In the framework of the relativistic mean field theory （RMFT）, the relativistic energy losses of the direct Urea processes with hyperons （Y-DURCA ） for reactions A → p ＋ e ＋ υe and ≡^-→ A＋e＋υe are studied...In the framework of the relativistic mean field theory （RMFT）, the relativistic energy losses of the direct Urea processes with hyperons （Y-DURCA ） for reactions A → p ＋ e ＋ υe and ≡^-→ A＋e＋υe are studied in neutron stars. We calculate the energy gap of A hyperons and investigate the effects of the ^1S0 superfluidity （SF） of A hyperons on the Y-DURCA processes. The calculated results are in line with the recent experimental data △ BAA ～ 1.01 ±0.20-0.11^＋0.18 MeV. The results indicate that the ^1S0 SF of A hyperons exists in most density ranges of happening the two reactions. The theoretical cooling curves are in agreement with observation data.展开更多
The numerical results of the populations for the baryon octet in neutron star matter have been presented by solving a set transcendental equations in the framework of the relativistic mean field approximation. The inf...The numerical results of the populations for the baryon octet in neutron star matter have been presented by solving a set transcendental equations in the framework of the relativistic mean field approximation. The influence of the hyperon interactions on hyperon populations in neutron star matter is discussed. The results manifest that when the ratio of the hyperon-to-nucleon couplings increases, all hyperons appear towards low baryon density direction.展开更多
The study of the charge conjugation and parity(CP)violation of hyperon is the precision frontier for probing possible new CP violation sources beyond the standard model(SM).With the large number of quantum entangled h...The study of the charge conjugation and parity(CP)violation of hyperon is the precision frontier for probing possible new CP violation sources beyond the standard model(SM).With the large number of quantum entangled hyperonantihyperon pairs to be produced at Super Tau-Charm Facility(STCF),the CP asymmetry of hyperon is expected to be tested with a statistical sensitivity of 10^(−4) or even better.To cope with the statistical precision,the systematic effects from various aspects are critical and need to be studied in detail.In this paper,the sensitivity effects on the CP violation parameters associated with the detector resolution,including those of the position and momentum,are studied and discussed in detail.The results provide valuable guidance for the design of STCF detector.展开更多
Decays of charmonium into hyperon and antihyperon pairs provide a pristine laboratory for exploring hyperon properties,such as their polarization and decay parameters,and for conducting tests of fundamental symmetries...Decays of charmonium into hyperon and antihyperon pairs provide a pristine laboratory for exploring hyperon properties,such as their polarization and decay parameters,and for conducting tests of fundamental symmetries.This brief review highlights the significant progress made in precise tests of CP symmetry at BESIII using entangled hyperon-antihyperon pairs。展开更多
The properties of thermal protoneutron star matter including hyperons are investigated in the framework of the relativistic mean field theory (RMFT). In protoneuron star matter, with the increase of the temperature, t...The properties of thermal protoneutron star matter including hyperons are investigated in the framework of the relativistic mean field theory (RMFT). In protoneuron star matter, with the increase of the temperature, the critical densities of hyperons decrease, the sequence for appearances of hyperons change, the abundances of hyperons as well as neutrinos increase, and the strong interactions between baryons get weaker. Meanwhile, the abundances of isospin multiple states for nucleons, Σ, and ■ become identical, leading to isospin saturated symmetric matter, respectively. Moreover, if a protoneutron star is born with higher temperature, it is less likely to convert to a black hole.展开更多
The deformations of multi-Λ hypernuclei corresponding to even-even core nuclei ranging from^(8)Be to^(40)Ca with 2,4,6,and 8 hyperons are studied using the deformed Skyrme-Hartree-Fock approach.It is found that the d...The deformations of multi-Λ hypernuclei corresponding to even-even core nuclei ranging from^(8)Be to^(40)Ca with 2,4,6,and 8 hyperons are studied using the deformed Skyrme-Hartree-Fock approach.It is found that the deformations are reduced when adding 2 or 8 Λ hyperons,but enhanced when adding 4 or 6 Λ hyperons.These differences are attributed to the fact that Λ hyperons are filled gradually into the three deformed p orbits,of which the [110] 1/2^(-)orbit is prolately deformed and the degenerate [101]1/2^(-)and [101]3/2^(-)orbits are oblately deformed.展开更多
