We compute the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>q</mi><mover accent="true"><mi>q</mi><mo stretchy="false">¯</mo></mover><mi>g</mi></math> contribution to the diffractive structure functions in high-energy deep inelastic scattering. The obtained result corresponds to a finite part of the next-to-leading-order contribution to the diffractive cross section. Previous phenomenological applications have included this contribution only in the high-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Q</mi><mn>2</mn></msup></math> or high-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>M</mi><mi>X</mi><mn>2</mn></msubsup></math> limits in the case of a soft gluon, and we numerically demonstrate that these existing estimates do not provide a good approximation for the full <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>q</mi><mover accent="true"><mi>q</mi><mo stretchy="false">¯</mo></mover><mi>g</mi></math> contribution. Furthermore, we demonstrate that in addition to the soft gluon contribution, there is an equally important soft quark contribution to the diffractive structure functions at high <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>Q</mi><mn>2</mn></msup></math>.

Abhiram Kaushik

Heikki Mäntysaari

Jani Penttala

Diffractive deep inelastic scattering in the dipole picture: The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>q</mi><mover accent="true"><mi>q</mi><mo stretchy="false">¯</mo></mover><mi>g</mi></math> contribution in exact kinematics

The ATLAS experiment has performed a measurement of coherent exclusive $\textit{J/ψ}$ → $\textit{μ}$ $\textit{μ}$ production in ultraperipheral Pb+Pb collisions at $$ \sqrt{s_{\textrm{NN}}}=5.36 $$ TeV. The data was recorded at the Large Hadron Collider (LHC) during 2023, and corresponds to an integrated luminosity of 79 $\textit{μ}$b . Exclusive $\textit{J/ψ}$ candidates were selected with a dedicated track-sensitive trigger based on the ATLAS transition radiation tracker. The analysis involves reconstruction of the dimuon invariant mass based on muon tracks from the inner detector, as the muon transverse momentum range of interest precludes the use of the standard muon reconstruction and identification algorithms. Differential cross sections are measured as a function of $\textit{J/ψ}$ rapidity and are compared with theoretical predictions. After extrapolation to $$ \sqrt{s_{\textrm{NN}}}=5.02 $$ TeV, they are also compared with previous measurements performed by other experiments using data from LHC Run 2. While the results agree reasonably well with theoretical predictions, they are in tension with previous Run-2 results for the central rapidity region.

France

G. Aad

Norway

E. Aakvaag

United States

B. Abbott

United Arab Emirates

S. Abdelhameed

Germany

K. Abeling

N. Abicht

S. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Y. Abulaiti

Italy

United Kingdom

B. Acharya

A. Ackermann

C. Adam Bourdarios

Poland

L. Adamczyk

S. Addepalli

M. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A. Affolder

Y. Afik

Spain

M. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

Azerbaijan

F. Ahmadov

S. Ahuja

China

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

B. Aitbenchikh

M. Akbiyik

Sweden

T. Åkesson

A. Akimov

Japan

D. Akiyama

N. Akolkar

S. Aktas

G. Alberghi

Canada

J. Albert

Switzerland

U. Alberti

P. Albicocco

G. Albouy

S. Alderweireldt

Z. Alegria

M. Aleksa

C. Alexa

I. Aleksandrov

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

Saudi Arabia

H. Ali

S. Ali

S. Alibocus

South Africa

M. Aliev

G. Alimonti

W. Alkakhi

C. Allaire

B. Allbrooke

D. Allen

J. Allen

P. Allport

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

Z. Alsolami

A. Alvarez Fernandez

M. Alves Cardoso

M. Alviggi

M. Aly

A. Ambler

C. Amelung

M. Amerl

C. Ames

T. Amezza

D. Amidei

B. Amini

K. Amirie

A. Amirkhanov

Portugal

S. Amor Dos Santos

K. Amos

D. Amperiadou

S. An

C. Anastopoulos

T. Andeen

J. Anders

A. Anderson

A. Andreazza

S. Angelidakis

A. Angerami

A. Anisenkov

A. Annovi

C. Antel

E. Antipov

M. Antonelli

F. Anulli

Measurement of coherent exclusive $\textit{J/ψ → μ}$ + $\textit{μ}$ $\textit{−}$ production in ultraperipheral Pb+Pb collisions at $$ \sqrt{s_{\textrm{NN}}}=5.36 $$ TeV with the ATLAS detector

