Pub Date : 2024-09-16DOI: 10.1103/physrevc.110.035202
Atharva Naik, Andrei Afanasev
The effect of the lepton's mass is significantly enhanced when the beam's energy is on the order of the lepton's mass. In the case of electrons, this corresponds to beam momenta on the order of a few and is negligible in higher energy experiments. In this paper, we calculate the differential cross section for the helicity-flip meson exchange interference in elastic muon-proton scattering . In particular, we examine the meson exchange in the channel for a longitudinally polarized beam and a transversely polarized target. We demonstrate the contribution to be larger for muons due to the lepton mass difference. Then we construct the corresponding beam-target double-spin asymmetries for the target polarized normal and parallel to the momentum transfer in the Breit frame, and then consider the model dependence of the calculation from the estimation of the vertex. The contribution was found to be on the order of for muons in the kinematic region of the Muon-Proton Scattering Experiment at the Paul-Scherrer Institute in Switzerland.
当光束的能量与轻子的质量相当时，轻子质量的影响就会明显增强。就电子而言，这相当于几 MeV/c 量级的束矩，在更高能量的实验中可以忽略不计。在本文中，我们计算了弹性μ介子-质子（μp）散射μ-p→μ-p中螺旋翻转介子交换干涉的差分截面dσ/dΩ。我们特别研究了纵向极化光束和横向极化目标在 t 频道中的π0 介子交换。我们证明，由于轻子质量的差异，μ介子的贡献更大。然后，我们在布赖特框架中为正向和平行于动量传递的极化目标构建了相应的束-目标双自旋不对称，然后从π0μμ顶点的估计中考虑了计算的模型依赖性。结果发现，在瑞士保罗-舍勒研究所的μ介子-质子散射实验的运动学区域中，μ介子的贡献率≈0.15%。
{"title":"Contribution of π0 exchange in elastic muon-proton scattering","authors":"Atharva Naik, Andrei Afanasev","doi":"10.1103/physrevc.110.035202","DOIUrl":"https://doi.org/10.1103/physrevc.110.035202","url":null,"abstract":"The effect of the lepton's mass is significantly enhanced when the beam's energy is on the order of the lepton's mass. In the case of electrons, this corresponds to beam momenta on the order of a few <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mtext>MeV</mtext><mo>/</mo><mtext>c</mtext></mrow></math> and is negligible in higher energy experiments. In this paper, we calculate the differential cross section <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>d</mi><mi>σ</mi><mo>/</mo><mi>d</mi><mi mathvariant=\"normal\">Ω</mi></mrow></math> for the helicity-flip meson exchange interference in elastic muon-proton <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>(</mo><mi>μ</mi><mi>p</mi><mo>)</mo></mrow></math> scattering <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mi>μ</mi><mo>−</mo></msup><mi>p</mi><mo>→</mo><msup><mi>μ</mi><mo>−</mo></msup><mi>p</mi></mrow></math>. In particular, we examine the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msup><mi>π</mi><mn>0</mn></msup></math> meson exchange in the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>t</mi></math> channel for a longitudinally polarized beam and a transversely polarized target. We demonstrate the contribution to be larger for muons due to the lepton mass difference. Then we construct the corresponding beam-target double-spin asymmetries for the target polarized normal and parallel to the momentum transfer in the Breit frame, and then consider the model dependence of the calculation from the estimation of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mi>π</mi><mn>0</mn></msup><mi>μ</mi><mi>μ</mi></mrow></math> vertex. The contribution was found to be on the order of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mo>≈</mo><mn>0.15</mn><mo>%</mo></mrow></math> for muons in the kinematic region of the Muon-Proton Scattering Experiment at the Paul-Scherrer Institute in Switzerland.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"16 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1103/physrevc.110.035203
Margaret E. Carrington, Gabor Kunstatter, Arghya Mukherjee
We study the real part of the static potential of a heavy quark-antiquark system in an anisotropic plasma medium. We use a quasiparticle approach where the collective dynamics of the plasma constituents is described using hard-loop perturbation theory. The parton distribution function is characterized by a set of parameters that can accurately describe the anisotropy of the plasma produced in a heavy ion collision. We calculate the potential numerically in strongly anisotropic systems and study the angular dependence of the distortion of the potential relative to the isotropic one. We obtain an analytic expression for the real part of the heavy quark potential in the limit of weak anisotropy using a model that expresses the potential in terms of effective screening masses that depend on the anisotropy parameters and the orientation of the quark-antiquark pair. A one-dimensional potential is formulated in terms of angle averaged screening masses that incorporate the anisotropy of the medium into a radial coordinate. We solve the corresponding Schrödinger equation and show that the magnitude of the binding energy typically increases with anisotropy. Anisotropy can play an important role, especially in states with nonzero angular momentum. This means that the number of bound states that are formed could depend on specific characteristics of the anisotropy of the plasma. Our study suggests that plasma anisotropy plays an important role in the dynamics of heavy quarkonium and motivates further study.
