Pub Date : 2020-07-02DOI: 10.1103/physrevc.102.054603
W. Brodzi'nski, J. Skalski
Using the idea of the instanton approach to quantum tunneling we try to obtain a method of calculating spontaneous fission rates for nuclei with the odd number of neutrons or protons. This problem has its origin in the failure of the adiabatic cranking approximation which serves as the basis in calculations of fission probabilities. Selfconsistent instanton equations, with and without pairing, are reviewed and then simplified to non-selfconsistent versions with phenomenological single-particle potential and seniority pairing interaction. Solutions of instanton-like equations without pairing and actions they produce are studied for the Woods-Saxon potential along realistic fission trajectories. Actions for unpaired particles are combined with cranking actions for even-even cores and fission hindrance for odd-A nuclei is studied in such a hybrid model. With the assumed equal mass parameters for neighbouring odd-A and even-even nuclei, the model shows that freezing the K {pi} configuration leads to a large overestimate of the fission hindrance factors. Actions with adiabatic configurations mostly show not enough hindrance; instanton-like actions for blocked nucleons correct this, but not sufficiently.
{"title":"Instanton-motivated study of spontaneous fission of odd-\u0000A\u0000 nuclei","authors":"W. Brodzi'nski, J. Skalski","doi":"10.1103/physrevc.102.054603","DOIUrl":"https://doi.org/10.1103/physrevc.102.054603","url":null,"abstract":"Using the idea of the instanton approach to quantum tunneling we try to obtain a method of calculating spontaneous fission rates for nuclei with the odd number of neutrons or protons. This problem has its origin in the failure of the adiabatic cranking approximation which serves as the basis in calculations of fission probabilities. Selfconsistent instanton equations, with and without pairing, are reviewed and then simplified to non-selfconsistent versions with phenomenological single-particle potential and seniority pairing interaction. Solutions of instanton-like equations without pairing and actions they produce are studied for the Woods-Saxon potential along realistic fission trajectories. Actions for unpaired particles are combined with cranking actions for even-even cores and fission hindrance for odd-A nuclei is studied in such a hybrid model. With the assumed equal mass parameters for neighbouring odd-A and even-even nuclei, the model shows that freezing the K {pi} configuration leads to a large overestimate of the fission hindrance factors. Actions with adiabatic configurations mostly show not enough hindrance; instanton-like actions for blocked nucleons correct this, but not sufficiently.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75307664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-02DOI: 10.1142/S0218301321500099
E. J. In, Youngman Kim, P. Papakonstantinou, Seung-Woo Hong
The location of the neutron drip line, currently known for only the lightest elements, remains a fundamental question in nuclear physics. Its description is a challenge for microscopic nuclear energy density functionals, as it must take into account in a realistic way not only the nuclear potential, but also pairing correlations, deformation effects and coupling to the continuum. The recently developed deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) aims to provide a unified description of even-even nuclei throughout the nuclear chart. Here, the DRHBc with the successful density functional PC-PK1 is used to investigate whether and how deformation influences the prediction for the neutron drip-line location for even-even nuclei with 8<=Z<=20, where many isotopes are predicted deformed. The results are compared with those based on the spherical relativistic continuum Hartree-Bogoliubov (RCHB) theory and discussed in terms of shape evolution and the variational principle. It is found that the Ne and Ar drip-line nuclei are different after the deformation effect is included. The direction of the change is not necessarily towards an extended drip line, but rather depends on the evolution of the degree of deformation towards the drip line. Deformation effects as well as pairing and continuum effects treated in a consistent way can affect critically the theoretical description of the neutron drip-line location.
