...We study multi-quark systems in lattice QCD. First, we revisit and summarize our accurate mass measurements of low-lying 5Q states with J = 1/2 and I = 0 in both positive- and negative-parity channels in anisotropic lattice QCD. The lowest positive-parity 5Q state is found to have a large mass of about 2.24 GeV after the chiral extrapolation. To single out the compact 5Q state from NK scattering states, we use the hybrid boundary condition (HBC), and find no evidence of the compact 5Q state below 1.75 GeV in the negative-parity channel. Second, we study the multi-quark potential in lattice QCD to clarify the inter-quark interaction in multi-quark systems. The 5Q potential V<sub>5Q</sub> for the QQ--QQ system is found to be well described by the “OGE Coulomb plus multi-Y Ansatz”: The sum of the one-gluon-exchange (OGE) Coulomb term and the multi-Y-type linear term based on the flux-tube picture. The 4Q potential V<sub>4Q</sub> for the QQ- system is also described by the OGE Coulomb plus multi-Y Ansatz, when QQ and are well separated. The 4Q system is described as a “two-meson” state with disconnected flux tubes, when the nearest quark and antiquark pair are spatially close. We observe a lattice-QCD evidence for the “flip-flop”, i.e., the fluxtube recombination between the connected 4Q state and the “two-meson” state. On the confinement mechanism, the lattice QCD results indicate the flux-tube-type linear confinement in multi-quark hadrons. Finally, we propose a proper quark-model Hamiltonian based on the lattice QCD results.展开更多
We develop a new framework for the study of the nuclear matter based on the linear sigma model. We introduce a completely new viewpoint on the treatment of the nuclear matter with the inclusion of the pion. We extend ...We develop a new framework for the study of the nuclear matter based on the linear sigma model. We introduce a completely new viewpoint on the treatment of the nuclear matter with the inclusion of the pion. We extend the relativistic chiral mean field model by using the similar method in the tensor optimized shell model. We also regulate the pion-nucleon interaction by considering the form-factor and short range repulsion effects. We obtain the equation of state of nuclear matter and study the importance of the pion effect.展开更多
We would like to emphasize that the in-flight (K-,N) reactions are particularly useful for the study of the K-nucleus interaction. Since the reaction mechanism is well known,there is little ambiguity to derive the K-n...We would like to emphasize that the in-flight (K-,N) reactions are particularly useful for the study of the K-nucleus interaction. Since the reaction mechanism is well known,there is little ambiguity to derive the K-nucleus interaction from the measured missing mass spectra. Here we discuss the missing mass spectra of the (K-,N) reactions on the 12C and 16O targets. The spectra show an appreciable amount of strength below the K-nucleus threshold which indicates that the K-nuclear potential is strongly attractive. Comparison of the missing mass spectra with theoretical calculations leads to a potential depth of around -190 MeV for the 12C(K-,n) reaction. A less deep potential of around -160 MeV reproduces well that of the 12C(K-,p) reaction. The difference can be due to isospin dependence of the interaction. Our data show that the K-nucleus potential is very deep to realize kaon condensation in the core of neutron stars.展开更多
The Monte Carlo method is used to simulate the beam optics of the WS beam line of RCNP, Osaka University in order to know the effect of collimators on the beam line to control the beam spot. According to the simulatio...The Monte Carlo method is used to simulate the beam optics of the WS beam line of RCNP, Osaka University in order to know the effect of collimators on the beam line to control the beam spot. According to the simulation, we do not need to use the collimator to cut the beam and the beam angular resolution can be better than 0.05° in achromatic mode. In the present paper, the actual beam condition during the beam adjustment is listed. The accelerator can provide a 12C beam in achromatic mode and the angular resolution σ=0.7775 mrad±0.0030 mrad.展开更多