Using an extended version of quantum hadrodynamics,I propose a new microscopic equation of state(EoS)that is able to correctly reproduce the main properties of symmetric nuclear matter at the saturation density,as wel...Using an extended version of quantum hadrodynamics,I propose a new microscopic equation of state(EoS)that is able to correctly reproduce the main properties of symmetric nuclear matter at the saturation density,as well as produce massive neutron stars and satisfactory results for the radius and the tidal parameter.I show that this EoS can reproduce at least a 2.00 solar mass neutron star,even when hyperons are present.The constraints about the radius of a 2.00 M_(⊙) and the minimum mass that enables a direct Urea effect are also checked.展开更多
Heavy-ion collisions are powerful tools for studying hypernuclear physics.We develop a dynamical coalescence model coupled with an ART model(version1.0) to study the production rates of light nuclear clusters and hype...Heavy-ion collisions are powerful tools for studying hypernuclear physics.We develop a dynamical coalescence model coupled with an ART model(version1.0) to study the production rates of light nuclear clusters and hypernuclei in heavy-ion reactions,for instance,the deuteron(d),triton(t),helium(~3He),and hypertriton(_A^3H)in minimum bias(0-80%centrality)~6Li+^(12)C reactions at beam energy of 3.5A GeV.The penalty factor for light clusters is extracted from the yields,and the distributions of 0 angle of particles,which provide direct suggesetions about the location of particle detectors in the near future facility-High Intensity heavy-ion Accelerator Facility(HIAF) are investigated.Our calculation demonstrates that HIAF is suitable for studying hypernuclear physics.展开更多
The work of Chinese scientists conducted at the Joint Institute for Nuclear Research(JINR)(1956–1965)was inextricably linked to the Sino-Soviet relations in the 1950 s–1960 s.During the early stage of the JINR,with ...The work of Chinese scientists conducted at the Joint Institute for Nuclear Research(JINR)(1956–1965)was inextricably linked to the Sino-Soviet relations in the 1950 s–1960 s.During the early stage of the JINR,with the aid of advanced equipment and the international cooperation mechanism,Chinese scientists yielded significant results,such as the discovery of the antisigma-minus hyperon and the proof of the law of partial conservation of axial current(PCAC).After the Sino-Soviet split,Chinese scientists’activities at the institute were hampered by political tensions,eventually resulting in China’s withdrawal from the JINR in 1965.But through the involvement at the JINR,Chinese scientists were trained in scientific practices and participated in international exchange and cooperation which turned them into a new force in China’s nuclear industry,boosting its nuclear weapons,particle physics theory,and accelerator technology.In the meantime,the scientists’activities extended the international influence of the JINR.The withdrawal of China from the institute impacted both the JINR and the development of science in China.展开更多
The structure and properties of a Keplerian rotating hyperon star with an equation of state （EOS） investigated using the relativistic σ-ω-p model are examined by employing an accurate numerical scheme. It is shown...The structure and properties of a Keplerian rotating hyperon star with an equation of state （EOS） investigated using the relativistic σ-ω-p model are examined by employing an accurate numerical scheme. It is shown that there is a clear rotating effect on the structure and properties, and that hyperon star matter cannot support a star with a mass larger than 1.9 M~, even a star rotating at the fastest allowed frequency. The constraints of the two known fastest rotating frequencies （716 Hz and 1122 Hz） on the mass and radius of a hyperon star are also explored. ~rthermore, our results indicate that the imprint of the rapid rotation of a hyperon star on the moment of inertia is clear; the backward equatorial redshift, the forward equatorial redshift and the polar redshift can be distinguished clearly, the forward equatorial redshift is always negative; and its figuration is far from a spherical symmetric shape.展开更多
In the context of the relativistic mean field theory,we propose two new hyperon coupling models,namely the limitation model and the potential well depth model,in the light of the observed data for the massive neutron ...In the context of the relativistic mean field theory,we propose two new hyperon coupling models,namely the limitation model and the potential well depth model,in the light of the observed data for the massive neutron PSR J0348+0432.The radius of PSR J0348+0432 given by the limitation model is found to be 12.52 km^12.97 km,while the radius given by the potential well depth model is found to be 12.19 km^12.89 km.We also calculate the gravitational redshift of PSR J0348+0432 within these two models,for which the limitation model gives 0.346~0.391 and the potential well depth model gives 0.350~0.409.Further exploration of these two models shows that,these two models are almost degenerate for neutron stars lighter than 1.85 M⊙,and start to give different results for massive neutron stars heavier than 1.85 M⊙.Therefore,the studies of massive neutron stars could be crucial for discriminating these two models and help deepen our understanding of hyper-nuclear interactions.展开更多
