We investigate a scalar–vector–tensor theory in which matter is minimally coupled to a Jordan-frame metric $$\tilde{g}_{\mu \nu }=(1+\Xi )g_{\mu \nu }$$ , while a massive vector sector interacts with the baryonic current. We show that the conformal scalar coupling modifies the physical expansion rate measured by matter observers, leading to an enhancement of the Hubble constant inferred at low redshift. We stress, however, that the Hubble rate is not a conformal invariant, whereas the acoustic angular scale $$\theta _s$$ is, and we derive the exact integral condition that the scalar field evolution must satisfy. We show that a single-signed scalar velocity cannot satisfy it, and we construct instead a two-epoch phenomenological evolution which matches $$\theta _s$$ exactly while retaining the late-time enhancement, at the cost of a small pre-recombination shift of the effective gravitational coupling. We stress that the scalar is not separately conserved, and that retaining the scalar–matter energy exchange in its continuity equation supplies a further restriction: positivity of the scalar energy density bounds the early component to $$z_E\lesssim 13$$ . Notably, the recombination $\textit{temperature}$ is unmodified, since particle masses are constant in the Jordan frame, only the expansion rate at that epoch being altered. The scalar potential naturally acts as a dynamical dark-energy sector, while the vector sector provides two distinct contributions. The temporal component, determined algebraically by the baryon current, yields an apparent matter-like term in the background expansion that is not a true fluid but rather a manifestation of the interaction energy. The propagating spatial modes, on the other hand, form a vector condensate that behaves as a collisionless pressureless component and can play the cosmological role of cold dark matter. Hence, the framework connects scalar dynamics, effective dark-energy evolution, and the $$H_0$$ tension within a single setup. Finally, local gravitational constraints require a chameleon-type screening mechanism, whose efficiency we discuss critically.

North Macedonia

Kimet Jusufi

Iran

Amir Khodahami

Ahmad Sheykhi

Malta

Jackson Said

Chile

China

Greece

Emmanuel Saridakis

Unified dark sector and Hubble-tension alleviation in scalar–vector–tensor gravity

Upcoming long-baseline neutrino oscillation experiments such as DUNE aim to achieve unprecedented precision, but their physics reach is ultimately constrained by systematic uncertainties in neutrino flux predictions and neutrino-nucleus cross sections. These limitations are especially critical for new-physics searches in neutrino oscillations at the near detector, including non-unitarity and sterile neutrinos, where the signal manifests as small distortions in the energy spectrum and is therefore highly sensitive to spectral uncertainties. The PRISM (Precision Reaction Independent Spectrum Measurement) technique offers a robust strategy to mitigate these effects by exploiting measurements at multiple off-axis angles, effectively providing a data-driven handle to reduce systematics. In this work, we demonstrate that PRISM can significantly reduce the impact of large systematic uncertainties, restoring sensitivity to non-unitarity and sterile neutrino scenarios in the electron and muon sectors to a level comparable to that obtained with small spectral uncertainties. We also include the results for the $\textit{τ}$ sector with PRISM; however, in this case, since the majority of the flux measured at off-axis angles lies below the $\textit{τ}$ production threshold, we find the improvement to be marginal. As part of this work, we have obtained neutrino and antineutrino fluxes for different off-axis angles with higher statistics than those provided by the DUNE collaboration. We make available these fluxes as auxiliary material to this manuscript.

