2024 Vol. , No. 7
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2024, 48(7): 073001. doi: 10.1088/1674-1137/ad380f
Abstract:
Signal reconstruction through software processing is a crucial component of the background and signal models in the PandaX-4T experiment, which is a multi-tonne dark matter direct search experiment. The accuracy of signal reconstruction is influenced by various detector artifacts, including noise, dark count of photomultiplier, photoionization of impurities in the detector, and other relevant considerations. In this study, we presented a detailed description of a semi-data-driven approach designed to simulate a signal waveform. This work provides a reliable model for the efficiency and bias of the signal reconstruction in the data analysis of PandaX-4T. By comparing critical variables that relate to the temporal shape and hit pattern of the signals, we found good agreement between the simulation and data.
Signal reconstruction through software processing is a crucial component of the background and signal models in the PandaX-4T experiment, which is a multi-tonne dark matter direct search experiment. The accuracy of signal reconstruction is influenced by various detector artifacts, including noise, dark count of photomultiplier, photoionization of impurities in the detector, and other relevant considerations. In this study, we presented a detailed description of a semi-data-driven approach designed to simulate a signal waveform. This work provides a reliable model for the efficiency and bias of the signal reconstruction in the data analysis of PandaX-4T. By comparing critical variables that relate to the temporal shape and hit pattern of the signals, we found good agreement between the simulation and data.
2024, 48(7): 073002. doi: 10.1088/1674-1137/ad3efe
Abstract:
Neutrinos from core-collapse supernovae are essential for understanding neutrino physics and stellar evolution. Dual-phase xenon dark matter detectors can be used to track explosions of galactic supernovae by detecting neutrinos through coherent elastic neutrino-nucleus scatterings. In this study, a variation of progenitor masses and explosion models are assumed to predict neutrino fluxes and spectra, which result in the number of expected neutrino events ranging from 6.6 to 13.7 at a distance of 10 kpc over a 10-s duration with negligible backgrounds at PandaX-4T. Two specialized triggering alarms for monitoring supernova burst neutrinos are built. The efficiency of detecting supernova explosions at various distances in the Milky Way is estimated. These alarms will be implemented in the real-time supernova monitoring system at PandaX-4T in the near future, which will provide supernova early warnings for the astronomical community.
Neutrinos from core-collapse supernovae are essential for understanding neutrino physics and stellar evolution. Dual-phase xenon dark matter detectors can be used to track explosions of galactic supernovae by detecting neutrinos through coherent elastic neutrino-nucleus scatterings. In this study, a variation of progenitor masses and explosion models are assumed to predict neutrino fluxes and spectra, which result in the number of expected neutrino events ranging from 6.6 to 13.7 at a distance of 10 kpc over a 10-s duration with negligible backgrounds at PandaX-4T. Two specialized triggering alarms for monitoring supernova burst neutrinos are built. The efficiency of detecting supernova explosions at various distances in the Milky Way is estimated. These alarms will be implemented in the real-time supernova monitoring system at PandaX-4T in the near future, which will provide supernova early warnings for the astronomical community.
2024, 48(7): 073003. doi: 10.1088/1674-1137/ad3dde
Abstract:
The prospects to study hyperon-nucleus/nucleon interactions at BESIII and similar\begin{document}$ e^+ e^- $\end{document} ![]()
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colliders are analyzed in this paper. Utilizing the large quantity of hyperons produced by the decay of 10 billion \begin{document}$ J/\psi $\end{document} ![]()
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and 2.7 billion \begin{document}$ \psi(3686) $\end{document} ![]()
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collected at BESIII, the cross sections of several specific elastic and inelastic hyperon-nucleus reactions can be measured via scattering between hyperons and nucleus in the dense objects of the BESIII detector. Subsequently, the cross sections of the corresponding hyperon-nucleon interactions can be extracted from further phenomenological calculations. The interactions between antihyperons and nucleus/nucleon, including scattering and annihilation, can also be studied using the method proposed in this study. The results will definitely benefit the realization of precise probes for hyperon-nuclei/nucleus interactions and establish constraints to study the potential of strong interaction, the origin of color confinement, a unified model for baryon-baryon interactions, and the internal structure of neutron stars. In addition, the desirable prospects of corresponding studies in the future Super Tau-Charm Factory (STCF) are discussed and estimated in this study.
The prospects to study hyperon-nucleus/nucleon interactions at BESIII and similar
2024, 48(7): 073004. doi: 10.1088/1674-1137/ad4267
Abstract:
Possible light bosonic dark matter interactions with the Standard Model photon have been searched using microwave resonant cavities. In this paper, we describe the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor\begin{document}$ Q_l=10^4 $\end{document} ![]()
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whose operation at a temperature of 22 mK is based on a dilution refrigerator. Our readout system consists of High Electron Mobility Transistors working as cryogenic amplifiers at 4 K, plus room-temperature amplifiers and a spectrum analyzer for signal power detection. We tested the system with a superconducting two-level system based on a single-photon source in the microwave frequency regime. We obtained an overall 95.6 dB system gain and –71.4 dB attenuation in the cavity's input channel. The effective noise temperature of the measurement system is 7.5 K.