With a weak hyperon-hyperon （YY） interaction deduced from the new experimental data of AA potential, this paper has performed a calculation of the direct Urca （DURCA） processes in the framework of the relativistic...With a weak hyperon-hyperon （YY） interaction deduced from the new experimental data of AA potential, this paper has performed a calculation of the direct Urca （DURCA） processes in the framework of the relativistic mean field theory （RMFT） including σ＊ and φ mesons, in comparison with the results calculated with the strong YY interaction and with no （σ＊ ,φ ） mesons included. In neutron star matter, the weak YY interaction supplies the additional repulsive interaction between hyperons while the strong YY interaction supplies the attractive one. With the weak YY interaction, the effective masses of hyperons are larger than those with the strong YY interaction while smaller than those with no （σ＊ ,φ） mesons included. The threshold star masses for the DURCA processes involving nucleons and A are not sensitive to the strength of the YY interaction. The weak YY interaction leads to larger threshold masses for the DURCA process involving [1]1 and [1]0 than the other two cases. The process involving [1]0 can take place in the neutron star only when the weak YY interaction is used. The weak YY interaction is able to bring in the agreement with the observation of the neutron star with larger mass and faster cooling than the strong YY interaction.展开更多
A quark meson coupling model based on SU(3)L × SU(3)R symmetry and scale invariance is proposed.The quarks and mesons get masses through symmetry broken. We apply this SU(3) chiral constituent quark model to inve...A quark meson coupling model based on SU(3)L × SU(3)R symmetry and scale invariance is proposed.The quarks and mesons get masses through symmetry broken. We apply this SU(3) chiral constituent quark model to investigating the nuclear matter at finite temperature and density. The effective baryon masses, compression modulus and hyperon potentials are all reasonable. The critical temperature ofliquid-gas phase transition is also calculated in this model.展开更多
Role of theΛ(1600)is studied in the K^-p→Λπ^0π^0 reaction by using the effective Lagrangian approach near the threshold.We perform a calculation for the total and differential cross sections by considering the co...Role of theΛ(1600)is studied in the K^-p→Λπ^0π^0 reaction by using the effective Lagrangian approach near the threshold.We perform a calculation for the total and differential cross sections by considering the contributions from theΛ(1600)andΛ(1670)intermediate resonances decaying intoπ^0∑^*0(1385)with∑^*0(1385)decaying intoπ^0Λ.Additionally,the non-resonance process from u-channel nucleon pole is also taken into account.With our model parameters,the current experimental data on the total cross sections of the K^-p→Λπ^0π^0 reaction can be well reproduced.It is shown that we really need the contribution from the A(1600)with spin-parity J^P=1/2^+,and that these measurements can be used to determine some of the properties of theΛ(1600)resonance.Furthermore,we also plot theπ0Λinvariant mass distributions which could be tested by the future experimental measurements.展开更多
The properties of hadronic matter at β equilibrium in a wide range of densities are described by appropriate equations of state in the framework of the relativistic mean field model. Strange meson fields, namely the ...The properties of hadronic matter at β equilibrium in a wide range of densities are described by appropriate equations of state in the framework of the relativistic mean field model. Strange meson fields, namely the scalar meson field σ＊（975） and the vector meson field φ（1020）, are included in the present work. We discuss and compare the results of the equation of state, nucleon effective mass, and strangeness fraction obtained by adopting the TM1, TMA, and GL parameter sets for nuclear sector and three different choices for the hypcron couplings. We find that the parameter set TM1 favours the onset of hyperons most, while at high densities the GL parameter set leads to the most hyperon-rich matter. For a certain parameter set （e.g. TM1）, the most hyperon-rich matter is obtained for the hyperon potential model. The influence of the hyperon couplings on the effective mass of nucleon, is much weaker than that on the nucleon parameter set. The nonstrange mesons dominate essentially the global properties of dense hyperon matter. The hyperon potential model predicts the lowest value of the neutron star maximum mass of about 1.45 Msun to be 0.4--0.5 Msun lower than the prediction by using the other choices for hyperon couplings.展开更多
The influences of hyperon-hyperon interaction on the overall properties of hadronic star are investigated in the framework of relativistic mean field （RMF） theory. For certain hyperon coupling, the weaker hyperon-hy...The influences of hyperon-hyperon interaction on the overall properties of hadronic star are investigated in the framework of relativistic mean field （RMF） theory. For certain hyperon coupling, the weaker hyperon-hyperon interaction can lead to the heavier hadronic star, which accords with the observation of heavy neutron star in X-ray binaries. We find that the threshold densities of the hyperons with larger masses are brought to a lower values with the increase of the hyperon-hyperon interaction. The possibility of the existence of hyperon star is checked with the consideration of hyperon-hyperon interaction.展开更多
