We systematically investigate theoretical uncertainties in perturbative analyses of first-order electroweak phase transitions (EWPTs). Utilizing the Standard Model effective field theory framework, we quantify the gauge dependence, renormalization scheme, and scale dependencies in predicting phase-transition parameters across both zero and finite chemical potential regimes. Our key findings reveal that: (1) The gauge-parameter dependence and the chemical potential are subdominant, and (2) Baryon number preservation criteria and phase transition observables exhibit pronounced sensitivity to the renormalization scale in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>MS</mi><mo stretchy="true">¯</mo></mover></math> scheme. Comparative analyses with the on-shell scheme demonstrate that within strongly first-order EWPT parameter spaces, the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>MS</mi><mo stretchy="true">¯</mo></mover></math> scheme predicts enhanced phase transition strengths and prolonged transition durations.

China

Yongzhao Zhu

Jie Liu

Renhui Qin

Ligong Bian

Theoretical uncertainties in first-order electroweak phase transitions

An important theoretical achievement of the last century was the realization that strict renormalizability can be a powerful criterion to select Lagrangians in the framework of perturbative quantum field theory. The Standard Model Lagrangian (without gravity) is strictly renormalizable from a perturbative point of view. On the other hand, the inclusion of gravity seems not to respect this criterion, since general relativity is perturbatively non-renormalizable. The aim of this work is to provide concrete evidence that strict renormalizability is still a valid criterion even when applied to gravity. First, we show that adding quadratic curvature terms to the Einstein-Hilbert action gives rise to a strictly renormalizable theory known as quadratic gravity. Second, we argue that this unique theory represents the most conservative approach to quantum gravity and, at the same time, is highly predictive, as it can explain new physics beyond general relativity already in the sub-Planckian regime. In particular, it provides one of the best fits to the CMB anisotropies via Starobinsky inflation and makes sharp cosmological predictions that can be tested in the near future. Finally, we comment on the (super-)Planckian regime and conclude with a historical note.

Netherlands

Luca Buoninfante

Strict renormalizability as a paradigm for fundamental physics

A measurement of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mi>W</mi></mrow><mi>Z</mi><mi>γ</mi></mrow></math> triboson production cross section is presented. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>138</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. The analysis focuses on the final state with three charged leptons, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>±</mo></mrow></msup></mrow><mi>ν</mi><mrow><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup></mrow><mrow><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>−</mo></mrow></msup></mrow></mrow></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>ℓ</mo><mo>=</mo><mi>e</mi></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>μ</mi></mrow></math>, accompanied by an additional photon. The observed (expected) significance of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>W</mi></mrow><mi>Z</mi><mrow><mi>γ</mi></mrow></math> signal is 5.4 (3.8) standard deviations. The cross section is measured in a fiducial region, where events with an ℓ originating from a tau lepton decay are excluded, to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5.48</mn><mo>±</mo><mn>1.11</mn><mtext> </mtext><mtext> </mtext><mi>fb</mi></math>, which is compatible with the prediction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.69</mn><mo>±</mo><mn>0.24</mn><mtext> </mtext><mtext> </mtext><mi>fb</mi></math> at next-to-leading order in quantum chromodynamics. Exclusion limits are set on anomalous quartic gauge couplings and on the production cross sections of massive axionlike particles.

