The analysis of RHIC hydrogen gas jet target polarimeter measurements of transverse analyzing powers <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>A</mi><mi mathvariant="normal">N</mi></msub><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> in proton-nucleus scattering requires accurate Coulomb corrections to both spin-flip and nonflip amplitudes. These corrections must cover a wide range of nuclear charges <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> and form factor slopes, with flexibility to vary form factors during data fitting. To avoid technically challenging calculations involving a small but finite fictitious photon mass, the Coulomb correction to the nonflip electromagnetic amplitude with an exponential form factor was related to the corresponding correction for the spin-flip amplitude. This approach allows soft photon contributions to all amplitudes, including those with nonexponential form factors, to be calculated in the massless photon limit using only analytical expressions and numerically stable integrals with nonsingular integrands and finite integration limits. In addition, an absorptive correction to the spin-flip electromagnetic amplitude, which plays a critical role in spin effects in forward polarized proton-nucleus scattering, was accurately evaluated.

United States

A.A. Poblaguev

Numerical calculation of Coulomb corrections in forward elastic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>p</mi><mo stretchy="false">↑</mo></msup><mi>p</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>p</mi></mrow><mrow><mo stretchy="false">↑</mo></mrow></msup><mi>A</mi></mrow></math> scattering

We propose a novel collider signature for neutral long-lived particles (LLPs): the emerging photon jet in the hadronic calorimeter (HCAL). This signature arises when a neutral LLP decays into photons within the HCAL, producing an electromagnetic shower without associated charged tracks or energy deposits in the electromagnetic calorimeter (ECAL). To demonstrate the viability of this approach, we consider the fermiophobic Higgs boson <math altimg='si1.svg'><msub><mrow><mi>h</mi></mrow><mrow><mi mathvariant='normal'>f</mi></mrow></msub></math> in the Type-I two-Higgs-doublet model as a representative scenario. In the ultralight regime ( <math altimg='si2.svg'><msub><mrow><mi>m</mi></mrow><mrow><msub><mrow><mi>h</mi></mrow><mrow><mi mathvariant='normal'>f</mi></mrow></msub></mrow></msub><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><mn>1</mn></math> GeV), <math altimg='si1.svg'><msub><mrow><mi>h</mi></mrow><mrow><mi mathvariant='normal'>f</mi></mrow></msub></math> decays exclusively into a photon pair via loop-induced processes, resulting in a suppressed width and consequently a long lifetime. Focusing on the golden channel <math altimg='si3.svg'><mi>p</mi><mi>p</mi><mo stretchy='false'>&#8594;</mo><msup><mrow><mi>H</mi></mrow><mrow><mo>&#177;</mo></mrow></msup><msub><mrow><mi>h</mi></mrow><mrow><mi mathvariant='normal'>f</mi></mrow></msub><mo stretchy='false'>&#8594;</mo><msup><mrow><mi>W</mi></mrow><mrow><mo>&#177;</mo></mrow></msup><msub><mrow><mi>h</mi></mrow><mrow><mi mathvariant='normal'>f</mi></mrow></msub><msub><mrow><mi>h</mi></mrow><mrow><mi mathvariant='normal'>f</mi></mrow></msub></math>, we analyze the exotic final state in which one <math altimg='si1.svg'><msub><mrow><mi>h</mi></mrow><mrow><mi mathvariant='normal'>f</mi></mrow></msub></math> decays in the ECAL and appears as a highly collimated photon jet (reconstructed as a single photon), while the other decays within the HCAL, producing an emerging photon jet. Through a detailed signal-to-background analysis incorporating realistic detector effects via fast simulation, we demonstrate that this signature achieves discovery-level sensitivity at the HL-LHC across a broad region of parameter space consistent with theoretical and experimental constraints. While our study focuses on the fermiophobic Higgs, the emerging photon jet in the HCAL constitutes a broadly applicable and previously unexplored strategy for detecting neutral LLPs decaying into photons, opening a new avenue in LLP searches at colliders.