The helicity amplitudes for the processes of e^＋e^- →J/ψ→γηc→γYY（Y： hyperon） are presented, together with the joint angular distributions for ηc decays into ∧∧,∑^0 ∑^0, and [1]-[1]＋. The sensitivities...The helicity amplitudes for the processes of e^＋e^- →J/ψ→γηc→γYY（Y： hyperon） are presented, together with the joint angular distributions for ηc decays into ∧∧,∑^0 ∑^0, and [1]-[1]＋. The sensitivities to measure the hyperon decay parameters in these decays are evaluated based on the helicity amplitudes. The prospects to test the Bell inequality in experiment using the decay of ηc→∧∧ are discussed.展开更多
An experiment for measuring the hyperon-related fission rate was carried out with the reaction 209^Bi（e, e＇K^＋）209^hPb at the Thomas Jefferson National Laboratory （Jlab）. In the experiment, the performance of th...An experiment for measuring the hyperon-related fission rate was carried out with the reaction 209^Bi（e, e＇K^＋）209^hPb at the Thomas Jefferson National Laboratory （Jlab）. In the experiment, the performance of the fission fragment detector （FFD） was dramaticlly crashed by the background particles in comparison with that during the test without beam. The scattering of the high intensity （500 nA） primary electrons was the dominant cause. Using the GEANT4 toolkit, this report simulates the experimental situation of the target chamber in which the FFD was located. The simulation results indicate that the background particles were dominantly （~ electrons, and protons and alpha particles were the important heavy background particles. The performance of the multi-wire proportional chambers （MWPCs） depends not only on the background-particle intensity but also the current density, which was also given by the simulation code. Furthermore, the measures to suppress the background particles were also investigated with the simulation code.展开更多
The eigen-frequencies of the axial w-mode oscillations of hyperon stars are examined. It is shown that as the appearance of hyperons softens the equation of state of the super-density matter, the frequency of gravitat...The eigen-frequencies of the axial w-mode oscillations of hyperon stars are examined. It is shown that as the appearance of hyperons softens the equation of state of the super-density matter, the frequency of gravitational waves from the axial w-mode of hyperon star becomes smaller than that of a traditional neutron star at the same stellar mass. Moreover, the eigenfrequencies of hyperon stars also have scaling universality. It is shown that the EURO third-generation gravitational-wave detector has the potential to detect the gravitational-wave signal emitted from the axial w-mode oscillations of a hyperon star.展开更多
Based on the recent measurements of the e^(+)e^(-)→∑^(+)∑^(-)^(-)and e^(+)e^(-)→∑^(-)∑^(-)^(+)processes by the Beijing SpectrometerⅢ(BESⅢ)collaboration,the electromagnetic form factors of the hyperon Σ^(+) a...Based on the recent measurements of the e^(+)e^(-)→∑^(+)∑^(-)^(-)and e^(+)e^(-)→∑^(-)∑^(-)^(+)processes by the Beijing SpectrometerⅢ(BESⅢ)collaboration,the electromagnetic form factors of the hyperon Σ^(+) and Σ^(-) in the timelike region are investigated using the vector-meson dominance model,where the contributions of theρ,ω,and φ mesons are taken into account.The model parameters are determined from the BESⅢexperimental data of the timelike effective form factors|G_(eff)|of the Σ^(+) and Σ^(-) baryons for center-of-mass energies from 2.3864 to 3.02 GeV.It is found that we can provide quantitative descriptions of the available data using as few as one adjustable model parameter.We then progress to an analysis of the electromagnetic form factors in the spacelike region and evaluate the spacelike form factors of the hyperons Σ^(+) and Σ^(-).The electromagnetic form factors obtained for the Σ^(+) and Σ^(-) baryons are comparable with those of other model calculations.展开更多
基金Supported by National Natural Science Foundation of China under Grant Nos. 10675024, 11075063the National Fundamental Fund project Subsidy Funds of Personnel Training J0730311
文摘In the framework of the relativistic mean field theory （RMFT）, the relativistic energy losses of the direct Urea processes with hyperons （Y-DURCA ） for reactions A → p ＋ e ＋ υe and ≡^-→ A＋e＋υe are studied in neutron stars. We calculate the energy gap of A hyperons and investigate the effects of the ^1S0 superfluidity （SF） of A hyperons on the Y-DURCA processes. The calculated results are in line with the recent experimental data △ BAA ～ 1.01 ±0.20-0.11^＋0.18 MeV. The results indicate that the ^1S0 SF of A hyperons exists in most density ranges of happening the two reactions. The theoretical cooling curves are in agreement with observation data.
