We study the new $Z'$ boson as a portal for the production of Higgs bosons $h_0$ and $H_0$ predicted by the Bestest Little Higgs Model through Higgs-strahlung processes $\mu^+\mu^- \to (Z, Z') \to Zh_0, ZH_0$ . We focus on the resonant and nonresonant effects of the $Zh_0, ZH_0$ signals. In our analysis, we consider the center-of-mass energies of $\sqrt{s}=3, 4, 6, 10, 30$ TeV and integrated luminosities of ${\cal{L}}=2, 4, 6, 10, 30$ ${ {\rm{ab}}^{-1}}$ projected for a future muon collider. The possibility of performing precision measurements for Higgs bosons $h_0$ and $H_0$ is very promising for the future muon collider. Furthermore, our results may be useful to the High Energy Physics community. Complementarily, we generate and provide the Feynman rules necessary for studying processes $\mu^+\mu^- \to (Z, Z') \to Zh_0, ZH_0$ .

J.M. Martínez-Martínez

A. Gutiérrez-Rodríguez

E. Cruz-Albaro

M.A. Hernández-Ruíz

New $\textit{Z}$' boson of the bestest little Higgs model as a portal to signatures of Higgs bosons $\textit{h}$ $_{0}$ and $\textit{H}$ $_{0}$ at the future muon collider

Using <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> collision data corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>10.6</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> collected at center-of-mass energies between 4.258 and 4.681 GeV with the BESIII detector at the BEPCII collider, we search for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>1</mn><mrow><mo>−</mo><mo>+</mo></mrow></msup></math> charmoniumlike hybrid via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>γ</mi><mi>η</mi><msub><mi>η</mi><mi>c</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>γ</mi><msup><mi>η</mi><mo>′</mo></msup><msub><mi>η</mi><mi>c</mi></msub></math> decays for the first time. No significant signal is observed, and the upper limits on the Born cross sections for both processes are set at the 90% confidence level.

China

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

JINR

O. Bakina

Y. Ban

H.R. Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

X.Y. Chai

J.F. Chang

G.R. Che

Y.Z. Che

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z.J. Chen

Z.K. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Y.T. Feng

Search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>1</mn><mrow><mo>−</mo><mo>+</mo></mrow></msup></math> charmoniumlike hybrid via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">→</mo><mi>γ</mi><msup><mrow><mi>η</mi></mrow><mrow><mo stretchy="false">(</mo><mo>′</mo><mo stretchy="false">)</mo></mrow></msup><msub><mrow><mi>η</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math> at center-of-mass energies between 4.258 and 4.681 GeV

We explore toponium, the smallest known quantum bound state of a top quark and its antiparticle, bound by the strong force. With a Bohr radius of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>8</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>18</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi mathvariant="normal">m</mi></mrow></math> and a lifetime of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>25</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi mathvariant="normal">s</mi></math>, toponium uniquely probes microphysics. Unlike all other hadrons, it is governed by ultraviolet freedom. This distinction offers novel insights into quantum chromodynamics. Our analysis reveals a toponium signal exceeding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math> in the distribution of the cross section ratio between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>q</mi><mover accent="true"><mi>q</mi><mo stretchy="false">¯</mo></mover></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>q</mi><mo>=</mo><mi>b</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>c</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>s</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>d</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>u</mi></mrow></math>), based on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>400</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> of data collected at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>≈</mo><mn>341</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. This discovery enables a top quark mass measurement with an uncertainty reduced by a factor of ten compared to current precision levels. Moreover, this method improves the systematic uncertainty by at least a factor of 2.7 compared to any other possible methods.

Jing-Hang Fu

Yu-Ji Li

Hui-Min Yang

Yu-Bo Li

Yu-Jie Zhang

Cheng-Ping Shen

Toponium: The smallest bound state and simplest hadron in quantum mechanics

We study localization of the low Dirac modes in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>3</mn><mo>+</mo><mn>1</mn></mrow></math> dimensional pure SU(3) gauge theory at zero and nonzero imaginary <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>θ</mi></math> angle, with the aim of better characterizing the relation between low-mode localization and topological features of gauge theories. We show that the mobility edge observed in the deconfined phase at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>θ</mi><mo>=</mo><mn>0</mn></math> is present also at nonzero <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>θ</mi></math>, appearing exactly at the deconfinement transition. We find that the mobility edge is affected by topology only indirectly, through its effects on the ordering of the Polyakov loop. Moreover, the change in the mobility edge is strongly correlated with the change in the Polyakov-loop expectation value, both as one moves along the critical line, and as one departs from it toward higher temperatures. This further strengthens the connection between low-mode localization and deconfinement, showing in particular the key role played by the ordering of the Polyakov loop.

