Chinese Physics C

2024-11 Contents

2024, 48(11): 1-3.

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Investigating higgsino dark matter in the semi-constrained NMSSM

Kun Wang, Jingya Zhu

2024, 48(11): 113101. doi: 10.1088/1674-1137/ad6e60

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In this study, we explored the characteristics of higgsino-dominated dark matter (DM) within the semi-constrained Next-to-Minimal Supersymmetric Standard Model (scNMSSM), covering a mass range from hundreds of GeV to several TeV. We carefully analyzed the parameter space under existing theoretical and experimental constraints to confirm the viability of higgsino-dominated lightest supersymmetric particles (LSPs) with masses between 100 GeV and 4 TeV. Our study examined various DM annihilation mechanisms, emphasizing the significant role of coannihilation with the next-to-lightest supersymmetric particle (NLSP), which includes other higgsino-dominated particles such as

\begin{document}$\tilde{\chi}^{0}_2$\end{document}

and

\begin{document}$\tilde{\chi}^{\pm}_1$\end{document}

. We categorize the annihilation processes into three main classes:

\begin{document}$\tilde{\chi}_1^{\pm}$\end{document}

coannihilation, Higgs funnel annihilation, and

\begin{document}$\tilde{\tau}_1$\end{document}

coannihilation. Each class combines interactions with

\begin{document}$\tilde{\chi}_1^{\pm}$\end{document}

. Our results indicate that achieving the correct relic density in heavier higgsino LSPs requires a combination of coannihilation and Higgs funnel mechanisms. We also assessed the potential of future experiments, such as XENONnT, LUX-ZEPLIN (LZ), PandaX-xT, and the Cherenkov Telescope Array (CTA), to probe these DM scenarios through direct and indirect detections. In particular, future spin-independent DM detections may cover all samples with the correct DM relic density for

\begin{document}$\mu \gtrsim 1300$\end{document}

GeV. Furthermore, future colliders such as the International Linear Collider (ILC) and Compact Linear Collider (CLIC) are expected to exceed the detection capabilities of current hadron colliders, especially for higher mass NLSPs. Notably, CLIC, which will operate at 3000 GeV, is anticipated to enable thorough investigation of all samples with insufficient DM relic density for

\begin{document}$\mu \lesssim 1300$\end{document}

GeV.

W boson mass in NP models with an extra U(1) gauge group

Jin-Lei Yang, Zhao-Feng Ge, Xiu-Yi Yang, Sheng-Kai Cui, Tai-Fu Feng

2024, 48(11): 113102. doi: 10.1088/1674-1137/ad7012

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The precise measurement of the W boson mass is closely related to the contributions of new physics (NP), which can significantly constrain the parameter space of NP models, particularly those with an additional

\begin{document}$ U(1) $\end{document}

local gauge group. The inclusion of a new Z' gauge boson and gauge couplings in these models can contribute to the oblique parameters S, T, and U and the W boson mass at tree level. Considering the effects of kinetic mixing, in this study, we calculate and analyze the oblique parameters S, T, and U and the W boson mass in such NP models. We find that the kinetic mixing effects can make significant contributions to the W boson mass, and these contributions can be eliminated by redefining the gauge boson fields by removing neutral currents with charged leptons if the leptonic Yukawa couplings are invariant under the extra

\begin{document}$ U(1) $\end{document}

local gauge group, even with nonzero kinetic mixing effects.

Polarized and unpolarized off-shell ${ \boldsymbol H^\ast{\bf\to} \boldsymbol Z\boldsymbol Z{\bf\rightarrow 4}\boldsymbol\ell}$ decay above the ${{\bf 2}\boldsymbol m_Z} $ threshold