South Korea

Jinheung Kim

Dongjoo Kim

Soojin Lee

Jeonghyeon Song

Emerging photon jets in the hadronic calorimeter: A novel signature of neutral long-lived particles at the LHC

This Letter presents the first search for dark matter axions with mass in the ranges <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>76.56</mn></mrow></math> to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>76.82</mn><mtext> </mtext><mtext> </mtext><mrow><mi mathvariant="normal">μ</mi><mi>eV</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>79.31</mn></mrow></math> to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>79.53</mn><mtext> </mtext><mtext> </mtext><mrow><mi mathvariant="normal">μ</mi><mi>eV</mi></mrow></math> using a prototype setup for the MAgnetized Disk and Mirror Axion eXperiment (MADMAX). The experimental setup employs a dielectric haloscope consisting of three sapphire disks and a mirror to resonantly enhance the axion-induced microwave signal within the magnetic dipole field provided by the 1.6 T Morpurgo magnet at CERN. Over 14.5 days of data collection, no axion signal was detected. A 95% CL upper limit on the axion-photon coupling strength down to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">|</mo><msub><mrow><mi>g</mi></mrow><mrow><mi>a</mi><mi>γ</mi></mrow></msub><mo stretchy="false">|</mo><mo>∼</mo><mn>2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> is set in the targeted mass ranges, surpassing previous constraints, assuming a local axion dark matter density <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ρ</mi><mi>a</mi></msub></math> of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0.3</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><msup><mrow><mi>cm</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math>. This study marks the first axion dark matter search using a dielectric haloscope.

Germany

B. Ary dos Santos Garcia

D. Bergermann

A. Caldwell

France

V. Dabhi

C. Diaconu

J. Diehl

G. Dvali

J. Egge

E. Garutti

S. Heyminck

F. Hubaut

A. Ivanov

J. Jochum

S. Knirck

M. Kramer

D. Kreikemeyer-Lorenzo

C. Krieger

C. Lee

D. Leppla-Weber

X. Li

A. Lindner

B. Majorovits

J.P.A. Maldonado

A. Martini

A. Miyazaki

E. Öz

P. Pralavorio

G. Raffelt

Spain

J. Redondo

A. Ringwald

J. Schaffran

A. Schmidt

F. Steffen

C. Strandhagen

I. Usherov

H. Wang

G. Wieching

First Search for Axion Dark Matter with a MADMAX Prototype

In this paper, we study the periodic orbits, characterized by zoom-whirl behavior, around a Schwarzschild-like black hole (BH) embedded within a Dehnen-type dark matter (DM) halo. We demonstrate how the DM halo modifies the gravitational dynamics of the black hole, influencing the energy and angular momentum of timelike particle geodesics and enhancing their interaction with the BH. We determine the radii of the marginally bound orbits (MBOs) and innermost stable circular orbits (ISCOs), showing that the DM halo increases both. This provides a deeper understanding of how the DM alters the behavior, energy, and angular momentum of timelike particle geodesics. Furthermore, we explore the gravitational waveforms emitted by a timelike particle in periodic orbits around a supermassive black hole (SMBH) within this BH-DM system. Using a semi-analytical approach, we calculate particle trajectories and derive the corresponding waveforms, demonstrating that the DM halo modifies the zoom-whirl orbital behavior, leading to distinct changes in the waveform structure. Our findings suggest that future gravitational wave (GW) observations could constrain the properties of DM halos surrounding BHs, providing new insights into the gravitational wave signatures arising from the interaction between BH gravity and DM.

Uzbekistan

China

Mirzabek Alloqulov

Tursunali Xamidov

Azerbaijan

Sanjar Shaymatov

Bobomurat Ahmedov

Gravitational waveforms from periodic orbits around a Schwarzschild black hole embedded in a Dehnen-type dark matter halo