{"title":"Effect of anisotropy on the formation of heavy quarkonium bound states","authors":"Margaret E. Carrington, Gabor Kunstatter, Arghya Mukherjee","doi":"10.1103/physrevc.110.035203","DOIUrl":"https://doi.org/10.1103/physrevc.110.035203","url":null,"abstract":"We study the real part of the static potential of a heavy quark-antiquark system in an anisotropic plasma medium. We use a quasiparticle approach where the collective dynamics of the plasma constituents is described using hard-loop perturbation theory. The parton distribution function is characterized by a set of parameters that can accurately describe the anisotropy of the plasma produced in a heavy ion collision. We calculate the potential numerically in strongly anisotropic systems and study the angular dependence of the distortion of the potential relative to the isotropic one. We obtain an analytic expression for the real part of the heavy quark potential in the limit of weak anisotropy using a model that expresses the potential in terms of effective screening masses that depend on the anisotropy parameters and the orientation of the quark-antiquark pair. A one-dimensional potential is formulated in terms of angle averaged screening masses that incorporate the anisotropy of the medium into a radial coordinate. We solve the corresponding Schrödinger equation and show that the magnitude of the binding energy typically increases with anisotropy. Anisotropy can play an important role, especially in states with nonzero angular momentum. This means that the number of bound states that are formed could depend on specific characteristics of the anisotropy of the plasma. Our study suggests that plasma anisotropy plays an important role in the dynamics of heavy quarkonium and motivates further study.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"15 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1103/physrevc.110.l031601
Rui Wang, Stefano Burrello, Maria Colonna, Francesco Matera
We investigate the dynamics of dilute systems composed of nucleons and light clusters within a linear response approach, taking into account the in-medium Mott effects on cluster appearance, through a density-dependent momentum cut-off. We find that spinodal instabilities and associated growth rates are severely affected by the presence of light clusters and, in particular, by the treatment of in-medium effects, foreshadowing intriguing consequences for fragment formation in heavy-ion collisions and in the broader astrophysical context.
{"title":"Dynamics of dilute nuclear matter with light clusters and in-medium effects","authors":"Rui Wang, Stefano Burrello, Maria Colonna, Francesco Matera","doi":"10.1103/physrevc.110.l031601","DOIUrl":"https://doi.org/10.1103/physrevc.110.l031601","url":null,"abstract":"We investigate the dynamics of dilute systems composed of nucleons and light clusters within a linear response approach, taking into account the in-medium Mott effects on cluster appearance, through a density-dependent momentum cut-off. We find that spinodal instabilities and associated growth rates are severely affected by the presence of light clusters and, in particular, by the treatment of in-medium effects, foreshadowing intriguing consequences for fragment formation in heavy-ion collisions and in the broader astrophysical context.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"16 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1103/physrevc.110.035808
W. P. Tan, A. Gula, K. Lee, A. Majumdar, S. Moylan, O. Olivas-Gomez, Shahina, M. Wiescher, E. F. Aguilera, D. Lizcano, E. Martinez-Quiroz, J. C. Morales-Rivera
The fusion reaction is critical for the understanding and interpretation of the late phases of stellar evolution as well as the ignition and nucleosynthesis in cataclysmic binary systems such as type Ia thermonuclear supernovas and x-ray superbursts. Direct measurement of this reaction has been performed at the University of Notre Dame using particle- coincidence and differential thick-target techniques with SAND (a silicon detector array) at the high-intensity 5U Pelletron accelerator. Partial cross section results for the channels of to and at center-of-mass energies of 2.65–5 MeV that are relevant to nuclear astrophysics are reported. The total factor is constructed by taking into account contributions from the missing channels. The recommended reaction rate and its impact on the carbon burning process under astrophysical scenarios will be discussed.