A. I. Hernández-Juárez, R. Gaitán, G. Tavares-Velasco

2024, 48(11): 113103. doi: 10.1088/1674-1137/ad62de

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An analysis of the off-shell

\begin{document}$ H^\ast\rightarrow ZZ \rightarrow \overline{\ell}_1\ell_1\overline{\ell}_2\ell_2 $\end{document}

decay width is presented for both unpolarized and polarized

\begin{document}$ Z $\end{document}

gauge bosons in the scenario with the most general

\begin{document}$ H^*ZZ $\end{document}

vertex function, which is expressed in terms of two

\begin{document}$\rm CP$\end{document}

-even (

\begin{document}$ \hat b_Z $\end{document}

and

\begin{document}$ \hat c_Z $\end{document}

) and one

\begin{document}$\rm CP$\end{document}

-odd (

\begin{document}$ \tilde b_Z $\end{document}

) anomalous couplings. The SM contributions to the

\begin{document}$ H^*ZZ $\end{document}

coupling up to the one-loop level are also included. Explicit analytic results for the unpolarized and polarized

\begin{document}$ H^\ast\rightarrow ZZ \rightarrow \overline{\ell}_1\ell_1\overline{\ell}_2\ell_2 $\end{document}

square amplitudes and the four-body phase space are presented, out of which several observable quantities can be obtained straightforwardly. Regarding numerical analysis, a cross-check was performed via

\begin{document}$\mathrm{MadGraph5\_aMC@NLO} $\end{document}

, where our model was implemented with the aid of FeynRules. We then considered the most stringent bounds on anomalous complex

\begin{document}$ H^*ZZ $\end{document}

couplings and analyzed the effects of the polarizations of the

\begin{document}$ Z $\end{document}

gauge bosons through the polarized

\begin{document}$ H^\ast\rightarrow ZZ \rightarrow \overline{\ell}_1\ell_1\overline{\ell}_2\ell_2 $\end{document}

decay width as well as left-right and forward-backward asymmetries, which were found to be sensitive to new-physics effects. Particular focus was put on the effects of the absorptive parts of the anomalous

\begin{document}$ H^*ZZ $\end{document}

couplings, which have been largely overlooked up to now in LHC analyses. It was found that the studied observable quantities, particularly the left-right asymmetries, can be helpful to search for effects of

\begin{document}$\rm CP$\end{document}

-violation in the

\begin{document}$ H^*ZZ $\end{document}

coupling and set bounds on the absorptive parts. For completeness, we also analyzed the case of unpolarized

\begin{document}$ Z $\end{document}

gauge bosons.

Analytical formula for the cross section of hadron production from e⁺e⁻ collisions around the narrow charmouinum resonances

Ya-Nan Wang, Ya-Di Wang, Ping Wang

2024, 48(11): 113104. doi: 10.1088/1674-1137/ad6c09

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The paper reports an analytical formula for the production cross section of e⁺e⁻ annihilation to hadrons in the vicinity of a narrow resonance, particularly in the τ-charm region, while considering initial state radiation. Despite some approximations in its derivation, comparison between the analytical formula and direct integration of ISR shows good accuracy, indicating that the analytical formula meets current experimental requirements. Furthermore, this paper presents a comparison of the cross section between the analytical formula and calculations using the ConExc Monte Carlo generator. The efficiency of the analytical formula in significantly reducing computing time makes it a favorable choice for the regression procedure to extract the parameters of narrow charmonium resonances in experiments.

Form factor for Dalitz decays from J/ψ to light pseudoscalars

Chunjiang Shi, Ying Chen, Xiangyu Jiang, Ming Gong, Zhaofeng Liu, Wei Sun

2024, 48(11): 113105. doi: 10.1088/1674-1137/ad641b

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We calculate the form factor

\begin{document}$M(q^2)$\end{document}

for the Dalitz decay

\begin{document}$J/\psi\to \gamma^*(q^2)\eta_{(N_f=1)}$\end{document}

with

\begin{document}$\eta_{(N_f)}$\end{document}

being the SU(

\begin{document}$N_f$\end{document}

) flavor singlet pseudoscalar meson. The difference among the partial widths

\begin{document}$\Gamma(J/\psi\to \gamma \eta_{(N_f)})$\end{document}

at different

\begin{document}$N_f$\end{document}

can be attributed in part to the

\begin{document}$N_f$\end{document}

and quark mass dependences induced by the

\begin{document}$\mathbf{U}_A(1)$\end{document}

anomaly dominance.

