Pub Date : 2024-08-08DOI: 10.1088/1674-1137/ad6d41
F. Rasulova, J. Khushvaktov, Alexander Kuznetsov, Toan Tran, Sergey Evseev, Vladimir Kobets, Sergey Rozov, E. Ruziev, Bekhzod Yuldashev, D. L. Demin, Mikhail Demichev, M. Gostkin, Evgeniy Yakushev, A. Solnyshkin, Sergey Belyshev, N. Fursova
Relative yields have been measured in the 40-130 MeV bremsstrahlung induced reactions of 59Co. The experiments have been performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line γ-ray spectrometric technique. The bremsstrahlung photon flux has been calculated with the Geant4 program. The cross sections were calculated by using computer code TALYS-1.96 with different models and are found to be in good agreement with the experimental data.
{"title":"Photonuclear reactions on 59Co at bremsstrahlung end-point energies of 40–130 MeV","authors":"F. Rasulova, J. Khushvaktov, Alexander Kuznetsov, Toan Tran, Sergey Evseev, Vladimir Kobets, Sergey Rozov, E. Ruziev, Bekhzod Yuldashev, D. L. Demin, Mikhail Demichev, M. Gostkin, Evgeniy Yakushev, A. Solnyshkin, Sergey Belyshev, N. Fursova","doi":"10.1088/1674-1137/ad6d41","DOIUrl":"https://doi.org/10.1088/1674-1137/ad6d41","url":null,"abstract":"\u0000 Relative yields have been measured in the 40-130 MeV bremsstrahlung induced reactions of 59Co. The experiments have been performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line γ-ray spectrometric technique. The bremsstrahlung photon flux has been calculated with the Geant4 program. The cross sections were calculated by using computer code TALYS-1.96 with different models and are found to be in good agreement with the experimental data.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":"5 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141927524","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 : 2024-07-25DOI: 10.1088/1674-1137/ad6752
Wei Kou, Xurong Chen
We propose searching for dark photon signals in the decay channel of $eta$ mesons, specifically through the leptonic decay ($A^prime to e^+e^-(mu^+mu^-)$) observable in photon-photon interactions during ultra-peripheral heavy-ion collisions. We estimate the total cross-section for dark photon production in ultra-peripheral $PbPb$ collisions at current and future hadron colliders. Our findings support the potential for detecting dark photon signals at the LHC, High-Luminosity LHC, High-Energy LHC, and the Future Circular Collider. 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":"Estimating the production of dark photons with $eta$ decay in high-energy collisions","authors":"Wei Kou, Xurong Chen","doi":"10.1088/1674-1137/ad6752","DOIUrl":"https://doi.org/10.1088/1674-1137/ad6752","url":null,"abstract":"\u0000 We propose searching for dark photon signals in the decay channel of $eta$ mesons, specifically through the leptonic decay ($A^prime to e^+e^-(mu^+mu^-)$) observable in photon-photon interactions during ultra-peripheral heavy-ion collisions. We estimate the total cross-section for dark photon production in ultra-peripheral $PbPb$ collisions at current and future hadron colliders. Our findings support the potential for detecting dark photon signals at the LHC, High-Luminosity LHC, High-Energy LHC, and the Future Circular Collider. 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":"7 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141803241","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 : 2024-07-24DOI: 10.1088/1674-1137/ad66c0
Baoqian Li, Min Xiao, Yonghao Chen, Jie-Ming Xue, Xinxiang Li, Han Yi, Pin-Jing Cheng, Rong Liu, Yiwei Yang, Z. Han, Da-Jun Zhao, Haoqiang Wang, Jirong Zhao, Peng Luan, Jing Liu, Zijun Liu, Chaomin Chen, Wen Luo, Bo Zheng, Song Feng
The neutron total cross-section of natCr plays a crucial role in new nuclear engineer design and fundamental science. A new measurement of neutron-induced total cross-sections of natCr has been performed using the transmission method on the back-streaming white neutron beamline (Back-n) at the China Spallation Neutron Source (CSNS). Neutron energy was determined using the time-of-flight technique. The neutron total cross-sections of natCr have been obtained across an exceptionally broad energy range (0.3 eV-20 MeV) with one experiment for the first time. The resulting effective total cross-sections has been compared with the existing experimental data in different energy ranges, and a good agreement with the evaluated libraries has been found. Theoretical calculation of the total cross-section in the energy range of 1.5 MeV to 20 MeV has been conducted using the TALYS-1.96 and compared with the present results. The measurement provides a high-quality total cross-section of natCr including detailed uncertainty data across a wide energy range, offering a valuable reference for nuclear data re-evaluating and nuclear engineering design.
