Pub Date : 2023-12-18DOI: 10.1088/1674-1137/ad1677
Mirzabek Alloqulov, Farruh Atamurotov, A. Abdujabbarov, B. Ahmedov, Vokhid Khamidov
In this work we have investigated the gravitational weak lensing and shadow of the Ellis-Bronnikov wormhole. First, we have studied the photon motion in plasma medium and wormhole shadow. It has been shown that the radius of the photon sphere of the Ellis-Bronnikov wormhole and the size of the wormhole shadow becomes larger under the influence of the parameter $a$. The upper limit of the parameter $a$ in the Ellis-Bronnikov wormhole spacetime has been obtained. Second, we have investigated the weak gravitational lensing for the Ellis-Bronnikov wormhole and have calculated the deflection angle for uniform and non uniform plasma cases. It has been shown that the value of the deflection angle for uniform plasma increased with the increase of the plasma parameter and for non uniform plasma vice versa. It has been also indicated that under influence of the parameter $a$ the values of the deflection angles for two cases are decreased. Finally, we have investigated the magnification of image brightness using the deflection angle of the light rays around the wormhole in Ellis-Bronnikov theory.
{"title":"Shadow and weak gravitational lensing for Ellis-Bronnikov wormhole","authors":"Mirzabek Alloqulov, Farruh Atamurotov, A. Abdujabbarov, B. Ahmedov, Vokhid Khamidov","doi":"10.1088/1674-1137/ad1677","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1677","url":null,"abstract":"In this work we have investigated the gravitational weak lensing and shadow of the Ellis-Bronnikov wormhole. First, we have studied the photon motion in plasma medium and wormhole shadow. It has been shown that the radius of the photon sphere of the Ellis-Bronnikov wormhole and the size of the wormhole shadow becomes larger under the influence of the parameter $a$. The upper limit of the parameter $a$ in the Ellis-Bronnikov wormhole spacetime has been obtained. Second, we have investigated the weak gravitational lensing for the Ellis-Bronnikov wormhole and have calculated the deflection angle for uniform and non uniform plasma cases. It has been shown that the value of the deflection angle for uniform plasma increased with the increase of the plasma parameter and for non uniform plasma vice versa. It has been also indicated that under influence of the parameter $a$ the values of the deflection angles for two cases are decreased. Finally, we have investigated the magnification of image brightness using the deflection angle of the light rays around the wormhole in Ellis-Bronnikov theory.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173374","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 : 2023-11-28DOI: 10.1088/1674-1137/ad102a
Soumya Saha
We have studied a comprehensive work on the neutron capture cross section for $^{12}mathrm C$ within the relevant astrophysical energy range. Through rigorous R-matrix analysis, we have determined the Maxwellian-averaged cross section to be 11.98$pm$0.25 $mu$b at kT=30 keV. This result is about 4 times higher than the thermal neutron capture cross section estimated in the earlier works assuming a $dfrac{1}{v}$ law. The implications of our findings extend to the region of inhomogeneous big-bang models in nuclear astrophysics, where understanding the behaviour of neutron capture cross sections plays a crucial role in elucidating the intricate processes that shaped the early universe.
{"title":"Cosmic Implications of $ ^{12}mathrm C(n,gamma)^{13}mathrm C$ Reaction: A Nuclear Astrophysical Perspective","authors":"Soumya Saha","doi":"10.1088/1674-1137/ad102a","DOIUrl":"https://doi.org/10.1088/1674-1137/ad102a","url":null,"abstract":"We have studied a comprehensive work on the neutron capture cross section for $^{12}mathrm C$ within the relevant astrophysical energy range. Through rigorous R-matrix analysis, we have determined the Maxwellian-averaged cross section to be 11.98$pm$0.25 $mu$b at kT=30 keV. This result is about 4 times higher than the thermal neutron capture cross section estimated in the earlier works assuming a $dfrac{1}{v}$ law. The implications of our findings extend to the region of inhomogeneous big-bang models in nuclear astrophysics, where understanding the behaviour of neutron capture cross sections plays a crucial role in elucidating the intricate processes that shaped the early universe.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139216287","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 : 2023-11-28DOI: 10.1088/1674-1137/ad1029
A. Morzabayev, Nurlan Amangeldi, awad A. ibraheem, D. Soldatkhan, Gani Yergaliuly, Bakytbek Mauyey, Anuar Aida Orazalievna, Sherief Hamada
The 7Li + 144Sm elastic scattering angular distributions over the energy range of 21.6–52 MeV are reanalyzed utilizing various interaction potentials. The analysis seeks to probe the consistency of the implemented potentials in representing the considered data and investigate the cluster nature of the weakly bound 7Li projectile to better understand the impacts of 7Li breakup on the elastic scattering channel. Strong coupling to the breakup channel has a substantial impact on elastic data and reproduces a repulsive dynamical polarization potential, which drastically diminishes the real potential strength. This reported impact was simulated by introducing a semi-microscopic repulsive DPP and by implementing the method of continuum discretized coupled channels.
