Inspired by quantum gravity frameworks predicting Planck-scale deviations from Lorentz invariance, we probe Lorentz symmetry violation via modified dispersion relations <math altimg='si1.svg'><msub><mrow><mi>&#969;</mi></mrow><mrow><mo stretchy='false'>|</mo><mtext mathvariant='bold'>k</mtext><mo stretchy='false'>|</mo></mrow></msub></math>. Departing from conventional approaches, we employ an Unruh-DeWitt detector to probe energy-dependent modifications to the dispersion relations. Two key methodological advances are introduced: (i) a generalized formulation for detector acceleration without assuming specific dispersion relations, and (ii) a momentum-resolved detection paradigm enabling spectral decomposition of <math altimg='si1.svg'><msub><mrow><mi>&#969;</mi></mrow><mrow><mo stretchy='false'>|</mo><mtext mathvariant='bold'>k</mtext><mo stretchy='false'>|</mo></mrow></msub></math> through localized momentum-shell integration. Analysis of deviations reveals disruption of the thermal spectrum under significant departures from the Lorentz invariance, while small perturbative regimes manifest as phase-modulated thermal distributions. By restricting detector-field interactions to narrow spectral windows and performing iterative Taylor expansions around reference momenta <math altimg='si12.svg'><mo stretchy='false'>|</mo><msub><mrow><mtext mathvariant='bold'>k</mtext></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy='false'>|</mo></math>, we derive coefficients encoding derivatives of <math altimg='si1.svg'><msub><mrow><mi>&#969;</mi></mrow><mrow><mo stretchy='false'>|</mo><mtext mathvariant='bold'>k</mtext><mo stretchy='false'>|</mo></mrow></msub></math>, reconstructing its global profile via momentum-space tomography. Our approach offers a scalable method to test Lorentz symmetry violation across energy scales, and establishes a foundation for experimental verification of Planck-scale relics through high-precision spectral measurements.

China

Hao Xu

Momentum-resolved probing of Lorentz-violating dispersion relations via Unruh-DeWitt detector

Quasi-Periodic Oscillations (QPOs) are an important phenomenon commonly observed in the X-ray radiation of black holes (BH) and neutron stars, closely related to the dynamics of accretion disks around Compact Objects (CO) and general relativistic effects. The objective of this study is to use the QPO phenomenon to distinguish between Dark Matter (DM)-BH systems and Naked Singularities (NS), as well as to investigate the effects of different dark matter models (Cold Dark Matter, CDM, and Scalar Field Dark Matter, SFDM) on the accretion disk dynamics. By introducing a DM correction model within the framework of general relativity, we systematically investigate the differences in dragging effects, characteristic frequency distribution, and the Innermost Stable Circular Orbit (ISCO) radius between DM-BH systems and NS, while analyzing the potential coupling between QPO frequencies and DM distribution. The main results of this study are as follows: In BH cases, the radial precession frequency $$\nu _r$$ is consistent with the High-Frequency QPO range only in the low-spin region ( $$a = 0.1 \sim 0.2$$ ); the vertical precession frequency $$\nu _\theta $$ matches the Low-Frequency QPO range around $$a = 0.5$$ , while the nodal precession frequency $$\nu _{\text {nod}}$$ agrees with the Low-Frequency QPO range around $$a = 0.7$$ , and exhibits frequency reversal in the high-spin region ( $$0.7< a < 1$$ ). NS cases, however, display markedly different characteristics: both radial and vertical precession frequencies show monotonic decrease with significant amplification, with $$\nu _r$$ reaching kHz levels at $$a = 1 \sim 1.2$$ , and $$\nu _\theta $$ reaching 700+ Hz at $$a = 1$$ , both far exceeding the QPO observational range; while the nodal precession frequency $$\nu _{\text {nod}}$$ remains consistently in the reverse state but with values falling within the High-Frequency QPO observational range. CDM and SFDM modulate the accretion disk dynamics at the order of $$10^{-6}$$ .

Zheng Ma

Zhaoyi Xu

Meirong Tang

Distinguishing between dark matter-black hole systems and naked singularities via quasi-periodic oscillations

Dark matter (DM) genesis via Ultraviolet (UV) freeze-in embeds the seed of reheating temperature and dynamics in its relic density. Thus, discovery of such a DM candidate can possibly open the window for post-inflationary dynamics. However, there are several challenges in this exercise, as freezing-in DM possesses feeble interaction with the visible sector and therefore very low production cross-section at the collider. We show that mono-photon (and dilepton) signal at the ILC, arising from DM effective operators connected to the SM field strength tensors, can still warrant a signal discovery. We study both the scalar and fermionic DM production during reheating via UV freeze-in, when the inflaton oscillates at the bottom of a general monomial potential. Interestingly, we see, right DM abundance can be achieved only in the case of bosonic reheating scenario, satisfying bounds from big bang nucleosynthesis (BBN). This provides a unique correlation between collider signal and the post-inflationary dynamics of the Universe within single-field inflationary models.