{"title":"New measurement of the neutron-induced total cross-sections of natCr in a wide energy range on the Back-n at CSNS","authors":"Baoqian Li, Min Xiao, Yonghao Chen, Jie-Ming Xue, Xinxiang Li, Han Yi, Pin-Jing Cheng, Rong Liu, Yiwei Yang, Z. Han, Da-Jun Zhao, Haoqiang Wang, Jirong Zhao, Peng Luan, Jing Liu, Zijun Liu, Chaomin Chen, Wen Luo, Bo Zheng, Song Feng","doi":"10.1088/1674-1137/ad66c0","DOIUrl":"https://doi.org/10.1088/1674-1137/ad66c0","url":null,"abstract":"\u0000 The neutron total cross-section of natCr plays a crucial role in new nuclear engineer design and fundamental science. A new measurement of neutron-induced total cross-sections of natCr has been performed using the transmission method on the back-streaming white neutron beamline (Back-n) at the China Spallation Neutron Source (CSNS). Neutron energy was determined using the time-of-flight technique. The neutron total cross-sections of natCr have been obtained across an exceptionally broad energy range (0.3 eV-20 MeV) with one experiment for the first time. The resulting effective total cross-sections has been compared with the existing experimental data in different energy ranges, and a good agreement with the evaluated libraries has been found. Theoretical calculation of the total cross-section in the energy range of 1.5 MeV to 20 MeV has been conducted using the TALYS-1.96 and compared with the present results. The measurement provides a high-quality total cross-section of natCr including detailed uncertainty data across a wide energy range, offering a valuable reference for nuclear data re-evaluating and nuclear engineering design.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":"11 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141806426","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 : 2024-07-23DOI: 10.1088/1674-1137/ad6669
Kang Song Ri, Sin Chol Hwang, Hyon Chol Ri
In this paper we consider a nonsingular bounce scenario with non-minimal kinetic coupling between two scalar fields.We derive the constraints on the model parameters from the finiteness of the physical quantities at the classical level and from the relation between the late-time accelerated expansion and particle production up to the bounce phase. We then determine the allowed parameter space for the model.
{"title":"Cosmological constraints on the background dynamics of a two-field nonsingular bounce model","authors":"Kang Song Ri, Sin Chol Hwang, Hyon Chol Ri","doi":"10.1088/1674-1137/ad6669","DOIUrl":"https://doi.org/10.1088/1674-1137/ad6669","url":null,"abstract":"\u0000 In this paper we consider a nonsingular bounce scenario with non-minimal kinetic coupling between two scalar fields.We derive the constraints on the model parameters from the finiteness of the physical quantities at the classical level and from the relation between the late-time accelerated expansion and particle production up to the bounce phase. We then determine the allowed parameter space for the model.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":"67 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141810383","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 : 2024-07-23DOI: 10.1088/1674-1137/ad666c
Qi-Qin 景琪钦 Jing, Ke-Jian He, Zhi 罗智 Luo
In this paper, we study the optical properties of asymmetric thin-shell wormholes (ATWs) with torsion charge. Utilizing the cut-and-paste method developed by Visser, we construct these wormholes and determine their key physical properties such as the radius of the photon sphere and critical impact parameters under different torsion charges. Furthermore, we investigate the effective potential and the behavior of photon motion within the wormhole spacetime, identifying a relationship between photon trajectories and impact parameters. The study focuses on scenarios where thin accretion disks act as the primary light source. It reveals that the optical features of the ATW with torsion charge significantly differ from those of a black hole (BH). Notably, an increase in the torsion charge leads to a reduction in the sizes of both extra photon rings and lensing bands, which serve as important markers for distinguishing and characterizing ATW spacetimes from BHs.