Ⅲ–Ⅴ semiconductors exhibit dynamic nuclear self-polarization(DYNASP) owing to the contact hyperfine interaction(HFI) between optically excited conduction electrons and lattice nuclei. In the self-polarization proce...Ⅲ–Ⅴ semiconductors exhibit dynamic nuclear self-polarization(DYNASP) owing to the contact hyperfine interaction(HFI) between optically excited conduction electrons and lattice nuclei. In the self-polarization process at a low temperature, electron spin state and the nuclear polarization(magnetization) exchange a positive feedback, increasing energy splitting of the conduction electron states, thereby a large nuclear polarization. This phenomenon was theoretically predicted previously for conduction electrons excited linearly and elliptically polarized light. The polarization of the conduction electrons was represented by a parameter α in a formula for nuclear polarization(Eq.(9) in Ref. [1]); however, the effect of external magnetic fields on the nuclear polarization was not considered. Therefore, this study introduces this effect by further extending the previous studies. Herein, α′represents the combination of the effects of elliptically polarized electrons and an external magnetic field, which is used in the equations presented in previous studies. When α′ = 0, a large nuclear polarization is obtained below critical temperature Tc, but no polarization occurs above Tc. When α′ > 0, the nuclear polarization is enhanced above Tc. Below Tc, the nuclear polarization follows a hysteresis curve when α′ is partially manipulated by adjusting the degree of the polarization of the exciting laser.展开更多
We are carrying out hadron photoproduction experiments by using polarized photon beams at SPring-8 in Japan. In 2005,we started developing a polarized HD target for future experiments using both the polarized photon b...We are carrying out hadron photoproduction experiments by using polarized photon beams at SPring-8 in Japan. In 2005,we started developing a polarized HD target for future experiments using both the polarized photon beams and the polarized target. The polarized HD target is an idealistic target for experiments observing reactions with small cross sections because the HD does not include heavy nuclei which produce many background events. The measurement of double polarization asymmetries is expected to give much important information to investigate the nucleon hidden structure,hadron photoproduction dynamics,and exotic hadron property. We report on the present status of the development of the polarized HD target at RCNP.展开更多
A multi-nucleon transfer and cluster decay experiment,^(7)Li(^(11)B,^(14)C^(*)→α+^(10)Be)α,is conducted at an incident beam energy of 55 MeV.This reaction channel has a significantly large 0-value,which favors popu...A multi-nucleon transfer and cluster decay experiment,^(7)Li(^(11)B,^(14)C^(*)→α+^(10)Be)α,is conducted at an incident beam energy of 55 MeV.This reaction channel has a significantly large 0-value,which favors populating the high lying resonant states in ^(14)C.The decay paths,from these resonances to various states of the final nucleus ^(10) Be,can be selected,owing to the experimentally achieved optimal resolution of the Q-value spectrum.A number of resonant states are reconstructed from the forward emitting 10Be+α fragments,and their major molecular structures can be detected according to the selective decay paths and relative decay widths.A state at 22.4(2)MeV validates the previously measured and theoretically predicted band head of the positive-parity σ-bond linear-chain mo-lecular band.Two additional resonances at 22.9(2)and 24.2(2)MeV are identified and consistent with the predicted 2^(+) and 4^(+) members of the same molecular band,thus providing novel evidences for the existence of the exotic clustering chain structure in neutron-rich carbon isotopes.A few high energy resonances,which also indicate the presence of the σ-bond molecular structure,are observed;however,further studies are still required to clarify their ascription in band systematics.展开更多
Differential and total cross sections of the γp→π0p and the γd→π0pn reaction were measured for photon energies between 640 and 1 150 MeV. The data have been compared with SAID and MAID model calculations. π0 ph...Differential and total cross sections of the γp→π0p and the γd→π0pn reaction were measured for photon energies between 640 and 1 150 MeV. The data have been compared with SAID and MAID model calculations. π0 photoproduction on the deuteron shows a strong suppression of the 2nd resonance which is clearly seen in the γp→π0p reaction.展开更多
We adopt the quark pair creation model to investigate the light meson emissions of several charmoniumlike states.The quark pair creation model is applied to four-body systems,and we calculate the pion/kaon emissions o...We adopt the quark pair creation model to investigate the light meson emissions of several charmoniumlike states.The quark pair creation model is applied to four-body systems,and we calculate the pion/kaon emissions of X(4700),Z_(c)(4430),Y(4230),Y(4360),Y(4390),and Y(4660)within compact tetraquark configurations.We find that the pion/kaon decay widths of X(4700)and Z_(c)(4430)the resonances Y(4230),Y(4360),Y(4390),and Y(4660)cay behaviors will provide useful information for future experimental searches and theoretical interpretations.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10435010 and 10221003, and the Doctoral Foundation from the Ministry of Education of China.