{"title":"Neutron drip line in the deformed relativistic Hartree–Bogoliubov theory in continuum: Oxygen to Calcium","authors":"E. J. In, Youngman Kim, P. Papakonstantinou, Seung-Woo Hong","doi":"10.1142/S0218301321500099","DOIUrl":"https://doi.org/10.1142/S0218301321500099","url":null,"abstract":"The location of the neutron drip line, currently known for only the lightest elements, remains a fundamental question in nuclear physics. Its description is a challenge for microscopic nuclear energy density functionals, as it must take into account in a realistic way not only the nuclear potential, but also pairing correlations, deformation effects and coupling to the continuum. The recently developed deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc) aims to provide a unified description of even-even nuclei throughout the nuclear chart. Here, the DRHBc with the successful density functional PC-PK1 is used to investigate whether and how deformation influences the prediction for the neutron drip-line location for even-even nuclei with 8<=Z<=20, where many isotopes are predicted deformed. The results are compared with those based on the spherical relativistic continuum Hartree-Bogoliubov (RCHB) theory and discussed in terms of shape evolution and the variational principle. It is found that the Ne and Ar drip-line nuclei are different after the deformation effect is included. The direction of the change is not necessarily towards an extended drip line, but rather depends on the evolution of the degree of deformation towards the drip line. Deformation effects as well as pairing and continuum effects treated in a consistent way can affect critically the theoretical description of the neutron drip-line location.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74150153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-01DOI: 10.1103/physrevd.102.116001
Bo Huang
We calculate the $T$-matrices of elastic pion-nucleon ($pi N$) scattering up to fourth order in SU(3) heavy baryon chiral perturbation theory. The baryon mass in the chiral limit $M_0$ and the pertinent low-energy constants are determined by fitting to empirical $pi N$ phase shifts below 200 MeV pion laboratory momentum in the physical region. The scattering lengths and scattering volumes are also extracted from the chiral amplitudes, and turn out to be in good agreement with those of other approaches and the available experimental values. On the basis of the various phase shifts and the threshold parameters, the convergence of the chiral expansion is analyzed in detail. A good convergence for $pi N$ scattering observables is obtained when working up to fourth order. In addition, we extend the fit to 250 MeV pion laboratory momentum, and obtain also a good description of the empirical $S$- and $P$-wave phase shifts.
{"title":"Pion-nucleon scattering to order \u0000p4\u0000 in SU(3) heavy baryon chiral perturbation theory","authors":"Bo Huang","doi":"10.1103/physrevd.102.116001","DOIUrl":"https://doi.org/10.1103/physrevd.102.116001","url":null,"abstract":"We calculate the $T$-matrices of elastic pion-nucleon ($pi N$) scattering up to fourth order in SU(3) heavy baryon chiral perturbation theory. The baryon mass in the chiral limit $M_0$ and the pertinent low-energy constants are determined by fitting to empirical $pi N$ phase shifts below 200 MeV pion laboratory momentum in the physical region. The scattering lengths and scattering volumes are also extracted from the chiral amplitudes, and turn out to be in good agreement with those of other approaches and the available experimental values. On the basis of the various phase shifts and the threshold parameters, the convergence of the chiral expansion is analyzed in detail. A good convergence for $pi N$ scattering observables is obtained when working up to fourth order. In addition, we extend the fit to 250 MeV pion laboratory momentum, and obtain also a good description of the empirical $S$- and $P$-wave phase shifts.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75373240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-01DOI: 10.1103/PHYSREVC.102.054905
Patrick Carzon, Skandaprasad Rao, M. Luzum, M. Sievert, J. Noronha-Hostler
Recent measurements have established the sensitivity of ultracentral heavy-ion collisions to the deformation parameters of non-spherical nuclei. In the case of ${}^{ 129}$Xe collisions, a quadrupole deformation of the nuclear profile led to an enhancement of elliptic flow in the most central collisions. In ${}^{ 208}$Pb collisions a discrepancy exists in similar centralities, where either elliptic flow is over-predicted or triangular flow is under-predicted by hydrodynamic models; this is known as the $v_2$-to-$v_3$ puzzle in ultracentral collisions. Motivated by low-energy nuclear structure calculations, we consider the possibility that $^{208}$Pb nuclei could have a pear shape deformation (octupole), which has the effect of increasing triangular flow in central PbPb collisions. Using the recent data from ALICE and ATLAS, we revisit the $v_2$-to-$v_3$ puzzle in ultracentral collisions, including new constraints from recent measurements of the triangular cumulant ratio $v_3left{4right}/v_3left{2right}$ and comparing two different hydrodynamic models. We find that, while an octupole deformation would slightly improve the ratio between $v_2$ and $v_3$, it is at the expense of a significantly worse triangular flow cumulant ratio. In fact, the latter observable prefers no octupole deformation, with $beta_3lesssim 0.0375$ for ${}^{ 208}$Pb, and is therefore consistent with the expectation for a doubly-magic nucleus even at top collider energies. The $v_2$-to-$v_3$ puzzle remains a challenge for hydrodynamic models.