{"title":"The Effects of Torsion Charge on Optical Appearances and Additional Photon Rings of an Asymmetric Thin-Shell Wormhole","authors":"Qi-Qin 景琪钦 Jing, Ke-Jian He, Zhi 罗智 Luo","doi":"10.1088/1674-1137/ad666c","DOIUrl":"https://doi.org/10.1088/1674-1137/ad666c","url":null,"abstract":"\u0000 In this paper, we study the optical properties of asymmetric thin-shell wormholes (ATWs) with torsion charge. Utilizing the cut-and-paste method developed by Visser, we construct these wormholes and determine their key physical properties such as the radius of the photon sphere and critical impact parameters under different torsion charges. Furthermore, we investigate the effective potential and the behavior of photon motion within the wormhole spacetime, identifying a relationship between photon trajectories and impact parameters. The study focuses on scenarios where thin accretion disks act as the primary light source. It reveals that the optical features of the ATW with torsion charge significantly differ from those of a black hole (BH). Notably, an increase in the torsion charge leads to a reduction in the sizes of both extra photon rings and lensing bands, which serve as important markers for distinguishing and characterizing ATW spacetimes from BHs.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":"129 48","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141811302","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 : 2024-07-23DOI: 10.1088/1674-1137/ad666a
Rui Guo, Lihua Zhu, Jingbin Lu, G. Fu, meng(萌) Wang(王), B. Sun, G. Zhang, Zhen(臻) Ren(任), Yi Heng Wu, Yun Zheng, Chuang-Ye 贺创业 He, Jin-Long Wang, Xiaoguang Wu, Shun He(顺和) Yao(姚)
Excited states of 206Rn have been studied via the 197Au(14N, 5n)206Rn fusion reaction at a beam energy of 78 MeV. A number of transitions and levels are identified by the γ-γ coincidence measurement, further enriching the level scheme of 206Rn. Both the full configuration shell model and the nucleon-pair approximation (NPA) were utilized to investigate the single-particle configurations and seniority structures in 206Rn. The results of these two calculations suggest that the 21 + and 41 + states exhibit only a 50% component of a seniority-two state associated with a broken neutron pair. The collectivity of these two states primarily arises from configuration mixing due to residual proton-neutron interactions. The 61 + and 81 + states are predominantly characterized by a seniority-two state marked by a broken proton pair.
