Pub Date : 2024-01-17DOI: 10.1088/1674-1137/ad2f22
Chuanhui Jiang, Hai Tao Li, Shi-Yuan Li, Zong-Guo Si
The finite mass of the heavy quark suppresses the collimated radiations, which is generally referred to as the dead cone effect. In this paper, we study the distribution of hadron multiplicity over the hadron opening angle with respect to the jet axis in various flavors of jets. The corresponding measurement can be the most straightforward and simplest to explore the dynamical evolution of the radiations in the corresponding jet, which can expose the mass effect. We also propose the transverse energy-weighted angular distribution which sheds light on the interplay between perturbative and nonperturbative effects in the radiation. With Monte-Carlo simulations, our calculation shows that the dead cone effect can be clearly seen by taking the ratio between the b jet and the light-quark (inclusive) jet, promising to be measured at the LHC in the future. 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":"Mass suppression effect in QCD radiation and hadron angular distribution in jet","authors":"Chuanhui Jiang, Hai Tao Li, Shi-Yuan Li, Zong-Guo Si","doi":"10.1088/1674-1137/ad2f22","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2f22","url":null,"abstract":"\u0000 The finite mass of the heavy quark suppresses the collimated radiations, which is generally referred to as the dead cone effect. In this paper, we study the distribution of hadron multiplicity over the hadron opening angle with respect to the jet axis in various flavors of jets. The corresponding measurement can be the most straightforward and simplest to explore the dynamical evolution of the radiations in the corresponding jet, which can expose the mass effect. We also propose the transverse energy-weighted angular distribution which sheds light on the interplay between perturbative and nonperturbative effects in the radiation. With Monte-Carlo simulations, our calculation shows that the dead cone effect can be clearly seen by taking the ratio between the b jet and the light-quark (inclusive) jet, promising to be measured at the LHC in the future. 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":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140505530","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 : 2024-01-14DOI: 10.1088/1674-1137/ad2362
Yu Zhang, Yi-Wei Huang, Wei-Tao Zhang, Mao Song, Ran Ding
In this work, we investigate the collider constraints on effective interactions between Dark Matter (DM) particles and electroweak gauge bosons in a systematic way. We consider the simplified models in which scalar or Dirac fermion DM candidates only couple to electroweak gauge bosons through high dimensional effective operators. Taking into account the induced DM-quarks and DM-gluons operators from the Renormalization Group Evolution (RGE) running effect, we present comprehensive constraints on effective energy scale $Lambda$ and Wilson coefficients $C_B(Lambda),,C_W(Lambda)$ from direct detection, indirect detection, and collider searches. In particular, we present the corresponding sensitivity from the Large Hadron Electron Collider (LHeC) and the Future Circular Collider in electron-proton mode (FCC-ep) for the first time, update the mono-$j$ and mono-$gamma$ search limits at the Large Hadron Collider (LHC), and derive the new limits at the Circular Electron Positron Collider (CEPC). 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":"Exploring dark matter-gauge boson effective interactions at the current and future colliders","authors":"Yu Zhang, Yi-Wei Huang, Wei-Tao Zhang, Mao Song, Ran Ding","doi":"10.1088/1674-1137/ad2362","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2362","url":null,"abstract":"\u0000 In this work, we investigate the collider constraints on effective interactions between Dark Matter (DM) particles and electroweak gauge bosons in a systematic way. We consider the simplified models in which scalar or Dirac fermion DM candidates only couple to electroweak gauge bosons through high dimensional effective operators. Taking into account the induced DM-quarks and DM-gluons operators from the Renormalization Group Evolution (RGE) running effect, we present comprehensive constraints on effective energy scale $Lambda$ and Wilson coefficients $C_B(Lambda),,C_W(Lambda)$ from direct detection, indirect detection, and collider searches. In particular, we present the corresponding sensitivity from the Large Hadron Electron Collider (LHeC) and the Future Circular Collider in electron-proton mode (FCC-ep) for the first time, update the mono-$j$ and mono-$gamma$ search limits at the Large Hadron Collider (LHC), and derive the new limits at the Circular Electron Positron Collider (CEPC). 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":"2024-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140508860","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 : 2024-01-11DOI: 10.1088/1674-1137/ad1d4b
H. Ganev
Microscopic shell-model description of the low-lying collective states in the weakly deformed nucleus $^{106}$Cd within the recently proposed microscopic version of the Bohr-Mottelson model is given. A good description of the excitation energies of the lowest ground, $gamma$, and $beta$ quasibands is obtained without the involvement of adjustable kinetic energy term. The $gamma$ degrees of freedom are shown to play a crucial role in the description of spectroscopy of this nucleus. A modified $SU(3)$ preserving high-order interaction is used to produce a $gamma$-unstable type of the odd-even staggering, observed experimentally between the states of the quasi-$gamma$ band. The present approach allows to describe the observed intraband and interband quadrupole collectivity. The results obtained in present work suggest a different interpretation of the fundamental question concerning the nature of low-energy vibrations and the emergence of deformation and collectivity in the weakly deformed atomic nuclei.
