We present a comprehensive theoretical investigation of a novel black hole (BH) spacetime: a Schwarzschild BH embedded in a Hernquist-type dark matter halo (HDMH) and surrounded by a cloud of strings CS-collectively termed the Schwarzschild-HDMH with CS (SHDMHCS) configuration. By analyzing the spacetime geometry, we explore how key geometrical parameters, such as, the core radius and halo density of the dark matter, along with the cloud of strings affect the geodesic motion of both massless and massive test particles. Our results show that the combined influence of HDMH and CS modifies the effective potentials for null and time-like geodesics, leading to distinct dynamical behavior compared to the standard Schwarzschild geometry. We perform a perturbative analysis for scalar (spin-0), electromagnetic (spin-1), and Dirac (spin-1/2) fields, deriving the associated effective potentials and showing how the dark matter halo and CS alter these field propagation and potential barriers. Moreover, the shadow of the selected BH is studied in detail, deriving analytical expressions for photon sphere and shadow radii, showing that CS tend to enlarge the shadow, while HDMH properties tend to shrink it. The combined effects of these parameters significantly influence the shadow’s shape and size, producing potentially observable signatures. Our results establish that the SHDMHCS configuration yields distinct observational imprints detectable by present and forthcoming astrophysical instruments. This framework provides new tools for probing exotic matter distributions via gravitational wave observations, orbital dynamics, and high-resolution BH imaging, offering a pathway to distinguish such configurations from simpler BH models in realistic environments.

India

Faizuddin Ahmed

Jordan

Ahmad Al-Badawi

Türkiye

İzzet Sakallı

Observable signatures of black hole with Hernquist dark matter halo having a cloud of strings: geodesic, perturbations, and shadow

<p>The absence of definitive results for WIMP dark matter has sparked growing interest in alternative dark matter candidates, such as axions and axionlike particles (ALPs), which also provide insight into the strong CP problem. The Mitchell Institute Neutrino Experiment at Reactor (MINER), conducted at the Nuclear Science Center of Texas A&M University, investigated ALPs near a 1 MW h TRIGA nuclear reactor core, positioned approximately 4 m away. This experiment employed cryogenic sapphire detectors with a low detection threshold (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>≈</mo><mn>100</mn><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>), equipped with a transition edge sensor capable of detecting athermal phonons. Due to the low-background environment, we were able to exclude ALPs with axion-photon coupling and axion-electron coupling as small as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>γ</mi><mi>γ</mi></mrow></msub><mo>=</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>g</mi><mrow><mi>a</mi><mi>e</mi><mi>e</mi></mrow></msub><mo>=</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math>, respectively. Energy depositions below 3 keV were not considered and remain blinded for our coherent elastic neutrino-nucleus scattering analysis. This is the first result demonstrating the MINER experiment’s potential to probe low-mass ALPs, enabled by its low-threshold detector and proximity to a reactor.</p>

United States

M. Mirzakhani

W. Baker

M. Chaudhuri

J.B. Dent

R. Dey

B. Dutta

Canada

V. Iyer

A. Jastram

V.K.S. Kashyap

A. Kubik

K. Lang

R. Mahapatra

S. Maludze

N. Mirabolfathi

B. Mohanty

D. Mondal

H. Neog

Australia

J.L. Newstead

M. Platt

S. Sahoo

J. Sander

L.E. Strigari

J. Walker

MINER reactor based search for axionlike particles using sapphire (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mtext>Al</mtext><mn>2</mn></msub><msub><mi mathvariant="normal">O</mi><mn>3</mn></msub></math>) detectors

In this work, we investigate the geodesic motion of both massless and massive test particles in the vicinity of a spherically symmetric Finslerian Hayward-like black hole (FHBH) that is coupled to a quintessence field (QF) and carries a global monopole (GM). By examining the combined effects of the GM and QF, we observe significant deviations in the geodesic structure for both null and time-like particles when compared to the conventional BH models. Additionally, we explore spin-0 scalar field perturbations by solving the massless Klein–Gordon equation in this modified BH space-time background and analyze the influence of the Finslerian geometry, GM, and QF on the resulting scalar perturbative potential. Using the effective potential derived from null geodesics, we compute the transmission and reflection coefficients and discuss their physical implications. Furthermore, we numerically calculate the quasinormal modes (QNMs) frequencies based on the scalar perturbations potential and assess how the Finslerian modifications, along with the presence of GM and QF, affect the QNM spectrum.