{"title":"Investigating the level structure of 206Rn: evolution from seniority regime to collective dynamics","authors":"Rui Guo, Lihua Zhu, Jingbin Lu, G. Fu, meng(萌) Wang(王), B. Sun, G. Zhang, Zhen(臻) Ren(任), Yi Heng Wu, Yun Zheng, Chuang-Ye 贺创业 He, Jin-Long Wang, Xiaoguang Wu, Shun He(顺和) Yao(姚)","doi":"10.1088/1674-1137/ad666a","DOIUrl":"https://doi.org/10.1088/1674-1137/ad666a","url":null,"abstract":"\u0000 Excited states of 206Rn have been studied via the 197Au(14N, 5n)206Rn fusion reaction at a beam energy of 78 MeV. A number of transitions and levels are identified by the γ-γ coincidence measurement, further enriching the level scheme of 206Rn. Both the full configuration shell model and the nucleon-pair approximation (NPA) were utilized to investigate the single-particle configurations and seniority structures in 206Rn. The results of these two calculations suggest that the 21\u0000 + and 41\u0000 + states exhibit only a 50% component of a seniority-two state associated with a broken neutron pair. The collectivity of these two states primarily arises from configuration mixing due to residual proton-neutron interactions. The 61\u0000 + and 81\u0000 + states are predominantly characterized by a seniority-two state marked by a broken proton pair.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":"127 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141811339","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 : 2024-07-22DOI: 10.1088/1674-1137/ad65dd
Shubhpreet Kaur, Raj Kumar, Manoj K. Sharma
Persistent theoretical and experimental attempts have been made to investigate the heavy ion induced reactions and their subsequent decay mechanisms in superheavy mass region. In addition, the region of transfermium elements is itself of great interest because of the neutron / proton shell effects. Here, we aim to study the subsequent decay mechanisms of two isotopes of Z = 102 nucleus, i.e. 248No and 250No. The dynamical cluster-decay model (DCM) based on Quantum Mechanical Fragmen- tation Theory (QMFT), is employed to conduct a comprehensive analysis of compound nucleus (CN) and non-compound nucleus (nCN) mechanisms such as fusion-fission (ff), Quasi fission (QF) and fast fission (FF), the role of centre of mass energy (Ec.m.) and angular momentum (ℓ) for 248No and 250No isotopes. The nuclear interaction potential is obtained using the Skyrme energy density formalism (SEDF) in the domain of GSkI force parameters. The probability of compound nucleus formation (PCN ) is determined using a function that depends on the centre of mass energy. The lifetimes for the fusion-fission (ff) quasi fission (QF) channels are explored. Here, CN and nCN decay mechanisms for two isotopes of Z = 102 nobelium are studied over the wide range of centre-of-mass (Ec.m.) by including the quadrupole deformation (β2) and optimum orientations (θopt.) of decaying fragments. The fragmentation potential, preformation probability, neck length parameter and reaction cross-sections are explored. Further, the calcula- tions are done for PCN in order to identify the decay modes of 248No and 250No isotopes. The fusion-fission lifetimes and quasi fission lifetimes are compared with the dinuclear system (DNS) approach. The most probable fragments such as 122Sn and 128T e are observed near to the magic shell closure Z = 50 and N = 82. The ff and qf lifetime decreases with increase in the excitation energy.
{"title":"Investigation of decay mechanisms and associated aspects of exotic Nobeliumisotopes using the Skyrme energy density formalism","authors":"Shubhpreet Kaur, Raj Kumar, Manoj K. Sharma","doi":"10.1088/1674-1137/ad65dd","DOIUrl":"https://doi.org/10.1088/1674-1137/ad65dd","url":null,"abstract":"\u0000 Persistent theoretical and experimental attempts have been made to investigate the heavy ion induced reactions and their subsequent decay mechanisms in superheavy mass region. In addition, the region of transfermium elements is itself of great interest because of the neutron / proton shell effects. Here, we aim to study the subsequent decay mechanisms of two isotopes of Z = 102 nucleus, i.e. 248No and 250No. The dynamical cluster-decay model (DCM) based on Quantum Mechanical Fragmen- tation Theory (QMFT), is employed to conduct a comprehensive analysis of compound nucleus (CN) and non-compound nucleus (nCN) mechanisms such as fusion-fission (ff), Quasi