Spain

Josu Hernández-García

Jacobo López-Pavón

France

Salvador Urreas

Sharpening new physics searches in neutrino oscillations with DUNE-PRISM

In the standard picture of cosmic strings, cusps are generic features of Nambu-Goto loops where the string momentarily reaches the speed of light. They have a characteristic sharp profile, following <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>y</mi><mo>∼</mo><msup><mrow><mi>x</mi></mrow><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math> in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>x</mi><mo>,</mo><mi>y</mi><mo stretchy="false">)</mo></math> plane, and produce strong gravitational-wave (GW) bursts with waveform <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>κ</mi><mo stretchy="false">˜</mo></mover><mo stretchy="false">(</mo><mi>ω</mi><mo stretchy="false">)</mo><mo>∝</mo><msup><mi>ω</mi><mrow><mo>−</mo><mn>4</mn><mo>/</mo><mn>3</mn></mrow></msup></math>, making them key targets for GW searches. However, under certain conditions, this generic picture can differ. We identify novel cusp solutions with different, including smooth, shapes and compute their massless GW and axion spectra. We derive a general expression for all possible Nambu-Goto cusp spectra with the asymptotic form <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>κ</mi><mo stretchy="false">˜</mo></mover><mo stretchy="false">(</mo><mi>ω</mi><mo stretchy="false">)</mo><mo>∝</mo><msup><mi>ω</mi><mrow><mo>−</mo><mi>n</mi><mo>/</mo><mo stretchy="false">(</mo><mn>2</mn><mi>n</mi><mo>−</mo><mn>1</mn><mo stretchy="false">)</mo></mrow></msup><msup><mi>ω</mi><mrow><mo>−</mo><mi>m</mi><mo>/</mo><mo stretchy="false">(</mo><mn>2</mn><mi>m</mi><mo>−</mo><mn>1</mn><mo stretchy="false">)</mo></mrow></msup></math> where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>n</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>m</mi><mo>≥</mo><mn>2</mn></mrow></math>. We calculate the effect on the waveform of realistic corrections to the Nambu-Goto description, such as those from backreaction and finite string width, which introduce a high-frequency cutoff.

Italy

United Kingdom

Amelia Drew

South Korea

Ivan Rybak

New massless spectra from cosmic string cusps

A central problem in formulating a theory of quantum gravity is to determine the size and structure of the Hilbert space of black holes. Here we use a quantum dynamical Krylov complexity approach to calculate the Hilbert space dimension of a black hole in (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2</mn><mo>+</mo><mn>1</mn></mrow></math>)-dimensional anti–de Sitter space. We achieve this by obtaining the spread of an initial thermofield double state over the Krylov basis. The associated Lanczos coefficients match those for chaotic motion on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>L</mi><mo stretchy="false">(</mo><mn>2</mn><mo>,</mo><mi mathvariant="double-struck">R</mi><mo stretchy="false">)</mo></math> group. By including nonperturbative effects in the path integral, which computes coarse-grained ensemble averages, we find that the complexity saturates at late times. The saturation value is given by the exponential of the Bekenstein-Hawking entropy plus logarithmic corrections. Our results introduce a new way to compute the Hilbert space dimension of complex interacting systems from the saturating value of spread complexity.

Belgium

United States

Vijay Balasubramanian

Germany

Israel

Rathindra Nath Das

Johanna Erdmenger

Jonathan Karl

Herman Verlinde

Complexity and the Hilbert space dimension of 3D gravity

We propose that quantum gravity may predict the Fermi scale. Fundamental scale invariance implies the scale invariant standard model. Both the Fermi scale and the Planck mass are given by fields, and their ratio is dictated by a dimensionless cosmon-Higgs coupling. For an ultraviolet fixed point of quantum gravity, this coupling is an irrelevant parameter of the renormalization flow and becomes predictable. An analytic scaling solution for quantum gravity admits no free parameter for the mass term of the Higgs boson. We discuss a new asymptotically safe quantum gravity fixed point for which the scalar potential is not flat. If the largest intrinsic mass scale generated by the renormalization flow away from this fixed point is sufficiently below the Fermi scale, the couplings of the scale invariant standard model are determined by the scaling solution. For a given short distance model remaining valid to infinitely small distances, the ratio Fermi scale over Planck mass can then be predicted. With reasonable assumptions for the ultraviolet fixed point, a numerical solution finds a tiny value for the ratio between the Fermi and Planck scales, very close to a second order quantum electroweak phase transition. This could explain the observed gauge hierarchy.