Some observable physical properties of Finslerian Hayward-like black hole with global monopole charge and quintessence field

We explore a static spherically symmetric black hole (BH) solution within the framework of Dunkl geometry, incorporating the effects of both ordinary and phantom global monopoles. This extends classical BH physics by introducing topological defects and modified symmetry structures via Dunkl operator formalism, with phantom global monopoles exhibiting exotic repulsive gravitational effects. We analyze null geodesics focusing on photon dynamics, trajectory nature, circular photon orbits, and stability through effective potential analysis. These results provide insight into how the Dunkl parameter and the presence of phantom global monopoles affect light propagation near the BH. We investigate time-like geodesics, analyzing massive particle motion in this BH background with topological defects, studying circular orbits, precession frequency, and orbital speed at large distances. Our findings show substantial deviations from classical solutions like Schwarzschild BH, highlighting the significant role of Dunkl parameter and global monopole. We explore BH thermodynamic properties, deriving Hawking temperature, entropy, Gibbs free energy, and specific heat, offering information about thermal behavior and phase transitions. These thermodynamic aspects are shown to be markedly influenced by both the Dunkl geometry and the presence of phantom global monopoles. In addition, we examine the formation and characteristics of BH shadows in this BH spacetime. Our findings demonstrate that the inclusion of Dunkl symmetry and phantom global monopoles leads to profound modifications in the physical and geometric properties of the BH spacetime.

Dunkl black hole with phantom global monopoles: geodesic analysis, thermodynamics and shadow

The structure of the proton-unbound nucleus <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Al</mi></mrow><mprescripts /><none /><mrow><mn>21</mn></mrow></mmultiscripts></math> has been studied via proton transfer from a <math altimg='si2.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Be</mi></mrow><mprescripts /><none /><mrow><mn>9</mn></mrow></mmultiscripts></math> target to a <math altimg='si3.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Mg</mi></mrow><mprescripts /><none /><mrow><mn>20</mn></mrow></mmultiscripts></math> beam at <math altimg='si4.svg'><mi>E</mi><mo stretchy='false'>/</mo><mi>A</mi></math> = 103 MeV. Three resonant states in <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Al</mi></mrow><mprescripts /><none /><mrow><mn>21</mn></mrow></mmultiscripts></math> are identified by the invariant-mass reconstruction of <math altimg='si5.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Ne</mi></mrow><mprescripts /><none /><mrow><mn>18</mn></mrow></mmultiscripts></math> + 3 <italic>p</italic> events. The decay-energy spectra for the two subsystems of <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Al</mi></mrow><mprescripts /><none /><mrow><mn>21</mn></mrow></mmultiscripts></math>, i.e. <math altimg='si5.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Ne</mi></mrow><mprescripts /><none /><mrow><mn>18</mn></mrow></mmultiscripts></math> + 1 <italic>p</italic> and <math altimg='si5.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Ne</mi></mrow><mprescripts /><none /><mrow><mn>18</mn></mrow></mmultiscripts></math> + 2 <italic>p</italic>, indicate that the observed resonant state with the lowest energy has decay branches consisting of three sequential steps of one-proton decay. Based on the <italic>ab initio</italic> and the distorted-wave Born approximation (DWBA) calculations, this resonant state at <math altimg='si7.svg'><msup><mrow><mi>E</mi></mrow><mrow><mo>&#8270;</mo></mrow></msup></math> = 6.09(11) MeV likely has a spin-parity of <math altimg='si8.svg'><mo stretchy='false'>(</mo><mn>1</mn><mo stretchy='false'>/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>- <math altimg='si9.svg'><mn>7</mn><mo stretchy='false'>/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup><mo stretchy='false'>)</mo></math>. Meanwhile, the possibility that the observed resonant peak represents an admixture of several states cannot be ruled out. The good isospin-symmetry of the low-lying states with <math altimg='si10.svg'><msub><mrow><mi>d</mi></mrow><mrow><mn>5</mn><mo stretchy='false'>/</mo><mn>2</mn></mrow></msub></math>, <math altimg='si11.svg'><msub><mrow><mi>d</mi></mrow><mrow><mn>3</mn><mo stretchy='false'>/</mo><mn>2</mn></mrow></msub></math> configurations in the <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Al</mi></mrow><mprescripts /><none /><mrow><mn>21</mn></mrow></mmultiscripts></math>- <math altimg='si12.svg'><mmultiscripts><mrow><mi mathvariant='normal'>O</mi></mrow><mprescripts /><none /><mrow><mn>21</mn></mrow></mmultiscripts></math> pair and the <italic>ab initio</italic> calculations indicate weak configuration mixing between the <italic>s</italic>- and <italic>d</italic>-orbital components. The systematics of experimental energy differences between the <math altimg='si13.svg'><mn>5</mn><mo stretchy='false'>/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> ground state and lowest-lying <math altimg='si14.svg'><mn>3</mn><mo stretchy='false'>/</mo><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> excited state for isotopes (isotones) of <math altimg='si15.svg'><mi>Z</mi><mo stretchy='false'>(</mo><mi>N</mi><mo stretchy='false'>)</mo></math> = 13 suggest a likely semimagic nature of <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>Al</mi></mrow><mprescripts /><none /><mrow><mn>21</mn></mrow></mmultiscripts></math>.