{"title":"Proton-neutron symplectic model description of $^{106}$Cd","authors":"H. Ganev","doi":"10.1088/1674-1137/ad1d4b","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1d4b","url":null,"abstract":"\u0000 Microscopic shell-model description of the low-lying collective states in the weakly deformed nucleus $^{106}$Cd within the recently proposed microscopic version of the Bohr-Mottelson model is given. A good description of the excitation energies of the lowest ground, $gamma$, and $beta$ quasibands is obtained without the involvement of adjustable kinetic energy term. The $gamma$ degrees of freedom are shown to play a crucial role in the description of spectroscopy of this nucleus. A modified $SU(3)$ preserving high-order interaction is used to produce a $gamma$-unstable type of the odd-even staggering, observed experimentally between the states of the quasi-$gamma$ band. The present approach allows to describe the observed intraband and interband quadrupole collectivity. The results obtained in present work suggest a different interpretation of the fundamental question concerning the nature of low-energy vibrations and the emergence of deformation and collectivity in the weakly deformed atomic nuclei.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139626861","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 : 2024-01-05DOI: 10.1088/1674-1137/ad1b3c
B. Irgaziev, A. Kabir, J. Nabi
The CNO cycle is the main source of energy in stars more massive than our Sun. It defines the energy production and the duration contributes in determining the lifetime of massive stars. The cycle is an important tool for the determination of the age of globular clusters. Radiative capture p + 14N →15O + γ, at energies of astrophysical interest, is one of the important processes in the CNO cycle. In this project, we apply a potential model to describe both non-resonant and resonant reactions in the channels where radiative capture occurs through electric E1 transitions. We employed the R-matrix method to describe the reactions going via M1 resonant transitions, when it was not possible to correctly reproduce the experimental data by a potential model. The partial components of the astrophysical S-factor were calculated for all possible electric and magnetic dipole transitions in 15O. The linear extrapolated S-factor at zero energy (S(0)) is in good agreement with earlier reported values for all types of transitions considered in this work. Based on the value of the total astrophysical S-factor, depending on the collision energy, we calculate the nuclear reaction rates for p + 14N →15O + γ. The computed rates are in good agreement with the results of the NACRE II Collaboration.