Possible light bosonic dark matter interactions with the Standard Model photon have been searched using microwave resonant cavities. In this paper, we describe the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor
2024, 48(7): 073101. doi: 10.1088/1674-1137/ad3b9c
Abstract:
We present that by predicting the spectrum in discrete space from the phase shift in continuous space, the neural network can remarkably reproduce the numerical Lüscher's formula to a high precision. The model-independent property of the Lüscher's formula is naturally realized by the generalizability of the neural network. This exhibits the great potential of the neural network to extract model-independent relation between model-dependent quantities, and this data-driven approach could greatly facilitate the discovery of the physical principles underneath the intricate data.
We present that by predicting the spectrum in discrete space from the phase shift in continuous space, the neural network can remarkably reproduce the numerical Lüscher's formula to a high precision. The model-independent property of the Lüscher's formula is naturally realized by the generalizability of the neural network. This exhibits the great potential of the neural network to extract model-independent relation between model-dependent quantities, and this data-driven approach could greatly facilitate the discovery of the physical principles underneath the intricate data.
2024, 48(7): 073102. doi: 10.1088/1674-1137/ad3c2e
Abstract:
The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively. The production of the heavy quarkonium is essential to testing our understanding of quantum chromodynamics (QCD) in both perturbative and non-perturbative aspects. The electron-positron collider will provide a suitable platform for the precise study of the heavy quarkonium. The higher excited heavy quarkonium may contribute significantly to the ground states, which should be considered for sound estimation. We study the production rates of the higher excited states quarkonium pair in\begin{document}$ e^+e^-\to Z^0 \to |(Q\bar{Q^\prime})[n]\rangle + |(Q^\prime \bar{Q})[n']\rangle $\end{document} ![]()
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(\begin{document}$ Q,\; Q^\prime=c $\end{document} ![]()
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- or b-quarks) at the future Z factory under the non-relativistic QCD (NRQCD) framework, where the \begin{document}$ [n] $\end{document} ![]()
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/\begin{document}$ [n^\prime] $\end{document} ![]()
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represents the color-singlet states \begin{document}$ [n^1S_0],\; [n^3S_1],\; [n^1P_1] $\end{document} ![]()
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, and \begin{document}$ [n^3P_J] $\end{document} ![]()
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(\begin{document}$ n=1,2,3;\; J=0,1,2 $\end{document} ![]()
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). The differential angle distribution of cross sections \begin{document}${\rm d}\sigma/{\rm d}{\rm cos}\theta$\end{document} ![]()
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is given. We also discuss the uncertainties of cross sections caused by the varying quark masses and the renormalization scale μ. We show that significant numbers of events for pairs of higher excited state quarkonia can be generated at the super Z factory.
The heavy constituent quark pair of the heavy quarkonium is produced perturbatively and subsequently undergoes hadronization into the bound state non-perturbatively. The production of the heavy quarkonium is essential to testing our understanding of quantum chromodynamics (QCD) in both perturbative and non-perturbative aspects. The electron-positron collider will provide a suitable platform for the precise study of the heavy quarkonium. The higher excited heavy quarkonium may contribute significantly to the ground states, which should be considered for sound estimation. We study the production rates of the higher excited states quarkonium pair in
2024, 48(7): 073103. doi: 10.1088/1674-1137/ad3c2c
Abstract:
In this study, we have investigated the mathematical components of the Dirac equation in curved spacetime and how they can be applied to the analysis of neutrino oscillations. More specifically, we have developed a method for calculating the phase shift in flavor neutrino oscillations by utilizing a Taylor series expansion of the action that takes into account\begin{document}$ \Delta m^4 $\end{document} ![]()
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orders. In addition, we have used this method to assess how the phase difference in neutrino mass eigenstates changes according to the gravitational field described by the Johannsen spacetime.
In this study, we have investigated the mathematical components of the Dirac equation in curved spacetime and how they can be applied to the analysis of neutrino oscillations. More specifically, we have developed a method for calculating the phase shift in flavor neutrino oscillations by utilizing a Taylor series expansion of the action that takes into account
2024, 48(7): 073104. doi: 10.1088/1674-1137/ad3ddd
Abstract:
Vectorlike quarks (VLQs) with masses at the TeV-scale have been predicted in many new physics scenarios beyond the Standard Model (SM). Based on a simplified\begin{document}$ \left(X,T\right) $\end{document} ![]()
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doublet model including the exotic vectorlike X quark (VLQ-X) with an electric charge \begin{document}$ 5/3 $\end{document} ![]()
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, we study the production of the VLQ-X decaying into \begin{document}$ tW $\end{document} ![]()
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at the future Compact Linear Collider (CLIC) with \begin{document}$ \sqrt{s}=3 $\end{document} ![]()
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TeV including the initial state radiation and beamstrahlung effects. We focus on the final signals, including same-sign dileptons (electrons or muons), at least one b-tagged jet, and large missing transverse momentum. By performing detailed signal-to-background analyses and detector simulations, we obtain the \begin{document}$ 2\sigma $\end{document} ![]()
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exclusion capabilities and \begin{document}$ 5\sigma $\end{document} ![]()
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discovery reaches, respectively, on the mass of the VLQ-X \begin{document}$ m_{X} $\end{document} ![]()
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as well as the relevant parameters (\begin{document}${\rm Br}(X\to tW)$\end{document} ![]()
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for \begin{document}$ m_{X}<1500 $\end{document} ![]()
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GeV and the coupling strength \begin{document}$ g^{*} $\end{document} ![]()
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for \begin{document}$ m_{X}\geq1500 $\end{document} ![]()
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GeV) for some typical luminosities at the 3 TeV CLIC.