China

L. Ni

Y. Jin

Z.H. Li

K.W. Brown

H. Hua

C.Y. Niu

J.G. Li

A.K. Anthony

J. Barney

R.J. Charity

D. Dell'Aquila

J.M. Elson

J. Estee

G. Jhang

W.G. Lynch

N. Michel

L.G. Sobotka

S. Sweany

F.C.E. Teh

A. Thomas

C.Y. Tsang

M.B. Tsang

S.M. Wang

H.Y. Wu

C.X. Yuan

K. Zhu

Observation of three-proton-decaying resonant states in <sup>21</sup>Al

In a recent article (Deglmann et al. in Ann Phys (NY) 475:169948, 2025), the authors obtained a static, cylindrically symmetric Anti-de Sitter (AdS) black string (BS) solutions, which are cylindrical generalizations of black holes (BHs), surrounded by a cloud of strings (CS) and the quintessence field (QF), and discussed its properties. In the present study, we present a comprehensive analysis of cylindrically symmetric AdS BSs surrounded by CS and QF. Our analysis yields several significant results. We demonstrate that the presence of CS (parameter $$\alpha $$ ) and QF (parameters $\textit{c}$ and $\textit{w}$) reduces the radius of circular photon orbits (CPO) and BH shadow size, with measurements constrained by Event Horizon Telescope (EHT) observations of Sagittarius A*. We find that time-like particle orbits show increased energy with higher $$\alpha $$ and $\textit{c}$ values. We calculate that C-energy, representing gravitational energy within cylindrical radius, decreases with radial distance but exhibits distinct responses to CS and QF parameters. We observe that scalar perturbation potential increases $\textit{r}$ for specific $$\alpha $$ and $\textit{c}$ values, indicating stronger field-spacetime interactions away from the BS. We determine that Hawking temperature increases linearly with Schwarzschild radius, with parameter-dependent behavior varying based on QF state parameter $\textit{w}$. These results demonstrate how CS and QF significantly modify the geodesic, perturbative, and thermodynamic properties of AdS BS, with potential observational implications for gravitational lensing, accretion disk dynamics, and BH evaporation signatures in future astronomical observations.

AdS black strings in a cosmic web: geodesics, shadows, and thermodynamics

In this study, we investigate a static, spherically symmetric black hole (BH) within the framework of Effective Quantum Gravity (EQG) in the presence of a cloud of strings (CS) and a quintessence field (QF). We derive the modified metric function incorporating quantum corrections and analyze its impact on the horizon structure, geodesic motion, shadow formation, scalar perturbations, and thermodynamics. The metric function is influenced by three key parameters: the quantum correction parameter <italic>&#958;</italic>, the CS parameter <italic>&#945;</italic>, and the parameters ( <math altimg='si1.svg'><mi>c</mi><mo>,</mo><mi>w</mi></math>) of the QF. Our results reveal that increasing <italic>&#958;</italic> primarily influences the Cauchy horizon, causing it to expand, while having a negligible effect on the event and cosmological horizons. On the other hand, larger values of <italic>&#945;</italic> and <italic>c</italic> lead to an increase in the event horizon radius while reducing the cosmological horizon. The study of null and time-like geodesics indicates that quantum effects modify photon trajectories and the stability of circular orbits. We derive analytical expressions for the radius of the photon sphere and the BH shadow. Our findings indicate that the presence of QF and CS enlarges the shadow radius, whereas the incorporation of effective quantum corrections ( <italic>&#958;</italic>) reduces it. Using the Regge-Wheeler equation, we analyze scalar perturbations and greybody factors, demonstrating that <italic>&#958;</italic> suppresses transmission probabilities while enhancing reflection coefficients. This study paves the way for further exploration of EQG-modified rotating BHs, gravitational wave emissions, and astrophysical tests of quantum corrections in future observational studies.