一氧化碳循环是比太阳质量更大的恒星的主要能量来源。它决定了能量的产生和持续时间，有助于确定大质量恒星的寿命。该周期是确定球状星团年龄的重要工具。在具有天体物理学意义的能量下，辐射捕获 p + 14N →15O + γ 是 CNO 循环的重要过程之一。在本项目中，我们采用了一种势能模型来描述通过电 E1 变换发生辐射俘获的通道中的非共振和共振反应。当电势模型无法正确再现实验数据时，我们采用了 R 矩阵方法来描述通过 M1 共振跃迁发生的反应。我们计算了 15O 中所有可能的电偶极和磁偶极跃迁的天体物理 S 因子的部分分量。零能量（S(0)）时的线性外推 S 因子与之前报道的本研究中所有类型跃迁的 S 因子值非常吻合。根据天体物理 S 因子的总值（取决于碰撞能量），我们计算了 p + 14N →15O + γ 的核反应速率。 计算出的速率与 NACRE II 合作组的结果非常一致。
{"title":"Radiative Capture of proton 14N(p,γ)15O at Low Energy","authors":"B. Irgaziev, A. Kabir, J. Nabi","doi":"10.1088/1674-1137/ad1b3c","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1b3c","url":null,"abstract":"\u0000 The CNO cycle is the main source of energy in stars more massive than our Sun. It defines the energy production and the duration contributes in determining the lifetime of massive stars. The cycle is an important tool for the determination of the age of globular clusters. Radiative capture p + 14N →15O + γ, at energies of astrophysical interest, is one of the important processes in the CNO cycle. In this project, we apply a potential model to describe both non-resonant and resonant reactions in the channels where radiative capture occurs through electric E1 transitions. We employed the R-matrix method to describe the reactions going via M1 resonant transitions, when it was not possible to correctly reproduce the experimental data by a potential model. The partial components of the astrophysical S-factor were calculated for all possible electric and magnetic dipole transitions in 15O. The linear extrapolated S-factor at zero energy (S(0)) is in good agreement with earlier reported values for all types of transitions considered in this work. Based on the value of the total astrophysical S-factor, depending on the collision energy, we calculate the nuclear reaction rates for p + 14N →15O + γ. The computed rates are in good agreement with the results of the NACRE II Collaboration.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139382020","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 : 2024-01-05DOI: 10.1088/1674-1137/ad1b3e
Wen-Bin Chang, De-fu Hou
In this work, we study the complexity growth in a holographic QCD model at finite temperature and chemical potential in D dimensions according to the complexity equals action conjecture. By inserting a fundamental string as a probe, we can analyze the properties of complexity growth. In this work, we utilize the complexity-action duality to study the evolution of complexity in a holographic QCD model at finite temperature and chemical potential. By inserting a fundamental string as a probe, we investigated the properties of complexity growth of this Einstein-Maxwell-scalar gravity system, which is affected by the string velocity, chemical potential, and temperature. Our results show that the complexity growth is maximized when the probe string is stationary, and it will decrease as the velocity of the string increases. When the string approaches relativistic velocities, the complexity growth always increases monotonically with respect to the chemical potential. Furthermore, we find that the complexity growth can be used to identify phase transitions and crossovers in the model.
{"title":"Complexity growth in a holographic QCD model","authors":"Wen-Bin Chang, De-fu Hou","doi":"10.1088/1674-1137/ad1b3e","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1b3e","url":null,"abstract":"\u0000 In this work, we study the complexity growth in a holographic QCD model at finite temperature and chemical potential in D dimensions according to the complexity equals action conjecture. By inserting a fundamental string as a probe, we can analyze the properties of complexity growth. In this work, we utilize the complexity-action duality to study the evolution of complexity in a holographic QCD model at finite temperature and chemical potential. By inserting a fundamental string as a probe, we investigated the properties of complexity growth of this Einstein-Maxwell-scalar gravity system, which is affected by the string velocity, chemical potential, and temperature. Our results show that the complexity growth is maximized when the probe string is stationary, and it will decrease as the velocity of the string increases. When the string approaches relativistic velocities, the complexity growth always increases monotonically with respect to the chemical potential. Furthermore, we find that the complexity growth can be used to identify phase transitions and crossovers in the model.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139381159","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 : 2024-01-04DOI: 10.1088/1674-1137/ad1a97
R. L., N. Sowmya, Sridhar K.N, Manjunatha Hc
A new empirical formula for the astronomical S-factor has been suggested as a function of the Coulomb interaction parameter, center of mass energy, and barrier height. About 22 fusion reactions with 40,48Ca as projectiles were considered for different targets leading to compound nuclei with the atomic and mass numbers varying between 40 ≤ Z ≤112 and 88 ≤ A ≤278 respectively. The fusion cross-sections have been estimated using the Geometric factor, Gamow-Sommerfield factor and empirical formula for the S-factor. A better agreement has been obtained for the present work with that of available experiments when compared to Wong’s formula. The present work leads to a smaller standard deviation value when compared to Wong’s formula when used to correlate with the experimental data of Calcium-induced fusion reactions. Wong’s formula provides a good approximation of fusion cross-sections when center of mass energy is below the fusion barrier when compared to above the fusion barrier.