fission (QF) and fast fission (FF), the role of centre of mass energy (Ec.m.) and angular momentum (ℓ) for 248No and 250No isotopes. The nuclear interaction potential is obtained using the Skyrme energy density formalism (SEDF) in the domain of GSkI force parameters. The probability of compound nucleus formation (PCN ) is determined using a function that depends on the centre of mass energy. The lifetimes for the fusion-fission (ff) quasi fission (QF) channels are explored. Here, CN and nCN decay mechanisms for two isotopes of Z = 102 nobelium are studied over the wide range of centre-of-mass (Ec.m.) by including the quadrupole deformation (β2) and optimum orientations (θopt.) of decaying fragments. The fragmentation potential, preformation probability, neck length parameter and reaction cross-sections are explored. Further, the calcula- tions are done for PCN in order to identify the decay modes of 248No and 250No isotopes. The fusion-fission lifetimes and quasi fission lifetimes are compared with the dinuclear system (DNS) approach. The most probable fragments such as 122Sn and 128T e are observed near to the magic shell closure Z = 50 and N = 82. The ff and qf lifetime decreases with increase in the excitation energy.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":"29 27","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141814032","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 : 2024-07-22DOI: 10.1088/1674-1137/ad65de
R. Muharlyamov, T. Pankratyeva, Shehabaldeen O. A. Bashir
We study the isotropization process of Bianchi-I space-times in the Horndeski theory with $G_3(X,phi)neq 0$ and $G_5=text{const}/X$. A global unidirectional electromagnetic field interacts with a scalar field according to the law $f^2(phi)F_{munu}F^{munu}$. In the Horndeski theory, the anisotropy can develop in different ways. The proposed reconstruction method allowed us to build models with acceptable the anisotropy behavior. To analyze space-time anisotropy, we used the relations $a_i/a$ ($i=1,2,3$), where $a_i$ are metric functions and $aequiv(a_1a_2a_3)^{1/3}$.
{"title":"Isotropization of the magnetic universe in the Horndeski theory with $G_3(X,phi)$ and $G_5(X)$","authors":"R. Muharlyamov, T. Pankratyeva, Shehabaldeen O. A. Bashir","doi":"10.1088/1674-1137/ad65de","DOIUrl":"https://doi.org/10.1088/1674-1137/ad65de","url":null,"abstract":"\u0000 We study the isotropization process of Bianchi-I space-times in the Horndeski theory with $G_3(X,phi)neq 0$ and $G_5=text{const}/X$. A global unidirectional electromagnetic field interacts with a scalar field according to the law $f^2(phi)F_{munu}F^{munu}$. In the Horndeski theory, the anisotropy can develop in different ways. The proposed reconstruction method allowed us to build models with acceptable the anisotropy behavior. To analyze space-time anisotropy, we used the relations $a_i/a$ ($i=1,2,3$), where $a_i$ are metric functions and $aequiv(a_1a_2a_3)^{1/3}$.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":"3 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141816598","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 : 2024-07-19DOI: 10.1088/1674-1137/ad654f
Parth Bambhaniya, Siddharth Madan
Naked singularities form during the gravitational collapse of inhomogeneous matter clouds. The final nature of the singularity depends on the initial conditions of the matter properties and types of matter profiles. These naked singularities can also be divided into two types: null-like and timelike singularities. The spacelike singularity of the Schwarzschild black hole can be distinguished from the null and timelike naked singularity spacetimes. In light of this, we investigate the precession of timelike bound orbits in the null naked singularity spacetime, as well as tidal force effects and geodesic deviation features. As a result, we find that the orbital precession of the timelike bound orbits in null naked singularity spacetime could be distinguished from the Schwarzschild precession case. The radial component of the tidal force has an intriguing profile, whereas the angular component has a profile which is comparable to that of a Schwarzschild black hole scenario. The geodesic deviation equation is then solved numerically, yielding results that resemble a Schwarzschild black hole. These characteristic features can then be used to discern amongst these singularities.
