Two Q-switched Nd：YAG lasers at 1064 nm wavelength have been employed to produce plasmas on aluminum-based alloy in single- and collinear double-pulse laser induced breakdown spectroscopy （LIBS）. Time resolved tech...Two Q-switched Nd：YAG lasers at 1064 nm wavelength have been employed to produce plasmas on aluminum-based alloy in single- and collinear double-pulse laser induced breakdown spectroscopy （LIBS）. Time resolved technique was used for detecting emission sig- nal by spectrometer equipped with ICCD detector. The intensity calibration of spectral response was performed by using deuterium and tungsten halogen lamps. Time evolution of the plasma temperature and electron number density was investigated in single- and collinear double-pulse experiments. Based on the investigation of plasma parameters, the emission signal enhancement mechanism was discussed qualitatively.展开更多
Extreme ultraviolet emission from laser-produced A1 plasma is experimentally and theoretically investigated. Spatial-evolution emission spectra are measured by using the spatio-temporally resolved laser produced plasm...Extreme ultraviolet emission from laser-produced A1 plasma is experimentally and theoretically investigated. Spatial-evolution emission spectra are measured by using the spatio-temporally resolved laser produced plasma technique. Based on the assumptions of a normalized Boltzmann distribution among the excited states and a steady-state collisional-radiative model, we succeed in reproducing the spectra at different detection positions, which are in good agreement with experiments. The decay curves about the electron temperature and electron density, as well as the fractions of individual A1 ions and average ionization stage with increasing the detection distance are obtained by comparison with the experimental measurements. These parameters are critical points for deeply understanding the expanding and cooling of laser produced plasmas in vacuum.展开更多
Laser-induced breakdown spectroscopy-assisted glow discharge(LIBS-GD)for analysis of elements in liquid was proposed,and it was applied to detect heavy metals in highly sensitive mixed solutions of Cu and Cr.During th...Laser-induced breakdown spectroscopy-assisted glow discharge(LIBS-GD)for analysis of elements in liquid was proposed,and it was applied to detect heavy metals in highly sensitive mixed solutions of Cu and Cr.During the experiments of GD and LIBS-GD,the experimental parameters have been optimized and the optimal voltage is 450 V,laser energy is 60 mJ,and the delay time is 4000 ns.Furthermore,the calibration curves of Cu and Cr under GD and LIBS-GD experiments have been established,and the limits of detection(LODs)of Cu and Cr were obtained with the method of GD and LIBS-GD,respectively.The LOD of Cu decreased from3.37(GD)to 0.16 mg l(LIBS-GD),and Cr decreased from 3.15 to 0.34 mg l.The results prove that the capability of elemental detection under LIBS-GD has improved compared with the GD method.Therefore,LIBS-GD is expected to be developed into a highly sensitive method for sewage detection.展开更多
Laser-induced breakdown spectroscopy （LIBS） has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection （LOD） and minimize the sample matrix eff...Laser-induced breakdown spectroscopy （LIBS） has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection （LOD） and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to the obtained LOD of 0.07 ppm for Cr element in solutions.展开更多
A state diagnosis of laser-produced plasma in air generated by a 1064 nm pulse laser was investigated by the Thomson scattering(TS)method.The evolutions of the electron temperature and electron density were obtained a...A state diagnosis of laser-produced plasma in air generated by a 1064 nm pulse laser was investigated by the Thomson scattering(TS)method.The evolutions of the electron temperature and electron density were obtained as a function of the time delay which ranged from 300-3200 ns.The heating effect produced by the 532 nm probe beam with different energies on the air plasma at different interaction times was further studied using a time-resolved optical emission spectroscopy technique.The influence of the probe beam on the electron density was found to be negligible,whereas its influence on electron temperature is evident.In addition,the heating effect of the probe beam on the plasma strongly depends on the energy of the probe beam,and gradually weakens with increasing time delay.Our results are helpful for further understanding the TS method and its application in plasma diagnostics.展开更多