Armenia

V. Chekhovsky

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

J.W. Andrejkovic

L. Benato

T. Bergauer

S. Chatterjee

K. Damanakis

M. Dragicevic

P.S. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

H. Kwon

T. Van Laer

P. Van Mechelen

N. Breugelmans

J. D’Hondt

S. Dansana

A. De Moor

M. Delcourt

F. Heyen

Y. Hong

S. Lowette

I. Makarenko

D. Müller

S. Tavernier

M. Tytgat

G.P. Van Onsem

S. Van Putte

D. Vannerom

B. Bilin

B. Clerbaux

A.K. Das

I. De Bruyn

G. De Lentdecker

H. Evard

L. Favart

P. Gianneios

A. Khalilzadeh

F.A. Khan

A. Malara

M.A. Shahzad

L. Thomas

M. Vanden Bemden

C. Vander Velde

P. Vanlaer

M. De Coen

D. Dobur

G. Gokbulut

J. Knolle

L. Lambrecht

D. Marckx

K. Skovpen

N. Van Den Bossche

J. van der Linden

J. Vandenbroeck

L. Wezenbeek

S. Bein

A. Benecke

A. Bethani

G. Bruno

C. Caputo

J. De Favereau De Jeneret

C. Delaere

I.S. Donertas

A. Giammanco

A.O. Guzel

Sa. Jain

V. Lemaitre

J. Lidrych

P. Mastrapasqua

T.T. Tran

S. Turkcapar

Brazil

G.A. Alves

E. Coelho

G. Correia Silva

C. Hensel

T. Menezes De Oliveira

C. Mora Herrera

P. Rebello Teles

M. Soeiro

E.J. Tonelli Manganote

A. Vilela Pereira

W.L. Aldá Júnior

M. Barroso Ferreira Filho

H. Brandao Malbouisson

W. Carvalho

J. Chinellato

Observation of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>Z</mi><mi>γ</mi></math> production and constraints on new physics scenarios in proton-proton collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>

We propose Integrated Collective Dynamics (ICD), a novel scalar-tensor theory inspired by emergent phenomena in complex systems, to provide a unified, purely theoretical framework for gravitational dynamics across galactic and cosmological scales without invoking dark matter or dark energy. Integrated Collective Dynamics conceptualizes gravitational systems as ensembles of interacting particles, where collective interactions, mediated by a massive scalar field, produce emergent modifications to gravity. In the Newtonian limit, Integrated Collective Dynamics employs a rigorously derived correction function to reproduce flat galactic rotation curves, eliminating the need for dark matter through a statistical mechanics-inspired approach. Relativistically, we formulate Integrated Collective Dynamics as a scalar-tensor theory with a meticulously constructed action, deriving field equations via variational principles and solving them analytically in various regimes. The scalar field naturally induces cosmic acceleration, supplanting dark energy, and predicts qualitative modifications to gravitational lensing, the cosmic microwave background, and structure formation. New additions include quantitative predictions for rotation curves, comparisons with alternative theories, and discussions of model limitations. These predictions, grounded in perturbation theory, asymptotic analysis, and rigorous mathematical derivations, highlight Integrated Collective Dynamics's potential to reshape our understanding of gravity. Rooted in field theory and statistical mechanics, Integrated Collective Dynamics offers a mathematically elegant alternative to the ΛCDM paradigm, addressing fundamental questions about the microscopic origins of gravity and its potential unification with quantum mechanics.

Iran

Esmail Dabbaghsaz

Alireza Mohebalhojeh

Integrated collective dynamics: A purely theoretical scalar-tensor framework for gravitational dynamics without dark components

United States

Samuel Ting

Discovery of the J particle at Brookhaven National Laboratory and the physics of electrons and positrons

Cosmic strings are powerful witnesses to cosmic events including any period of early matter domination. If such a period of matter domination was catalyzed by metastable, long-lived particles, then there will be complementary signals to ascertain the nature of the dark sector in experiments detecting primordial features in the gravitational wave (GW) power spectrum and laboratory searches for long-lived particles. We give explicit examples of global and local <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><mo stretchy="false">)</mo></math> gauge extended dark sectors to demonstrate such a complementarity as the union of the two experiments reveals more information about the dark sector than either experiment. Demanding that Higgs-portal long-lived scalar be looked for, in various experiments such as DUNE, FASER, FASER-II, MATHUSLA, and SHiP, we identify the parameter space that leads to complementary observables for GW detectors such as the Laser Interferometer Space Antenna and Einstein Telescope.

Satyabrata Datta

India

Ambar Ghosal

Poland

Anish Ghoshal

United Kingdom

Graham White

Complementarity between cosmic string gravitational waves and long-lived particle searches in a laboratory

Coherent elastic neutrino-nucleus scattering (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math>) is a key process for probing Standard Model and beyond the Standard Model (BSM) properties. Following its first detection by the COHERENT Collaboration, recent reactor-based experiments provide a unique opportunity to refine our current understanding. In particular, the high-precision data from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CONUS</mi><mo>+</mo></mrow></math>, combined with the strong bounds from TEXONO, not only validate the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math> process at low energies but also provide improved constraints on the weak mixing angle, neutrino electromagnetic properties (including the charge radius, millicharge, and magnetic moment), and nonstandard interactions and light mediators. We also examine the role of elastic neutrino-electron scattering, which gains significance in certain BSM scenarios and allows us to obtain the best limit for the millicharge of the electron neutrinos. By combining reactor and higher-energy spallation neutron source measurements, this work strengthens <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math> as a precision tool for testing the Standard Model and beyond.