\begin{document}$M(q^2)$\end{document}

in both

\begin{document}$N_f=1,2$\end{document}

is well described by the single pole model

\begin{document}$M(q^2)=M(0)/(1-q^2/\Lambda^2)$\end{document}

. Combined with the known experimental results of the Dalitz decays

\begin{document}$J/\psi\to Pe^+e^-$\end{document}

, the pseudoscalar mass

\begin{document}$m_P$\end{document}

dependence of the pole parameter

\begin{document}$\Lambda$\end{document}

is approximated by

\begin{document}$\Lambda(m_P^2)=\Lambda_1(1-m_P^2/\Lambda_2^2)$\end{document}

with

\begin{document}$\Lambda_1={2.65(5)}~\mathrm{GeV}$\end{document}

and

\begin{document}$\Lambda_2={2.90(35)}~\mathrm{GeV}$\end{document}

. These results provide inputs for future theoretical and experimental studies on the Dalitz decays

\begin{document}$J/\psi\to Pe^+e^-$\end{document}

.

Principles and prospects of Bose-Einstein correlation study at BESIII

Hai-Ming Hu, Guang-Shun Huang

2024, 48(11): 113106. doi: 10.1088/1674-1137/ad84bb

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One method for determining the characteristic parameters of a hadron production source is to measure the Bose-Einstein correlation functions. In this study, we present fundamental concepts and formulas related to the Bose-Einstein correlations, focusing on the measurement principles and the Lund model from an experimental perspective. We perform Monte Carlo simulations using the Lund model generator in the 2–3 GeV energy range. Through these feasibility studies, we identify key features of the Bose-Einstein correlations that offer valuable insights for experimental measurements. Utilizing data samples collected at BESIII, we perform measurements of the Bose-Einstein correlation functions, with an expected experimental precision of a few percent for the hadron source radius and incoherence parameter.

Investigating the level structure of ²⁰⁶Rn: evolution from seniority regime to collective dynamics

Rui Guo, Li-Hua Zhu, Jing-Bin Lu, Guan-Jian Fu, Meng Wang, Bao-Hua Sun, Gao-Long Zhang, Zhen Ren, Yi-Heng Wu, Yun Zheng, Chuang-Ye He, Jin-Long Wang, Xiao-Guang Wu, Shun-He Yao

2024, 48(11): 114001. doi: 10.1088/1674-1137/ad666a

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Excited states of

\begin{document}$ ^{206} {\rm{Rn}}$\end{document}

have been examined via the

\begin{document}$ ^{197} {\rm{Au}}$\end{document}

(

\begin{document}$ ^{14} {\rm{N}}$\end{document}

, 5n)

\begin{document}$ ^{206} {\rm{Rn}}$\end{document}

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

\begin{document}$ ^{206} {\rm{Rn}}$\end{document}

. The full configuration shell model and nucleon-pair approximation (NPA) were utilized to investigate the single-particle configurations and seniority structures in

\begin{document}$ ^{206} {\rm{Rn}}$\end{document}

. The results of these two calculations suggest that

\begin{document}$ 2_1^{+} $\end{document}

and

\begin{document}$ 4_1^{+} $\end{document}

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. Furthermore,

\begin{document}$ 6_1^{+} $\end{document}

and

\begin{document}$ 8_1^{+} $\end{document}

states are predominantly characterized by a seniority-two state marked by a broken proton pair.

Photonuclear reactions on ⁵⁹Co at bremsstrahlung end-point energies of 40–130 MeV

F. A. Rasulova, S. S. Belyshev, M. A. Demichev, D. L. Demin, S. A. Evseev, N. Yu. Fursova, M. I. Gostkin, J. H. Khushvaktov, V. V. Kobets, A. A. Kuznetsov, S. V. Rozov, E. T. Ruziev, A. A. Solnyshkin, T. N. Tran, E. A. Yakushev, B. S. Yuldashev

2024, 48(11): 114002. doi: 10.1088/1674-1137/ad6d41

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Relative yields were measured in the 40−130 MeV bremsstrahlung induced reactions of ⁵⁹Co. The experiments were performed with the beam from the electron linear accelerator LINAC-200 using the activation and off-line γ-ray spectrometric techniques. The bremsstrahlung photon flux was calculated with the Geant4 program. The cross sections were calculated by using the computer code TALYS-1.96 with different models and were found to be in good agreement with the experimental data.