Effective quantum gravity black hole with cloud of strings surrounded by quintessence field

This work presents a comprehensive analysis of the geodesic motion, scalar field perturbations, and thermodynamic behavior of a static, spherically symmetric black hole solution arising within the framework of non-commutative geometry and incorporating the presence of a global monopole. The study is motivated by the interplay between quantum gravity effects (modeled via non-commutative geometry) and topological defects such as global monopoles, both of which contribute to significant deviations from classical black hole solutions. We begin by formulating the effective potential governing the motion of test particles-both massive and massless-in the modified spacetime. The effects of the non-commutative parameter and the global monopole are systematically examined in the context of various key features: the photon sphere radius, light deflection angle, stability of circular orbits, and the innermost stable circular orbit (ISCO). Our results show that the presence of the non-commutative structure enlarges the photon sphere radius and increases the deflection of light, while simultaneously destabilizing circular orbits. Furthermore, we observe that the ISCO radius is highly sensitive to the global monopole parameter, with a noticeable increase for certain ranges of the non-commutative parameter. These findings suggest that non-commutative geometry and topological defects significantly affect the observable properties of black hole environments. In the second part of the study, we explore linear perturbations of a massless scalar field by solving the Klein-Gordon equation in the background spacetime. The resulting effective potential for scalar perturbations is shown to be deeply influenced by both the non-commutative geometry and the global monopole, modifying the scattering and decay characteristics of the scalar field. By employing the eikonal approximation, we compute the complex quasinormal mode (QNM) frequencies and analyze how their real and imaginary parts evolve with changes in the underlying parameters. The results provide insight into the stability of the black hole under perturbations and offer potential observational signatures of non-commutative and monopole-induced corrections. Finally, the thermodynamic properties of the black hole are investigated. We derive the expressions for the Hawking temperature, specific heat, and Gibbs free energy, showing how these quantities deviate from their counterparts in the standard Schwarzschild solution. Notably, we find that the introduction of a non-commutative structure and global monopole leads to non-trivial modifications in the thermodynamic phase structure. In particular, the black hole may exhibit modified thermal stability and phase transitions depending on the values of the non-commutative and monopole parameters.

Exploring geodesics, quantum fields and thermodynamics of Schwarzschild-AdS black hole with a global monopole in non-commutative geometry

This study investigates the shadows, scalar perturbations, and quasinormal modes (QNMs) of Grumiller black holes (BHs) within the framework of the Generalized Uncertainty Principle (GUP). The GUP introduces quantum corrections that are most significant near the event horizon, while the Rindler acceleration parameter predominantly influences the spacetime at larger distances. We derive analytical expressions for the photon sphere and shadow radii, showing that quantum corrections cause both to decrease. Additionally, we explore the dynamics of massless scalar perturbations and compute the quasinormal frequencies using the higher-order WKB approximation, supported by time-domain analysis. Our results indicate that while the Rindler acceleration significantly impacts the oscillation frequency and damping rate of gravitational wave (GW) ring downs, the effect of the GUP parameters is relatively small. This work clarifies how these distinct influences operate in different regions of the black hole spacetime and provides valuable insights into the quantum-corrected features of black holes, including their shadows and QNMs.

Azerbaijan

Dhruba Jyoti Gogoi

Yassine Sekhmani

Kazakhstan

Kuantay Boshkayev

Shadow and quasinormal modes of GUP corrected Grumiller black holes

In this paper, we theoretically investigate gravitational lensing within the space-time framework of traversable wormholes, focusing on the combined effects of a global monopole and a cosmic string. Specifically, we examine the Ellis-Bronnikov-Morris-Thorne wormhole metric and analyze how these topological defects influence photon trajectories. By considering the weak-field limit, we derive analytical expressions for the photon deflection angle, highlighting how factors such as the wormhole throat radius, the global monopole charge, and the cosmic string influence the gravitational lensing phenomenon. We also examine the weak-field limit of lensing phenomena for a zero wormhole throat radius and derive an analytical expression for the deflection angle of photon light in this scenario.

Gravitational lensing phenomena of Ellis-Bronnikov-Morris-Thorne wormhole with global monopole and cosmic string