C. Bourdarios

M. Tamlihat

A. Fernandez

M. Cardoso

Brazil

Y. Coutinho

S. Santos

M. Aoki

Erratum: The environmental impact, carbon emissions and sustainability of computing in the ATLAS experiment

In the present work, we incorporate redshift space distortion measurement to investigate the growth of large scale structure within the framework of multi-fluid cosmology in the context of $\textit{f}$($\textit{G}$) gravity. Using 3 different $\textit{f}$($\textit{G}$) gravity models, where $\textit{f}$($\textit{G}$) is the function of Gauss–Bonnet invariant, we compare the predictions of $\textit{f}$($\textit{G}$) gravity expansion history—through the Friedmann equation with Hubble data, BAO data sets and constrain models parameters such as $$\Omega _{m}$$ and $$H_{0}$$ . Within the context of multi-fluid cosmology in $\textit{f}$($\textit{G}$) gravity, we obtain the structure growth equation. This equation is then combined with $$\sigma _{8}$$ to get $$f\sigma _{8}$$ predictions—which is compared with redshift space distortion data to constrain models parameters to obtain best-fit values including $$\sigma _{8}$$ . This involves performing a Markov Chain Monte Carlo (MCMC) analysis for these specific forms of $\textit{f}$($\textit{G}$) models. we also perform a statistical analysis incorporating the Akaike Information Criterion (AIC), the Bayesian Information Criterion (BIC), to assess the goodess-of-fit of the considered models.

India

Praveen Dhankar

Rwanda

Albert Munyeshyaka

Aritra Sanyal

Safiqul Islam

Farook Rahaman

Constraints on multi-fluid cosmology in $\textit{f}$($\textit{G}$) gravity with different observational data sets

The reduced cross section of the semiexclusive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>l</mi><mo>,</mo><msup><mi>l</mi><mo>′</mo></msup><mi>p</mi><mo stretchy="false">)</mo></math> lepton scattering process irrespective of the type of interaction is determined mainly by the bound nucleon momentum distribution in the target and nucleon final state interaction with the residual nucleus. These cross sections can be identified with distorted nuclear spectral functions and therefore, they are similar up to Coulomb corrections for neutrino and electron scattering on nuclei. In this article, we exploit this similarity and use data with precise kinematics and large statistics for semiexclusive electron scattering on an oxygen target to test models employed in the genie neutrino event generator. We find that these models cannot reproduce well the measured reduced cross sections in all allowed kinematic regions and the genie event generator needs to describe better both the nuclear ground states and nucleon final state interaction. The approach presented in this paper provides a great opportunity to better test the accuracy of nuclear models of quasielastic neutrino-nucleus scattering, employed in neutrino event generators.

A.V. Butkevich

S.V. Luchuk

Test of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathsize="small">G</mi><mi mathsize="small">E</mi><mi mathsize="small">N</mi><mi mathsize="small">I</mi><mi mathsize="small">E</mi></mrow></math> neutrino event generator against reduced cross sections extracted from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mmultiscripts><mrow><mi mathvariant="normal">O</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>16</mn></mrow></mmultiscripts></mrow><mo stretchy="false">(</mo><mi>e</mi><mo>,</mo><msup><mrow><mi>e</mi></mrow><mrow><mo>′</mo></mrow></msup><mi>p</mi><mo stretchy="false">)</mo></mrow></math> data