Study of one-step and two-step neutron transfer in the reaction ⁶Li + ⁹Be

A.K. Azhibekov, S.M. Lukyanov, Yu.E. Penionzhkevich, B.A. Urazbekov, M.A. Naumenko, V.V. Samarin, T. Issatayev, V.A. Maslov, K. Mendibayev, D. Aznabayev, T.K. Zholdybayev, A. Temirzhanov

2024, 48(11): 114101. doi: 10.1088/1674-1137/ad6d40

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This paper presents the results of experiments conducted to measure the cross-sections for elastic scattering and nucleon transfer channels in the ⁶Li+⁹Be reaction at an incident energy of 68 MeV: ⁹Be(⁶Li,⁶Li)⁹Be, ⁹Be(⁶Li,⁷Li)⁸Be, ⁹Be(⁶Li,⁷Li)⁸Be₂₊, ⁹Be(⁶Li,⁸Li)⁷Be, and ⁹Be(⁶Li,⁷Be)⁸Li. The objective of the study is to elucidate the manifestation of the cluster structure of ⁹Be. Theoretical analysis of the contributions of the one-step and two-step neutron transfer mechanisms is performed using the distorted wave Born approximation method with the Fresco code. Good agreement between the calculations and the experimental data is obtained for the channels of elastic scattering ⁹Be(⁶Li,⁶Li)⁹Be, neutron ⁹Be(⁶Li,⁷Li)⁸Be, and proton transfer ⁹Be(⁶Li,⁷Be)⁸Li, as well as for the transfer of two neutrons ⁹Be(⁶Li,⁸Li)⁷Be. The dineutron cluster transfer mechanism makes a dominant contribution to the ⁹Be(⁶Li,⁸Li)⁷Be reaction channel at forward angles.

Thermal pairing treatment within the path integral formalism

M. Fellah, N.H. Allal, M. R. Oudih

2024, 48(11): 114102. doi: 10.1088/1674-1137/ad641a

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A method for the treatment of pairing correlations at finite temperature is proposed within the path integral formalism, based on the square root extraction of the pairing term in the Hamiltonian of the system. Gap equations and expressions for the pairing gap parameter Δ, energy E, and heat capacity C are established. The formalism is first tested using the Richardson model, which enables comparison with an exact solution. The results obtained using this formalism are also compared with the finite temperature BCS (FTBCS) results. An improvement over the FTBCS model is noted, especially at low temperatures. Indeed, the agreement between the Δ values of this study and the exact values is good at low temperatures. This leads to better agreement between the values of E and C of this model and the exact values than with the FTBCS values. However, a critical value of temperature remains. Subsequently, realistic cases are considered using single-particle energies of a deformed Woods-Saxon mean-field for the nuclei

\begin{document}$ ^{162} $\end{document}

Dy and

\begin{document}$ ^{172} $\end{document}

Yb. In the framework of the current approach, pairing effects persist beyond the FTBCS critical temperature. Moreover, at low temperatures, a good agreement between the model and semiexperimental values of the heat capacity is observed, and a clear improvement compared to the FTBCS method is noted. This is no more the case at higher temperatures.

Holographic Einstein ring of a charged Rastall AdS black hole with bulk electromagnetic field

M. Israr Aslam, Xiao-Xiong Zeng, Rabia Saleem, Xin-Yun Hu

2024, 48(11): 115101. doi: 10.1088/1674-1137/ad6551

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We study the Einstein images of a charged Rastall AdS black hole (BH) within the fabric of AdS/CFT correspondence. Considering the holographic setup, we analyze the amplitude of the total response function for various values of model parameters. With an increase in parameter λ and temperature T, the amplitude of the response function decreases, while it increases with an increase in electric charge e and chemical potential μ. The influence of frequency ω also plays an important role in the bulk field, as it is found that decreasing ω leads to an increase in the periods of the waves, which means that the amplitude of the response function also depends on the wave source. The relation between T and the inverse of the horizon

\begin{document}$r_{h}$\end{document}

for various values of parameter λ is interpreted under fixed values of other involved parameters. These, in turn, affect the behavior of the response function and the Einstein ring, which may be used to differentiate the present study from previous ones. We construct the holographic images of the BH in bulk via a special optical system. The results show that the Einstein ring always appears with concentric stripes at the position of the north pole, and this ring transforms into a luminosity-deformed ring or bright light spot when the distant observer lies away from the north pole. Finally, we discuss the influence of the associated parameters on the Einstein ring radius, which is consistent with wave optics.