{"title":"Coincident measurement of the C12+C12 fusion cross section via the differential thick-target technique","authors":"W. P. Tan, A. Gula, K. Lee, A. Majumdar, S. Moylan, O. Olivas-Gomez, Shahina, M. Wiescher, E. F. Aguilera, D. Lizcano, E. Martinez-Quiroz, J. C. Morales-Rivera","doi":"10.1103/physrevc.110.035808","DOIUrl":"https://doi.org/10.1103/physrevc.110.035808","url":null,"abstract":"The <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mmultiscripts><mi mathvariant=\"normal\">C</mi><mprescripts></mprescripts><none></none><mn>12</mn></mmultiscripts><mo>+</mo><mmultiscripts><mi mathvariant=\"normal\">C</mi><mprescripts></mprescripts><none></none><mn>12</mn></mmultiscripts></mrow></math> fusion reaction is critical for the understanding and interpretation of the late phases of stellar evolution as well as the ignition and nucleosynthesis in cataclysmic binary systems such as type Ia thermonuclear supernovas and x-ray superbursts. Direct measurement of this reaction has been performed at the University of Notre Dame using particle-<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>γ</mi></math> coincidence and differential thick-target techniques with SAND (a silicon detector array) at the high-intensity 5U Pelletron accelerator. Partial cross section results for the channels of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>p</mi><mn>1</mn></msub></math> to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>p</mi><mn>10</mn></msub></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>α</mi><mn>1</mn></msub></math> at center-of-mass energies of 2.65–5 MeV that are relevant to nuclear astrophysics are reported. The total <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msup><mi>S</mi><mo>*</mo></msup><mrow><mo>(</mo><mi>E</mi><mo>)</mo></mrow></mrow></math> factor is constructed by taking into account contributions from the missing channels. The recommended reaction rate and its impact on the carbon burning process under astrophysical scenarios will be discussed.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"44 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.1103/physrevc.110.034613
Pavneet Kaur, Moumita Maiti, Rishabh Kumar, Ankur Singh, Himanshu Sharma, Yasir Arafat, N. Saneesh, A. Parihari, M. Kumar, K. S. Golda, A. Jhingan, P. Sugathan
Background: Asymmetric mass splits observed in the extremely neutron-deficient () lead-island isotopes brought much interest for the scientific community to explore this region. Although several experiments have been performed adopting -delayed fission and heavy-ion induced reactions, the role of shell effects associated with asymmetric fission is still not fully understood.
{"title":"Investigation of the mass distribution of the Si28+Gd158 system: Role of shell effects","authors":"Pavneet Kaur, Moumita Maiti, Rishabh Kumar, Ankur Singh, Himanshu Sharma, Yasir Arafat, N. Saneesh, A. Parihari, M. Kumar, K. S. Golda, A. Jhingan, P. Sugathan","doi":"10.1103/physrevc.110.034613","DOIUrl":"https://doi.org/10.1103/physrevc.110.034613","url":null,"abstract":"<b>Background:</b> Asymmetric mass splits observed in the extremely neutron-deficient (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>1.15</mn><mo>≤</mo><mi>N</mi><mo>/</mo><mi>Z</mi><mo>≤</mo><mn>1.55</mn></mrow></math>) lead-island isotopes brought much interest for the scientific community to explore this region. Although several experiments have been performed adopting <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>β</mi></math>-delayed fission and heavy-ion induced reactions, the role of shell effects associated with asymmetric fission is still not fully understood.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"37 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-13DOI: 10.1103/physrevc.110.034315
Z. Yueet al.(IDS Collaboration)
The changes in the mean-squared charge radius of () and () relative to have been measured for the first time using the in-source laser resonance-ionization spectroscopy technique with the Laser Ion Source and Trap (LIST) at ISOLDE (CERN). The application of the LIST suppresses the dominant background from isobaric francium isotopes and allows access to thallium nuclides with . The characteristic kink in the charge radii at the neutron shell closure, as well as the odd-even effect similar to that in the adjacent bismuth, lead, and mercury isotopic chains, have been observed. The self-consistent theory of finite Fermi systems based on the energy density functional by Fayans et al. reproduces the behavior of charge radii in these isotopic chains near . The comparison with calculations in the framework of the relativistic mean field (RMF) approach is also presented. In the case of the Fayans functional it is a specific form of pairing interaction with the dependence on the density gradient that is essential to provide agreement with the experimental charge radii. In particular, the kink is reproduced without the inversion of and neutron single-particle states, which is a prerequisite to correctly describe the kink in the RMF models.