Christof Wetterich

Fermi scale from quantum gravity scaling solution

The Weak Gravity Conjecture (WGC) is a swampland criterion of long standing: any consistent theory of quantum gravity must contain a charged particle whose charge-to-mass ratio exceeds that of an extremal black hole, so that gravity remains the weakest force. Quasinormal modes of a near-extremal black hole are poles of a retarded Green’s function of the conformal quantum mechanics living on the near-horizon AdS $$_2$$ throat, and their damping rate is bounded from below by the Hawking temperature. We show that this pairing fixes the WGC bound in closed form. Only two numbers survive from the bulk geometry, the AdS $$_2$$ radius $$L_2$$ and the electric-field parameter $$e_d$$ of the throat, and the conjecture reads $$q/m \ge L_2/e_d$$ . We evaluate this quantity for two backgrounds that fall outside the Reissner–Nordström idealisation in different ways: static spherically symmetric black holes in dRGT massive gravity, and electrically charged black holes in Einstein–ModMax non-linear electrodynamics, the latter taken throughout in its purely electric sector, where the pseudoscalar invariant $\textit{G}$ vanishes. For dRGT the massive-gravity couplings do not drop out. The bound becomes $$q/m \ge \sqrt{D/A}$$ with $$A = 1+\zeta +\Lambda r_+^2 + 2\gamma _g r_+$$ and $$D = 1+\zeta +2\Lambda r_+^2+3\gamma _g r_+$$ , so the deviation from the Reissner–Nordström value is second order in the graviton mass and is positive whenever $$\Lambda r_+ + \gamma _g > 0$$ . For Einstein–ModMax the duality parameter enters through the charge normalisation of the non-linear displacement field, giving $$q/m \ge e^{\gamma /2}$$ , which coincides identically with the charge-to-mass ratio $$Q_\textrm{ext}/M_\textrm{ext}$$ of the extremal solution. That coincidence is a sharp check on the whole construction. We then relax exact extremality, minimal coupling and the two-derivative truncation, and follow how each relaxation feeds back into $$L_2$$ and $$e_d$$ . Every closed form is cross-checked twice, once symbolically and once against a Runge–Kutta integration of the full radial Klein–Gordon equation that extracts the conformal weight from the horizon exponents without using the throat approximation; the two agree to eleven digits.

Saeed Gashti

Azerbaijan

Behnam Pourhassan

Türkiye

İzzet Sakallı

CFT constraints on the weak gravity conjecture

We study Matrix theory at strong coupling in a setting describing two static objects a fixed distance apart, using numerical techniques. We reproduce the exact general relativistic force law between the two objects as an entropic force in Matrix theory. This involves employing an operator algebra that represents an external observer measuring the relative positions and momenta of the two objects. We identify the location of the horizons of the objects from this entropic force and are led to a modification of the Schwarzschild spacetime inside the horizon. We find evidence that the inside of a black hole is instead to be described by AdS space. The conclusions constitute numerical validation of Verlinde’s entropic gravity proposition and the fuzzball paradigm.

Korin Aldam-Tajima

Vatche Sahakian

On entropic gravity from BFSS matrix theory

We extend the hidden zeros and 2-split of tree-level Tr($\textit{ϕ}$ ) amplitudes to loop-level Feynman integrands, apart from some physically irrelevant scaleless integrals. Our method is based on a certain factorization mechanism that occurs in Feynman diagrams when summing over shuffle permutations. The loop-level hidden zeros and 2-split identified in this work differ from those in the literature. In our result, the kinematic conditions for loop-level hidden zeros and 2-split are remarkably simple. Their connection is as tight as at tree-level, with the same procedure for obtaining the 2-split condition from the zero condition. The resulting 2-split formula at loop-level represents a generalization of that at tree-level: the $\textit{L}$-loop integrand is expressed as a sum over $\textit{L}$ + 1 terms, each of which exhibits a 2-split structure.