{"title":"Possible octupole deformation of \u0000Pb208\u0000 and the ultracentral \u0000v2\u0000 to \u0000v3\u0000 puzzle","authors":"Patrick Carzon, Skandaprasad Rao, M. Luzum, M. Sievert, J. Noronha-Hostler","doi":"10.1103/PHYSREVC.102.054905","DOIUrl":"https://doi.org/10.1103/PHYSREVC.102.054905","url":null,"abstract":"Recent measurements have established the sensitivity of ultracentral heavy-ion collisions to the deformation parameters of non-spherical nuclei. In the case of ${}^{ 129}$Xe collisions, a quadrupole deformation of the nuclear profile led to an enhancement of elliptic flow in the most central collisions. In ${}^{ 208}$Pb collisions a discrepancy exists in similar centralities, where either elliptic flow is over-predicted or triangular flow is under-predicted by hydrodynamic models; this is known as the $v_2$-to-$v_3$ puzzle in ultracentral collisions. Motivated by low-energy nuclear structure calculations, we consider the possibility that $^{208}$Pb nuclei could have a pear shape deformation (octupole), which has the effect of increasing triangular flow in central PbPb collisions. Using the recent data from ALICE and ATLAS, we revisit the $v_2$-to-$v_3$ puzzle in ultracentral collisions, including new constraints from recent measurements of the triangular cumulant ratio $v_3left{4right}/v_3left{2right}$ and comparing two different hydrodynamic models. We find that, while an octupole deformation would slightly improve the ratio between $v_2$ and $v_3$, it is at the expense of a significantly worse triangular flow cumulant ratio. In fact, the latter observable prefers no octupole deformation, with $beta_3lesssim 0.0375$ for ${}^{ 208}$Pb, and is therefore consistent with the expectation for a doubly-magic nucleus even at top collider energies. The $v_2$-to-$v_3$ puzzle remains a challenge for hydrodynamic models.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84911036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-30DOI: 10.1103/physrevc.102.054301
W. G. Jiang, A. Ekström, C. Forss'en, G. Hagen, G. Jansen, T. Papenbrock
We optimize $Delta$-full nuclear interactions from chiral effective field theory. The low-energy constants of the contact potentials are constrained by two-body scattering phase shifts, and by properties of bound-state of $A=2$ to $4$ nucleon systems and nuclear matter. The pion-nucleon couplings are taken from a Roy-Steiner analysis. The resulting interactions yield accurate binding energies and radii for a range of nuclei from $A=16$ to $A=132$, and provide accurate equations of state for nuclear matter and realistic symmetry energies. Selected excited states are also in agreement with data.