{"title":"Dynamics of 7Li Breakup and its Influence on Elastic Scattering: A Study of 7Li + 144Sm System","authors":"A. Morzabayev, Nurlan Amangeldi, awad A. ibraheem, D. Soldatkhan, Gani Yergaliuly, Bakytbek Mauyey, Anuar Aida Orazalievna, Sherief Hamada","doi":"10.1088/1674-1137/ad1029","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1029","url":null,"abstract":"The 7Li + 144Sm elastic scattering angular distributions over the energy range of 21.6–52 MeV are reanalyzed utilizing various interaction potentials. The analysis seeks to probe the consistency of the implemented potentials in representing the considered data and investigate the cluster nature of the weakly bound 7Li projectile to better understand the impacts of 7Li breakup on the elastic scattering channel. Strong coupling to the breakup channel has a substantial impact on elastic data and reproduces a repulsive dynamical polarization potential, which drastically diminishes the real potential strength. This reported impact was simulated by introducing a semi-microscopic repulsive DPP and by implementing the method of continuum discretized coupled channels.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139223711","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 : 2023-11-28DOI: 10.1088/1674-1137/ad102c
C. Tran, Mikhail A. Ivanov, Pietro Santorelli, Quang-Chau Vo
Radiative decays $D^*_{(s)}to D_{(s)}gamma$ are revisited in light of new experimental data from textit{BABAR} and BESIII collaborations. The radiative couplings $g_{D^*Dgamma}$ encoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us. We compare our results with other theoretical studies and experimental data. The couplings (in $textrm{GeV}^{-1}$) $|g_{D^{*+}D^+gamma}| = 0.45(9)$ and $|g_{D^{*0}D^0gamma}| = 1.72(34)$ calculated in our model agree with the experimental data $|g_{D^{*+}D^+gamma}|=0.47(7)$ and $|g_{D^{*0}D^0gamma}|=1.77(16)$. The most interesting case is the decay $D^*_sto D_sgamma$, for which the recent prediction based on light-cone sum rules at next-to-leading order $|g_{D^*_s D_sgamma}|=0.60(19)$ deviates from the first (and so far the only) lattice QCD result $|g_{D^*_s D_sgamma}|=0.11(2)$ at nearly $3sigma$. Our calculation yields $|g_{D^*_s D_sgamma}|=0.29(6)$, which falls somehow between the two mentioned results, but is larger than those predicted in other studies using quark models or QCD sum rules. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
{"title":"Radiative decays bm{$D^*_{(s)}to D_{(s)}gamma$} in covariant confined quark model","authors":"C. Tran, Mikhail A. Ivanov, Pietro Santorelli, Quang-Chau Vo","doi":"10.1088/1674-1137/ad102c","DOIUrl":"https://doi.org/10.1088/1674-1137/ad102c","url":null,"abstract":"Radiative decays $D^*_{(s)}to D_{(s)}gamma$ are revisited in light of new experimental data from textit{BABAR} and BESIII collaborations. The radiative couplings $g_{D^*Dgamma}$ encoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us. We compare our results with other theoretical studies and experimental data. The couplings (in $textrm{GeV}^{-1}$) $|g_{D^{*+}D^+gamma}| = 0.45(9)$ and $|g_{D^{*0}D^0gamma}| = 1.72(34)$ calculated in our model agree with the experimental data $|g_{D^{*+}D^+gamma}|=0.47(7)$ and $|g_{D^{*0}D^0gamma}|=1.77(16)$. The most interesting case is the decay $D^*_sto D_sgamma$, for which the recent prediction based on light-cone sum rules at next-to-leading order $|g_{D^*_s D_sgamma}|=0.60(19)$ deviates from the first (and so far the only) lattice QCD result $|g_{D^*_s D_sgamma}|=0.11(2)$ at nearly $3sigma$. Our calculation yields $|g_{D^*_s D_sgamma}|=0.29(6)$, which falls somehow between the two mentioned results, but is larger than those predicted in other studies using quark models or QCD sum rules. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139218916","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 : 2023-11-22DOI: 10.1088/1674-1137/ad0f13