提出了一个新的天文 S 因子经验公式，它是库仑相互作用参数、质心能量和屏障高度的函数。考虑了以 40,48Ca 为射弹的约 22 个不同目标的聚变反应，这些聚变反应导致原子序数和质量数分别在 40 ≤ Z ≤112 和 88 ≤ A ≤278 之间变化的化合物核。聚变截面是利用几何因子、伽莫-索默菲尔德因子和 S 因子的经验公式估算出来的。与黄氏公式相比，目前的工作与现有的实验获得了更好的一致性。在与钙诱导核聚变反应的实验数据相关联时，与 Wong 公式相比，本研究的标准偏差值较小。当质心能量低于聚变势垒与高于聚变势垒时，Wong 公式提供了聚变截面的良好近似值。
{"title":"Empirical model for fusion cross sections of Ca-induced reactions.","authors":"R. L., N. Sowmya, Sridhar K.N, Manjunatha Hc","doi":"10.1088/1674-1137/ad1a97","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1a97","url":null,"abstract":"\u0000 A new empirical formula for the astronomical S-factor has been suggested as a function of the Coulomb interaction parameter, center of mass energy, and barrier height. About 22 fusion reactions with 40,48Ca as projectiles were considered for different targets leading to compound nuclei with the atomic and mass numbers varying between 40 ≤ Z ≤112 and 88 ≤ A ≤278 respectively. The fusion cross-sections have been estimated using the Geometric factor, Gamow-Sommerfield factor and empirical formula for the S-factor. A better agreement has been obtained for the present work with that of available experiments when compared to Wong’s formula. The present work leads to a smaller standard deviation value when compared to Wong’s formula when used to correlate with the experimental data of Calcium-induced fusion reactions. Wong’s formula provides a good approximation of fusion cross-sections when center of mass energy is below the fusion barrier when compared to above the fusion barrier.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139385329","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 : 2024-01-04DOI: 10.1088/1674-1137/ad1a98
liping Sun
We present a complete study on the $J/psi$ pair hadroproduction at next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with the pair of $cbar{c}$ either in ${}^{3}S_1^{[1]}$ or ${}^{1}S_0^{[8]}$ fock state. We find that the contribution of ${}^{1}S_0^{[8]}$ channel at NLO is essential, and for the ATLAS, the NRQCD results can describe the experimental data to a certain extent.
{"title":"$J/psi$ Pair Hadroproduction at Next-to-Leading Order in Nonrelativistic-QCD at ATLAS","authors":"liping Sun","doi":"10.1088/1674-1137/ad1a98","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1a98","url":null,"abstract":"\u0000 We present a complete study on the $J/psi$ pair hadroproduction at next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with the pair of $cbar{c}$ either in ${}^{3}S_1^{[1]}$ or ${}^{1}S_0^{[8]}$ fock state. We find that the contribution of ${}^{1}S_0^{[8]}$ channel at NLO is essential, and for the ATLAS, the NRQCD results can describe the experimental data to a certain extent.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139384626","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}
The ground-state mass excess of the Tz = −2 drip-line nucleus 22Al is measured for the first time to be 18103(10) keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in Lanzhou. The new mass excess value allowed us to determine the excitation energies of the two low-lying 1+ states in 22Al with significantly reduced uncertainties of 51 keV. Comparing to the analogue states in its mirror nucleus 22F, the mirror energy differences of the two 1+ states in the 22Al-22F mirror pair are determined to be −625(51) keV and −330(51) keV, respectively. The excitation energies and the mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field theory. The mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of the πs1/2 orbital.