Effects of torsion charge on optical appearance and additional photon rings of an asymmetric thin-shell wormhole

Qi-Qin Jing, Ke-Jian He, Zhi Luo

2024, 48(11): 115102. doi: 10.1088/1674-1137/ad666c

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In this paper, we study the optical properties of asymmetric thin-shell wormholes (ATWs) under 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 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 ATWs under torsion charge significantly differ from those of black holes (BHs). Notably, an increase in 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 those of BHs.

Cosmological constraints on the background dynamics of a two-field nonsingular bounce model

Kang Song Ri, Sin Chol Hwang, Hyon Chol Ri

2024, 48(11): 115103. doi: 10.1088/1674-1137/ad6669

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In this study, we consider a nonsingular two-field bounce scenario with non-minimal kinetic coupling between two scalar fields. We derive 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.

Nonexistence of Majorana fermions in Kerr-Newman type spacetimes with nontrivial charge

He-Qun Zhang, Xiao Zhang

2024, 48(11): 115104. doi: 10.1088/1674-1137/ad709e

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We show that the Dirac equation is separated into four differential equations for time-periodic Majorana fermions in Kerr-Newman and Kerr-Newman-(A)dS spacetimes. Although they cannot be transformed into radial and angular equations, the four differential equations yield two algebraic identities. When the electric or magnetic charge is nonzero, they conclude that there is no differentiable time-periodic Majorana fermions outside the event horizon in Kerr-Newman and Kerr-Newman-AdS spacetimes, or between the event horizon and the cosmological horizon in Kerr-Newman-dS spacetime.

A new perspective on the diffuse gamma-ray emission excess

En-Sheng Chen, Kun Fang, Xiao-Jun Bi

2024, 48(11): 115105. doi: 10.1088/1674-1137/ad72d4

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The Large High-Altitude Air Shower Observatory (LHAASO) recently published measurements of diffuse Galactic gamma-ray emission (DGE) in the 10−1000 TeV energy range. The measured DGE flux is significantly higher than the expectation from hadronic interactions between cosmic rays (CRs) and the interstellar medium. This excess has been proposed to originate from unknown extended sources produced by electron radiation, such as pulsar wind nebulae or pulsar halos (PWNe/halos). In this paper, we propose a new perspective to explain the DGE excess observed by LHAASO. The masking regions used in the LHAASO DGE measurement may not fully encompass the extended signals of

\begin{document}$\textit{known} $\end{document}

PWNe/halos. By employing a two-zone diffusion model for electrons around pulsars, we find that the DGE excess in most regions of the Galactic plane can be well explained by the signal leakage model under certain parameters. Our results indicate that this signal leakage from known sources and contributions from unresolved sources should be considered as complementary in explaining the DGE excess.

Generated genuine tripartite steering and its monogamy in the background of a Kerr-Newman black hole

Xiaoli Huang, Haoyu Wu, Shumin Wu

2024, 48(11): 115106. doi: 10.1088/1674-1137/ad6e5f

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We study the redistribution of quantum steering and its monogamy in the presence of a four-dimensional Kerr-Newman black hole. The gravitational effect of the Kerr-Newman black hole is shown to generate genuine tripartite steering between causally disconnected regions, depending on the polar angle, angular momentum, electric charge, and magnetic charge of the black hole. We obtain strong evidence of steering monogamy, that is, the "sudden death" of the A → B steering results in the "sudden birth" of B → B steering. We also obtain the condition of maximal steering asymmetry, that is,

\begin{document}$\eta_{0}={\rm{arccosh}}\sqrt{1+\tanh^{2}(s)} $\end{document}

, revealing the transition between two-way and one-way steering in Kerr-Newman spacetime.