Ai-Chao Wang, N. Wei, Fei Huang
The photoproduction of f1(1285) meson off proton is investigated within an effective Lagrangian approach. The t-channel ρ- and ω-exchange diagrams, u-channel nucleon-exchange diagram, generalized contact term, and s-channel pole diagrams of nucleon and a minimal number of nucleon resonances are taken into account in constructing the reaction amplitudes to describe the experimental data. Three different models, i.e., the Feynman model, the Regge model, and the interpolated Regge model, are employed where the t-channel reaction amplitudes are constructed in Feynman type, Regge type, and interpolated Regge type, respectively. The results show that in neither Feynman model nor interpolated Regge model can the available data for γp → f1(1285)p be satisfactorily reproduced. Nevertheless, in the Regge model, when any one of the N(1990)7/2+, N(2000)5/2+, N(2040)3/2+, N(2060)5/2−, N(2100)1/2+, N(2120)3/2−, N(2190)7/2−, N(2300)1/2+, and N(2570)5/2−resonances is considered, the data can be well described. The resulted resonance parameters are consistent with those advocated in Particle Data Group (PDG) review. Further analysis shows that in high-energy region, the peaks of γp → f1(1285)p differential cross sections at forward angles are dominated by the contributions from t-channel ρ- and ω-exchange diagrams, while in low-energy region, the s-channel pole diagrams of resonances also provide significant contributions to the γp → f1(1285)p cross sections.
在有效拉格朗日方法中研究了质子外f1(1285)介子的光生成。在构建描述实验数据的反应振幅时，考虑了核子的 t 道 ρ- 和 ω 交换图、u 道核子交换图、广义接触项和 s 道极点图以及极少数量的核子共振。采用了三种不同的模型，即费曼模型、雷格模型和插值雷格模型，分别以费曼型、雷格型和插值雷格型构建 t 道反应振幅。结果表明，在费曼模型和插值雷格模型中，γp → f1(1285)p 的现有数据都不能令人满意地再现。然而，在雷格模型中，当考虑 N(1990)7/2+、N(2000)5/2+、N(2040)3/2+、N(2060)5/2-、N(2100)1/2+、N(2120)3/2-、N(2190)7/2-、N(2300)1/2+ 和 N(2570)5/2 共振中的任何一个共振时，数据都能得到很好的描述。得出的共振参数与粒子数据小组（PDG）评论中主张的参数一致。进一步的分析表明，在高能区，γp → f1(1285)p差分截面在正向角的峰值主要来自t沟道ρ-和ω-交换图的贡献，而在低能区，共振的s沟道极图也对γp → f1(1285)p截面有重要贡献。
{"title":"Analysis of the data for γp → f1(1285)p photoproduction","authors":"Ai-Chao Wang, N. Wei, Fei Huang","doi":"10.1088/1674-1137/ad0f13","DOIUrl":"https://doi.org/10.1088/1674-1137/ad0f13","url":null,"abstract":"The photoproduction of f1(1285) meson off proton is investigated within an effective Lagrangian approach. The t-channel ρ- and ω-exchange diagrams, u-channel nucleon-exchange diagram, generalized contact term, and s-channel pole diagrams of nucleon and a minimal number of nucleon resonances are taken into account in constructing the reaction amplitudes to describe the experimental data. Three different models, i.e., the Feynman model, the Regge model, and the interpolated Regge model, are employed where the t-channel reaction amplitudes are constructed in Feynman type, Regge type, and interpolated Regge type, respectively. The results show that in neither Feynman model nor interpolated Regge model can the available data for γp → f1(1285)p be satisfactorily reproduced. Nevertheless, in the Regge model, when any one of the N(1990)7/2+, N(2000)5/2+, N(2040)3/2+, N(2060)5/2−, N(2100)1/2+, N(2120)3/2−, N(2190)7/2−, N(2300)1/2+, and N(2570)5/2−resonances is considered, the data can be well described. The resulted resonance parameters are consistent with those advocated in Particle Data Group (PDG) review. Further analysis shows that in high-energy region, the peaks of γp → f1(1285)p differential cross sections at forward angles are dominated by the contributions from t-channel ρ- and ω-exchange diagrams, while in low-energy region, the s-channel pole diagrams of resonances also provide significant contributions to the γp → f1(1285)p cross sections.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139247488","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 : 2023-11-21DOI: 10.1088/1674-1137/ad0e5a