Based on the governing equations which include the heat conduction equation in the target and the fluid equations of the vapor plasma,a two-dimensional axisymmetric model for ns-laser ablation considering the Knudsen ...Based on the governing equations which include the heat conduction equation in the target and the fluid equations of the vapor plasma,a two-dimensional axisymmetric model for ns-laser ablation considering the Knudsen layer and plasma shielding effect is developed.The equations of state of the plasma are described by a real gas approximation,which divides the internal energy into the thermal energy of atoms,ions and electrons,ionization energy and the excitation energy of atoms and ions.The dynamic evolution of the silicon target and plasma during laser ablation is studied by using this model,and the distributions of the temperature,plasma density,Mach number related to the evaporation/condensation of the target surface,laser transmissivity as well as internal energy of the plasma are given.It is found that the evolution of the target surface during laser ablation can be divided into three stages:(1)the target surface temperature increases continuously;(2)the sonic and subsonic evaporation;and(3)the subsonic condensation.The result of the internal energy distribution indicates that the ionization and excitation energy plays an important role in the internal energy of the plasma during laser ablation.This model is suitable for the case that the temperature of the target surface is lower than the critical temperature.展开更多
Armed with four different steady-state collisional-radiative(CR) models,we investigated the effect of dielectronic recombination(DR) on the charge-state distribution in laser-produced silicon plasma. To assess this ef...Armed with four different steady-state collisional-radiative(CR) models,we investigated the effect of dielectronic recombination(DR) on the charge-state distribution in laser-produced silicon plasma. To assess this effect,we performed a series of temporally resolved spectra of highly charged Si ions in the extreme ultraviolet region.Ab initio calculations of the DR rate coefficients were done for Si^(6+)–Si^(4+) ions. We also analyzed the evolution of the collisional ionization, radiative recombination, three-body recombination, photo-ionization, and DR rate coefficients as a function of electron temperature. The electron temperature and electron density for different delay times were obtained by comparing the normalized experimental and simulated spectra. The ion fraction and average charge state from the four different CR models were also obtained. The results indicate that the DR process has a greater influence in the stage of plasma evolution that cannot be neglected in plasma diagnoses.展开更多
In order to provide detailed information about Cd structure and gain more insight regarding ionization degrees and types of transition,as well as the understanding of the temporal evolution behavior of laser produced ...In order to provide detailed information about Cd structure and gain more insight regarding ionization degrees and types of transition,as well as the understanding of the temporal evolution behavior of laser produced Cd plasmas,extreme ultraviolet spectra of laser-produced cadmium(Cd)plasmas have been measured in the 8.4-12 nm region using spatiotemporally resolved laser-produced plasma spectroscopy technique.Spectral features were analyzed by the Hartree-Fock(HF)method with relativistic correlations(HFR)using the Cowan code.The results showed that the 4p-5s resonance transition arrays from Cd^9+to Cd^13+merged to form intense lines in this spectral region.A number of new spectral features from Cd^9+and Cd^10+ions are reported in this study.Based on the assumption of a normalized Boltzmann distribution among the excited states associated with a steady-state collisional-radiative model,the plasma parameters were obtained by comparing the experimental and simulated spectra.As a result,we succeeded in reproducing the synthetic spectra for different time delays,which yielded good agreement with the experiments.The temporal evolution behaviors of electron temperature and electron density of plasma were also analyzed.展开更多
Accurate data for dielectronic recombination of tungsten ions are essential in the modeling of tungsten impurity transport and radiative power loss in International Thermonuclear Experimental Reactor （ITER）. Theoret...Accurate data for dielectronic recombination of tungsten ions are essential in the modeling of tungsten impurity transport and radiative power loss in International Thermonuclear Experimental Reactor （ITER）. Theoretical calculations have been made for dielectronic recombi- nation （DR） rate coefficients of Br-like tungsten ions using a flexible relativistic atomic code （FAC） from i eV to 50 keV. Level-by-level calculations are carried out for evaluating the contributions to DR through all the relevant Kr-like tungsten ions autoionizing inner-shell excited configuration complexes： （3s23p63d10）-14s24p5nlntl＇ （n = 4-5, n＇ = 4-100,l＇ = 0-8）, （4s24pS）-lnln＇l＇ （n = 4-6, n＇ = 4-100, l＇ = 0-12）. Comparison of the rate coefficients for 3s, 3p, 3d, 4s and 4p subshell excitations shows that the 4p subshell excitation dominates over the whole temperature region, 4s subshell excitation at low temperature and 3p, 3d subshell excitations at high temperature can not be neglected. In order to facilitate simple applications, the total DR rate coefficient, △n = 0,1 and 2 core excitations DR rate coefficients are fitted to an empirical formula.展开更多