The Event Horizon Telescope (EHT) imaged black holes M87 $$^*$$ (angular diameter $$\theta _d = 42 \pm 3\,\upmu \text {as},$$ mass $$\sim 6.5 \times 10^9\,M_\odot )$$ and Sgr A $$^*$$ $$(\theta _d = 48.7 \pm 7\,\upmu \text {as},$$ shadow deviation $$\delta \approx -0.08^{+0.09}_{-0.09}$$ (VLTI), $$-0.04^{+0.09}_{-0.10})$$ (Keck). These observations enable tests of gravity in strong regimes. We propose a rotating non-commutative inspired Kiselev black hole (RNKBH), incorporating dark energy $$(\omega )$$ and non-commutative $$(\Theta )$$ parameters, extending Kerr solutions. Our analysis reveals that $$\omega = -2/3$$ allows larger $$\Theta $$ but requires $$a \ge 0.16M$$ to maintain horizons. Shadow calculations show significant deviations from Kerr predictions: for $$\Theta = 0.001-0.005M^2,$$ shadows shrink by 8-15% and distortion increases by 20-35% for rapidly spinning $$(a > 0.5M)$$ black holes. The $$\omega = -2/3$$ exhibits shadow squeezing near the cosmological horizon. We compute shadow observables and compare them with EHT data. For Sgr A $$^*$$ $$(50^\circ $$ inclination), the bounds are $$0.001497 \le \Theta \le 0.002868\,M^2$$ at $$a =0.9146$$ $$(\omega = -2/3)$$ . For M87 $$^*$$ $$(17^\circ )$$ , $$0 \le \Theta \le 0.004993 \,M^2$$ at $$a=0.0.6167$$ $$(\omega = -2/3)$$ . While EHT cannot yet distinguish RNKBH from Kerr BH, our results highlight its viability as an astrophysical candidate.

Fazlay Ahmed

India

Heena Ali

Qiang Wu

Tao Zhu

South Africa

Sushant Ghosh

Shadows of rotating non-commutative Kiselev black holes: constraints from EHT observations of M87* and Sgr A*

Particle azimuthal anisotropies inside jets, defined within the momentum plane perpendicular to the jet axis, carry the information of the QCD cascade process for jet formation. In this work, we propose to measure the medium-induced modifications of the elliptic anisotropy inside jets in relativistic heavy-ion collisions to provide novel insight into the jet quenching phenomenon. By simulating the jet propagation in the hot and dense nuclear medium with a Linear Boltzmann Transport model, we observe a de-correlation in the two-particle azimuthal angular distribution for inclusive jet production in AA collisions relative to that in <italic>pp</italic> collisions, which results in significant suppression of the in-jet elliptic anisotropy coefficient <math altimg='si1.svg'><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math>. This phenomenon arises from the stochastic and strong interactions with the thermal QGP medium undergone by the jet particles. Furthermore, the nuclear modifications of the in-jet <math altimg='si1.svg'><msub><mrow><mi>v</mi></mrow><mrow><mn>2</mn></mrow></msub></math> are found to be sensitive to the medium properties in the model study, which provide a potential probe for the jet tomography of nuclear matter.

Meng-Quan Yang

Wei-Xi Kong

Peng Ru

Ben-Wei Zhang

Suppression of elliptic anisotropy inside jets: A new perspective for jet quenching

In this paper, we investigate a <math altimg='si1.svg'><mo stretchy='false'>(</mo><mn>1</mn><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mn>3</mn><mo stretchy='false'>)</mo></math>-dimensional static Friedmann-Robertson-Walker (FRW) space-time, pierced by a cosmic string. Our analysis begins with a detail study of the geodesic motion of photon rays in this curved background, focusing on the behavior of the associated effective potential. This allows us to understand how the cosmic string and curvature of space-time influence the trajectories of light rays. Moving beyond ray optics, we explore wave optics by solving the covariant Helmholtz equation in this gravitational setting. By transforming the resulting radial equation into a Schr&#246;dinger-like form, we extract an effective potential and derive a frequency-dependent refractive index. This refractive index shows the combined effects of the cosmic string and the curvature parameter, showing their influence on the wave propagation. Furthermore, we extend our study to a <math altimg='si2.svg'><mo stretchy='false'>(</mo><mn>1</mn><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mn>2</mn><mo stretchy='false'>)</mo></math>-dimensional space-time with disclinations, where we analyze the wave optics phenomena. Through the Helmholtz equation in this lower-dimensional case, we determine the refractive index and discuss how it is affected by the geometric parameters of this lower-dimensional space-time. Through both geometric and wave optics approaches, our work provides a comprehensive understanding of how topological defects and curvature impact geometric and physical optics in curved space-time of three- and four-dimensions.