Vectorlike quarks (VLQs) with masses at the TeV-scale have been predicted in many new physics scenarios beyond the Standard Model (SM). Based on a simplified
2024, 48(7): 073105. doi: 10.1088/1674-1137/ad4268
Abstract:
Motivated by experimental hints and theoretical frameworks indicating the existence of an extended Higgs sector, we explore the feasibility of detecting a 95 GeV light Higgs boson decaying into a diphoton within the minimal dilaton model at the 14 TeV LHC. Initially, we identify the correlations between the production cross section, decay branching ratios, and model parameters, e.g., the scalar mixing angle\begin{document}$ \sin\theta_S $\end{document} ![]()
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. Subsequently, we utilize Monte Carlo simulations to generate the signal of the light Higgs boson via the \begin{document}$ pp \to t\bar{t}(s\to \gamma\gamma) $\end{document} ![]()
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process, along with the corresponding backgrounds. To effectively separate the signal from the dominant backgrounds \begin{document}$ tt\gamma\gamma $\end{document} ![]()
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, we employ a meticulous cut-based selection process. Ultimately, we find that with an integrated luminosity of \begin{document}$ L = 3000 \; {{\rm{fb}}}^{-1} $\end{document} ![]()
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, the regions of \begin{document}$ |\sin\theta_S|>0.2 $\end{document} ![]()
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can be covered over the \begin{document}$ 3\sigma $\end{document} ![]()
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level.
Motivated by experimental hints and theoretical frameworks indicating the existence of an extended Higgs sector, we explore the feasibility of detecting a 95 GeV light Higgs boson decaying into a diphoton within the minimal dilaton model at the 14 TeV LHC. Initially, we identify the correlations between the production cross section, decay branching ratios, and model parameters, e.g., the scalar mixing angle
2024, 48(7): 073106. doi: 10.1088/1674-1137/ad39cd
Abstract:
The S-wave\begin{document}$ \bar{q}q\bar{s}Q \;\; (q=u,\,d;\,Q=c,\,b) $\end{document} ![]()
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tetraquarks, with spin-parities \begin{document}$ J^P=0^+ $\end{document} ![]()
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, \begin{document}$ 1^+ $\end{document} ![]()
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, and \begin{document}$ 2^+ $\end{document} ![]()
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, in both isoscalar and isovector sectors, are systematically studied using a chiral quark model. The meson-meson, diquark-antidiquark, and K-type arrangements of quarks and all possible color wave functions are comprehensively considered. The four-body system is solved using the Gaussian expansion method, a highly efficient computational approach. Additonally, a complex-scaling formulation of the problem is established to disentangle bound, resonance, and scattering states. This theoretical framework has already been successfully applied in various tetra- and penta-quark systems. For the complete coupled channel and within the complex-range formulation, several narrow resonances of \begin{document}$ \bar{q}q\bar{s}c $\end{document} ![]()
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and \begin{document}$ \bar{q}q\bar{s}b $\end{document} ![]()
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systems are obtained, in each allowed \begin{document}$ I(J^P) $\end{document} ![]()
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-channel, within the energy regions of \begin{document}$ 2.4-3.4 $\end{document} ![]()
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GeV and \begin{document}$ 5.7-6.7 $\end{document} ![]()
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GeV, respectively. The predicted exotic states, which indicate a richer color structure when going towards multiquark systems beyond mesons and baryons, are expected to be confirmed in future high-energy particle and nuclear experiments.
The S-wave
2024, 48(7): 074001. doi: 10.1088/1674-1137/ad4264
Abstract:
The complete and incomplete fusion cross sections for 6Li+209Bi were measured using the in-beam γ-ray method around the Coulomb barrier. The cross sections of (deuteron captured) incomplete fusion (ICF) products were re-quantified experimentally for this reaction system. The results reveal that the ICF cross section is equivalent to that of complete fusion (CF) above the Coulomb barrier and dominant near or below the Coulomb barrier. A theoretical calculation based on the continuum discretized coupled channel (CDCC) method was performed for the aforementioned CF and ICF cross sections; the result is consistent with the experiments. The universal fusion function (UFF) was also compared with the measured CF cross section for different barrier parameters, demonstrating that the CF suppression factor is significantly influenced by the choice of potential, which can reflect both dynamic and static effects of breakup on the fusion process.