Spain

Claudio Bonanno

Hungary

Matteo Giordano

Localization in the Dirac spectrum and gauge-field topology

Based on periodic orbit theory, we address the individual-system versus ensemble interpretation of quantum gravity from a quantum chaos perspective. To this end, we show that the spectrum of geodesic motion on high-dimensional hyperbolic manifolds, described by the Selberg trace formula, displays a Schwarzian (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>sinh</mi><mn>2</mn><mi>π</mi><msqrt><mi>E</mi></msqrt></math>) mean level density. Due to its chaotic classical limit, this quantum system also shows all universal signatures of quantum chaos. These two properties imply a possible duality to Jackiw-Teitelboim-type quantum gravity at the level of a single system instead of an ensemble of systems like matrix- and Sachdev-Ye-Kitaev models. Moving beyond the universal regime, we show how the full wormhole geometry on the gravity side emerges from the discreteness of the set of periodic orbits. Thereby, we take initial steps towards a duality between gravitational and mesoscopic chaotic quantum systems through the topological, respectively, periodic orbit expansions of their correlators.

Fabian Haneder

Juan Diego Urbina

Camilo Moreno

Torsten Weber

Klaus Richter

Beyond the ensemble paradigm in low-dimensional quantum gravity: Schwarzian density, quantum chaos, and wormhole contributions

The gravitational decoupling method systematically generates hairy modifications to the solutions in general relativity due to new gravitational sources. In view of the recent advances in astronomical observations, these hairy solutions are expected to be testable in near-term observations. In this paper, we study the radiative property and optical appearance of the thin accretion disk around the rotating hairy black holes obtained by gravitational decoupling. We numerically compute the radiative flux, temperature, differential luminosity, spectral luminosity, and radiative efficiency of the thin accretion disk, and we also show its bolometric image by the ray-tracing method. By comparing with the results for the Kerr metric, we found that the deviations of the observational properties of the thin accretion disk from those of Kerr metric becomes significant in the rapid rotating case, or in the inner region of the disk. These results guide the observational investigations on the rotating hairy black hole.

Zhen Li

Xiao-Kan Guo

Thin accretion disk around rotating hairy black hole: radiative property and optical appearance

In this paper, we study the effect of the presence of plasma and different accretion models on the shadow and optical appearance of static spherically symmetric black holes containing the Kalb– field. We derive the motion equations for photons around the Kalb–Ramond black hole and constrain the Lorentz symmetry breaking parameters $$\lambda $$ and $$\gamma $$ using observational data released by the Event Horizon Telescope collaboration. The results indicate that, under the static spherical accretion model, as $$\lambda $$ or $$\gamma $$ increase, the peak value of the observed intensity for Kalb–Ramond black holes is enhanced and consistently exceeds that of the corresponding Schwarzschild black holes. In the presence of plasma, we find that as the plasma frequency increases, the photon sphere radius increases, whereas the black hole shadow radius decreases. In addition, compared to inhomogeneous plasma, the effect of homogeneous plasma on these features is more significant. Specifically, when the plasma is homogeneous, an increase in plasma frequency further enhances the observed intensity peaks. This suggests that the shadow of the Kalb–Ramond black hole is brighter due to the presence of plasma. Additionally, for the same Kalb–Ramond black hole model parameters and plasma frequency, the shadow of the Kalb–Ramond black hole in inhomogeneous plasma is larger than in the case of homogeneous plasma. Under the thin disk accretion model, an increase in the Lorentz symmetry breaking parameters decreases the observed intensity peak and increases the thickness of the photon ring and the lensed ring. The presence of plasma significantly alters the optical appearance of Kalb–Ramond black hole, providing a possible way to distinguish Kalb–Ramond black hole from Schwarzschild black hole.