Electron impact excitation cross sections from the ground state and the lowest metastable state 5p56s J=2 to the excited states of the 5p57p configuration of xenon are calculated systematically using the fully relativ...Electron impact excitation cross sections from the ground state and the lowest metastable state 5p56s J=2 to the excited states of the 5p57p configuration of xenon are calculated systematically using the fully relativistic distorted wave method. Special attention is paid to the configuration interaction effects in the wave-function expansion of target states. The results are in good agreement with the recent experimental data by Jung et al. [Phys. Rev. A 80 （2009） 062708] over the measured energy range. These accurate theoretical results can be used in the modeling and diagnosis of plasmas containing xenon.展开更多
Electron impact excitation cross sections from the ground state to the individual magnetic sublevels of 1s2p 3＇1P1 states in high-temperature dense plasmas are calculated for highly charged He-like Fe24＋ ions by usi...Electron impact excitation cross sections from the ground state to the individual magnetic sublevels of 1s2p 3＇1P1 states in high-temperature dense plasmas are calculated for highly charged He-like Fe24＋ ions by using a fully relativistic distorted-wave method. The Debye-Huckel screening model is used to screen the projectile electron from the nucleus and target electrons. The linear polarization degrees for these lines are obtained. It is found that the cross sections at all incident energies decrease with the increase of the screening for these excitations. The influence of screening on linear polarization degrees of the 1P1 line is very small. The linear polarization degrees of aP1 line decrease sharply at low incident energy with the increase of the screening.展开更多
Using the one-boson-exchange model,we studied the possible existence of very loosely bound hidden-charm molecular baryons composed of an anti-charmed meson and a charmed baryon.Our numerical results indicate that the ...Using the one-boson-exchange model,we studied the possible existence of very loosely bound hidden-charm molecular baryons composed of an anti-charmed meson and a charmed baryon.Our numerical results indicate that the Σ c ＊ and Σ c states exist,but that the Λ c and Λ c ＊ molecular states do not.展开更多
The existence of doubly heavy flavor baryons has not been well established experimentally so far. In this Letter we systematically investigate the weak decays of the doubly charmed baryons, Ξ;and Ξ;, which should be...The existence of doubly heavy flavor baryons has not been well established experimentally so far. In this Letter we systematically investigate the weak decays of the doubly charmed baryons, Ξ;and Ξ;, which should be helpful for experimental searches for these particles. The long-distance contributions are first studied in the doubly heavy baryon decays, and found to be significantly enhanced. Comparing all the processes, Ξ;→Λ;K;π;π;andΞ;π;are the most favorable decay modes for experiments to search for doubly heavy baryons.展开更多
The initial single pion emission （ISPE） mechanism is applied to the processes r（5S）→πB（＊）B-（＊）, whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell＇s measu...The initial single pion emission （ISPE） mechanism is applied to the processes r（5S）→πB（＊）B-（＊）, whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell＇s measurements; that is, we succeed in reproducing the enhancement structures of Zb（10610） and Zb（10650）. Inspired by this success, we also predict the corresponding enhancement structures in open charm oue-pion decays of higher charmonia near the thresholds of D＊D- and D＊D-＊.展开更多
Compared with the charmed baryons, the bottom baryons are not very well known, either experimentally Or theoretically. In this paper, we investigate the dipion strong decays of the P-wave and D-wave excited bottom bar...Compared with the charmed baryons, the bottom baryons are not very well known, either experimentally Or theoretically. In this paper, we investigate the dipion strong decays of the P-wave and D-wave excited bottom baryons in the framework of the QPC model. We also extend the same analysis to the charmed baryons.展开更多