{"title":"Charge radii of thallium isotopes near the N=126 shell closure","authors":"Z. Yueet al.(IDS Collaboration)","doi":"10.1103/physrevc.110.034315","DOIUrl":"https://doi.org/10.1103/physrevc.110.034315","url":null,"abstract":"The changes in the mean-squared charge radius of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Tl</mi><none></none><mi>g</mi><mprescripts></mprescripts><none></none><mn>209</mn></mmultiscripts></math> (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>128</mn></mrow></math>) and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Tl</mi><none></none><mi>m</mi><mprescripts></mprescripts><none></none><mn>207</mn></mmultiscripts></math> (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>126</mn></mrow></math>) relative to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Tl</mi><mprescripts></mprescripts><none></none><mn>205</mn></mmultiscripts></math> have been measured for the first time using the in-source laser resonance-ionization spectroscopy technique with the Laser Ion Source and Trap (LIST) at ISOLDE (CERN). The application of the LIST suppresses the dominant background from isobaric francium isotopes and allows access to thallium nuclides with <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>A</mi><mo>⩾</mo><mn>207</mn></mrow></math>. The characteristic kink in the charge radii at the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>126</mn></mrow></math> neutron shell closure, as well as the odd-even effect similar to that in the adjacent bismuth, lead, and mercury isotopic chains, have been observed. The self-consistent theory of finite Fermi systems based on the energy density functional by Fayans <i>et al.</i> reproduces the behavior of charge radii in these isotopic chains near <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>126</mn></mrow></math>. The comparison with calculations in the framework of the relativistic mean field (RMF) approach is also presented. In the case of the Fayans functional it is a specific form of pairing interaction with the dependence on the density gradient that is essential to provide agreement with the experimental charge radii. In particular, the kink is reproduced without the inversion of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>g</mi><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow></msub></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>i</mi><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub></math> neutron single-particle states, which is a prerequisite to correctly describe the kink in the RMF models.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"46 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-13DOI: 10.1103/physrevc.110.034906
Taesoo Song, Ilia Grishmanovskii, Olga Soloveva, Elena Bratkovskaya
We investigate the thermal production of charm quarks in the strongly interacting quark-gluon plasma (sQGP) created in heavy-ion collisions at relativistic energies. Our study is based on the off-shell parton-hadron-string dynamics (PHSD) transport approach describing the full time evolution of heavy-ion collisions on a microscopic basis with hadronic and partonic degrees of freedom. The sQGP is realized within the effective dynamical quasiparticle model (DQPM) which is adjusted to reproduce the lattice quantum chromodynamics (lQCD) results for the thermodynamic observables of the sQGP. Relying on the fact that the DQPM successfully describes the spatial diffusion coefficients from the lQCD, which control the interaction of charm quarks with thermal partons (expressed in terms of strongly interacting off-shell quasiparticles), we evaluate the production of charm quark pairs through the rotation of Feynman diagrams such that the incoming charm quark and outgoing light parton in elastic scattering diagrams are exchanged. The charm quark annihilation is realized by detailed balance. We find that the number of produced thermal charm quark pairs strongly depends on the charm quark mass in the QGP. While for the heavy charm quarks of mass it is subdominant compared to the primary charm production by binary nucleon-nucleon collisions at BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC) energies, the numbers of primary and thermal charm quarks become comparable for a smaller (bare) . Compared with the experimental data on the of mesons in heavy-ion collisions at RHIC and LHC energies, it is more favorable for charm quarks in the QGP to gain additional mass due to thermal effects rather than to have a low bare mass.