{"title":"Ground-state mass of 22Al and test of state-of-the-art ab initio calculations","authors":"Ming-Ze Sun, Yue Yu, Xinpeng Wang, Meng 王猛 Wang, Jianguo Li, Yu-Hu 张玉虎 Zhang, klaus blaum, Zuyi Chen, Rui-Jiu Chen, Han-Yu Deng, Chaoyi Fu, Wenwen Ge, W. Huang, Hongyang Jiao, Honghui Li, H. Li, Yinfang Luo, Ting Liao, Y. Litvinov, Min Si, Peng Shuai, Jin-Yang Shi, Qian Wang, Yuanming Xing, X. Xu, Hu-Shan 徐瑚珊 Xu, Fu-Rong 许甫荣 Xu, Qi Yuan, Takayuki Yamaguchi, Xinliang Yan, Jianxin Yang, You-Jin 原有进 Yuan, Xiao-Hong 周小红 Zhou, Xu Zhou, Min Zhang, Qi Zeng","doi":"10.1088/1674-1137/ad1a0a","DOIUrl":"https://doi.org/10.1088/1674-1137/ad1a0a","url":null,"abstract":"\u0000 The ground-state mass excess of the Tz = −2 drip-line nucleus 22Al is measured for the first time to be 18103(10) keV using the newly-developed Bρ-defined isochronous mass spectrometry method at the cooler storage ring in Lanzhou. The new mass excess value allowed us to determine the excitation energies of the two low-lying 1+ states in 22Al with significantly reduced uncertainties of 51 keV. Comparing to the analogue states in its mirror nucleus 22F, the mirror energy differences of the two 1+ states in the 22Al-22F mirror pair are determined to be −625(51) keV and −330(51) keV, respectively. The excitation energies and the mirror energy differences are used to test the state-of-the-art ab initio valence-space in-medium similarity renormalization group calculations with four sets of interactions derived from the chiral effective field theory. The mechanism leading to the large mirror energy differences is investigated and attributed to the occupation of the πs1/2 orbital.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139388773","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 : 2024-01-03DOI: 10.1088/1674-1137/ad361e
Jun Li, Xiao-Jun Bi, Lin-Qing Gao, Xiaoyuan Huang, Run-Min Yao, P. Yin
High-energy photons may oscillate with axion-like particles (ALPs) when they propagate through the Milky Way's magnetic field, resulting in an alteration in the observed photon energy spectrum. The ultra-high energy gamma-ray spectra, measured by the Large High Altitude Air Shower Observatory (LHAASO) up to $mathcal{O}(1)~mathrm{PeV}$, provide a promising opportunity to investigate the ALP-photon oscillation effect. In this study, we utilize the gamma-ray spectra of four Galactic sources measured by LHAASO, including the Crab Nebula, LHAASO J2226+6057, LHAASO J1908+0621, and LHAASO J1825-1326, to explore this effect. We employ the $rm CL_s$ method to set constraints on the ALP parameters. Combing the observations of the four sources, our analysis reveals that the ALP-photon coupling $g_{agamma}$ is constrained to be smaller than $1.4times10^{-10}$ ${rm GeV}^{-1}$ for the ALP mass of $sim 4times10^{-7} ~mathrm{eV}$ at the 95% C.L. By combing the observations of the Crab Nebula from LHAASO and other experiments, we find that the ALP-photon coupling could be set to be about $7.5times10^{-11}$ ${rm GeV}^{-1}$ for the ALP mass $sim 4 times10^{-7}~mathrm{eV}$ , which is in close proximity to the CAST constraint.