India

Basabendu Barman

Subhaditya Bhattacharya

Sahabub Jahedi

Dipankar Pradhan

Abhik Sarkar

Lepton collider as a window to reheating via freezing in dark matter detection. Part II

The study of leptoquarks and their couplings to fermions with different chiralities provides a powerful tool for distinguishing among different leptoquark models. As a case study, we focus on two specific third-generation scalar leptoquark models, $\textit{S}$ and $\textit{R}$ , which differ in their electroweak quantum numbers and chiral structures of couplings to the top quark, leading to distinct top-quark polarization states. To enhance the efficacy of the analysis, we employ jet substructure techniques like Soft Drop, $\textit{N}$-subjettiness, and our custom $\textit{b}$-tagging method, along with other event variables. The analysis has been performed using both fixed radius and dynamic radius jet clustering algorithms. A multivariate analysis using a boosted decision tree (BDT) is performed to isolate signal from the Standard Model background. For a leptoquark mass of 1250 GeV, the analysis achieves a signal significance of up to 5$\textit{.}$3 $\textit{σ}$ at the 14 TeV HL-LHC. Furthermore, a $\textit{CL}$ -based profile likelihood estimator is applied to polarization-sensitive variables to discriminate between the two models. To enhance separation between the two models, an additional BDT classifier score is obtained by training a BDT network to distinguish between the $\textit{S}$ and $\textit{R}$ models. In the chosen signal region, the BDT classifier score provides a separation score of up to 3$\textit{.}$2 $\textit{σ}$, outperforming traditional variables such as $\textit{E}$ /$\textit{E}$ and cos $\textit{θ}$ .

Anupam Ghosh

Partha Konar

Tousik Samui

Ritesh Singh

Jet substructure probe on scalar leptoquark models via top polarization

Conformal higher-spin gravity is the log-divergent part of the effective action of the scalar field coupled to background fields via higher-spin currents, as was defined by Segal and Tseytlin, which can be worked out over the flat space background. We revisit the problem of the scalar field in a higher-spin background and propose a manifestly covariant version thereof. The construction utilizes the Fedosov quantization of the cotangent bundle and the action is written with the help of the trace on a curved phase space that is provided by the Feigin-Felder-Shoikhet cocycle. The same construction allows one to formulate quantum mechanics on a curved space, the phase space being the cotangent bundle.

Belgium

Thomas Basile

Shailesh Dhasmana

Evgeny Skvortsov

Scalar field on a higher-spin background via Fedosov quantization

Extensive air showers produce high-energy muons that can be utilized to probe hadronic interaction models in cosmic ray interactions. Most muons originate from pion and kaon decays, called $\textit{conventional}$ muons, while a smaller fraction, referred to as $\textit{prompt}$ muons, arises from the decay of heavier, short-lived hadrons. The option of the air shower simulation tool is used in this work to investigate the prompt and conventional muon flux in the energy range of $${100}\,\hbox {TeV}$$ – $${100}\,\hbox {PeV}$$ , utilizing the newly developed open-source python software . Identifying the muon parent particles allows for scaling the contribution of prompt particles, which can be leveraged by future experimental analyses to measure the normalization of the prompt muon flux. Obtained prompt muon spectra from are compared to results. The relevance to large-volume neutrino detectors, such as IceCube and KM3NeT, and the connection to hadronic interaction models is discussed.

Sweden

Germany

Ludwig Neste

Pascal Gutjahr

United States

Mirco Hünnefeld

Jean-Marco Alameddine

Wolfgang Rhode

Julia Tjus

Felix Riehn

Kevin Kröninger

Johannes Albrecht

Prompt and conventional high-energy muon spectra from a full Monte Carlo simulation via

Gravitational wave observation has provided numerous insights into the merger of astrophysical black holes. In contrast to other violent events ( <italic>e.g.</italic> supernovae), they are, however, not expected to lead to significant emissions of photons and neutrinos. In this paper we discuss a scenario that would lead to characteristic observable gamma ray bursts, which would provide numerous hints to physics beyond General Relativity. Starting from the hypothesis that micro-black holes (called <italic>morsels</italic>) are formed during the merger process, we show that it is possible to observe their Hawking radiation, which takes the form of gamma ray bursts of a uniquely characteristic form: with energies in the TeV range, their temporal structure is unlike that stemming from any other astrophysical event. Notably, the time delay from the gravitational wave event is correlated to the mass distribution of the morsels. The integrated mass of the morsels, allowed by the unaccounted merger mass, leads to a Hawking radiation in photons that is above the sensitivity of atmospheric Cherenkov telescopes such as HESS, LHAASO and HAWC, and gamma ray space telescopes, such as Fermi-LAT. This renders the hypothesis of morsel creation experimentally testable, and we provide the first concrete bounds on the total mass of morsels formed in specific events.