A. Hingu, Surjit Mukherjee, S. Parashari, S. Arora, A. Gandhi, Mahima Upadhyay, Mahesh Choudhary, Sumit Bamal, N. Singh, G. Mishra, S. De, Saurav Sood, Sajin Prasad, G. Saxena, Ajay Kumar, R. Thomas, B. K. Agrawal, Karel Katovsky, A. Kumar
The excitation function of the $rm {}^{58}Ni ( n, p ){}^{58}Co$ reaction is measured by using the well-established neutron activation technique and $gamma$-ray spectroscopy. Neutrons in the energy range of 1.7 to 2.7 $rm MeV$ were generated using the $rm ^{7}Li(p, n)$ reaction. The neutron flux was measured by using the standard $rm {}^{115}In ( n, n^{'} ){}^{115m}In$ monitor reaction. The results of neutron spectrum averaged cross-section of $rm {}^{58}Ni ( n, p ){}^{58}Co$ reactions are compared with existing cross-section data available in the EXFOR data library as well as with various evaluated data libraries like ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0 and CENDL-3.2. Theoretical calculations were performed using the nuclear reaction code TALYS. Various nuclear level density (NLD) models were tested and compared with the present findings. Realistic NLDs are also obtained through the spectral distribution method (SDM). The cross-section results are reported along with the absolute errors by investigating uncertainty propagation, using the covariance technique. The corrections for $gamma$-ray true coincidence summing, low-energy background neutrons and $gamma$-ray self attenuation are performed. The experimental cross-section obtained in the present study is consistent with previously published experimental data, evaluated libraries and theoretical calculations carried out using the TALYS code.
利用成熟的中子活化技术和伽马射线光谱法测量了 $rm {}^{58}Ni ( n, p ){}^{58}Co$ 反应的激发函数。能量范围在 1.7 到 2.7 $rm MeV$ 的中子是通过 $rm ^{7}Li(p, n)$ 反应产生的。中子通量是通过标准的 $rm {}^{115}In ( n, n^{'} ){}^{115m}In$ 监控反应测量的。$rm {}^{58}Ni ( n, p ){}^{58}Co$ 反应的中子谱平均截面结果与 EXFOR 数据库中的现有截面数据以及各种评估数据库（如 ENDF/B-VIII.0、JEFF-3.3、JENDL-4.0 和 CENDL-3.2）进行了比较。理论计算使用核反应代码 TALYS 进行。对各种核级密度（NLD）模型进行了测试，并与目前的研究结果进行了比较。此外，还通过频谱分布法（SDM）获得了真实的核级密度。通过使用协方差技术研究不确定性传播，报告了截面结果和绝对误差。对伽马射线真实重合和、低能背景中子和伽马射线自衰减进行了校正。本研究获得的实验截面与之前公布的实验数据、评估库和使用 TALYS 代码进行的理论计算一致。
{"title":"Investigation of $rm {}^{58}Ni ( n, p ){}^{58}Co$ reaction cross-section with covariance analysis","authors":"A. Hingu, Surjit Mukherjee, S. Parashari, S. Arora, A. Gandhi, Mahima Upadhyay, Mahesh Choudhary, Sumit Bamal, N. Singh, G. Mishra, S. De, Saurav Sood, Sajin Prasad, G. Saxena, Ajay Kumar, R. Thomas, B. K. Agrawal, Karel Katovsky, A. Kumar","doi":"10.1088/1674-1137/ad0e5a","DOIUrl":"https://doi.org/10.1088/1674-1137/ad0e5a","url":null,"abstract":"The excitation function of the $rm {}^{58}Ni ( n, p ){}^{58}Co$ reaction is measured by using the well-established neutron activation technique and $gamma$-ray spectroscopy. Neutrons in the energy range of 1.7 to 2.7 $rm MeV$ were generated using the $rm ^{7}Li(p, n)$ reaction. The neutron flux was measured by using the standard $rm {}^{115}In ( n, n^{'} ){}^{115m}In$ monitor reaction. The results of neutron spectrum averaged cross-section of $rm {}^{58}Ni ( n, p ){}^{58}Co$ reactions are compared with existing cross-section data available in the EXFOR data library as well as with various evaluated data libraries like ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0 and CENDL-3.2. Theoretical calculations were performed using the nuclear reaction code TALYS. Various nuclear level density (NLD) models were tested and compared with the present findings. Realistic NLDs are also obtained through the spectral distribution method (SDM). The cross-section results are reported along with the absolute errors by investigating uncertainty propagation, using the covariance technique. The corrections for $gamma$-ray true coincidence summing, low-energy background neutrons and $gamma$-ray self attenuation are performed. The experimental cross-section obtained in the present study is consistent with previously published experimental data, evaluated libraries and theoretical calculations carried out using the TALYS code.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139251852","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 : 2023-11-20DOI: 10.1088/1674-1137/ad0e04