The complete and incomplete fusion cross sections for 6Li+209Bi were measured using the in-beam γ-ray method around the Coulomb barrier. The cross sections of (deuteron captured) incomplete fusion (ICF) products were re-quantified experimentally for this reaction system. The results reveal that the ICF cross section is equivalent to that of complete fusion (CF) above the Coulomb barrier and dominant near or below the Coulomb barrier. A theoretical calculation based on the continuum discretized coupled channel (CDCC) method was performed for the aforementioned CF and ICF cross sections; the result is consistent with the experiments. The universal fusion function (UFF) was also compared with the measured CF cross section for different barrier parameters, demonstrating that the CF suppression factor is significantly influenced by the choice of potential, which can reflect both dynamic and static effects of breakup on the fusion process.
2024, 48(7): 074101. doi: 10.1088/1674-1137/ad432c
Abstract:
A cross section evaluation of neutron induced reactions on 48Ti is undertaken using the Unified Monte Carlo-B (UMC-B) approach. The evaluation concentrates on estimating the covariance and the use of the UMC-B allows avoiding the deficiencies of linear regression brought by the traditional least squares method. Eight main neutron and charged particle emission reactions from n+48Ti in the fast neutron energy region below 20 MeV are studied in this work. The posterior probability density function (PDF) of each neutron cross section is obtained in a UMC-B Bayesian approach by convoluting the model PDFs sampled based on model parameters and the likelihood functions for the experimental data. Nineteen model parameters including level density, pair corrections, optical model and Kalbach matrix element parameter are stochastically sampled with the assumption of normal distributions to estimate the model uncertainty. The Cholesky factorization approach is applied to consider potential parameter correlations. Finally, the posterior covariance matrices are generated using the UMC-B generated weights. The new evaluated results are compared with the CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, TENDL-2021 and JENDL-5 evaluations and differences are discussed.
A cross section evaluation of neutron induced reactions on 48Ti is undertaken using the Unified Monte Carlo-B (UMC-B) approach. The evaluation concentrates on estimating the covariance and the use of the UMC-B allows avoiding the deficiencies of linear regression brought by the traditional least squares method. Eight main neutron and charged particle emission reactions from n+48Ti in the fast neutron energy region below 20 MeV are studied in this work. The posterior probability density function (PDF) of each neutron cross section is obtained in a UMC-B Bayesian approach by convoluting the model PDFs sampled based on model parameters and the likelihood functions for the experimental data. Nineteen model parameters including level density, pair corrections, optical model and Kalbach matrix element parameter are stochastically sampled with the assumption of normal distributions to estimate the model uncertainty. The Cholesky factorization approach is applied to consider potential parameter correlations. Finally, the posterior covariance matrices are generated using the UMC-B generated weights. The new evaluated results are compared with the CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, TENDL-2021 and JENDL-5 evaluations and differences are discussed.
2024, 48(7): 074102. doi: 10.1088/1674-1137/ad3d4b
Abstract:
In this paper, using the α particle preformation probabilities\begin{document}$ P_{\alpha} $\end{document} ![]()
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from Xu et al. [Xu and Ren, Nucl. Phys. A 760, 303 (2005)], which were extracted by fitting experimental half-lives of α decay, based on a phenomenological harmonic oscillator potential model (HOPM) [Bayrak, J Phys G 47, 025102 (2020)], refitting 178 α decay half-lives of even-even nuclei obtained from the latest nuclear property table NUBASE2020, we obtain the only one adjustable parameter \begin{document}$ V_0=162.6 $\end{document} ![]()
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MeV in the HOPM, i.e., the depth of nuclear potential. The corresponding root-mean-square (rms) deviation is \begin{document}$ \sigma=0.322 $\end{document} ![]()
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. Furthermore, to consider the contribution of centrifugal potential to unfavored α decay half-lives, adding a new term \begin{document}$ d\sqrt{l(l+1)} $\end{document} ![]()
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(d and l are the adjustable parameter and orbital angular momentum carried away by emitted α particle) to the logarithmic form of favored α decay half-lives under the HOPM framework, we propose an improved simple model (ISM) for calculating favored and unfavored α decay half-lives. Fitting the experimental half-lives of 205 unfavored α decay, we obtain \begin{document}$ d=0.381 $\end{document} ![]()
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. The ISM is used to calculate the unfavored α decay half-lives of 128 odd-A and 77 odd-odd nuclei. The results improve by 54.2% and 53.6%, respectively, compared with HOPM. In addition, we extend the ISM to predict the α decay half-lives of 144 nuclei with \begin{document}$ Z = 117,118,119 $\end{document} ![]()
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, and 120. For comparison, the improved model with eight parameters (DUR) proposed by Deng et al. [Deng, Phys. Rev. C 101, 034307 (2020)] and the modified universal decay law (MUDL) proposed by Soylu et al. [Soylu, Nucl. Phys. A 1013, 122221 (2021)] are also used. The predictions of these models and/or formulas are generally consistent with each other.
In this paper, using the α particle preformation probabilities
2024, 48(7): 074103. doi: 10.1088/1674-1137/ad39cc
Abstract:
We explore the properties of 4110 nuclides from\begin{document}$ Z=5 $\end{document} ![]()
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to \begin{document}$ Z=82 $\end{document} ![]()
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with the Sky3D code and the composition of the outer crust in magnetars under extreme magnetic fields. The effects of the variation in nuclear masses due to magnetic fields on the outer crust are comprehensively studied. The neutron-drip transition pressure, equation of state, and neutron fraction in the outer crust are also discussed.
