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

Parametric deviations of quasinormal modes (QNMs) is a common feature of beyond General Relativity (GR) theories. For theories with additional degrees of freedom, such as scalars and vectors, new family of modes might appear, usually called scalar-led and vector-led modes. Although a power series expansion in terms of the new parameters entering the potential is usually suitable to describe the frequency of the modes, the time-evolution of signals might present a richer structure, with different behavior in the tail, the presence of new modes (such as massive modes), or even instabilities. All these features are not explicitly exposed by a pure frequency domain analysis and might give hints of new physics. In this paper, we investigate the time evolution of signals considering potentials that slightly deviate from the ones coming from GR, looking into scalar, vector and metric perturbations. We focus on deviations that can be parametrized by a sum of $$\sim 1/r^j$$ terms in the effective potential, analyzing the effect of each term on the time domain profile

Brazil

Orival de Medeiros

Mateus Corrêa

Caio Macedo

Time evolution of perturbations in quasi-Schwarzschild black holes

On the basis of computer simulation, the ionization energy loss distributions (spectra) of high-energy positrons impinging on a silicon crystal at various angles $$\psi $$ with respect to the axis $$\langle 100\rangle $$ are considered. The method of simulation of high-energy particle ionization loss in oriented crystals is presented in detail. It is demonstrated that along with the probability of particle close collisions with atoms, the probability of distant collisions can be also sensitive to the particle position in the crystal lattice. Evolution of the ionization loss spectra with the change of crystal orientation relative to the incident particle momentum from the axial $$\langle 100\rangle $$ to the planar (100) and (110) with the increase of $$\psi $$ is investigated. It is shown that in the transition $$\langle 100\rangle \rightarrow (100)$$ the most probable energy loss $$E_\mathrm{{MP}}$$ experiences a sharp maximum and discontinuity, while in the transition $$\langle 100\rangle \rightarrow (110)$$ the amplitude of its variation is much smaller. Behavior of the average restricted energy loss $$E_\mathrm{{AV}}$$ in these transitions is investigated as well. Correlation of the dependences of $$E_\mathrm{{MP}}$$ and $$E_\mathrm{{AV}}$$ on $$\psi $$ with the change of the particle motion regime is discussed.

Ukraine

S. Trofymenko

I. Kyryllin

Evolution of high-energy positron ionization loss spectra in a silicon crystal with the change of its orientation from axial to planar

A precise determination of the CKM angle $\textit{γ}$ from $$ {B}_s^0 $$ oscillations in $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays offers a critical test of the Standard Model and probes for new physics. We present a comprehensive study on the prospects of measuring $\textit{γ}$ at a future Tera-$\textit{Z}$ factory, utilizing the baseline detector concept of the Circular Electron Positron Collider (CEPC). A two-dimensional simultaneous fit framework, incorporating flavor tagging, decay time resolution modeling, and acceptance corrections, is developed using full Monte Carlo simulations of $$ {B}_s^0\to {D}_s^{\mp}\left(\to {K}^{\mp }{K}^{\pm }{\pi}^{\mp}\right){K}^{\pm } $$ decays and inclusive background processes. The effective flavor tagging power reaches 23.6%, while the decay time resolution is determined to be 26 fs. Projecting to full statistics of signal events across three dominant $$ {D}_s^{-} $$ decay channels, we estimate a statistical precision of $\textit{σ}$($\textit{γ}$) = 0$\textit{.}$69 , which corresponds to 4.1 Tera-$\textit{Z}$ boson equivalent data. This study has established the feasibility of sub-degree level $\textit{γ}$ measurements at a $\textit{Z}$ factory, highlighting its unique advantages in time-dependent $\textit{CP}$ violation studies through ultra-precise vertexing and background suppression capabilities.

China

Ji Peng

Mingrui Zhao

Xiaolin Wang

Manqi Ruan

Hengne Li

Shanzhen Chen

Prospect for measurement of $\textit{CP}$-violating observables in $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays at a future $\textit{Z}$ factory

We show that the Mathieu groups $\textit{M}$ and $\textit{M}$ in the isometry group of the odd Leech lattice do not lift to subgroups of the automorphism group of its lattice vertex operator (super)algebra. In other words, the subgroups 2 .$\textit{M}$ and 2 .$\textit{M}$ of the automorphism group of the odd Leech lattice vertex operator algebra are non-split extensions. Our method can also confirm a similar result for the Conway group Co and the Leech lattice, which was already shown by Griess in [1]. This study is motivated by the moonshine-type observation on the $$ \mathcal{N} $$ = 2 extremal elliptic genus of central charge 24 by Benjamin, Dyer, Fitzpatrick, and Kachru [2]. We also investigate weight-1 and weight- $$ \frac{3}{2} $$ currents invariant under the subgroup 2 .$\textit{M}$ or 2 .$\textit{M}$ of the automorphism group of the odd Leech lattice vertex operator algebra, and revisit an $$ \mathcal{N} $$ = 2 superconformal algebra in it.