Zehan Wu, Dehua 文德华 Wen
The equation of state (EOS) of dense nuclear matter is a key factor to determine the internal structure and properties of neutron stars. However, the EOS of high-density nuclear matter has great uncertainty mainly because the terrestrial nuclear experiments cannot reproduce matter as dense as that in the inner core of a neutron star. Fortunately, continuous improvements in astronomical observations of neutron stars provide the opportunity to inversely constrain the EOS of high-density nuclear matter. A number of methods have been proposed to implement this inverse constraint, such as the Bayesian analysis algorithm, the Lindblom's approach, and so on. Neural network algorithm is an effective new method developed in recent years. By employing a set of isospin-dependent parametric EOSs as the training sample of neural network algorithm, we set up an effective way to reconstruct the EOS with relative accuracy through a few mass-radius data. Based on the obtained neural network algorithms and according to the NICER observations on masses and radii of neutron stars with assumed precision, we get the inversely constrained EOS and further calculate the corresponding macroscopic properties of the neutron star. The results are basically consistent with the constraint on EOS from the Huth et~ al. based on Bayesian analysis. Moreover, the results show that even though the neural network algorithm was obtained by using the finite parameterized EOS as the training set, it is valid for any rational parameter combination of the parameterized EOS model.
致密核物质的状态方程（EOS）是确定中子星内部结构和性质的关键因素。然而，高密度核物质的状态方程具有很大的不确定性，这主要是因为地面核实验无法再现像中子星内核那样致密的物质。幸运的是，中子星天文观测的不断改进为反向约束高密度核物质的EOS提供了机会。人们提出了许多方法来实现这种反向约束，如贝叶斯分析算法、林德布洛姆方法等。神经网络算法是近年来发展起来的一种有效的新方法。通过采用一组等空间依赖的参数EOS作为神经网络算法的训练样本，我们建立了一种通过少量质量半径数据相对准确地重建EOS的有效方法。基于得到的神经网络算法，并根据NICER对中子星质量和半径的假定精度观测，我们得到了反向约束的EOS，并进一步计算了中子星相应的宏观性质。结果与基于贝叶斯分析的 Huth 等人的 EOS 约束基本一致。此外，结果表明，尽管神经网络算法是以有限参数化EOS作为训练集得到的，但它对参数化EOS模型的任何合理参数组合都是有效的。
{"title":"From masses and radii of neutron stars to EOS of nuclear matter through neural network","authors":"Zehan Wu, Dehua 文德华 Wen","doi":"10.1088/1674-1137/ad0e04","DOIUrl":"https://doi.org/10.1088/1674-1137/ad0e04","url":null,"abstract":"The equation of state (EOS) of dense nuclear matter is a key factor to determine the internal structure and properties of neutron stars. However, the EOS of high-density nuclear matter has great uncertainty mainly because the terrestrial nuclear experiments cannot reproduce matter as dense as that in the inner core of a neutron star. Fortunately, continuous improvements in astronomical observations of neutron stars provide the opportunity to inversely constrain the EOS of high-density nuclear matter. A number of methods have been proposed to implement this inverse constraint, such as the Bayesian analysis algorithm, the Lindblom's approach, and so on. Neural network algorithm is an effective new method developed in recent years. By employing a set of isospin-dependent parametric EOSs as the training sample of neural network algorithm, we set up an effective way to reconstruct the EOS with relative accuracy through a few mass-radius data. Based on the obtained neural network algorithms and according to the NICER observations on masses and radii of neutron stars with assumed precision, we get the inversely constrained EOS and further calculate the corresponding macroscopic properties of the neutron star. The results are basically consistent with the constraint on EOS from the Huth et~ al. based on Bayesian analysis. Moreover, the results show that even though the neural network algorithm was obtained by using the finite parameterized EOS as the training set, it is valid for any rational parameter combination of the parameterized EOS model.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139257485","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 : 2023-09-23DOI: 10.1088/1674-1137/ad181b