{"title":"Thermal production of charm quarks in relativistic heavy-ion collisions","authors":"Taesoo Song, Ilia Grishmanovskii, Olga Soloveva, Elena Bratkovskaya","doi":"10.1103/physrevc.110.034906","DOIUrl":"https://doi.org/10.1103/physrevc.110.034906","url":null,"abstract":"We investigate the thermal production of charm quarks in the strongly interacting quark-gluon plasma (sQGP) created in heavy-ion collisions at relativistic energies. Our study is based on the off-shell parton-hadron-string dynamics (PHSD) transport approach describing the full time evolution of heavy-ion collisions on a microscopic basis with hadronic and partonic degrees of freedom. The sQGP is realized within the effective dynamical quasiparticle model (DQPM) which is adjusted to reproduce the lattice quantum chromodynamics (lQCD) results for the thermodynamic observables of the sQGP. Relying on the fact that the DQPM successfully describes the spatial diffusion coefficients <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>D</mi><mi>s</mi></msub></math> from the lQCD, which control the interaction of charm quarks with thermal partons (expressed in terms of strongly interacting off-shell quasiparticles), we evaluate the production of charm quark pairs through the rotation of Feynman diagrams such that the incoming charm quark and outgoing light parton in elastic scattering diagrams are exchanged. The charm quark annihilation is realized by detailed balance. We find that the number of produced thermal charm quark pairs strongly depends on the charm quark mass in the QGP. While for the heavy charm quarks of mass <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>m</mi><mi>c</mi></msub><mo>=</mo><mn>1.8</mn><mspace width=\"0.16em\"></mspace><mi>GeV</mi></mrow></math> it is subdominant compared to the primary charm production by binary nucleon-nucleon collisions at BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC) energies, the numbers of primary and thermal charm quarks become comparable for a smaller (bare) <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>m</mi><mi>c</mi></msub><mo>=</mo><mn>1.2</mn><mspace width=\"0.16em\"></mspace><mi>GeV</mi></mrow></math>. Compared with the experimental data on the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>R</mi><mi>AA</mi></msub></math> of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>D</mi></math> mesons in heavy-ion collisions at RHIC and LHC energies, it is more favorable for charm quarks in the QGP to gain additional mass due to thermal effects rather than to have a low bare mass.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"43 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-13DOI: 10.1103/physrevc.110.l031901
Roy A. Lacey
Anisotropy scaling functions derived from comprehensive measurements of transverse momentum- and centrality-dependent anisotropy coefficients and in collisions at 5.02 and 2.76 TeV, collisions at 5.44 TeV, and collisions at 0.2 TeV offer new insights into the ultracentral flow puzzle. These functions integrate diverse measurements into a single curve, clarifying anisotropy attenuation throughout the entire and centrality range. They reveal the influence of initial-state eccentricities (), dimensionless size (), radial flow, viscous correction to the thermal distribution function (), the medium's stopping power (), and specific shear viscosity () on the observed anisotropies. This analysis not only enhances understanding of transport coefficients but also provides crucial constraints on nuclear deformation.
在 5.02 和 2.76 TeV 的 Pb+Pb 对撞、5.44 TeV 的 Xe+Xe 对撞和 0.2 TeV 的 Au+Au 对撞中，通过对横动量和中心度相关的各向异性系数 v2(pT,cent) 和 v3(pT,cent) 的全面测量，得出了各向异性缩放函数，为超中心流之谜提供了新的见解。这些函数将不同的测量结果整合成一条曲线，澄清了整个 pT 和中心度范围内的各向异性衰减。它们揭示了初始状态偏心率（ɛn）、无量纲大小（R）、径向流动、热分布函数的粘性修正（δf）、介质的停止力（q̂）和特定剪切粘度（η/s）对观测到的各向异性的影响。这一分析不仅加深了对传输系数的理解，还为核变形提供了重要的约束条件。
{"title":"Anisotropy scaling functions in heavy-ion collisions: Insights into the ultracentral flow puzzle and constraints on transport coefficients and nuclear deformation","authors":"Roy A. Lacey","doi":"10.1103/physrevc.110.l031901","DOIUrl":"https://doi.org/10.1103/physrevc.110.l031901","url":null,"abstract":"Anisotropy scaling functions derived from comprehensive measurements of transverse momentum- and centrality-dependent anisotropy coefficients <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>v</mi><mn>2</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>T</mi></msub><mo>,</mo><mtext>cent</mtext><mo>)</mo></mrow></mrow></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><msub><mi>v</mi><mn>3</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>T</mi></msub><mo>,</mo><mtext>cent</mtext><mo>)</mo></mrow></mrow></math> in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Pb</mi><mo>+</mo><mi>Pb</mi></mrow></math> collisions at 5.02 and 2.76 TeV, <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Xe</mi><mo>+</mo><mi>Xe</mi></mrow></math> collisions at 5.44 TeV, and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>Au</mi><mo>+</mo><mi>Au</mi></mrow></math> collisions at 0.2 TeV offer new insights into the ultracentral flow puzzle. These functions integrate diverse measurements into a single curve, clarifying anisotropy attenuation throughout the entire <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>p</mi><mi>T</mi></msub></math> and centrality range. They reveal the influence of initial-state eccentricities (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>ɛ</mi><mi>n</mi></msub></math>), dimensionless size (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi mathvariant=\"double-struck\">R</mi></math>), radial flow, viscous correction to the thermal distribution function (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msub><mi>δ</mi><mi>f</mi></msub></math>), the medium's stopping power (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mover accent=\"true\"><mi>q</mi><mo>̂</mo></mover></math>), and specific shear viscosity (<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>η</mi><mo>/</mo><mi>s</mi></mrow></math>) on the observed anisotropies. This analysis not only enhances understanding of transport coefficients but also provides crucial constraints on nuclear deformation.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"62 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-13DOI: 10.1103/physrevc.110.034316