{"title":"Constraints on Axion-like Particles from the Observation of Galactic Sources by LHAASO","authors":"Jun Li, Xiao-Jun Bi, Lin-Qing Gao, Xiaoyuan Huang, Run-Min Yao, P. Yin","doi":"10.1088/1674-1137/ad361e","DOIUrl":"https://doi.org/10.1088/1674-1137/ad361e","url":null,"abstract":"\u0000 High-energy photons may oscillate with axion-like particles (ALPs) when they propagate through the Milky Way's magnetic field, resulting in an alteration in the observed photon energy spectrum. The ultra-high energy gamma-ray spectra, measured by the Large High Altitude Air Shower Observatory (LHAASO) up to $mathcal{O}(1)~mathrm{PeV}$, provide a promising opportunity to investigate the ALP-photon oscillation effect. In this study, we utilize the gamma-ray spectra of four Galactic sources measured by LHAASO, including the Crab Nebula, LHAASO J2226+6057, LHAASO J1908+0621, and LHAASO J1825-1326, to explore this effect. We employ the $rm CL_s$ method to set constraints on the ALP parameters. Combing the observations of the four sources, our analysis reveals that the ALP-photon coupling $g_{agamma}$ is constrained to be smaller than $1.4times10^{-10}$ ${rm GeV}^{-1}$ for the ALP mass of $sim 4times10^{-7} ~mathrm{eV}$ at the 95% C.L. By combing the observations of the Crab Nebula from LHAASO and other experiments, we find that the ALP-photon coupling could be set to be about $7.5times10^{-11}$ ${rm GeV}^{-1}$ for the ALP mass $sim 4 times10^{-7}~mathrm{eV}$ , which is in close proximity to the CAST constraint.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140514636","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 : 2023-12-28DOI: 10.1088/1674-1137/ad1925
Fakeha Farooq, J. Nabi, Ramoona Shehzadi
Key nuclear inputs for the astrophysical r-process simulations are the weak interaction rates. Consequently, the accuracy of these inputs directly affects the reliability of nucleosynthesis modeling. Majority of the stellar rates, used in simulation studies, are calculated invoking the Brink-Axel (BA) hypothesis. The BA hypothesis assumes that the strength functions of all parent excited states are the same as for the ground state, only shifted in energies. However, BA hypothesis has to be tested against microscopically calculated state-by-state rates. In this project we study the impact of the BA hypothesis on calculated stellar β--decay and electron capture rates. Our investigation include both Unique First Forbidden (U1F) and allowed transitions for 106 neutron-rich trans-iron nuclei ([27, 77] ≤ [Z, A] ≤ [82, 208]). The calculations were performed using the deformed proton-neutron quasi-particle random-phase approximation (pn-QRPA) model with a simple plus quadrupole separable and schematic interaction. Waiting-point and several key r-process nuclei lie within the considered mass region of the nuclear chart. We computed electron capture and β--decay rates using two different prescriptions for strength functions. One was based by invoking BA hypothesis and the other was the state-by-state calculation of strength functions, under stellar density and temperature conditions ([10, 1] ≤ [ρYe(g/cm3), T(GK)] ≤ [1011, 30]). Our results show that BA hypothesis invoked U1F β-− rates are overestimated by 4–5 orders of magnitude as compared to microscopic rates. For capture rates, more than 2 orders of magnitude difference was noted when applying BA hypothesis. It was concluded that the BA hypothesis is not a reliable approximation, especially for the β--decay forbidden transitions.
天体物理学 r 过程模拟的关键核输入是弱相互作用率。因此，这些输入的准确性直接影响到核合成建模的可靠性。模拟研究中使用的大多数恒星速率都是根据布林克-阿克塞尔（BA）假说计算得出的。布林克-阿克塞尔假说假定所有母激发态的强度函数与基态相同，只是在能量上有所偏移。然而，BA 假说必须根据微观计算的逐态速率进行检验。在这个项目中，我们研究了BA假说对恒星β衰变和电子俘获率计算的影响。我们的研究包括106个富中子反铁核（[27, 77] ≤ [Z, A] ≤ [82, 208]）的独特第一禁止（U1F）和允许跃迁。计算采用了变形质子-中子准粒子随机相近似（pn-QRPA）模型，以及简单的加四极可分离和示意相互作用。等待点和几个关键的 r 过程核位于核图的考虑质量区域内。我们使用两种不同的强度函数计算了电子俘获率和β-衰变率。一种是基于 BA 假说，另一种是在恒星密度和温度条件（[10, 1] ≤ [ρYe(g/cm3), T(GK)] ≤ [1011, 30]）下对强度函数进行逐态计算。我们的结果表明，与微观速率相比，BA 假设中引用的 U1F β--速率被高估了 4-5 个数量级。在捕获率方面，应用 BA 假说时发现两者相差 2 个数量级以上。结论是 BA 假说并不是一个可靠的近似值，特别是对于 β--衰变的禁止转变。
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