文摘A reflection asymmetric relativistic mean field (RAS-RMF) approach is developed by expanding the equations of motion for both the nucleons and the mesons on the eigenfunctions of the two-centre harmonic-oscillator potential. The efficiency and reliability of the RAS-RMF approach are demonstrated in its application to the well-known octupole deformed nucleus 226Ra and the available data, including the binding energy and the deformation parameters, are well reproduced.
基金Supported by National Natural Science Foundation of China(Nos.11475013,11035007 and 11175011)State Key Laboratory of Software Development Environment(No.SKLSDE-2014ZX-08)+1 种基金Fundamental Research Funds for the Central Universitiesthe Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences
文摘In order to study the effect of tensor force,we plan to perform a(p,d)reaction with a 400–1600 Me V proton beam on the RIBLL2 at Lanzhou.Based on the experimental conditions of RIBLL2,a Monte Carlo method is used to simulate(p,d)reaction process.The distributions of primary beam and scattered deuterons are given on the target and at the F1,F2,F3,and F4 positions.Considering the yield of the deuteron,to separate the produced deuteron from the background particles,the target thickness is optimized.To obtain a clear particle identification spectrum by time of flight(TOF)and energy loss(?E),the distance between the two detectors,as well as the energy and timing resolution of detectors are simulated.As a result,the distance between F2 and F4 is fit for that of TOF.After taking into account the particle distribution at F4,both sizes of Multi-Wire Drift Chamber,namely MWDC2 and MWDC3,are selected to be 50 mm×50 mm.
基金supported by the National Natural Science Foundation of China(Grant Nos.11490560 and 11321064)the National Basic Research Program of China(Grant No.2013CB834406)
文摘Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of^(25)Mg(p,γ)^(26)Al,^(19)F(p,α)^(16)O,^(13)C(α,n)^(16)O and ^(12)C(α,γ)^(16)O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 90103019, 10375003 and 10421503, the Doctoral Program Foundation of Institution of Higher Education under Grant No. KJCX2-SW-N10. S.L. Zhu thanks B.A. Li for very helpful criticism and N. Kochelev and X.G. He for useful discussions.
基金Supported by the Innovation Foundation of BUAA for PhD Graduates and National Natural Science Foundation of China(Nos.11035007,11235002 and 11175011)
文摘The experimental data of 100 A MeV12C +12C elastic scattering are checked by using two-body kinematic calculation and12 C + p elastic scattering. It is shown that the measured data are true and reliable. In the paper,the transformation between the excited energy spectra of the12 C +12C system and the ground state energy spectra of the12 C + p system is introduced. The method of subtraction of the hydrogen background in the natural carbon target used in the experiment is elaborately described and the results are discussed. It is indicated that this method of subtraction of hydrogen background is reasonable and can be used in the data analysis. Based on the elastic scattering cross section of the previous experiment of12C+p at 95.3A MeV, the hydrogen content entered into the reaction is analyzed. The final hydrogen content in the natural carbon target is(2.73 ± 0.12)%.
文摘The continuum-discritized coupled channel method and the glauber model are applied for the description of deuteron elastic breakup and the stripping processes,respectively.Combined with the conventional two-component exciton model for pre-equilibrium processes and the Hauser-Feshbach theory for compound process,an approach based on models is proposed to analyze the inclusive proton energy spectra of a deuteron-induced reaction.The contributions from each process to the energy spectra of the 58Ni(d,xp)reaction are quantitatively given.The results show that this approach is able to reasonably reproduce the experimental data of the double differential cross sections,energy spectra and cross sections,although further improvements are needed.
基金the National Basic Research Program of China under Grant No 2013CB834402the National Natural Science Foundation of China under Grant Nos 11035001 and 11275011.
文摘We report on the first observation of the neutron-rich nucleus^(131)Ag.This isotope was produced via fragmentation reactions of intense secondary radioactive ion beams,including 134,135Sn.The secondary beams were produced from induced fission reactions from a stable 238U beam at 345 MeV/nucleon.Secondary reaction residues were selected by the ZeroDegree spectrometer and identified by measuring their magnetic rigidity,time of flight,energy loss,and total kinetic energy.