We explore the properties of 4110 nuclides from
2024, 48(7): 074104. doi: 10.1088/1674-1137/ad4269
Abstract:
The consistent three-body model reaction methodology (TBMRM) proposed by J. Lee et al. [ Phys. Rev. C 69, 064313 (2004); Phys. Rev. C 73, 044608 (2006); Phys. Rev. C 75, 064320 (2007)], which includes adopting the simple zero-range adiabatic wave approximation, constraining the single-particle potentials using modern Hartree–Fock calculations, and using global nucleon optical model potential (OMP) geometries, are widely applied in systematic studies of transfer reactions. In this study, we investigate the influence of different nucleon OMPs in extracting spectroscopic factors (SFs) from (\begin{document}$ p, d $\end{document} ![]()
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) reactions. Our study covers 32 sets of angular distribution data of (\begin{document}$ p, d $\end{document} ![]()
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) reactions on four targets and a large range of incident energies (20-200 MeV/nucleon). This study uses two semi-microscopic nucleon OMPs, i.e., Jeukenne, Lejeune, and Mahaux (JLM) [Phys. Rev. C 16, 80 (1977); Phys. Rev. C 58, 1118 (1998)] and CTOM [Phys. Rev. C 94, 034606 (2016)], and a pure microscopic nucleon potential, i.e., WLH [Phys. Rev. Lett. 127, 182502 (2021)]. The results are compared with those using the phenomenological global optical potential KD02 [Nucl. Phys. A 713, 231 (2003)]. We find that the incident energy dependence of spectroscopic factors extracted from (\begin{document}$ p, d $\end{document} ![]()
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) reactions is evidently suppressed when microscopic OMPs are employed for 12C, 28Si, and 40Ca. In addition, spectroscopic factors extracted using the systematic microscopic optical potential CTOM based on the Dirac-Brueckner-Hartree-Fock theory are more in line with the results obtained from (\begin{document}$ e, e'p $\end{document} ![]()
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) measurements, except for 16O and 40Ca at high energies (> 100 MeV), necessitating an exact treatment of double-magic nuclei. The results obtained by using the pure microscopic optical potential, WLH, based on the EFT theory show the same trend as those of CTOM but are generally higher. The JLM potential, which relies on simplified nuclear matter calculations with old-fashioned bare interactions, produces results that are very similar to those of the phenomenological potential KD02. Our results indicate that modern microscopic OMPs are reliable tools for probing the nuclear structure using transfer reactions across a wide energy range.
The consistent three-body model reaction methodology (TBMRM) proposed by J. Lee et al. [ Phys. Rev. C 69, 064313 (2004); Phys. Rev. C 73, 044608 (2006); Phys. Rev. C 75, 064320 (2007)], which includes adopting the simple zero-range adiabatic wave approximation, constraining the single-particle potentials using modern Hartree–Fock calculations, and using global nucleon optical model potential (OMP) geometries, are widely applied in systematic studies of transfer reactions. In this study, we investigate the influence of different nucleon OMPs in extracting spectroscopic factors (SFs) from (
2024, 48(7): 074105. doi: 10.1088/1674-1137/ad3b9d
Abstract:
Accurate and reliable nuclear decay databases are essential for fundamental and applied nuclear research studies. However, decay data are not usually as accurate as expected and need improvement. Hence, a new Chinese nuclear decay database in the fission product mass region (A = 66−172) based on several major national evaluated data libraries has been developed under joint efforts in the CNDC working group. A total of 2358 nuclides have been included in this decay database. Two main data formats, namely ENSDF and ENDF, have been adopted. For the total mean β and γ energies, available data from total absorption gamma ray spectroscopy measurements have been adopted. For some nuclides without experimental measurements, theoretically calculated values have been added.
Accurate and reliable nuclear decay databases are essential for fundamental and applied nuclear research studies. However, decay data are not usually as accurate as expected and need improvement. Hence, a new Chinese nuclear decay database in the fission product mass region (A = 66−172) based on several major national evaluated data libraries has been developed under joint efforts in the CNDC working group. A total of 2358 nuclides have been included in this decay database. Two main data formats, namely ENSDF and ENDF, have been adopted. For the total mean β and γ energies, available data from total absorption gamma ray spectroscopy measurements have been adopted. For some nuclides without experimental measurements, theoretically calculated values have been added.