基金The project supported by National Natural Science Foundation of China under Grant Nos.10047001 and 10275029+2 种基金the State Key Basic Research Development Program under Grant No.G2000-0774-07the CAS Knowledge Innovation Project under Contract No.KJCX2-SW-N02
文摘The numerical results of the populations for the baryon octet in neutron star matter have been presented by solving a set transcendental equations in the framework of the relativistic mean field approximation. The influence of the hyperon interactions on hyperon populations in neutron star matter is discussed. The results manifest that when the ratio of the hyperon-to-nucleon couplings increases, all hyperons appear towards low baryon density direction.
基金supported by the National Key R&D Program of China(2022YFA1602200)the International Partnership Program of the Chinese Academy of Sciences(211134KYSB20200057).
文摘The study of the charge conjugation and parity(CP)violation of hyperon is the precision frontier for probing possible new CP violation sources beyond the standard model(SM).With the large number of quantum entangled hyperonantihyperon pairs to be produced at Super Tau-Charm Facility(STCF),the CP asymmetry of hyperon is expected to be tested with a statistical sensitivity of 10^(−4) or even better.To cope with the statistical precision,the systematic effects from various aspects are critical and need to be studied in detail.In this paper,the sensitivity effects on the CP violation parameters associated with the detector resolution,including those of the position and momentum,are studied and discussed in detail.The results provide valuable guidance for the design of STCF detector.
基金supported by the National Natural Science Foundation of China(Grant No.12225509),the National Natural Science Foundation of China(Grant No.12247101)the Polish National Science Centre(Grant No.2024/53/B/ST2/00975)+2 种基金the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2024-jdzx06)the Natural Science Foundation of Gansu Province(Grant No.22JR5RA389)the‘111 Center’under Grant No.B20063。
文摘Decays of charmonium into hyperon and antihyperon pairs provide a pristine laboratory for exploring hyperon properties,such as their polarization and decay parameters,and for conducting tests of fundamental symmetries.This brief review highlights the significant progress made in precise tests of CP symmetry at BESIII using entangled hyperon-antihyperon pairs。
基金Supported by National Natural Science Foundation of China (10275029, 10675024)
文摘The properties of thermal protoneutron star matter including hyperons are investigated in the framework of the relativistic mean field theory (RMFT). In protoneuron star matter, with the increase of the temperature, the critical densities of hyperons decrease, the sequence for appearances of hyperons change, the abundances of hyperons as well as neutrinos increase, and the strong interactions between baryons get weaker. Meanwhile, the abundances of isospin multiple states for nucleons, Σ, and ■ become identical, leading to isospin saturated symmetric matter, respectively. Moreover, if a protoneutron star is born with higher temperature, it is less likely to convert to a black hole.
基金Supported by the National Natural Science Foundation of China (12175071, 11775081, 11905165)。
文摘The deformations of multi-Λ hypernuclei corresponding to even-even core nuclei ranging from^(8)Be to^(40)Ca with 2,4,6,and 8 hyperons are studied using the deformed Skyrme-Hartree-Fock approach.It is found that the deformations are reduced when adding 2 or 8 Λ hyperons,but enhanced when adding 4 or 6 Λ hyperons.These differences are attributed to the fact that Λ hyperons are filled gradually into the three deformed p orbits,of which the [110] 1/2^(-)orbit is prolately deformed and the degenerate [101]1/2^(-)and [101]3/2^(-)orbits are oblately deformed.