Faizuddin Ahmed

Algeria

Abdelmalek Bouzenada

Ray and wave dynamics in a static FRW spacetime with conical singularity

Atmospheric neutrino oscillations are important to the study of neutrino properties, including the neutrino mass ordering problem. A good capability to identify neutrinos’ flavor and neutrinos against antineutrinos is crucial in such measurements. In this paper, we present a machine-learning-based approach for identifying atmospheric neutrino events in a large homogeneous liquid scintillator detector. This method identifies features of photomultiplier tube waveforms that reflect event topologies and uses them as input to machine learning models. In addition, neutron-capture information is utilized to achieve neutrino vs antineutrino discrimination. Preliminary performances based on Monte Carlo simulations are presented, which demonstrate such a detector’s potential in future measurements of atmospheric neutrinos such as the one planned for the JUNO experiment.

Jiaxi Liu

Fanrui Zeng

Hongyue Duyang

Wanlei Guo

Xinhai He

Teng Li

Zhen Liu

Wuming Luo

Wing Yan Ma

Xiaohan Tan

Liangjian Wen

Zekun Yang

Yongpeng Zhang

Neutrino type identification for atmospheric neutrinos in a large homogeneous liquid scintillation detector

We study a strongly anisotropic self-organized critical system coupled to an isotropic random fluid environment. The former is described by a continuous (coarse-grained) model due to Hwa and Kardar. The latter is modelled by the Navier—Stokes equation with a random stirring force of a rather general form that includes, in particular, the overall shaking of the system and a non-local part with power-law spectrum <math altimg='si1.svg'><mo>&#8764;</mo><msup><mrow><mi>k</mi></mrow><mrow><mn>4</mn><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mi>d</mi><mo linebreak='badbreak' linebreakstyle='after'>&#8722;</mo><mi>y</mi></mrow></msup></math> that describes, in the limiting case <math altimg='si2.svg'><mi>y</mi><mo stretchy='false'>&#8594;</mo><mn>4</mn></math>, a turbulent fluid. The full problem of the two coupled stochastic equations is represented as a field theoretic model which is shown to be multiplicatively renormalizable and logarithmic at <math altimg='si3.svg'><mi>d</mi><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>4</mn></math>. Due to the interplay between isotropic and anisotropic interactions, the corresponding renormalization group (RG) equations reveal a rich pattern of possible infrared (large scales, long times) regimes of asymptotic behaviour of various Green's functions. The attractors of the RG equations in the five-dimensional space of coupling parameters include a two-dimensional surface of Gaussian (free) fixed points, a single fixed point that corresponds to the plain advection by the turbulent fluid (the Hwa&#8211;Kardar self-interaction is irrelevant) and a one-dimensional curve of fixed points that corresponds to the case where the Hwa&#8211;Kardar nonlinearity and the uniform stirring are simultaneously relevant. The character of attractiveness is determined by the exponent <italic>y</italic> and the dimension of space <italic>d</italic>; the most interesting case <math altimg='si4.svg'><mi>d</mi><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>3</mn></math> and <math altimg='si2.svg'><mi>y</mi><mo stretchy='false'>&#8594;</mo><mn>4</mn></math> is described by the single fixed point. The corresponding critical dimensions of the frequency and the basic fields are found exactly.

Russia

N.V. Antonov

P.I. Kakin

N.M. Lebedev

A.Yu. Luchin

Renormalization group analysis of a continuous model with self-organized criticality: Effects of randomly moving environment

Among the three known types of static solutions proposed within the Hamiltonian constraint approach to effective quantum gravity (EQG), the first two have been extensively investigated, whereas the third type-which preserves general covariance, is free of Cauchy horizons, and was only recently obtained-remains relatively unexplored. This solution can describe a black hole with an event horizon for certain parameter ranges, or a horizonless compact object beyond those ranges. In this paper, we focus on the third type and show that its light rings feature both stable and unstable branches, and that the black hole shadow size grows with the quantum parameter-unlike in the first two types. However, when we account for both the shadow and the lensing ring, the overall behavior closely resembles that of the second type, in which an increasing quantum parameter leads to a larger portion of the lensing ring being occupied by the shadow. This feature can serve as a hallmark of black holes in EQG, offering a potential way to distinguish them from their GR counterparts. Remarkably, the parameter ranges under which the solution remains a black hole are highly consistent with the current observational constraints on black hole shadows, lending strong support to the classification of the third type of compact object in EQG as a black hole endowed with an event horizon.

Wentao Liu

Di Wu

Jieci Wang

Light rings and shadows of static black holes in effective quantum gravity II: A new solution without Cauchy horizons