The code benchmarking for hadron linac using the 3D Particle-In-Cell (PIC) code is an important task in the European framework “High Intensity Pulsed Proton Injector” (HIPPI). PARMILA and HALODYN are two of the code...The code benchmarking for hadron linac using the 3D Particle-In-Cell (PIC) code is an important task in the European framework “High Intensity Pulsed Proton Injector” (HIPPI). PARMILA and HALODYN are two of the codes involved in this work. Both of these codes have been developed and used for linac design and beam dynamics studies. In this paper, the simulation results of the beam dynamics were compared and analyzed. As predicted by two codes, the simulation results show some agreements. The physical design strategy which was adopted in two codes was also discussed.展开更多
In the framework of the one-boson-exchange model, we have performed an extensive study of the possible B＊B, B B＊ D＇D, D＇D＊ molecular states with various quantum numbers after considering the S-wave and D-wave m...In the framework of the one-boson-exchange model, we have performed an extensive study of the possible B＊B, B B＊ D＇D, D＇D＊ molecular states with various quantum numbers after considering the S-wave and D-wave mixing. We also discuss the possible experimental research of these interesting states.展开更多
基金supported by National Natural Science Foundation of China(Nos.11274254,11364037,11064012)the JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics(No.11261140328)the International Scientic and Technologic Cooperative Project of Gansu Province,China(No.1104WCGA186)
文摘Two Q-switched Nd：YAG lasers at 1064 nm wavelength have been employed to produce plasmas on aluminum-based alloy in single- and collinear double-pulse laser induced breakdown spectroscopy （LIBS）. Time resolved technique was used for detecting emission sig- nal by spectrometer equipped with ICCD detector. The intensity calibration of spectral response was performed by using deuterium and tungsten halogen lamps. Time evolution of the plasma temperature and electron number density was investigated in single- and collinear double-pulse experiments. Based on the investigation of plasma parameters, the emission signal enhancement mechanism was discussed qualitatively.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11064012,11364037 and 11564037the Basic Scientific Foundation of Higher Learning of Gansu Provincethe Natural Science Foundation of Gansu Province under Grant Nos 1308RJZA166 and 1104WCGA186
文摘Extreme ultraviolet emission from laser-produced A1 plasma is experimentally and theoretically investigated. Spatial-evolution emission spectra are measured by using the spatio-temporally resolved laser produced plasma technique. Based on the assumptions of a normalized Boltzmann distribution among the excited states and a steady-state collisional-radiative model, we succeed in reproducing the spectra at different detection positions, which are in good agreement with experiments. The decay curves about the electron temperature and electron density, as well as the fractions of individual A1 ions and average ionization stage with increasing the detection distance are obtained by comparison with the experimental measurements. These parameters are critical points for deeply understanding the expanding and cooling of laser produced plasmas in vacuum.
基金supported by National Natural Science Foundation of China(Nos.61965015,11564037,and 161741513)the Industrial Support Program for Colleges of Gansu Province(No.2020C-17)+1 种基金the Science and Technology Project of Gansu Province(No.21JR7RA131)the Young Teachers Scientific Research Ability Promotion Plan of Northwest Normal University(No.NWNU-LKQN2019-1)。
文摘Laser-induced breakdown spectroscopy-assisted glow discharge(LIBS-GD)for analysis of elements in liquid was proposed,and it was applied to detect heavy metals in highly sensitive mixed solutions of Cu and Cr.During the experiments of GD and LIBS-GD,the experimental parameters have been optimized and the optimal voltage is 450 V,laser energy is 60 mJ,and the delay time is 4000 ns.Furthermore,the calibration curves of Cu and Cr under GD and LIBS-GD experiments have been established,and the limits of detection(LODs)of Cu and Cr were obtained with the method of GD and LIBS-GD,respectively.The LOD of Cu decreased from3.37(GD)to 0.16 mg l(LIBS-GD),and Cr decreased from 3.15 to 0.34 mg l.The results prove that the capability of elemental detection under LIBS-GD has improved compared with the GD method.Therefore,LIBS-GD is expected to be developed into a highly sensitive method for sewage detection.