文摘Using an extended version of quantum hadrodynamics,I propose a new microscopic equation of state(EoS)that is able to correctly reproduce the main properties of symmetric nuclear matter at the saturation density,as well as produce massive neutron stars and satisfactory results for the radius and the tidal parameter.I show that this EoS can reproduce at least a 2.00 solar mass neutron star,even when hyperons are present.The constraints about the radius of a 2.00 M_(⊙) and the minimum mass that enables a direct Urea effect are also checked.
基金supported in part by the Major State Basic Research Development Program in China(Nos.2014CB845401 and2015CB856904)the National Natural Science Foundation of China(Nos.11421505,11520101004,11275250,11322547 and U1232206)Key Program of CAS for the Frontier Science(No.QYZDJ-SSW-SLH002)
文摘Heavy-ion collisions are powerful tools for studying hypernuclear physics.We develop a dynamical coalescence model coupled with an ART model(version1.0) to study the production rates of light nuclear clusters and hypernuclei in heavy-ion reactions,for instance,the deuteron(d),triton(t),helium(~3He),and hypertriton(_A^3H)in minimum bias(0-80%centrality)~6Li+^(12)C reactions at beam energy of 3.5A GeV.The penalty factor for light clusters is extracted from the yields,and the distributions of 0 angle of particles,which provide direct suggesetions about the location of particle detectors in the near future facility-High Intensity heavy-ion Accelerator Facility(HIAF) are investigated.Our calculation demonstrates that HIAF is suitable for studying hypernuclear physics.
基金supported in part by the Youth Innovation Promotion Association CAS(2018186)the National Science Foundation of China(NSFC)under Grant No.11775207。
文摘The work of Chinese scientists conducted at the Joint Institute for Nuclear Research(JINR)(1956–1965)was inextricably linked to the Sino-Soviet relations in the 1950 s–1960 s.During the early stage of the JINR,with the aid of advanced equipment and the international cooperation mechanism,Chinese scientists yielded significant results,such as the discovery of the antisigma-minus hyperon and the proof of the law of partial conservation of axial current(PCAC).After the Sino-Soviet split,Chinese scientists’activities at the institute were hampered by political tensions,eventually resulting in China’s withdrawal from the JINR in 1965.But through the involvement at the JINR,Chinese scientists were trained in scientific practices and participated in international exchange and cooperation which turned them into a new force in China’s nuclear industry,boosting its nuclear weapons,particle physics theory,and accelerator technology.In the meantime,the scientists’activities extended the international influence of the JINR.The withdrawal of China from the institute impacted both the JINR and the development of science in China.
基金supported by the National Natural Science Foundation of China (Grant No. 10947023)the Fundamental Research Funds for the Central University,China (Grant No. 2009ZM0193)
文摘The structure and properties of a Keplerian rotating hyperon star with an equation of state （EOS） investigated using the relativistic σ-ω-p model are examined by employing an accurate numerical scheme. It is shown that there is a clear rotating effect on the structure and properties, and that hyperon star matter cannot support a star with a mass larger than 1.9 M~, even a star rotating at the fastest allowed frequency. The constraints of the two known fastest rotating frequencies （716 Hz and 1122 Hz） on the mass and radius of a hyperon star are also explored. ~rthermore, our results indicate that the imprint of the rapid rotation of a hyperon star on the moment of inertia is clear; the backward equatorial redshift, the forward equatorial redshift and the polar redshift can be distinguished clearly, the forward equatorial redshift is always negative; and its figuration is far from a spherical symmetric shape.