Isotropization of the magnetic universe in Horndeski theory with G₃(X,ϕ) and G₅(X)

Ruslan K. Muharlyamov, Tatiana N. Pankratyeva, Shehabaldeen O.A. Bashir

2024, 48(11): 115107. doi: 10.1088/1674-1137/ad65de

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We study the isotropization process of Bianchi-I space-times in Horndeski theory with

\begin{document}$G_3(X,\phi)\neq 0$\end{document}

and

\begin{document}$G_5=\text{const}/X$\end{document}

. A global unidirectional electromagnetic field interacts with a scalar field according to the law

\begin{document}$f^2(\phi)F_{\mu\nu}F^{\mu\nu}$\end{document}

. In Horndeski theory, the anisotropy can develop in different ways. The proposed reconstruction method allows us to build models with acceptable anisotropy behavior. To analyze space-time anisotropy, we use the relations

\begin{document}$a_i/a$\end{document}

(

\begin{document}$i=1,2,3$\end{document}

), where

\begin{document}$a_i$\end{document}

are metric functions, and

\begin{document}$a\equiv(a_1a_2a_3)^{1/3}$\end{document}

.

Tidal force effects and bound orbits in null naked singularity spacetime

Siddharth Madan, Parth Bambhaniya

2024, 48(11): 115108. doi: 10.1088/1674-1137/ad654f

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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 that is comparable to that of a Schwarzschild black hole scenario. The geodesic deviation equation is then solved numerically, yielding results that resemble Schwarzschild black holes. These characteristic features can then be used to discern among these singularities.

Cosmological test of dark energy parametrizations within the framework of Horava-Lifshitz gravity via baryon acoustic oscillation

Himanshu Chaudhary, Shibesh Kumar Jas Pacif, Ujjal Debnath, Farook Rahaman, G. Mustafa

2024, 48(11): 115109. doi: 10.1088/1674-1137/ad6419

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We conduct an investigation to explore late-time cosmic acceleration through various dark energy parametrizations (Wettrich, Efstathiou, and Ma-Zhang) within the Horava-Lifshitz gravity framework. As an alternative to general relativity, this theory introduces anisotropic scaling at ultraviolet scales. Our primary objective is to constrain the key cosmic parameters and baryon acoustic oscillation (BAO) scale, specifically the sound horizon (r_d), by utilizing 24 uncorrelated measurements of BAOs derived from recent galaxy surveys spanning a redshift range from z = 0.106 to z = 2.33. Additionally, we integrate the most recent Hubble constant measurement by Riess in 2022 (denoted as R22) as an extra prior. For the parametrizations of Wettrich, Efstathiou, and Ma-Zhang, our analysis of BAO data yields sound horizon results of r_d = 148.1560 ± 2.7688 Mpc, r_d = 148.6168 ± 10.2469 Mpc, and r_d = 147.9737 ± 10.6096 Mpc, respectively. Incorporating the R22 prior into the BAO dataset results in r_d = 139.5806 ± 3.8522 Mpc, r_d = 139.728025 ± 2.7858 Mpc, and r_d = 139.6001 ± 2.7441 Mpc. These outcomes highlight a distinct inconsistency between early and late observational measurements, analogous to the H₀ tension. A notable observation is that, when we do not include the R22 prior, the outcomes for r_d tend to be in agreement with Planck and SDSS results. Following this, we conducted a cosmography test and comparative study of each parametrization within the Lambda Cold Dark Matter paradigm. Our diagnostic analyses demonstrate that all models fit seamlessly within the phantom region. All dark energy parametrizations predict an equation of state parameter close to

\begin{document}$ \omega $\end{document}

= –1, indicating a behavior similar to that of a cosmological constant. The statistical analysis indicates that neither of the two models can be ruled out based on the latest observational measurements.