2024, 48(7): 074106. doi: 10.1088/1674-1137/ad47aa
Abstract:
Neutron-rich P, Cl, and K isotopes, particularly those with neutron numbers of approximately\begin{document}$ N=28 $\end{document} ![]()
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, have attracted extensive experimental and theoretical interest. We utilize the ab initio valence-space in-medium similarity renormalization group approach, based on chiral nucleon-nucleon and three-nucleon forces, to investigate the exotic properties of these isotopes. Systematic calculations of the low-lying spectra are performed. A key finding is the level inversion between \begin{document}$ 3/2_1^+ $\end{document} ![]()
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and \begin{document}$ 1/2_1^+ $\end{document} ![]()
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states in odd-A isotopes, attributed to the inversion of \begin{document}$ \pi 0d_{3/2} $\end{document} ![]()
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and \begin{document}$ \pi 1s_{1/2} $\end{document} ![]()
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single-particle states. The ab initio calculations, which incorporate the three-nucleon forces, correlate closely with existing experimental data. Further calculations of effective proton single-particle energies provide deeper insights into the shell evolution for \begin{document}$ Z=14 $\end{document} ![]()
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and \begin{document}$ 16 $\end{document} ![]()
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sub-shells. Our results indicate that the three-body force plays important roles in the shell evolution for \begin{document}$ Z=14 $\end{document} ![]()
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and \begin{document}$ 16 $\end{document} ![]()
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sub-shells with neutron numbers ranging from 20 to 28. Additionally, systematic ab initio calculations are conducted for the low-lying spectra of odd-odd nuclei. The results correspond with experimental data and provide new insights for future research into these isotopes up to and beyond the drip line.
Neutron-rich P, Cl, and K isotopes, particularly those with neutron numbers of approximately
2024, 48(7): 075101. doi: 10.1088/1674-1137/ad34c1
Abstract:
We investigate the dynamic and thermodynamic laws governing rotating regular black holes. By analyzing dynamic properties, i.e., the interaction between scalar particles and rotating regular black holes, we establish the criteria that determine whether such black holes satisfy the laws of thermodynamics. In addition, we provide the general form of conserved quantities related to rotating regular black holes, including the relevant flows associated with neutral scalar particles. Meanwhile, we reexamine the relationship between the third law of thermodynamics and weak cosmic censorship conjecture for rotating regular black holes. Based on the abovementioned criteria, we discuss the laws of thermodynamics for three models of rotating regular black holes: Rotating Hayward black holes, Kerr black-bounce solutions, and loop quantum gravity black holes. Our findings indicate that none of the three models satisfies the first law of thermodynamics. In particular, the first and third models fail to comply with the three laws of thermodynamics, whereas the second model satisfies only the second and third laws of thermodynamics. Finally, we attempt to rescue the laws of thermodynamics by modifying entropy or extending the phase space. However, the two scenarios cannot ensure the three laws of thermodynamics in the three models, which reveals an unusual property of rotating regular black holes.
We investigate the dynamic and thermodynamic laws governing rotating regular black holes. By analyzing dynamic properties, i.e., the interaction between scalar particles and rotating regular black holes, we establish the criteria that determine whether such black holes satisfy the laws of thermodynamics. In addition, we provide the general form of conserved quantities related to rotating regular black holes, including the relevant flows associated with neutral scalar particles. Meanwhile, we reexamine the relationship between the third law of thermodynamics and weak cosmic censorship conjecture for rotating regular black holes. Based on the abovementioned criteria, we discuss the laws of thermodynamics for three models of rotating regular black holes: Rotating Hayward black holes, Kerr black-bounce solutions, and loop quantum gravity black holes. Our findings indicate that none of the three models satisfies the first law of thermodynamics. In particular, the first and third models fail to comply with the three laws of thermodynamics, whereas the second model satisfies only the second and third laws of thermodynamics. Finally, we attempt to rescue the laws of thermodynamics by modifying entropy or extending the phase space. However, the two scenarios cannot ensure the three laws of thermodynamics in the three models, which reveals an unusual property of rotating regular black holes.
2024, 48(7): 075102. doi: 10.1088/1674-1137/ad3942
Abstract:
Fast radio bursts (FRBs) are useful cosmological probes with numerous applications in cosmology. The distribution of the dispersion measurement contribution from the intergalactic medium is a key issue. A quasi-Gaussian distribution has been used to replace the traditional Gaussian distribution, yielding promising results. However, this study suggests that there may be additional challenges in its application. We used 35 well-localized FRBs to constrain the Hubble constant\begin{document}$ H_0 $\end{document} ![]()
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along with two FRB-related parameters, yielding \begin{document}$H_0=60.99^{+4.57}_{-4.90}\ {\rm{km\; s^{-1}}\; Mpc^{-1}}$\end{document} ![]()
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. The best-fitting Hubble constant \begin{document}$ H_0 $\end{document} ![]()
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is smaller than the value obtained from the Cosmic Microwave Background (CMB), which may be caused by the small sample size of current FRB data. Monte Carlo simulations indicate that a set of 100 simulated FRBs provides a more precise fitting result for the Hubble constant. However, the precision of the Hubble constant does not improve when further enlarging the FRB sample. Additional simulations reveal a systematic deviation in the fitting results of \begin{document}$ H_0 $\end{document} ![]()
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, attributed to the quasi-Gaussian distribution of the dispersion measure in the intergalactic medium. Despite this, the results remain reliable within 1σ uncertainty, assuming that a sufficient number of FRB data points are available.