基金Supported by the National Key R&D Program of China under Grant Nos.2018YFA0404403,2016YFE0129300the National Natural Science Foundation of China under Grant Nos.11535004,11761161001,11375086,11120101005,11175085,11235001,11565010,and 11881240623+1 种基金the Science and Technology Development Fund of Macao under Grant No.008/2017/AFJsupported by a Project funded by China Postdoctoral Science Foundation under Grant No.2018M640470
文摘In the context of the relativistic mean field theory,we propose two new hyperon coupling models,namely the limitation model and the potential well depth model,in the light of the observed data for the massive neutron PSR J0348+0432.The radius of PSR J0348+0432 given by the limitation model is found to be 12.52 km^12.97 km,while the radius given by the potential well depth model is found to be 12.19 km^12.89 km.We also calculate the gravitational redshift of PSR J0348+0432 within these two models,for which the limitation model gives 0.346~0.391 and the potential well depth model gives 0.350~0.409.Further exploration of these two models shows that,these two models are almost degenerate for neutron stars lighter than 1.85 M⊙,and start to give different results for massive neutron stars heavier than 1.85 M⊙.Therefore,the studies of massive neutron stars could be crucial for discriminating these two models and help deepen our understanding of hyper-nuclear interactions.
基金Supported by the Natural Science Fundamental Research Project of Jiangsu Colleges and Universities under Grant No.10KJB140002
文摘With a weak hyperon-hyperon （YY） interaction deduced from the new experimental data of AA potential, this paper has performed a calculation of the direct Urca （DURCA） processes in the framework of the relativistic mean field theory （RMFT） including σ＊ and φ mesons, in comparison with the results calculated with the strong YY interaction and with no （σ＊ ,φ ） mesons included. In neutron star matter, the weak YY interaction supplies the additional repulsive interaction between hyperons while the strong YY interaction supplies the attractive one. With the weak YY interaction, the effective masses of hyperons are larger than those with the strong YY interaction while smaller than those with no （σ＊ ,φ） mesons included. The threshold star masses for the DURCA processes involving nucleons and A are not sensitive to the strength of the YY interaction. The weak YY interaction leads to larger threshold masses for the DURCA process involving [1]1 and [1]0 than the other two cases. The process involving [1]0 can take place in the neutron star only when the weak YY interaction is used. The weak YY interaction is able to bring in the agreement with the observation of the neutron star with larger mass and faster cooling than the strong YY interaction.
文摘A quark meson coupling model based on SU(3)L × SU(3)R symmetry and scale invariance is proposed.The quarks and mesons get masses through symmetry broken. We apply this SU(3) chiral constituent quark model to investigating the nuclear matter at finite temperature and density. The effective baryon masses, compression modulus and hyperon potentials are all reasonable. The critical temperature ofliquid-gas phase transition is also calculated in this model.
基金partly supported by the National Natural Science Foundation of China under Grant Nos.11735003,1191101015 and 11475227the Youth Innovation Promotion Association CAS(No.2016367).
文摘Role of theΛ(1600)is studied in the K^-p→Λπ^0π^0 reaction by using the effective Lagrangian approach near the threshold.We perform a calculation for the total and differential cross sections by considering the contributions from theΛ(1600)andΛ(1670)intermediate resonances decaying intoπ^0∑^*0(1385)with∑^*0(1385)decaying intoπ^0Λ.Additionally,the non-resonance process from u-channel nucleon pole is also taken into account.With our model parameters,the current experimental data on the total cross sections of the K^-p→Λπ^0π^0 reaction can be well reproduced.It is shown that we really need the contribution from the A(1600)with spin-parity J^P=1/2^+,and that these measurements can be used to determine some of the properties of theΛ(1600)resonance.Furthermore,we also plot theπ0Λinvariant mass distributions which could be tested by the future experimental measurements.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10575119 and 10235030）, the Knowledge Innovation Program of Chinese Academy of Sciences （Grant No KJCX2-SW-N02）, the State Key Development Program for Basic Research of China （Grant No G2000077400）, the Key Preresearch Program of the Ministry of Science and Technology of China （Grant No 2002CCB00200）, and the Asia Europe Link project of the European Commission （Grant No CN/ASIA-LINK/008（94791））.
文摘The properties of hadronic matter at β equilibrium in a wide range of densities are described by appropriate equations of state in the framework of the relativistic mean field model. Strange meson fields, namely the scalar meson field σ＊（975） and the vector meson field φ（1020）, are included in the present work. We discuss and compare the results of the equation of state, nucleon effective mass, and strangeness fraction obtained by adopting the TM1, TMA, and GL parameter sets for nuclear sector and three different choices for the hypcron couplings. We find that the parameter set TM1 favours the onset of hyperons most, while at high densities the GL parameter set leads to the most hyperon-rich matter. For a certain parameter set （e.g. TM1）, the most hyperon-rich matter is obtained for the hyperon potential model. The influence of the hyperon couplings on the effective mass of nucleon, is much weaker than that on the nucleon parameter set. The nonstrange mesons dominate essentially the global properties of dense hyperon matter. The hyperon potential model predicts the lowest value of the neutron star maximum mass of about 1.45 Msun to be 0.4--0.5 Msun lower than the prediction by using the other choices for hyperon couplings.