基金supported by National Natural Science Foundation of China(Nos.11064012,11274254,11364037)the JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics(No.11261140328)the International Scientic and Technologic Cooperative Project of Gansu Province,China(No.1104WCGA186)
文摘Laser-induced breakdown spectroscopy （LIBS） has been applied to the analysis of heavy metals in liquid samples. A new approach was presented to lower the limit of detection （LOD） and minimize the sample matrix effects, in which dried wood pellets absorbed the given amounts of Cr standard solutions and then were baked because they have stronger and rapid absorption properties for liquid samples as well as simple elemental compositions. In this work, we have taken a typical heavy metal Cr element as an example, and investigated the spectral feasibility of Cr solutions and dried wood pellets before and after absorbing Cr solutions at the same experimental conditions. The results were demonstrated to successfully produce a superior analytical response for heavy metal elements by using wood pellet as sample matrix according to the obtained LOD of 0.07 ppm for Cr element in solutions.
基金This work is supported by the National Key Research and Development Program of China(No.2017YFA0402300)National Natural Science Foundation of China(Nos.11874051,11564037,61741513,11904293)the Special Fund Project for Guiding Scientific and Technological Inno-vation of Gansu Province(No.2019zx-10).
文摘A state diagnosis of laser-produced plasma in air generated by a 1064 nm pulse laser was investigated by the Thomson scattering(TS)method.The evolutions of the electron temperature and electron density were obtained as a function of the time delay which ranged from 300-3200 ns.The heating effect produced by the 532 nm probe beam with different energies on the air plasma at different interaction times was further studied using a time-resolved optical emission spectroscopy technique.The influence of the probe beam on the electron density was found to be negligible,whereas its influence on electron temperature is evident.In addition,the heating effect of the probe beam on the plasma strongly depends on the energy of the probe beam,and gradually weakens with increasing time delay.Our results are helpful for further understanding the TS method and its application in plasma diagnostics.
基金supported by the National Key Research and Development Program of China (No. 2017YFA0402300)National Natural Science Foundation of China (Nos.11904293, 12064040 and 11874051)+2 种基金the Science and technology project of Gansu Province (No. 20JR5RA530)the Young Teachers Scientific Research Ability Promotion Plan of Northwest Normal University (No. NWNU-LKQN-18-32)the Funds for Innovative Fundamental Research Group Project of Gansu Province (No. 20JR5RA541).
文摘Based on the governing equations which include the heat conduction equation in the target and the fluid equations of the vapor plasma,a two-dimensional axisymmetric model for ns-laser ablation considering the Knudsen layer and plasma shielding effect is developed.The equations of state of the plasma are described by a real gas approximation,which divides the internal energy into the thermal energy of atoms,ions and electrons,ionization energy and the excitation energy of atoms and ions.The dynamic evolution of the silicon target and plasma during laser ablation is studied by using this model,and the distributions of the temperature,plasma density,Mach number related to the evaporation/condensation of the target surface,laser transmissivity as well as internal energy of the plasma are given.It is found that the evolution of the target surface during laser ablation can be divided into three stages:(1)the target surface temperature increases continuously;(2)the sonic and subsonic evaporation;and(3)the subsonic condensation.The result of the internal energy distribution indicates that the ionization and excitation energy plays an important role in the internal energy of the plasma during laser ablation.This model is suitable for the case that the temperature of the target surface is lower than the critical temperature.