N. Chen, J. G. Li, H. H. Li
A shell model effective interaction for nuclei beyond the double magic nucleus is constructed. First, the single-particle evolutions for valence neutrons above the double magic are systematically explored in the isotones using the large scale shell model (LSSM) calculations based on the constructed effective interaction. Subsequently, we calculate the excitation energies of states and reduced electric quadrupole transition probabilities for isotones. Notably, our calculation gives the result most consistent with the trend of the values observed in the isotones, especially for , a result that poses a serious challenge to the theoretical model. Furthermore, the collectivity in isotones, as well as the roles of pseudo-SU(3) symmetry, are investigated via the calculated primary configurations of their ground states and the first excited states. Additionally, the low-lying structures and band characteristics of neutron-rich Ge and Se isotopes are investigated. The ground state and the -soft band are constructed in our LSSM calculations, aligning well with available experimental evidence. Finally, we present the calculated evolutions of low-lying states in neutron-rich Ge and Se isotopes. The predictions for the as-yet unobserved low-lying states in these nuclei provide a comprehensive dataset to guide and inform future experimental efforts to decipher the evolution of shell structures and collectivity.
构建了双魔核 Ni78 以外原子核的壳模型有效相互作用。首先，根据构建的有效相互作用，利用大尺度壳模型（LSSM）计算，系统地探索了双魔核 Ni78 以上价中子在 N=51 等位体中的单粒子演化。随后，我们计算了 N=52 同位素的 21+ 态激发能量和还原电四极转换概率 B(E2;2+→0+)。值得注意的是，我们的计算结果与在 N=52 同位素中观察到的 B(E2)值趋势最为一致，尤其是 Ge84，这一结果对理论模型提出了严峻的挑战。此外，通过计算其基态和第一激发态的主构型，研究了 N=52 同位素的集合性以及伪 SU(3) 对称性的作用。此外，还研究了富中子 Ge 和 Se 同位素的低洼结构和能带特性。我们的 LSSM 计算构建了基态和 γ 软带，与现有的实验证据非常吻合。最后，我们介绍了富中子 Ge 和 Se 同位素低洼态的计算演化。对这些原子核中尚未观测到的低洼态的预测提供了一个全面的数据集，为今后的实验工作提供指导和信息，以破译壳结构和集合性的演化。
{"title":"Large scale shell model calculation for collectivity in nuclei beyond Ni78","authors":"N. Chen, J. G. Li, H. H. Li","doi":"10.1103/physrevc.110.034316","DOIUrl":"https://doi.org/10.1103/physrevc.110.034316","url":null,"abstract":"A shell model effective interaction for nuclei beyond the double magic nucleus <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Ni</mi><mprescripts></mprescripts><none></none><mn>78</mn></mmultiscripts></math> is constructed. First, the single-particle evolutions for valence neutrons above the double magic <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Ni</mi><mprescripts></mprescripts><none></none><mn>78</mn></mmultiscripts></math> are systematically explored in the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>51</mn></mrow></math> isotones using the large scale shell model (LSSM) calculations based on the constructed effective interaction. Subsequently, we calculate the excitation energies of <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup></math> states and reduced electric quadrupole transition probabilities <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>B</mi><mo>(</mo><mi>E</mi><mn>2</mn><mo>;</mo><msup><mn>2</mn><mo>+</mo></msup><mo>→</mo><msup><mn>0</mn><mo>+</mo></msup><mo>)</mo></mrow></math> for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>52</mn></mrow></math> isotones. Notably, our calculation gives the result most consistent with the trend of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>B</mi><mo>(</mo><mi>E</mi><mn>2</mn><mo>)</mo></mrow></math> values observed in the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>52</mn></mrow></math> isotones, especially for <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Ge</mi><mprescripts></mprescripts><none></none><mn>84</mn></mmultiscripts></math>, a result that poses a serious challenge to the theoretical model. Furthermore, the collectivity in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>52</mn></mrow></math> isotones, as well as the roles of pseudo-SU(3) symmetry, are investigated via the calculated primary configurations of their ground states and the first excited states. Additionally, the low-lying structures and band characteristics of neutron-rich Ge and Se isotopes are investigated. The ground state and the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mi>γ</mi></math>-soft band are constructed in our LSSM calculations, aligning well with available experimental evidence. Finally, we present the calculated evolutions of low-lying states in neutron-rich Ge and Se isotopes. The predictions for the as-yet unobserved low-lying states in these nuclei provide a comprehensive dataset to guide and inform future experimental efforts to decipher the evolution of shell structures and collectivity.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"19 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-13DOI: 10.1103/physrevc.110.034314