A search for the Higgs boson decay to a <italic>Z</italic> boson and a photon in the &#8467;&#8467; <italic>&#947;</italic> ( <math altimg='si38.svg'><mrow><mi>&#8467;</mi><mo linebreak='goodbreak'>=</mo><mi>e</mi><mo>,</mo><mi>&#956;</mi></mrow></math>) final state is performed using <italic>pp</italic> collisions at <math altimg='si39.svg'><mrow><msqrt><mi>s</mi></msqrt><mo linebreak='goodbreak'>=</mo><mn>13.6</mn></mrow></math> TeV recorded with the ATLAS detector at the Large Hadron Collider during 2022&#8211;2024, corresponding to an integrated luminosity of 165 fb <math altimg='si40.svg'><msup><mrow /><mrow><mo>&#8722;</mo><mn>1</mn></mrow></msup></math>. The signal yield, normalised to the Standard Model prediction, is measured to be <math altimg='si41.svg'><mrow><mi>&#956;</mi><mo linebreak='goodbreak'>=</mo><mn>0</mn><mo>.</mo><msubsup><mn>9</mn><mrow><mo>&#8722;</mo><mn>0.6</mn></mrow><mrow><mo>+</mo><mn>0.7</mn></mrow></msubsup></mrow></math>, compatible with the expected value of <math altimg='si42.svg'><mrow><mi>&#956;</mi><mo linebreak='goodbreak'>=</mo><mn>1.0</mn><mo>&#177;</mo><mn>0.7</mn></mrow></math>. This corresponds to an observed (expected) signal significance of 1.4 (1.5) standard deviations under the background-only hypothesis. This result is combined with that of a similar search performed with 140 fb <math altimg='si40.svg'><msup><mrow /><mrow><mo>&#8722;</mo><mn>1</mn></mrow></msup></math> of <math altimg='si37.svg'><mrow><msqrt><mi>s</mi></msqrt><mo linebreak='goodbreak'>=</mo><mn>13</mn></mrow></math> TeV <italic>pp</italic> collisions to provide the best expected sensitivity to date to this rare decay, namely an observed (expected) signal strength of <math altimg='si43.svg'><mrow><mi>&#956;</mi><mo linebreak='goodbreak'>=</mo><mn>1</mn><mo>.</mo><msubsup><mn>3</mn><mrow><mo>&#8722;</mo><mn>0.5</mn></mrow><mrow><mo>+</mo><mn>0.6</mn></mrow></msubsup></mrow></math> ( <math altimg='si44.svg'><mrow><mi>&#956;</mi><mo linebreak='goodbreak'>=</mo><mn>1</mn><mo>.</mo><msubsup><mn>0</mn><mrow><mo>&#8722;</mo><mn>0.5</mn></mrow><mrow><mo>+</mo><mn>0.6</mn></mrow></msubsup></mrow></math>), corresponding to an observed (expected) significance of 2.5 (1.9) standard deviations. The measurement is consistent with the Standard Model expectation.

N.J. Abicht

S.H. Abidi

B.S. Acharya

S.V. Addepalli

M.J. Addison

A.A. Affolder

M.N. Agaras

T.P.A. Åkesson

A.V. Akimov

N.N. Akolkar

G.L. Alberghi

G.L. Albouy

Z.L. Alegria

I.N. Aleksandrov

H.M.J. Ali

S.W. Alibocus

B.M.M. Allbrooke

J.S. Allen

J.F. Allen

P.P. Allport

Z.M.K. Alsolami

M.G. Alviggi

Y. Amaral Coutinho

C.G. Ames

S.P. Amor Dos Santos

K.R. Amos

J.K. Anders

A.C. Anderson

A.V. Anisenkov

Search for the Higgs boson decay to a <italic>Z</italic> boson and a photon in <italic>pp</italic> collisions at <math altimg='si37.svg'><mrow><msqrt><mi>s</mi></msqrt><mo linebreak='goodbreak'>=</mo><mn>13</mn></mrow></math> TeV and 13.6 TeV with the ATLAS detector

A model-agnostic search for Beyond the Standard Model physics is presented, targeting final states with at least four light leptons (electrons or muons). The search regions are separated by event topology and unsupervised machine learning is used to identify anomalous events in the full 140 fb $$^{-1}$$ of proton–proton collision data collected with the ATLAS detector during Run 2. No significant excess above the Standard Model background expectation is observed. Model-agnostic limits are presented in each topology, along with limits on several benchmark models including vector-like leptons, wino-like charginos and neutralinos, or smuons. Limits are set on the flavourful vector-like lepton model for the first time.