我们从手性有效场理论出发，优化了$Delta$-满核相互作用。接触势的低能常数受两体散射相移、A=2 ~ 4$核子系统和核物质束缚态性质的限制。介子-核子耦合取自罗伊-斯坦纳分析。由此产生的相互作用为$ a =16$到$ a =132$范围内的原子核提供了精确的结合能和半径，并提供了核物质和真实对称能的精确状态方程。所选择的激发态也与数据一致。
{"title":"Accurate bulk properties of nuclei from \u0000A=2\u0000 to \u0000∞\u0000 from potentials with \u0000Δ\u0000 isobars","authors":"W. G. Jiang, A. Ekström, C. Forss'en, G. Hagen, G. Jansen, T. Papenbrock","doi":"10.1103/physrevc.102.054301","DOIUrl":"https://doi.org/10.1103/physrevc.102.054301","url":null,"abstract":"We optimize $Delta$-full nuclear interactions from chiral effective field theory. The low-energy constants of the contact potentials are constrained by two-body scattering phase shifts, and by properties of bound-state of $A=2$ to $4$ nucleon systems and nuclear matter. The pion-nucleon couplings are taken from a Roy-Steiner analysis. The resulting interactions yield accurate binding energies and radii for a range of nuclei from $A=16$ to $A=132$, and provide accurate equations of state for nuclear matter and realistic symmetry energies. Selected excited states are also in agreement with data.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91332071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-30DOI: 10.1103/PhysRevD.104.034027
S. Singh, P. Ghosh, Jajati k. Nayak
We study the chemical freeze-out dynamics of strange particles ($K,, Lambda,, Sigma$) from a homogeneous and isotropically expanding hadronic system of $pi, K, rho, N, Lambda$ and $Sigma$ with zero net baryon density. We use the momentum integrated Boltzmann equation and study their evolution over the bulk hadronic matter, a condition being similar to the one created at top RHIC and LHC energies. The cross-sections, which are input to the equations, are taken either from phenomenological models or parameterized by comparing against experimental data. From this microscopic calculation we find that these strange particles freeze-out near transition temperature $approx T_c$ due to large relaxation time. The continuous cease of the inelastic processes due to gradual fall in the temperature and decrease in the number density, thus lead to early freeze out of strange hadrons $K, Lambda$ and $Sigma$ which happens sequentially near $T_c$. However, freeze-out of these strange species near Tc appears as a sudden and simultaneous process, which is mostly predicted by thermal model while explaining the yield of identified particles at RHIC and LHC energies.
我们研究了净重子密度为零的均匀和各向同性膨胀的$pi, K, rho, N, Lambda$和$Sigma$强子系统中奇异粒子($K,, Lambda,, Sigma$)的化学冻结动力学。我们使用动量积分玻尔兹曼方程并研究它们在整体强子物质上的演化，这种情况类似于在RHIC和LHC的最高能量下产生的情况。输入方程的横截面要么取自现象学模型，要么通过与实验数据比较而参数化。从微观计算中我们发现，由于弛豫时间大，这些奇怪的粒子在转变温度$approx T_c$附近被冻结。由于温度的逐渐下降和数量密度的降低，非弹性过程的持续停止，导致奇异强子$K, Lambda$和$Sigma$的早期冻结，并在$T_c$附近依次发生。然而，这些奇怪的物质在Tc附近的冻结是一个突然而同步的过程，这主要是用热模型来预测的，同时解释了在RHIC和LHC能量下确定的粒子的产率。
{"title":"Study of freeze-out dynamics of strange hadrons","authors":"S. Singh, P. Ghosh, Jajati k. Nayak","doi":"10.1103/PhysRevD.104.034027","DOIUrl":"https://doi.org/10.1103/PhysRevD.104.034027","url":null,"abstract":"We study the chemical freeze-out dynamics of strange particles ($K,, Lambda,, Sigma$) from a homogeneous and isotropically expanding hadronic system of $pi, K, rho, N, Lambda$ and $Sigma$ with zero net baryon density. We use the momentum integrated Boltzmann equation and study their evolution over the bulk hadronic matter, a condition being similar to the one created at top RHIC and LHC energies. The cross-sections, which are input to the equations, are taken either from phenomenological models or parameterized by comparing against experimental data. From this microscopic calculation we find that these strange particles freeze-out near transition temperature $approx T_c$ due to large relaxation time. The continuous cease of the inelastic processes due to gradual fall in the temperature and decrease in the number density, thus lead to early freeze out of strange hadrons $K, Lambda$ and $Sigma$ which happens sequentially near $T_c$. However, freeze-out of these strange species near Tc appears as a sudden and simultaneous process, which is mostly predicted by thermal model while explaining the yield of identified particles at RHIC and LHC energies.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77263829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-30DOI: 10.1103/physrevc.102.065801
Sofija Anti'c, J. Stone, J. Miller, K. Martinez, A. Thomas, P. Guichon
The outer crust properties of cold non-accreting neutron stars are studied within the framework of the quark-meson coupling (QMC) model, which includes the effects of modifications of the quark structure inside individual nucleons when they are within a high-density nuclear medium. With a unique set of five well-constrained adjustable parameters, which have a clear physical basis, the QMC model gives predictions for the ground state observables of even-even nuclei which agree with experiment as well as traditional models. Furthermore, it gives improved theoretical values for nuclei thought to play a role in the outer crusts of neutron stars but for which experimental data is not available. Using the latest experimental data tables wherever possible but otherwise the predictions from the QMC model, we construct an equation of state for the outer crust which is then used within stellar model calculations to obtain an equilibrium sequence of crustal layers, each characterized by a particular neutron rich nuclei. Various properties of the layers are calculated for a range of neutron-star masses, and comparisons are made with alternative equations of state from the literature. This leads to the conclusion that the QMC model successfully predicts the outer crust properties and is fully comparable with the more traditional mass models, which all depend on a larger number of parameters.