M. S. Martinet al.
High-precision lifetime measurements in were performed to study neutron shell evolution in Mg isotopes and the onset of the island of inversion. Using both the recoil distance and Doppler shift attenuation methods, five lifetimes were measured in addition to six upper limits. The observation of two long-lived, negative-parity states demonstrate the importance of studying Mg isotopes for the contribution of intruder configurations to -shell nuclei. Lifetimes of the and states of 1.81(5) ps and , respectively, demonstrate a loss of collectivity with increasing spin in the yrast band, permitting for distinguishing between current theoretical models. These measurements also highlight the progression of yrast structure across the Mg isotopic chain from rotational at to large shape mixing at and back to collective behavior at but with dominating intruder configurations.
{"title":"B(E2) measurements in the yrast band of Mg28: Implications for the N=20 island of inversion","authors":"M. S. Martinet al.","doi":"10.1103/physrevc.110.034314","DOIUrl":"https://doi.org/10.1103/physrevc.110.034314","url":null,"abstract":"High-precision lifetime measurements in <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mmultiscripts><mi>Mg</mi><mprescripts></mprescripts><none></none><mn>28</mn></mmultiscripts></math> were performed to study neutron shell evolution in Mg isotopes and the onset of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>20</mn></mrow></math> island of inversion. Using both the recoil distance and Doppler shift attenuation methods, five lifetimes were measured in addition to six upper limits. The observation of two long-lived, negative-parity states demonstrate the importance of studying Mg isotopes for the contribution of intruder configurations to <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>s</mi><mi>d</mi></mrow></math>-shell nuclei. Lifetimes of the <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msubsup><mn>2</mn><mn>1</mn><mo>+</mo></msubsup></math> and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><msubsup><mn>4</mn><mn>1</mn><mo>+</mo></msubsup></math> states of 1.81(5) ps and <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mn>172</mn><msub><mrow><msubsup><mo>(</mo><mrow><mo>−</mo><mn>10</mn></mrow><mrow><mo>+</mo><mn>11</mn></mrow></msubsup><mo>)</mo></mrow><mrow><mi>stat</mi><mo>.</mo></mrow></msub><msub><mrow><mo>(</mo><mn>4</mn><mo>)</mo></mrow><mrow><mi>stop</mi><mo>.</mo></mrow></msub><msub><mrow><mo>(</mo><mn>8</mn><mo>)</mo></mrow><mrow><mi>feed</mi><mo>.</mo></mrow></msub><msub><mrow><mo>(</mo><mn>4</mn><mo>)</mo></mrow><mrow><mi>targ</mi><mo>.</mo></mrow></msub><mspace width=\"0.16em\"></mspace><mi>fs</mi></mrow></math>, respectively, demonstrate a loss of collectivity with increasing spin in the yrast band, permitting for distinguishing between current theoretical models. These measurements also highlight the progression of yrast structure across the Mg isotopic chain from rotational at <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>12</mn></mrow></math> to large shape mixing at <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>16</mn></mrow></math> and back to collective behavior at <math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow><mi>N</mi><mo>=</mo><mn>20</mn></mrow></math> but with dominating intruder configurations.","PeriodicalId":20122,"journal":{"name":"Physical Review C","volume":"202 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142255833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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