{"title":"Tidal force effects and bound orbits in null naked singularity spacetime","authors":"Parth Bambhaniya, Siddharth Madan","doi":"10.1088/1674-1137/ad654f","DOIUrl":"https://doi.org/10.1088/1674-1137/ad654f","url":null,"abstract":"\u0000 Naked singularities form during the gravitational collapse of inhomogeneous matter clouds. The final nature of the singularity depends on the initial conditions of the matter properties and types of matter profiles. These naked singularities can also be divided into two types: null-like and timelike singularities. The spacelike singularity of the Schwarzschild black hole can be distinguished from the null and timelike naked singularity spacetimes. In light of this, we investigate the precession of timelike bound orbits in the null naked singularity spacetime, as well as tidal force effects and geodesic deviation features. As a result, we find that the orbital precession of the timelike bound orbits in null naked singularity spacetime could be distinguished from the Schwarzschild precession case. The radial component of the tidal force has an intriguing profile, whereas the angular component has a profile which is comparable to that of a Schwarzschild black hole scenario. The geodesic deviation equation is then solved numerically, yielding results that resemble a Schwarzschild black hole. These characteristic features can then be used to discern amongst these singularities.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":" May","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141824090","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 : 2024-07-19DOI: 10.1088/1674-1137/ad654e
R. Saleem, Muhammad Hamza Rasool, M. Aslam, Iqra Shahid
This manuscript aims to study cosmic warm inflation (WI) in the framework of $f(Q)$ gravity, where $Q$ represents the nonmetricity (NM) scalar. To accomplish this task, we introduce the Tsallis, Renyi, and Barrow holographic dark energy (HDE) entropies into the standard Friedmann equations. Utilizing the slow-roll (SR) approximation, we find exact analytic solutions for the inflaton field, the effective potential necessary to produce inflation, and the scale factor for both low and high-dissipative regimes. We calculate key parameters, including SR parameters, the number of e-folds, the scalar spectral index and its running, and finally tensor-to-scalar ratio to assess the accuracy of the chosen DE models in light of the published observational data. The allowed ranges of the involved free parameters are found from the limits on inflationary observables imposed by the Planck data. It is concluded that the obtained results are consistent with proposed theoretical predictions up to $2sigma$ confidence level.
本手稿旨在$f(Q)$引力框架下研究宇宙暖膨胀（WI），其中$Q$代表非度量（NM）标量。为了完成这一任务，我们在标准弗里德曼方程中引入了查里斯、雷尼和巴罗全息暗能量（HDE）熵。利用慢速滚动（SR）近似，我们找到了膨胀场的精确解析解、产生膨胀所需的有效势，以及低耗散和高耗散状态下的尺度因子。我们计算了关键参数，包括 SR 参数、e-折叠数、标量谱指数及其运行，以及最后的张量标量比，以便根据已公布的观测数据评估所选 DE 模型的准确性。所涉及的自由参数的允许范围是根据普朗克数据对通胀观测值的限制而确定的。结论是所得到的结果与所提出的理论预测一致，置信度可达 2 美元。
{"title":"Warm Inflation Triggered by Entropies of Some Recent Dark Energy Models within $f(Q)$ Gravity","authors":"R. Saleem, Muhammad Hamza Rasool, M. Aslam, Iqra Shahid","doi":"10.1088/1674-1137/ad654e","DOIUrl":"https://doi.org/10.1088/1674-1137/ad654e","url":null,"abstract":"\u0000 This manuscript aims to study cosmic warm inflation (WI) in the framework of $f(Q)$ gravity, where $Q$ represents the nonmetricity (NM) scalar. To accomplish this task, we introduce the Tsallis, Renyi, and Barrow holographic dark energy (HDE) entropies into the standard Friedmann equations. Utilizing the slow-roll (SR) approximation, we find exact analytic solutions for the inflaton field, the effective potential necessary to produce inflation, and the scale factor for both low and high-dissipative regimes. We calculate key parameters, including SR parameters, the number of e-folds, the scalar spectral index and its running, and finally tensor-to-scalar ratio to assess the accuracy of the chosen DE models in light of the published observational data. The allowed ranges of the involved free parameters are found from the limits on inflationary observables imposed by the Planck data. It is concluded that the obtained results are consistent with proposed theoretical predictions up to $2sigma$ confidence level.","PeriodicalId":504778,"journal":{"name":"Chinese Physics C","volume":" 629","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141823817","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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