{"title":"Outer crust of a cold, nonaccreting neutron star within the quark-meson-coupling model","authors":"Sofija Anti'c, J. Stone, J. Miller, K. Martinez, A. Thomas, P. Guichon","doi":"10.1103/physrevc.102.065801","DOIUrl":"https://doi.org/10.1103/physrevc.102.065801","url":null,"abstract":"The outer crust properties of cold non-accreting neutron stars are studied within the framework of the quark-meson coupling (QMC) model, which includes the effects of modifications of the quark structure inside individual nucleons when they are within a high-density nuclear medium. With a unique set of five well-constrained adjustable parameters, which have a clear physical basis, the QMC model gives predictions for the ground state observables of even-even nuclei which agree with experiment as well as traditional models. Furthermore, it gives improved theoretical values for nuclei thought to play a role in the outer crusts of neutron stars but for which experimental data is not available. Using the latest experimental data tables wherever possible but otherwise the predictions from the QMC model, we construct an equation of state for the outer crust which is then used within stellar model calculations to obtain an equilibrium sequence of crustal layers, each characterized by a particular neutron rich nuclei. Various properties of the layers are calculated for a range of neutron-star masses, and comparisons are made with alternative equations of state from the literature. This leads to the conclusion that the QMC model successfully predicts the outer crust properties and is fully comparable with the more traditional mass models, which all depend on a larger number of parameters.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88456275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-26DOI: 10.1103/PHYSREVC.103.024304
D. Rodkin, Yu. M. Tchuvil'sky
A new convenient method for precise theoretical calculations of quantities of traditional theory of nuclear reactions such as widths of resonances (including sub-threshold), and asymptotic normalization coefficients is proposed. This method may be considered as a step on the road to full theoretical ab initio description of light nuclei spectroscopic data. As an illustration of this method the computational results for all relevant two-body channels for all known and some theoretically predicted states of 7Li nucleus are shown. Well-proven on a large amount of data Daejeon16 potential was used in the calculations. The most part of the results turn out to be in a good agreement with the experimental data contained in spectroscopic tables.