Polytropic gas cosmology and late-time acceleration

Safae Dahmani, Himanshu Chaudhary, Amine Bouali, Shibesh Kumar Jas Pacif, Taoufik Ouali

2024, 48(11): 115110. doi: 10.1088/1674-1137/ad74e4

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The accelerated expansion of the Universe has sparked significant interest in the mysterious concept of dark energy within cosmology. Various theories have been proposed to explain dark energy, and many models have been developed to understand its origins and properties. This research explores cosmic expansion using the Polytropic Gas (PG) approach, which combines Dark Matter (DM) and Dark Energy (DE) into a single mysterious fluid. We used the principles of general relativity and built our model within the homogeneous and isotropic framework of Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime. We revised the Original Polytropic Gas (OPG) model to expand its applicability beyond the OPG, to the ΛCDM model. Our model's parameters were carefully adjusted to reflect key cosmological features of the variable PG approach. To validate our model, we performed a Markov chain Monte Carlo analysis using recent Supernova data from the Pantheon+ survey, 36 observational

\begin{document}$ H(z) $\end{document}

data points, 162 Gamma-Ray Bursts, and 24 binned Quasars distance modulus data. The AIC and BIC criteria indicate that our model is slightly preferred over the ΛCDM model based on observational data. We also tested our model with

\begin{document}$ H(z) $\end{document}

data, Supernova, Gamma-Ray Bursts, and Quasars and found that it exhibits a transition from a quintessential to phantom regime. The Polytropic dark fluid model (PDFM) is a promising candidate that effectively addresses the interplay between cosmic acceleration and dark energy.

Maxwell's equal area law for Vaidya-Bonner-de Sitter black hole under Lorentz invariance violation

Yenshembam Priyobarta Singh, Telem Ibungochouba Singh, Sapam Niranjan Singh

2024, 48(11): 115111. doi: 10.1088/1674-1137/ad75f2

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In this study, we investigate the tunneling of fermions with arbitrary spin near the event horizon of a nonstationary Vaidya-Bonner-de Sitter (VBdS) black hole under Lorentz invariance violation (LIV). The modified Hawking temperature of VBdS black holes is calculated by using tortoise coordinate transformation, Feynman prescription, and Wentzel–Kramers–Brillouin approximation. By considering the cosmological constant as a thermodynamic pressure in the extended phase space, we construct a Maxwell's equal area law under LIV and study the phase transitions of VBdS black hole in

\begin{document}$ P-\tilde{v} $\end{document}

,

\begin{document}$ P-V $\end{document}

, and

\begin{document}$ T-S $\end{document}

planes. The LIV increases the length of the liquid-gas coexistence region. The thermodynamic quantities such as the entropy, heat capacity, Helmholtz free energy, internal energy, enthalpy, and Gibbs free energy of the VBdS black hole are discussed. These quantities tend to increase under LIV. The stability of the black hole is also discussed in the presence of LIV.

Determination of dark matter distribution in Ursa Major III and constraints on dark matter annihilation

Yi Zhao, Xiao-Jun Bi, Su-Jie Lin, Peng-Fei Yin

2024, 48(11): 115112. doi: 10.1088/1674-1137/ad6753

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Abstract:
The recently discovered satellite dwarf galaxy Ursa Major III provides a promising opportunity to explore the signatures resulting from dark matter (DM) annihilation owing to its proximity and large J-factor. Given the absence of an excess of γ-ray signatures originating from Ursa Major III, observations of γ-rays, such as those from Fermi-LAT, can be utilized to set constraints on the DM annihilation cross-section. In this study, we determined the DM density profile and considered the relationship between DM density and velocity dispersion at different locations within Ursa Major III through Jeans analysis. We calculated the J-factor of Ursa Major III for s-wave annihilation along with the effective J-factors for p-wave and Sommerfeld enhanced annihilation scenarios. Employing these derived J-factors, we set stringent constraints on DM annihilation cross-sections in three scenarios. Given the substantial impact of member star identification on the J-factor of Ursa Major III, we further calculated J-factors under the exclusion of the largest velocity outlier. Our analysis reveals a notable reduction in the median value and an increase in the deviation of J-factors, thereby leading to considerably weaker constraints.