Japan

Masaki Okada

On the symmetry of odd Leech lattice CFT

Aiming to uncover the CP properties of spin-0 particle Dark Matter (DM), we explore a two-component DM scenario within the framework of 3-Higgs Doublet Models (3HDMs), a well-motivated set-up previously studied due to the complementarity of its collider and astrophysical probes. We devise benchmark points in which the two components of DM have same CP in one case and opposite CP in another. We then show several cross section distributions of observables at collider experiments where the two cases are clearly distinguishable.

Ireland

A. Dey

Mexico

J. Hernández-Sánchez

Finland

V. Keus

United Kingdom

Sweden

S. Moretti

T. Shindou

On the CP properties of spin-0 dark matter

Gravitational chiral anomaly connects the topological charge of spacetime and the chirality of fermions. It has been known that the chirality is carried by the particles (or the excited states) and also by vacuum. While the gravitational anomaly equation has been applied to cosmology, distinction between these two contributions has been rarely discussed. In the study of gravitational leptogenesis, for example, lepton asymmetry associated with the chiral gravitational waves (GWs) sourced during inflation is evaluated only by integrating the anomaly equation. This approach, however, does not reveal how these two contributions are distributed in this scenario. Meanwhile, the dominance of vacuum contribution is observed in some specific types of Bianchi spacetime with parity-violating gravitational fields. One may wonder whether such a vacuum dominance takes place also in the system with chiral GWs around the flat background, which is more suitable for application to realistic cosmology. In this work, we apply an analogy between U(1) electromagnetism and the weak gravity to the spacetime that captures the characteristics of the one considered in the gravitational leptogenesis. With this approach, we try to obtain intuitive understanding of the fermion chirality generation under the parity-violating spin-2 gravitational field. By assuming the emergence of Landau level-like dispersion relation in our setup, we observe that spin-2 nature seems to make the level-crossing inefficient, indicating that the chrial charge is likely to accumulate in the vacuum. On this basis, phenomenological implications for gravitational leptogenesis are discussed.

Kohei Kamada

Italy

Jun’ya Kume

On the inefficiency of fermion level-crossing under the parity-violating spin-2 gravitational field

This work is an extension of a previous publication [1] where we fitted the strong coupling $\textit{α}$ together with the non-perturbative parameter $\textit{α}$ from event-shape and jet-shape distributions using power corrections computed in the three-jet region. In ref. [1] only ALEPH data at the $\textit{Z}$-pole were used in the fit. Here, instead, we include a large data sample from various $\textit{e}$ $\textit{e}$ experiments at energies ranging from 22 to 207 GeV and revisited the treatment of theoretical uncertainties. We find that the inclusion of different energies, while not changing the central fit result considerably, helps to disentangle the dependence of perturbative and non-perturbative corrections. Our best fit result is $\textit{α}$ ($\textit{M}$ ) = $$ {0.1181}_{-0.0005-0.0021}^{+0.0002+0.0018} $$ , where the first error includes experimental uncertainties and the second one includes uncertainties associated with scale variation, mass effects, fit limits, non-perturbative schemes and non- perturbative uncertainties.

Germany

Paolo Nason

Giulia Zanderighi

Fits of $\textit{α}$

In this paper, we extend the study of wave packets from the AdS /CFT correspondence to AdS /CFT and examine properties of their energy density. We find that, while the energy still localizes on the light cone, its spatial distribution exhibits momentum dependence and is no longer localized in higher dimensions. This result is significant as it reflects leading 1/$\textit{N}$ corrections to the generalized free field theory associated with the free bulk theory at $\textit{N}$ = ∞. Our findings are consistent with previous studies on entanglement wedge reconstruction including 1/$\textit{N}$ corrections, and also provide new insights into the structure of wave packets in higher-dimensional holography.

Norihiro Tanahashi

Seiji Terashima

Shiki Yoshikawa

Holographic description of bulk wave packets in AdS

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