Fast radio bursts (FRBs) are useful cosmological probes with numerous applications in cosmology. The distribution of the dispersion measurement contribution from the intergalactic medium is a key issue. A quasi-Gaussian distribution has been used to replace the traditional Gaussian distribution, yielding promising results. However, this study suggests that there may be additional challenges in its application. We used 35 well-localized FRBs to constrain the Hubble constant
2024, 48(7): 075103. doi: 10.1088/1674-1137/ad3c2d
Abstract:
This paper investigates observable signatures of hot spots orbiting Reissner-Nordström (RN) black holes and naked singularities. For an RN black hole, we find two discernible lensing image tracks in time integrated images, capturing a complete orbit of hot spots and a image shadow within the critical curve where photons with a small impact parameter fall into the event horizon. Conversely, in RN singularities, additional image tracks can be found within the critical curve, originating from photons reflected by the infinitely high effective potential well. Moreover, we find incomplete and converging tracks from the time integrated images of hot spot orbiting RN singularities that have no photon sphere. The presence of these additional image tracks significantly influences temporal magnitudes at their local maxima, enabling us to differentiate between RN black holes and RN naked singularities.
This paper investigates observable signatures of hot spots orbiting Reissner-Nordström (RN) black holes and naked singularities. For an RN black hole, we find two discernible lensing image tracks in time integrated images, capturing a complete orbit of hot spots and a image shadow within the critical curve where photons with a small impact parameter fall into the event horizon. Conversely, in RN singularities, additional image tracks can be found within the critical curve, originating from photons reflected by the infinitely high effective potential well. Moreover, we find incomplete and converging tracks from the time integrated images of hot spot orbiting RN singularities that have no photon sphere. The presence of these additional image tracks significantly influences temporal magnitudes at their local maxima, enabling us to differentiate between RN black holes and RN naked singularities.
2024, 48(7): 075104. doi: 10.1088/1674-1137/ad3b7e
Abstract:
Considering the nonminimal coupling of the dilaton field to the massive graviton field in Maxwell-dilaton-massive gravity, we obtain a class of analytical solutions of charged black holes, which are neither asymptotically flat nor (A)dS. The calculated thermodynamic quantities, such as mass, temperature, and entropy, verify the validity of the first law of black hole thermodynamics. Moreover, we further investigate the critical behaviors of these black holes in the grand canonical and canonical ensembles and find a novel critical phenomenon never before observed, known as the "reverse" reentrant phase transition with a tricritical point. It implies that the system undergoes a novel "SBH-LBH-SBH" phase transition process and is the reverse of the "LBH-SBH-LBH" process observed in reentrant phase transitions.
Considering the nonminimal coupling of the dilaton field to the massive graviton field in Maxwell-dilaton-massive gravity, we obtain a class of analytical solutions of charged black holes, which are neither asymptotically flat nor (A)dS. The calculated thermodynamic quantities, such as mass, temperature, and entropy, verify the validity of the first law of black hole thermodynamics. Moreover, we further investigate the critical behaviors of these black holes in the grand canonical and canonical ensembles and find a novel critical phenomenon never before observed, known as the "reverse" reentrant phase transition with a tricritical point. It implies that the system undergoes a novel "SBH-LBH-SBH" phase transition process and is the reverse of the "LBH-SBH-LBH" process observed in reentrant phase transitions.
2024, 48(7): 075105. doi: 10.1088/1674-1137/ad3f95
Abstract:
In this study, we constructed ten dark energy models to test whether they can reconcile the Hubble tension and how much it is affected by parameterization. To establish a fair test, the models are diverse, encompassing fractional, logarithmic, exponential, and inverse exponential forms as well as several non-parameterized models. The dataset we used includes the NPIPE pipeline of cosmic microwave background (CMB) power-spectrum data from Planck2020, Pantheon+ samples from Supernovae Type Ia, and baryon acoustic oscillations. The MCMC calculations imply dark energy transferring from\begin{document}$ w< -1 $\end{document} ![]()
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to \begin{document}$ w > -1 $\end{document} ![]()
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for the four parameterized dark energy models. However, these models cannot adequately reconcile the Hubble tension. Notably, we found that phantom-like dark energy with \begin{document}$ w < -1 $\end{document} ![]()
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can achieve the greatest reduction in the Hubble tension to \begin{document}$ 0.1808\sigma $\end{document} ![]()
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. However, AIC analysis indicates that this alleviation is at the cost of high AIC. We also investigated the effect of constructions on the derivative of the equation of state \begin{document}$ {\rm d}w/{\rm d}a $\end{document} ![]()
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, cosmic density parameter, CMB power spectrum \begin{document}$ C^{TT} $\end{document} ![]()
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, and matter spectra \begin{document}$ P(k) $\end{document} ![]()
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. We also found that the Hubble tension may be related to the reionization process.
In this study, we constructed ten dark energy models to test whether they can reconcile the Hubble tension and how much it is affected by parameterization. To establish a fair test, the models are diverse, encompassing fractional, logarithmic, exponential, and inverse exponential forms as well as several non-parameterized models. The dataset we used includes the NPIPE pipeline of cosmic microwave background (CMB) power-spectrum data from Planck2020, Pantheon+ samples from Supernovae Type Ia, and baryon acoustic oscillations. The MCMC calculations imply dark energy transferring from
2024, 48(7): 075106. doi: 10.1088/1674-1137/ad3eff
Abstract:
Horndeski theory constitutes the most general model of scalar-tensor theories. It has attracted much attention in recent years in relation with black holes, celestial dynamics, stability analysis, etc. It is important to note that, for certain subclasses of Horndeski models, one can obtain analytic solutions for the background fields. This facilitates the investigation of the corresponding stability problems in detail. In particular, we aim to determine the constraints to the model or theory under which the stability conditions can be satisfied. In this study, we focused on a subclass of Horndeski theory and a set of analytic background solutions. In addition, the odd-parity gravitational perturbation and 2nd-order Lagrangian were investigated. Through careful analysis, the instability was identified within the neighborhood of the event horizon. This allows exclusion of a specific geometry for the model. Such an instability is implanted in the structure of the corresponding Lagrangian and is not erased by simply adding numerical constraints on the coupling parameters. As a starting point of our research, the current study provides insights for further exploration of the Horndeski theory.