基金Supported by the National Natural Science Foundation of China(NSFC)(11335009)International Partnership Program of Chinese Academy of Sciences(113111KYSB20190035)。
文摘A new Goldstone particle named Majoron is introduced in order to explain the origin of neutrino mass via some new physics models assuming that neutrinos are Majorana particles.By expanding the signal region and using likelihood analysis,it becomes possible to search for Majoron using experiments originally designed to search forμ-e conversion.For the COMET experiment,the sensitivity of processμ→eJ is able to reach B(μ→eJ)=2.3×10-5in Phase-I and O(10-8)in Phase-II.Meanwhile,the sensitivities to search for Majoron in future experiments are also discussed in this article.
文摘We study multi-quark systems in lattice QCD. First, we revisit and summarize our accurate mass measurements of low-lying 5Q states with J = 1/2 and I = 0 in both positive- and negative-parity channels in anisotropic lattice QCD. The lowest positive-parity 5Q state is found to have a large mass of about 2.24 GeV after the chiral extrapolation. To single out the compact 5Q state from NK scattering states, we use the hybrid boundary condition (HBC), and find no evidence of the compact 5Q state below 1.75 GeV in the negative-parity channel. Second, we study the multi-quark potential in lattice QCD to clarify the inter-quark interaction in multi-quark systems. The 5Q potential V<sub>5Q</sub> for the QQ--QQ system is found to be well described by the “OGE Coulomb plus multi-Y Ansatz”: The sum of the one-gluon-exchange (OGE) Coulomb term and the multi-Y-type linear term based on the flux-tube picture. The 4Q potential V<sub>4Q</sub> for the QQ- system is also described by the OGE Coulomb plus multi-Y Ansatz, when QQ and are well separated. The 4Q system is described as a “two-meson” state with disconnected flux tubes, when the nearest quark and antiquark pair are spatially close. We observe a lattice-QCD evidence for the “flip-flop”, i.e., the fluxtube recombination between the connected 4Q state and the “two-meson” state. On the confinement mechanism, the lattice QCD results indicate the flux-tube-type linear confinement in multi-quark hadrons. Finally, we propose a proper quark-model Hamiltonian based on the lattice QCD results.
基金Ministry of Education Research Grand,Japan : Kakenhi(18540269)Japanese MEXT Fellowship
文摘We develop a new framework for the study of the nuclear matter based on the linear sigma model. We introduce a completely new viewpoint on the treatment of the nuclear matter with the inclusion of the pion. We extend the relativistic chiral mean field model by using the similar method in the tensor optimized shell model. We also regulate the pion-nucleon interaction by considering the form-factor and short range repulsion effects. We obtain the equation of state of nuclear matter and study the importance of the pion effect.
基金Scientific Research of Ministry of Education, Culture,Sports,Science and Technology,Japan( MEXT17070003)
文摘We would like to emphasize that the in-flight (K-,N) reactions are particularly useful for the study of the K-nucleus interaction. Since the reaction mechanism is well known,there is little ambiguity to derive the K-nucleus interaction from the measured missing mass spectra. Here we discuss the missing mass spectra of the (K-,N) reactions on the 12C and 16O targets. The spectra show an appreciable amount of strength below the K-nucleus threshold which indicates that the K-nuclear potential is strongly attractive. Comparison of the missing mass spectra with theoretical calculations leads to a potential depth of around -190 MeV for the 12C(K-,n) reaction. A less deep potential of around -160 MeV reproduces well that of the 12C(K-,p) reaction. The difference can be due to isospin dependence of the interaction. Our data show that the K-nucleus potential is very deep to realize kaon condensation in the core of neutron stars.
基金Supported by National Nature Science Foundation of China(11035007,11235002,11175011)State Key Laboratory of Software Development Environment(SKLSDE-2014ZX-08 as well as by the Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences.)
文摘The Monte Carlo method is used to simulate the beam optics of the WS beam line of RCNP, Osaka University in order to know the effect of collimators on the beam line to control the beam spot. According to the simulation, we do not need to use the collimator to cut the beam and the beam angular resolution can be better than 0.05° in achromatic mode. In the present paper, the actual beam condition during the beam adjustment is listed. The accelerator can provide a 12C beam in achromatic mode and the angular resolution σ=0.7775 mrad±0.0030 mrad.