France

Denmark

Giacomo Cacciapaglia

Italy

Stefan Hohenegger

Francesco Sannino

Looking for black hole morsels in astrophysical mergers via Hawking radiation

We propose a novel mechanism of primordial black hole (PBH) formation through inverted bubble collapse. In this scenario, bubbles nucleate sparsely in an incomplete first-order phase transition, such that they remain isolated and do not percolate or collide with each other due to the extremely low nucleation rate. This is followed by a bulk phase transition in the rest of the universe that inverts these pre-existing bubbles into false vacuum regions. These spherically symmetric false-vacuum bubbles subsequently collapse to form PBHs. Unlike conventional PBH formation mechanisms associated with domain wall collapse or bubble coalescence, our inverted bubble collapse mechanism naturally ensures spherical collapse. We demonstrate that, when applied to the singlet extension of the Standard Model, this mechanism can produce highly monochromatic PBHs with masses up to $$ \mathcal{O} $$ (10 – 10 )$\textit{M}$ , which potentially explain the microlensing events observed in the OGLE and Subaru HSC data.

Japan

Kai Murai

Kodai Sakurai

Fuminobu Takahashi

Primordial black hole formation via inverted bubble collapse

Utilizing 4.5 $ \text{fb}^{-1} $ of $ e^+e^- $ annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider, we searched for singly Cabibbo-suppressed hadronic decays $ \Lambda_{c}^{+}\to\Sigma^{0} K^{+}\pi^{0} $ and $ \Lambda_{c}^{+}\to\Sigma^{0}K^{+} \pi^+ \pi^- $ with a single-tag method. No significant signals were observed for both decays. The upper limits on the branching fractions at the 90% confidence level were determined to be $ 5.0\times 10^{-4} $ for $ \Lambda_{c}^{+}\to\Sigma^{0} K^{+}\pi^{0} $ and $ 6.5\times 10^{-4} $ for $ \Lambda_c^{+}\to\Sigma^0K^{+}\pi^{+}\pi^{-} $ .

M. Ablikim

Russia

M.N. Achasov

P. Adlarson

X.C. Ai

R. Aliberti

A. Amoroso

Q. An

Y. Bai

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

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

G. Chelkov

C. Chen

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

Y.B. Chen

Y.Q. Chen

Z.J. Chen

Z.K. Chen

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

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

Z.H. 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

Y.T. Feng

M. Fritsch

C.D. Fu

J.L. Fu

Search for Cabibbo-suppressed decays ${\boldsymbol\Lambda_{\boldsymbol c}^{\bf +} }$ → Σ$^{0}$ $\textit{K}$ $^{+}$ $\textit{π}$ $^{0}$ and $ {\boldsymbol\Lambda_{\boldsymbol c}^{\bf +} }$ → Σ$^{0}$ $\textit{K}$ $^{+}$ $\textit{π}$ $^{+}$ $\textit{π}$ $^{−}$ * This study has been supported in part by National Key R&D Program of China (2020YFA0406300, 2020YFA0406400, 2023YFA1606000); National Natural Science Foundation of China (NSFC) (12205141, 11635010, 11735014, 11935015, 11935016, 11935018, 12025502, 12035009, 12035013, 12061131003, 12192260, 12192261, 12192262, 12192263, 12192264, 12192265, 12221005, 12225509, 12235017, 12361141819); Natural Science Foundation of Hunan Province (2024JJ2044); the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the CAS Center for Excellence in Particle Physics (CCEPP); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1832207); 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; German Research Foundation DFG (FOR5327); Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation (2021.0174, 2021.0299); Ministry of Development of Turkey (DPT2006K-120470); National Research Foundation of Korea (NRF-2022R1A2C1092335); National Science and Technology fund of Mongolia; National Science Research and Innovation Fund (NSRF) via the Program Management Unit for Human Resources & Institutional Development, Research and Innovation of Thailand (B16F640076, B50G670107); Polish National Science Centre (2019/35/O/ST2/02907); Swedish Research Council (2019.04595); The Swedish Foundation for International Cooperation in Research and Higher Education (CH2018-7756); and U. S. Department of Energy (DE-FG02-05ER41374)

<p>We consider a bulk plus boundary extension of Jackiw-Teitelboim gravity coupled with non-Abelian gauge fields. The generalization is performed in the Poisson sigma model formulation and it is derived as a dimensional reduction of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>AdS</mi><mn>3</mn></msub></math> Chern-Simons theory with Wess-Zumino-Witten (WZW) boundary terms. We discuss the role of boundary conditions in relation to the symmetries of the boundary dynamics and we show that the boundary action can be written in terms of coadjoint orbits of an appropriate Virasoro-Kac-Moody group. We obtain a Schwarzian action and interaction terms with additional edge modes that match the effective low-energy action of recent Sachdev–Ye–Kitaev-like tensor models.</p>

Goffredo Chirco

Lucio Vacchiano

Patrizia Vitale

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="fraktur">s</mi><mi mathvariant="fraktur">o</mi></mrow><mo stretchy="false">(</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo stretchy="false">)</mo></math> extension of Jackiw-Teitelboim gravity via the Virasoro-Kac-Moody semidirect product