Horndeski theory constitutes the most general model of scalar-tensor theories. It has attracted much attention in recent years in relation with black holes, celestial dynamics, stability analysis, etc. It is important to note that, for certain subclasses of Horndeski models, one can obtain analytic solutions for the background fields. This facilitates the investigation of the corresponding stability problems in detail. In particular, we aim to determine the constraints to the model or theory under which the stability conditions can be satisfied. In this study, we focused on a subclass of Horndeski theory and a set of analytic background solutions. In addition, the odd-parity gravitational perturbation and 2nd-order Lagrangian were investigated. Through careful analysis, the instability was identified within the neighborhood of the event horizon. This allows exclusion of a specific geometry for the model. Such an instability is implanted in the structure of the corresponding Lagrangian and is not erased by simply adding numerical constraints on the coupling parameters. As a starting point of our research, the current study provides insights for further exploration of the Horndeski theory.
2024, 48(7): 075107. doi: 10.1088/1674-1137/ad32bf
Abstract:
Here, we study the quantum coherence of N-partite Greenberger-Horne-Zeilinger (GHZ) and W states in the multiverse consisting of N causally disconnected de Sitter spaces. Interestingly, N-partite coherence increases monotonically with curvature, whereas the curvature effect destroys quantum entanglement and discord, indicating that the curvature effect is beneficial to quantum coherence and harmful to quantum correlations in the multiverse. We find that with an increase in n expanding de Sitter spaces, the N-partite coherence of the GHZ state increases monotonically for any curvature, whereas the quantum coherence of the W state decreases or increases monotonically depending on the curvature. We find a distribution relationship, which indicates that the correlated coherence of the N-partite W state is equal to the sum of all bipartite correlated coherence in the multiverse. Multipartite coherence exhibits unique properties in the multiverse, suggesting that it may provide some evidence for the existence of the multiverse.
Here, we study the quantum coherence of N-partite Greenberger-Horne-Zeilinger (GHZ) and W states in the multiverse consisting of N causally disconnected de Sitter spaces. Interestingly, N-partite coherence increases monotonically with curvature, whereas the curvature effect destroys quantum entanglement and discord, indicating that the curvature effect is beneficial to quantum coherence and harmful to quantum correlations in the multiverse. We find that with an increase in n expanding de Sitter spaces, the N-partite coherence of the GHZ state increases monotonically for any curvature, whereas the quantum coherence of the W state decreases or increases monotonically depending on the curvature. We find a distribution relationship, which indicates that the correlated coherence of the N-partite W state is equal to the sum of all bipartite correlated coherence in the multiverse. Multipartite coherence exhibits unique properties in the multiverse, suggesting that it may provide some evidence for the existence of the multiverse.
2024, 48(7): 075108. doi: 10.1088/1674-1137/ad3e67
Abstract:
This paper investigates the physical properties and predicted radii of compact stars generated by the Tolman-IV complexity-free model within the background of modified gravity theory, particularly the\begin{document}$ f(\mathcal{R},T) $\end{document} ![]()
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-gravity theory, under complexity formalism for a spherically symmetric spacetime proposed by L. Herrera [Phys Rev D 97: 044010, 2018]. By solving the resulting set of differential equations, we obtain the explicit forms of the energy-momentum (EM) tensor components, including the density, radial pressure, and tangential pressure. The influence of the parameter χ on various physical properties of the star is thoroughly investigated. The model undergoes a series of rigorous tests to determine its physical relevance. The findings indicate that the model exhibits regularity, stability, and a surface with vanishing pressure. The boundary of this surface is determined by carefully selecting the parameter space. The complexity method employed in \begin{document}$ f(\mathcal{R},T) $\end{document} ![]()
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gravity offers an interesting approach for developing astrophysical models that are consistent with observable events as demonstrated by recent experiments. In this regard, we use observational data from the GW190814 event, detected by the LIGO and Virgo observatories, to investigate the validity of the Tolman-IV model in \begin{document}$f(\mathcal{R},T)$\end{document} ![]()
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gravity. The analysis includes comparing the model's predictions with the observed characteristics of the compact object involved in the merger. In addition, data from two-millisecond pulsars, PSR J1614-2230 and PSR J0952-0607, are incorporated to further constrain the theoretical theories. However, we present a diagram depicting the relationship between the total mass and radius of the compact object candidates for different values of χ.
This paper investigates the physical properties and predicted radii of compact stars generated by the Tolman-IV complexity-free model within the background of modified gravity theory, particularly the
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