基金supported by the Grant-in-Aid for Scientific Research(C)of Japan Society for the Promotion of Science(JSPS)(Nos.21540307,26400298)
文摘Ⅲ–Ⅴ semiconductors exhibit dynamic nuclear self-polarization(DYNASP) owing to the contact hyperfine interaction(HFI) between optically excited conduction electrons and lattice nuclei. In the self-polarization process at a low temperature, electron spin state and the nuclear polarization(magnetization) exchange a positive feedback, increasing energy splitting of the conduction electron states, thereby a large nuclear polarization. This phenomenon was theoretically predicted previously for conduction electrons excited linearly and elliptically polarized light. The polarization of the conduction electrons was represented by a parameter α in a formula for nuclear polarization(Eq.(9) in Ref. [1]); however, the effect of external magnetic fields on the nuclear polarization was not considered. Therefore, this study introduces this effect by further extending the previous studies. Herein, α′represents the combination of the effects of elliptically polarized electrons and an external magnetic field, which is used in the equations presented in previous studies. When α′ = 0, a large nuclear polarization is obtained below critical temperature Tc, but no polarization occurs above Tc. When α′ > 0, the nuclear polarization is enhanced above Tc. Below Tc, the nuclear polarization follows a hysteresis curve when α′ is partially manipulated by adjusting the degree of the polarization of the exciting laser.
文摘We are carrying out hadron photoproduction experiments by using polarized photon beams at SPring-8 in Japan. In 2005,we started developing a polarized HD target for future experiments using both the polarized photon beams and the polarized target. The polarized HD target is an idealistic target for experiments observing reactions with small cross sections because the HD does not include heavy nuclei which produce many background events. The measurement of double polarization asymmetries is expected to give much important information to investigate the nucleon hidden structure,hadron photoproduction dynamics,and exotic hadron property. We report on the present status of the development of the polarized HD target at RCNP.
基金Supported by the National Key research and development Program of China(2018YFA0404403)the National Natural Science Foundation of China(11875074,11875073,12027809,11635015,11961141003)the Continuous Basic Scientific Research Project(WDJC-2019-13)。
文摘A multi-nucleon transfer and cluster decay experiment,^(7)Li(^(11)B,^(14)C^(*)→α+^(10)Be)α,is conducted at an incident beam energy of 55 MeV.This reaction channel has a significantly large 0-value,which favors populating the high lying resonant states in ^(14)C.The decay paths,from these resonances to various states of the final nucleus ^(10) Be,can be selected,owing to the experimentally achieved optimal resolution of the Q-value spectrum.A number of resonant states are reconstructed from the forward emitting 10Be+α fragments,and their major molecular structures can be detected according to the selective decay paths and relative decay widths.A state at 22.4(2)MeV validates the previously measured and theoretically predicted band head of the positive-parity σ-bond linear-chain mo-lecular band.Two additional resonances at 22.9(2)and 24.2(2)MeV are identified and consistent with the predicted 2^(+) and 4^(+) members of the same molecular band,thus providing novel evidences for the existence of the exotic clustering chain structure in neutron-rich carbon isotopes.A few high energy resonances,which also indicate the presence of the σ-bond molecular structure,are observed;however,further studies are still required to clarify their ascription in band systematics.
文摘Differential and total cross sections of the γp→π0p and the γd→π0pn reaction were measured for photon energies between 640 and 1 150 MeV. The data have been compared with SAID and MAID model calculations. π0 photoproduction on the deuteron shows a strong suppression of the 2nd resonance which is clearly seen in the γp→π0p reaction.
基金Supported by the National Natural Science Foundation of China(11705056,12175037,11947224,11475192,11975245,U1832173)the Key Project of Hunan Provincial Education Department under(21A0039)+3 种基金the State Scholarship Fund of China Scholarship Council(22006725011)the Sino-German CRC 110“Symmetries and the Emergence of Structure in QCD”project by NSFC(12070131001)the Key Research Program of Frontier Sciences,CAS(Y7292610K1)the National Key Research and Development Program of China(2020YFA0406300)。
文摘We adopt the quark pair creation model to investigate the light meson emissions of several charmoniumlike states.The quark pair creation model is applied to four-body systems,and we calculate the pion/kaon emissions of X(4700),Z_(c)(4430),Y(4230),Y(4360),Y(4390),and Y(4660)within compact tetraquark configurations.We find that the pion/kaon decay widths of X(4700)and Z_(c)(4430)the resonances Y(4230),Y(4360),Y(4390),and Y(4660)cay behaviors will provide useful information for future experimental searches and theoretical interpretations.