Mou Xu

Ruonan Li

Jianbo Lu

Shining Yang

Shu-Min Wu

Optical appearance and shadow of Kalb–Ramond black hole: effects of plasma and accretion models

The current status of ‘fat-brane’ minimal Universal Extra Dimension (fat-mUED) is studied in light of recent results reported by the ATLAS experiment. At the Large Hadron Collider (LHC), color charged first-level Kaluza–Klein (KK) particles (first-level excited quarks and gluons) can be abundantly pair-produced due to conserved quantity, viz., KK-parity, and the strong interaction. The cascade decay of these particles to one or more Standard Model (SM) particle(s) and lighter first-level KK particle(s) stops after producing the lightest excited massive state, named as the lightest KK particle (LKP). In the presence of gravity induced decays, the stability of the LKP is lost, allowing it to decay to photon or Z-boson by radiating KK-excited gravitons, leading to final states with photon(s) at the LHC. A variant signal topology emerges when pair-produced first-level colored KK particles undergo direct decay to their associated SM partners together with KK-excitations of gravitons resulting in a signature characterized by two hard jets and substantial missing energy. The ATLAS experiment lately reported two relevant searches at the 13 TeV LHC with 139 inverse-femtobarn of data: (i) multi-jet, and (ii) photon and jets accompanied by missing energy. Neither search observed substantial deviations from SM background expectations. Provided the absence of any number of excess events in both searches, we constrained parameters of the fat-mUED model, viz., the higher-dimensional Planck mass and the compactification scale.

Esra Akyumuk

Durmus Karabacak

‘Fat-brane’ universal extra dimension model confronted with the ATLAS multi-jet and photonic searches at 13 TeV LHC

In this work, the Schwarzschild black hole immersed in a Dehnen-type dark matter halo is considered for analyzing its various properties such as thermodynamics (through various entropies), shadow and optical appearance. For this purpose, we analytically describe the thermodynamic characteristics of BHs, like heat capacity and Helmholtz and Gibbs free energy, to study the local and global stability of such BHs by utilizing different entropy models. We also investigate the sparsity of Hawking radiations and found that the halo core radius and density are key factors determining the sparsity of this black hole. Astrophysical BHs are believed to be surrounded by luminous accretion disks. By considering the geometrically and optically thin accretion flow around the Schwarzschild black hole immersed in a Dehnen-type dark matter halo, we investigate the shadow and optical appearance of such a black hole. We show that in addition to the structure of the space-time geometry, the black hole’s image depends on the location of the accretion disk. By analyzing three specific radii, we determine the impact of direct emissions, photon rings, and lensing rings on the total intensity. The results indicate that direct emissions dominate the intensity while lensing and photon rings contribute minimally.

Pakistan

Shamaila Rani

Abdul Jawad

Iran

Malihe Heydari-Fard

Japan

Usman Zafar

Thermodynamic and shadow analysis of Dehnen type dark matter Halo corrected Schwarzschild black hole surrounded by thin disk

We study a simplified model of two colourless heavy vector resonances in the singlet representation of SU(2) , with zero and unit hypercharge. We discuss mixing with the Standard Model gauge bosons due to electroweak symmetry breaking, semi-analytic formulae for production at proton colliders, requirements to obey the narrow width approximation and selected low energy constraints. We show current LHC constraints and sensitivity projections for the HL-LHC, HE-LHC, SPPC and FCC-hh on the charged and neutral heavy vectors. The utility of the simplified model Lagrangian is demonstrated by matching these results onto three explicit models: a weakly coupled abelian extension of the Standard Model gauge group, a weakly coupled non-abelian extension and a strongly coupled minimal composite Higgs model. All our results are presented in terms of physical resonance masses, using expressions which are accurate even at vector masses near the electroweak scale due to a parameter inversion we derive. We discuss the importance of this inversion and point out that its effect, and the effects of electroweak symmetry breaking, can remain important up to resonance masses of several TeV. Finally, we clarify the relation between this simplified model and the Heavy Vector Triplet (HVT) model, a simplified model for heavy SU(2) triplets with zero hypercharge, and provide exact and approximate matching relations.