Holographic timelike entanglement entropy from Rindler method

Peng-Zhang He, Hai-Qing Zhang

2024, 48(11): 115113. doi: 10.1088/1674-1137/ad57a8

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Abstract:
For a Lorentzian invariant theory, the entanglement entropy should be a function of the domain of dependence of the subregion under consideration. More precisely, it should be a function of the domain of dependence and the appropriate cut-off. In this study, we refine the concept of cut-off to make it applicable to timelike regions and assume that the usual entanglement entropy formula also applies to timelike intervals. Using the Rindler method, the timelike entanglement entropy can be regarded as the thermal entropy of the CFT after the Rindler transformation plus a constant

\begin{document}${\rm i}\pi c/6$\end{document}

, where c denotes the central charge. The gravitational dual of the 'covariant' timelike entanglement entropy is presented following this method.

Critical collapse of massless scalar fields in asymptotically anti-de Sitter spacetime

Li-Jie Xin, Cheng-Gang Shao

2024, 48(11): 115114. doi: 10.1088/1674-1137/ad70a1

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Abstract:
We conduct numerical investigations on the critical collapse of spherically symmetric massless scalar fields in asymptotically anti-de Sitter spacetime. Our primary focus is on the behavior of the critical amplitude under various initial configurations of the scalar field. Through our numerical results, we obtain a formula that determines critical amplitude

\begin{document}$ A^{*} $\end{document}

in terms of cosmological constant Λ:

\begin{document}$ A^{*}\propto (0.01360 \sigma/v_{0}+ 0.001751)\Lambda $\end{document}

, where σ denotes the initial width of the scalar field and

\begin{document}$ v_{0} $\end{document}

is the initial position of the scalar field. Notably, we highlight that the slope of this linear relationship depends on the initial configuration of the scalar field.

Thermodynamic topology of quantum corrected AdS-Reissner-Nordstrom black holes in Kiselev spacetime

Jafar Sadeghi, Saeed Noori Gashti, Mohammad Reza Alipour, Mohammad Ali S. Afshar

2024, 48(11): 115115. doi: 10.1088/1674-1137/ad711b

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Abstract:
In this paper, we consider the intricate thermodynamic topology of quantum-corrected Anti-de Sitter-Reissner-Nordstrm (AdS-RN) black holes within the framework of Kiselev spacetime. By employing the generalized off-shell Helmholtz free energy approach, we meticulously compute the thermodynamic topology of these selected black holes. Furthermore, we establish their topological classifications. Our findings reveal that quantum correction terms influence the topological charges of black holes in Kiselev spacetime, leading to novel insights into topological classifications. Our research findings elucidate that, in contrast to the scenario in which ω = 0 and a = 0.7 with total topological charge W = 0 and ω = –4/3 with total topological charge W = –1, in other cases, the total topological charge for the black hole under consideration predominantly stabilizes at +1. This stabilization occurs with the significant influence of the parameters a, c, and ω on the number of topological charges. Specifically, when ω assumes the values of ω = –1/3, ω = –2/3, and ω = –1, the total topological charge will consistently be W = +1.

Shadow and gravitational weak lensing for quantum improved charged black hole in plasma

Mirzabek Alloqulov, Farruh Atamurotov, Ahmadjon Abdujabbarov, Bobomurat Ahmedov, Nozima Juraeva

2024, 48(11): 115116. doi: 10.1088/1674-1137/ad6e5e

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Abstract:
We investigated the shadow and weak gravitational lensing for the quantum-improved charged black hole (BH). First, the photon motion and BH shadow were studied in a plasma medium. It can be seen from our analysis that the radius of the photon sphere of the quantum-improved charged BH and size of the BH shadow decrease under the influence of the plasma parameter

\begin{document}$ \Omega $\end{document}

. Furthermore, the gravitational weak lensing is considered for the quantum-improved charged BH, and we have obtained the deflection angle of light rays around a compact object for uniform and non-uniform plasma cases. It is shown that the value of the deflection angle for uniform plasma increases with increasing plasma parameter, and vice versa for non-uniform plasma. It has been also indicated that under the influence of the plasma parameter

\begin{document}$ \Omega $\end{document}

and BH charge

\begin{document}$ Q $\end{document}

, the values of the deflection angles for the two cases decrease. Finally, we investigated the magnification of image brightness using the deflection angle of the light rays around the quantum-improved charged BH.

2024 Vol. 48, No. 11