D. Fang
With recent measurements of the two neutrino double beta decay high precision electron spectra, combining with charge exchange or $beta$-decay experimental data, we give severe constraints over the current nuclear many body calculations. Our calculation shows that Quasi-particle Random Phase Approximation (QRPA) approach can well reproduce the measured spectra for the two open shell nuclei, $^{82}$Se and $^{100}$Mo. For the closed shell nucleus $^{136}$Xe, QRPA can also reproduce the spectra with proper treatments. We also find that considering the high-lying state reduction, Nuclear Shell Model can also well reproduce the spectra as well as Gamow-Teller transition strength under a unique quenched Axial-vector coupling constant $g_A$. For $^{136}$Xe, we find that the flip of the sign for the decay strength will lead the spectra to go beyond the so-called High-lying state dominance hypothesis. These results call for future high precision measurement of charge-exchange reaction.
{"title":"What can we learn from recent $2nubetabeta$ experiments?","authors":"D. Fang","doi":"10.1088/1674-1137/ad181b","DOIUrl":"https://doi.org/10.1088/1674-1137/ad181b","url":null,"abstract":"With recent measurements of the two neutrino double beta decay high precision electron spectra, combining with charge exchange or $beta$-decay experimental data, we give severe constraints over the current nuclear many body calculations. Our calculation shows that Quasi-particle Random Phase Approximation (QRPA) approach can well reproduce the measured spectra for the two open shell nuclei, $^{82}$Se and $^{100}$Mo. For the closed shell nucleus $^{136}$Xe, QRPA can also reproduce the spectra with proper treatments. We also find that considering the high-lying state reduction, Nuclear Shell Model can also well reproduce the spectra as well as Gamow-Teller transition strength under a unique quenched Axial-vector coupling constant $g_A$. For $^{136}$Xe, we find that the flip of the sign for the decay strength will lead the spectra to go beyond the so-called High-lying state dominance hypothesis. These results call for future high precision measurement of charge-exchange reaction.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139336838","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 : 2023-09-19DOI: 10.1088/1674-1137/ad13f7
Yi Zhao, Xiaojun Bi, Su-jie Lin, P. Yin
Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way. The potential existence of a nearby subhalo could have important implications for our understanding of dark matter (DM) annihilation. In this study, we investigate the hypothetical presence of a nearby subhalo and set the upper limits on the DM annihilation cross section by analyzing the cosmic-ray antiproton spectrum. By presenting the ratios of annihilation cross section limits for scenarios with and without a nearby subhalo, we can quantitatively evaluate the potential impact of the nearby subhalo on the limits of the DM annihilation cross section. The impacts of the concentration model and the subhalo probability distribution have been considered. We explore the antiproton contribution of the potential nearby DM subhalo accounting for the DAMPE $e^pm$ spectrum at $sim 1.4$ TeV and find that the current AMS-02 antiproton results do not place the constraint on this contribution.