文摘The influences of hyperon-hyperon interaction on the overall properties of hadronic star are investigated in the framework of relativistic mean field （RMF） theory. For certain hyperon coupling, the weaker hyperon-hyperon interaction can lead to the heavier hadronic star, which accords with the observation of heavy neutron star in X-ray binaries. We find that the threshold densities of the hyperons with larger masses are brought to a lower values with the increase of the hyperon-hyperon interaction. The possibility of the existence of hyperon star is checked with the consideration of hyperon-hyperon interaction.
基金Supported by the National Natural Science Foundation of ChinaYouth Innovation Project of IHEPthe Innovation Projcct of Guangxi Graduate Eduction under Grant No. 2007106020702M54
文摘The helicity amplitudes for the processes of e^＋e^- →J/ψ→γηc→γYY（Y： hyperon） are presented, together with the joint angular distributions for ηc decays into ∧∧,∑^0 ∑^0, and [1]-[1]＋. The sensitivities to measure the hyperon decay parameters in these decays are evaluated based on the helicity amplitudes. The prospects to test the Bell inequality in experiment using the decay of ηc→∧∧ are discussed.
基金supported by the Fundamental Research Funds for the Central Universities of China (No.HEUCF101501)the Fundamental Research Funds of Harbin Engineering University of China (No.002150260713)
文摘An experiment for measuring the hyperon-related fission rate was carried out with the reaction 209^Bi（e, e＇K^＋）209^hPb at the Thomas Jefferson National Laboratory （Jlab）. In the experiment, the performance of the fission fragment detector （FFD） was dramaticlly crashed by the background particles in comparison with that during the test without beam. The scattering of the high intensity （500 nA） primary electrons was the dominant cause. Using the GEANT4 toolkit, this report simulates the experimental situation of the target chamber in which the FFD was located. The simulation results indicate that the background particles were dominantly （~ electrons, and protons and alpha particles were the important heavy background particles. The performance of the multi-wire proportional chambers （MWPCs） depends not only on the background-particle intensity but also the current density, which was also given by the simulation code. Furthermore, the measures to suppress the background particles were also investigated with the simulation code.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10947023)the Fundamental Research Funds for the Central Universities (Grant No. 2012ZZ0079)
文摘The eigen-frequencies of the axial w-mode oscillations of hyperon stars are examined. It is shown that as the appearance of hyperons softens the equation of state of the super-density matter, the frequency of gravitational waves from the axial w-mode of hyperon star becomes smaller than that of a traditional neutron star at the same stellar mass. Moreover, the eigenfrequencies of hyperon stars also have scaling universality. It is shown that the EURO third-generation gravitational-wave detector has the potential to detect the gravitational-wave signal emitted from the axial w-mode oscillations of a hyperon star.
基金partly supported by the National Natural Science Foundation of China under Grant Nos.12075288,11735003,and 11961141012。
文摘Based on the recent measurements of the e^(+)e^(-)→∑^(+)∑^(-)^(-)and e^(+)e^(-)→∑^(-)∑^(-)^(+)processes by the Beijing SpectrometerⅢ(BESⅢ)collaboration,the electromagnetic form factors of the hyperon Σ^(+) and Σ^(-) in the timelike region are investigated using the vector-meson dominance model,where the contributions of theρ,ω,and φ mesons are taken into account.The model parameters are determined from the BESⅢexperimental data of the timelike effective form factors|G_(eff)|of the Σ^(+) and Σ^(-) baryons for center-of-mass energies from 2.3864 to 3.02 GeV.It is found that we can provide quantitative descriptions of the available data using as few as one adjustable model parameter.We then progress to an analysis of the electromagnetic form factors in the spacelike region and evaluate the spacelike form factors of the hyperons Σ^(+) and Σ^(-).The electromagnetic form factors obtained for the Σ^(+) and Σ^(-) baryons are comparable with those of other model calculations.