Kang Zhou

Towards new hidden zero and 2-split of loop-level Feynman yntegrands in Tr($\textit{ϕ}$ 3) model

A search for a new heavy scalar resonance decaying to two Z bosons, each subsequently decaying to a pair of electrons or muons, is presented. The results are based on a proton-proton collision data set collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb . The search is performed over a wide range of resonance masses from 130 GeV to 3 TeV, considering both narrow- and broad-width scenarios, and considering the gluon fusion and vector boson fusion production processes. For the broad-width scenario, the interference between the new resonance, the 125 GeV Higgs boson production, and the continuum background is taken into account. No significant excess with respect to the standard model background expectation is observed in the examined phase space. Upper limits at the 95% confidence level are set on the product of the heavy scalar resonance production cross section and the branching fraction for its decay into two Z bosons. The exclusion limits range from 0.05–0.1 pb in the low-mass region to 0.005 pb in the high-mass region.

Armenia

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

L. Benato

T. Bergauer

M. Dragicevic

C. Giordano

P. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

M. Matthewman

J. Schieck

R. Schöfbeck

M. Shooshtari

M. Sonawane

W. Waltenberger

C.E. Wulz

T. Janssen

H. Kwon

D. Ocampo Henao

T. Van Laer

P. Van Mechelen

J. Bierkens

N. Breugelmans

J. D’Hondt

S. Dansana

A. De Moor

M. Delcourt

F. Heyen

Y. Hong

P. Kashko

S. Lowette

I. Makarenko

D. Müller

J. Song

S. Tavernier

M. Tytgat

G. Van Onsem

S. Van Putte

D. Vannerom

B. Bilin

B. Clerbaux

A. Das

I. De Bruyn

G. De Lentdecker

H. Evard

L. Favart

P. Gianneios

A. Khalilzadeh

F. Khan

A. Malara

M. Shahzad

A. Sharma

L. Thomas

M. Vanden Bemden

C. Vander Velde

P. Vanlaer

F. Zhang

M. De Coen

D. Dobur

G. Gokbulut

D. Marckx

K. Skovpen

A. Tomaru

N. Van Den Bossche

J. Linden

J. Vandenbroeck

L. Wezenbeek

H. Aarup Petersen

S. Bein

A. Benecke

A. Bethani

G. Bruno

A. Cappati

J. De Favereau De Jeneret

C. Delaere

F. Gameiro Casalinho

A. Giammanco

A. Guzel

V. Lemaitre

J. Lidrych

P. Malek

P. Mastrapasqua

S. Turkcapar

Brazil

G. Alves

M. Barroso Ferreira Filho

E. Coelho

C. Hensel

D. Matos Figueiredo

T. Menezes De Oliveira

C. Mora Herrera

P. Rebello Teles

M. Soeiro

E. Tonelli Manganote

A. Vilela Pereira

W. Aldá Júnior

H. Brandao Malbouisson

Search for a new heavy scalar resonance decaying to a pair of Z bosons in the four-lepton final state in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV

Precision Higgs physics offers a sensitive window into physics beyond the Standard Model. In parallel, neutrino-oscillation experiments have established the existence of nonzero neutrino masses, thus implying the presence of new physics. Motivated by these facts, we investigate the one-loop contributions of light and heavy Majorana neutrinos to the $\textit{ZZh}$ vertex within a variant of the type-I seesaw mechanism in which light-neutrino masses vanish at tree level and are then generated radiatively. We analyze the $\textit{CP}$ -conserving and $\textit{CP}$ -violating anomalous couplings which characterize the $\textit{ZZh}$ vertex and study their phenomenological implications in two relevant kinematic scenarios at future lepton colliders: Higgsstrahlung production and Higgs production via neutral-current vector-boson fusion. We find that $\textit{CP}$ -conserving effects can reach magnitudes of order 10 , potentially within projected future experimental sensitivities, whereas $\textit{CP}$ -violating contributions are strongly suppressed, lying well beyond such projections.

Mexico

Héctor Novales-Sánchez

Humberto Vázquez-Castro

Mónica Salinas

New physics in the $\textit{ZZh}$ vertex: one-loop contributions from a radiative seesaw model