基金supported by the National Key Research and Development Program of China (Grant No. 2017YFA0402300)National Natural Science Foundation of China (NSFC) (Grant Nos. 11904293, 11874051)。
文摘Armed with four different steady-state collisional-radiative(CR) models,we investigated the effect of dielectronic recombination(DR) on the charge-state distribution in laser-produced silicon plasma. To assess this effect,we performed a series of temporally resolved spectra of highly charged Si ions in the extreme ultraviolet region.Ab initio calculations of the DR rate coefficients were done for Si^(6+)–Si^(4+) ions. We also analyzed the evolution of the collisional ionization, radiative recombination, three-body recombination, photo-ionization, and DR rate coefficients as a function of electron temperature. The electron temperature and electron density for different delay times were obtained by comparing the normalized experimental and simulated spectra. The ion fraction and average charge state from the four different CR models were also obtained. The results indicate that the DR process has a greater influence in the stage of plasma evolution that cannot be neglected in plasma diagnoses.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0402300)the National Natural Science Foundation of China(Grant Nos.11874051,11904293,and 61965015)the Special Fund Project for Guiding Scientific and Technological Innovation of Gansu Province,China(Grant No.2019zx-10).
文摘In order to provide detailed information about Cd structure and gain more insight regarding ionization degrees and types of transition,as well as the understanding of the temporal evolution behavior of laser produced Cd plasmas,extreme ultraviolet spectra of laser-produced cadmium(Cd)plasmas have been measured in the 8.4-12 nm region using spatiotemporally resolved laser-produced plasma spectroscopy technique.Spectral features were analyzed by the Hartree-Fock(HF)method with relativistic correlations(HFR)using the Cowan code.The results showed that the 4p-5s resonance transition arrays from Cd^9+to Cd^13+merged to form intense lines in this spectral region.A number of new spectral features from Cd^9+and Cd^10+ions are reported in this study.Based on the assumption of a normalized Boltzmann distribution among the excited states associated with a steady-state collisional-radiative model,the plasma parameters were obtained by comparing the experimental and simulated spectra.As a result,we succeeded in reproducing the synthetic spectra for different time delays,which yielded good agreement with the experiments.The temporal evolution behaviors of electron temperature and electron density of plasma were also analyzed.
基金supported by the International Atomic Energy Agency(No.16266)National Natural Science Foundation of China(Nos.91126007,11064012)
文摘Accurate data for dielectronic recombination of tungsten ions are essential in the modeling of tungsten impurity transport and radiative power loss in International Thermonuclear Experimental Reactor （ITER）. Theoretical calculations have been made for dielectronic recombi- nation （DR） rate coefficients of Br-like tungsten ions using a flexible relativistic atomic code （FAC） from i eV to 50 keV. Level-by-level calculations are carried out for evaluating the contributions to DR through all the relevant Kr-like tungsten ions autoionizing inner-shell excited configuration complexes： （3s23p63d10）-14s24p5nlntl＇ （n = 4-5, n＇ = 4-100,l＇ = 0-8）, （4s24pS）-lnln＇l＇ （n = 4-6, n＇ = 4-100, l＇ = 0-12）. Comparison of the rate coefficients for 3s, 3p, 3d, 4s and 4p subshell excitations shows that the 4p subshell excitation dominates over the whole temperature region, 4s subshell excitation at low temperature and 3p, 3d subshell excitations at high temperature can not be neglected. In order to facilitate simple applications, the total DR rate coefficient, △n = 0,1 and 2 core excitations DR rate coefficients are fitted to an empirical formula.
基金Supported by the National Natural Science Foundation of China Grant Nos 11274254 and 11147018, and the Scientific Research Foundation of the Higher Education Institutions of Gansu Province.
文摘Electron impact excitation cross sections from the ground state and the lowest metastable state 5p56s J=2 to the excited states of the 5p57p configuration of xenon are calculated systematically using the fully relativistic distorted wave method. Special attention is paid to the configuration interaction effects in the wave-function expansion of target states. The results are in good agreement with the recent experimental data by Jung et al. [Phys. Rev. A 80 （2009） 062708] over the measured energy range. These accurate theoretical results can be used in the modeling and diagnosis of plasmas containing xenon.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11147018, 11274254, 91126007 and U1331122, and the Natural Science Foundation of Gansu Province under Grant Nos 1107RJYA003 and 1010RJZA014.