{"title":"Asymptotic characteristics of decay channels of states of light nuclei in the \u0000ab initio\u0000 approach","authors":"D. Rodkin, Yu. M. Tchuvil'sky","doi":"10.1103/PHYSREVC.103.024304","DOIUrl":"https://doi.org/10.1103/PHYSREVC.103.024304","url":null,"abstract":"A new convenient method for precise theoretical calculations of quantities of traditional theory of nuclear reactions such as widths of resonances (including sub-threshold), and asymptotic normalization coefficients is proposed. This method may be considered as a step on the road to full theoretical ab initio description of light nuclei spectroscopic data. As an illustration of this method the computational results for all relevant two-body channels for all known and some theoretically predicted states of 7Li nucleus are shown. Well-proven on a large amount of data Daejeon16 potential was used in the calculations. The most part of the results turn out to be in a good agreement with the experimental data contained in spectroscopic tables.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85143017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-26DOI: 10.1103/physrevc.102.054326
L. Coraggio, G. De Gregorio, A. Gargano, N. Itaco, T. Fukui, Y. Z. Ma, F. Xu
We report in this paper a study in terms of the nuclear shell model about the location of the calcium isotopes drip line. The starting point is considering the realistic two-body potential derived by Entem and Machleidt within chiral perturbation theory at next-to-next-to-next-to-leading order (N3LO), as well as a chiral three-body force at next-to-next-to-leading order (N2LO) whose structure and low-energy constants are consistent with the two-body potential. Then we construct the effective single-particle energies and residual interaction needed to diagonalize the shell-model Hamiltonian. The calculated two-neutron separation energies agree nicely with experiment until 56Ca, which is the heaviest isotope whose mass has been measured, and do not show any sign of two-neutron emission until 70Ca. We discuss the role of the choice of the model space in determining the neutron drip line, and also the dependence of the results on the parameters of the shell-model Hamiltonian.
{"title":"Shell-model study of calcium isotopes toward their drip line","authors":"L. Coraggio, G. De Gregorio, A. Gargano, N. Itaco, T. Fukui, Y. Z. Ma, F. Xu","doi":"10.1103/physrevc.102.054326","DOIUrl":"https://doi.org/10.1103/physrevc.102.054326","url":null,"abstract":"We report in this paper a study in terms of the nuclear shell model about the location of the calcium isotopes drip line. The starting point is considering the realistic two-body potential derived by Entem and Machleidt within chiral perturbation theory at next-to-next-to-next-to-leading order (N3LO), as well as a chiral three-body force at next-to-next-to-leading order (N2LO) whose structure and low-energy constants are consistent with the two-body potential. Then we construct the effective single-particle energies and residual interaction needed to diagonalize the shell-model Hamiltonian. The calculated two-neutron separation energies agree nicely with experiment until 56Ca, which is the heaviest isotope whose mass has been measured, and do not show any sign of two-neutron emission until 70Ca. We discuss the role of the choice of the model space in determining the neutron drip line, and also the dependence of the results on the parameters of the shell-model Hamiltonian.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75884392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-25DOI: 10.1103/physrevc.102.044904
Y. Ivanov
Global polarization of $Lambda$ and $bar{Lambda}$ is calculated based on the axial vortical effect (AVE). Simulations are performed within the model of the three-fluid dynamics. Equations of state with the deconfinement transition result in a good agreement with STAR data for both $Lambda$ and $bar{Lambda}$ polarization, in particular, with the $Lambda$-$bar{Lambda}$ splitting. Suppression of the gravitational-anomaly contribution required for the data reproduction is in agreement with predictions of the QCD lattice simulations. Predictions for the global polarization in forthcoming experiments at lower collision energies are made. These forthcoming data will provide a critical test for the AVE and thermodynamic mechanisms of the polarization.
{"title":"Global polarization in heavy-ion collisions based on the axial vortical effect","authors":"Y. Ivanov","doi":"10.1103/physrevc.102.044904","DOIUrl":"https://doi.org/10.1103/physrevc.102.044904","url":null,"abstract":"Global polarization of $Lambda$ and $bar{Lambda}$ is calculated based on the axial vortical effect (AVE). Simulations are performed within the model of the three-fluid dynamics. Equations of state with the deconfinement transition result in a good agreement with STAR data for both $Lambda$ and $bar{Lambda}$ polarization, in particular, with the $Lambda$-$bar{Lambda}$ splitting. Suppression of the gravitational-anomaly contribution required for the data reproduction is in agreement with predictions of the QCD lattice simulations. Predictions for the global polarization in forthcoming experiments at lower collision energies are made. These forthcoming data will provide a critical test for the AVE and thermodynamic mechanisms of the polarization.","PeriodicalId":8463,"journal":{"name":"arXiv: Nuclear Theory","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73136470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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