{"title":"Impact of a nearby subhalo on the constraint of dark matter annihilation from cosmic ray antiprotons","authors":"Yi Zhao, Xiaojun Bi, Su-jie Lin, P. Yin","doi":"10.1088/1674-1137/ad13f7","DOIUrl":"https://doi.org/10.1088/1674-1137/ad13f7","url":null,"abstract":"Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way. The potential existence of a nearby subhalo could have important implications for our understanding of dark matter (DM) annihilation. In this study, we investigate the hypothetical presence of a nearby subhalo and set the upper limits on the DM annihilation cross section by analyzing the cosmic-ray antiproton spectrum. By presenting the ratios of annihilation cross section limits for scenarios with and without a nearby subhalo, we can quantitatively evaluate the potential impact of the nearby subhalo on the limits of the DM annihilation cross section. The impacts of the concentration model and the subhalo probability distribution have been considered. We explore the antiproton contribution of the potential nearby DM subhalo accounting for the DAMPE $e^pm$ spectrum at $sim 1.4$ TeV and find that the current AMS-02 antiproton results do not place the constraint on this contribution.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139338955","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 : 2023-09-17DOI: 10.1088/1674-1137/ad0f89
Jie Wang, Jinghong Ma, Jing Gao, Xiao-Fang Han, Lei Wang
Combining the dark matter and muon $g-2$ anomaly, we study the $U(1)_{L_mu-L_tau}$ breaking phase transition, gravitational wave spectra, and the direct detection at the LHC in an extra $U(1)_{L_mu-L_tau}$ gauge symmetry extension of the standard model. The new fields includes vector-like leptons ($E_1,~ E_2,~ N$), $U(1)_{L_mu-L_tau}$ breaking scalar $S$ and gauge boson $Z'$, as well as the dark matter candidate $X_I$ and its heavy partner $X_R$. A joint explanation of the dark matter relic density and muon $g-2$ anomaly excludes the region where both $min(m_{E_1},m_{E_2},m_N,m_{X_R})$ and $min(m_{Z'},m_S)$ are much larger than $m_{X_I}$. In the parameter space accommodating the DM relic density and muon $g-2$ anomaly, the model can achieve a first order $U(1)_{L_mu-L_tau}$ breaking phase transition, whose strength is sensitive to the parameters of Higgs potential. The corresponding gravitational wave spectra can reach the sensitivity of U-DECIGO. In addition, the direct searches at the LHC impose stringent bound on the mass spectra of the vector-like leptons and dark matter. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
{"title":"The $U(1)_{L_mu-L_tau}$ breaking phase transition, muon $g-2$, dark matter, collider and gravitational wave","authors":"Jie Wang, Jinghong Ma, Jing Gao, Xiao-Fang Han, Lei Wang","doi":"10.1088/1674-1137/ad0f89","DOIUrl":"https://doi.org/10.1088/1674-1137/ad0f89","url":null,"abstract":"Combining the dark matter and muon $g-2$ anomaly, we study the $U(1)_{L_mu-L_tau}$ breaking phase transition, gravitational wave spectra, and the direct detection at the LHC in an extra $U(1)_{L_mu-L_tau}$ gauge symmetry extension of the standard model. The new fields includes vector-like leptons ($E_1,~ E_2,~ N$), $U(1)_{L_mu-L_tau}$ breaking scalar $S$ and gauge boson $Z'$, as well as the dark matter candidate $X_I$ and its heavy partner $X_R$. A joint explanation of the dark matter relic density and muon $g-2$ anomaly excludes the region where both $min(m_{E_1},m_{E_2},m_N,m_{X_R})$ and $min(m_{Z'},m_S)$ are much larger than $m_{X_I}$. In the parameter space accommodating the DM relic density and muon $g-2$ anomaly, the model can achieve a first order $U(1)_{L_mu-L_tau}$ breaking phase transition, whose strength is sensitive to the parameters of Higgs potential. The corresponding gravitational wave spectra can reach the sensitivity of U-DECIGO. In addition, the direct searches at the LHC impose stringent bound on the mass spectra of the vector-like leptons and dark matter. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139339356","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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