文摘Electron impact excitation cross sections from the ground state to the individual magnetic sublevels of 1s2p 3＇1P1 states in high-temperature dense plasmas are calculated for highly charged He-like Fe24＋ ions by using a fully relativistic distorted-wave method. The Debye-Huckel screening model is used to screen the projectile electron from the nucleus and target electrons. The linear polarization degrees for these lines are obtained. It is found that the cross sections at all incident energies decrease with the increase of the screening for these excitations. The influence of screening on linear polarization degrees of the 1P1 line is very small. The linear polarization degrees of aP1 line decrease sharply at low incident energy with the increase of the screening.
基金Supported by National Natural Science Foundation of China (11175073,11075004,11021092,11035006,11047606,10805048)Ministry of Science and Technology of China (2009CB825200)+1 种基金Ministry of Education of China (FANEDD 200924,DPFIHE20090211120029,NCET NCET-10-0442)Fundamental Research Funds for the Central Universities(lzujbky-2010-69)
文摘Using the one-boson-exchange model,we studied the possible existence of very loosely bound hidden-charm molecular baryons composed of an anti-charmed meson and a charmed baryon.Our numerical results indicate that the Σ c ＊ and Σ c states exist,but that the Λ c and Λ c ＊ molecular states do not.
基金Supported by National Natural Science Foundation of China(11505083,11505098,11647310,11575110,11375208,11521505,11621131001,11235005,11447032,U1732101)Natural Science Foundation of Shanghai(15DZ2272100)
文摘The existence of doubly heavy flavor baryons has not been well established experimentally so far. In this Letter we systematically investigate the weak decays of the doubly charmed baryons, Ξ;and Ξ;, which should be helpful for experimental searches for these particles. The long-distance contributions are first studied in the doubly heavy baryon decays, and found to be significantly enhanced. Comparing all the processes, Ξ;→Λ;K;π;π;andΞ;π;are the most favorable decay modes for experiments to search for doubly heavy baryons.
基金Supported by National Natural Science Foundation of China(11175073,11005129,11035006)Ministry of Education of China(FANEDD(200924)+2 种基金DPFIHE(20090211120029)NCET(NCET-10-0442)Fundamental Research Funds for Central Universities and West Light Foundation of The Chinese Academy of Sciences
文摘The initial single pion emission （ISPE） mechanism is applied to the processes r（5S）→πB（＊）B-（＊）, whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell＇s measurements; that is, we succeed in reproducing the enhancement structures of Zb（10610） and Zb（10650）. Inspired by this success, we also predict the corresponding enhancement structures in open charm oue-pion decays of higher charmonia near the thresholds of D＊D- and D＊D-＊.
基金Supported by National Natural Science Foundation of China(11222547,11175073,11035006,11375240,11261130311)Ministry of Education of China(FANEDD(200924)+2 种基金DPFIHE(20090211120029)NCET(NCET-10-0442)Fundamental Research Funds for Central Universities
文摘Compared with the charmed baryons, the bottom baryons are not very well known, either experimentally Or theoretically. In this paper, we investigate the dipion strong decays of the P-wave and D-wave excited bottom baryons in the framework of the QPC model. We also extend the same analysis to the charmed baryons.
文摘The code benchmarking for hadron linac using the 3D Particle-In-Cell (PIC) code is an important task in the European framework “High Intensity Pulsed Proton Injector” (HIPPI). PARMILA and HALODYN are two of the codes involved in this work. Both of these codes have been developed and used for linac design and beam dynamics studies. In this paper, the simulation results of the beam dynamics were compared and analyzed. As predicted by two codes, the simulation results show some agreements. The physical design strategy which was adopted in two codes was also discussed.
基金Supported by National Natural Science Foundation of China (11175073, 11021092, 11035006, 11047606, 10805048)Ministry of Science and Technology of China (2009CB825200)+1 种基金Ministry of Education of China (FANEDD 200924, DPFIHE 20090211120029, NCET-10-0442)Fundamental Research Funds for the Central Universities
文摘In the framework of the one-boson-exchange model, we have performed an extensive study of the possible B＊B, B B＊ D＇D, D＇D＊ molecular states with various quantum numbers after considering the S-wave and D-wave mixing. We also discuss the possible experimental research of these interesting states.