Italy

M. Atzori Corona

M. Cadeddu

N. Cargioli

F. Dordei

C. Giunti

Reactor antineutrinos <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CE</mi><mi>ν</mi><mi>NS</mi></mrow></math> on germanium: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>CONUS</mi><mo>+</mo></mrow></math> and TEXONO as a new gateway to SM and BSM physics

Machine learning is becoming increasingly popular in the context of particle physics. Supervised learning, which uses labeled Monte Carlo (MC) simulations, remains one of the most widely used methods for discriminating signals beyond the Standard Model. However, this paper suggests that supervised models may depend excessively on artifacts and approximations from Monte Carlo simulations, potentially limiting their ability to generalize well to real data. This study aims to enhance the generalization properties of supervised models by reducing the sharpness of local minima. It reviews the application of four distinct white-box adversarial attacks in the context of classifying Higgs boson decay signals. The attacks are divided into weight-space attacks and feature-space attacks. To study and quantify the sharpness of different local minima, this paper presents two analysis methods: gradient ascent and reduced Hessian eigenvalue analysis. The results show that white-box adversarial attacks significantly improve generalization performance, albeit with increased computational complexity.

Switzerland

Franck Rothen

Samuel Klein

Matthew Leigh

Tobias Golling

Enhancing generalization in high-energy physics using white-box adversarial attacks

Quantum information methods have been brought to bear on high-energy physics, including the study of entanglement and Bell nonlocality in collider experiments. Quantum information observables have also been employed to constrain possible new-physics effects. We improve on this point by introducing quantum information tools routinely used to compare quantum states: the trace distance and the fidelity. We find that the former outperforms other quantum information observables considered in the literature and, together with the cross section, yields the strongest bounds on possible departures from the Standard Model. The power of the proposed methodology is demonstrated with three examples of new-physics searches. The first concerns the chromomagnetic dipole moment of the top quark and yields the first bound computed by means of quantum tomography and actual experimental data. The other two examples use Monte Carlo simulations and set the projected limits on the anomalous couplings of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> leptons at Belle and at a future collider—which is taken to be LEP3. For these new-physics searches, we also compare the sensitivity of the trace distance to those of other quantum information quantities like concurrence, magic, and the fidelity distance. In passing, we provide the first determinations of magic in collider data by analyzing the top-quark pair production at the LHC and the charmonium decays. The significance is well above the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math> level in both the cases.

M. Fabbrichesi

M. Low

Estonia

L. Marzola

Trace distance between density matrices: A nifty tool in new-physics searches

Future planned lepton colliders, both in the circular and linear configurations, can effectively work as virtual and quasireal photon-photon colliders and are expected to stimulate an intense physics program in the next few years. In this paper, we suggest to consider photon-photon scattering as a useful source of information on transverse-momentum-dependent fragmentation functions (TMD FFs), complementing semi-inclusive deeply inelastic scattering 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></math> annihilation processes, which provide most of the present phenomenological information on TMD FFs. As a first illustrative example, we study two-hadron azimuthal asymmetries around the jet thrust axis in the process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">→</mo><msup><mrow><mi>γ</mi></mrow><mrow><mo>*</mo></mrow></msup><mi>γ</mi><mo stretchy="false">→</mo><mi>q</mi><mover accent="true"><mrow><mi>q</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">→</mo><msub><mrow><mi>h</mi></mrow><mrow><mn>1</mn></mrow></msub><msub><mrow><mi>h</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>+</mo><mi>X</mi></mrow></math>, in which in a circular lepton collider one tagged, deeply virtual photon scatters off an untagged quasireal photon, both originating from the initial lepton beams, producing inclusively an almost back-to-back light-hadron pair with large transverse momentum, in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>γ</mi><mo>*</mo></msup><mi>γ</mi></math> center-of-mass frame. Similar processes, in a more complicated environment due to the presence of initial hadronic states, can also be studied in ultraperipheral collisions at the LHC and the planned future hadron colliders.

Simone Anedda

Francesco Murgia

Cristian Pisano

First insight into transverse-momentum-dependent fragmentation physics at photon-photon colliders