Search for Beyond the Standard Model physics with anomaly detection in multilepton final states in $\textit{pp}$ collisions at $$\sqrt{s}=13~\textrm{TeV}$$ with the ATLAS detector

We apply Bayesian inference to the order-by-order chiral perturbation theory ( <italic>&#967;</italic>PT) expansions for the axial-vector coupling constant <italic>g<inf>A</inf></italic> and the nucleon mass <italic>m<inf>N</inf></italic>, and thereby infer the scales at which <italic>&#967;</italic>PT breaks down for these two observables. Using a pointwise Bayesian analysis, we find that the inferred breakdown scales are notably different for the two observables. For the chiral expansion of <italic>g<inf>A</inf></italic>, we obtain <math altimg='si20.svg'><msubsup><mn>251</mn><mrow><mo>&#8722;</mo><mn>50</mn></mrow><mrow><mo>+</mo><mn>20</mn></mrow></msubsup></math> MeV and <math altimg='si21.svg'><msubsup><mn>211</mn><mrow><mo>&#8722;</mo><mn>30</mn></mrow><mrow><mo>+</mo><mn>20</mn></mrow></msubsup></math> MeV using two distinct sets of low-energy constants, while for the chiral expansion of <italic>m<inf>N</inf></italic> we infer a significantly larger breakdown scale of <math altimg='si22.svg'><msubsup><mn>491</mn><mrow><mo>&#8722;</mo><mn>90</mn></mrow><mrow><mo>+</mo><mn>60</mn></mrow></msubsup></math> MeV.

Andreas Ekström

Daniel R. Phillips

Lucas Platter

Matthias R. Schindler

Inferring the breakdown scales of the chiral expansions for <italic>g<inf>A</inf></italic> and <italic>m<inf>N</inf></italic>

A search for Standard Model Higgs bosons produced in association with a high-energy photon and decaying to <math altimg='si39.svg'><mrow><mi>b</mi><mover accent='true'><mi>b</mi><mo>&#175;</mo></mover></mrow></math> is performed using 133 fb <math altimg='si40.svg'><msup><mrow /><mrow><mo>&#8722;</mo><mn>1</mn></mrow></msup></math> of <math altimg='si41.svg'><mrow><msqrt><mi>s</mi></msqrt><mo linebreak='goodbreak'>=</mo><mn>13</mn></mrow></math> TeV <italic>pp</italic> collision data collected with the ATLAS detector at the Large Hadron Collider at CERN. The photon requirement reduces the multijet background, and the <math altimg='si42.svg'><mrow><mi>H</mi><mo>&#8594;</mo><mi>b</mi><mover accent='true'><mi>b</mi><mo>&#175;</mo></mover></mrow></math> decay is the dominant decay mode. Event selection requirements target events produced by vector-boson fusion, the dominant production mode in this channel. Several improvements enhance the search sensitivity compared to previous measurements. These improvements include better background modelling and characterization, the use of a neural-network classifier, and an updated signal extraction strategy adopting a direct binned-likelihood fit to the classifier output. With these improvements, the Higgs boson signal strength is measured to be 0.2&#8239;&#177;&#8239;0.7 relative to the Standard Model prediction. This corresponds to an observed significance of 0.3 standard deviations, compared to an expectation of 1.5 standard deviations assuming the Standard Model.

V. Ananiev

T. Aoki

Search for Higgs bosons produced in association with a high-energy photon via vector-boson fusion and decaying to a pair of <italic>b</italic>-quarks in the ATLAS detector

In this work, we explore the formulation of the Misner-Sharp energy within the framework of <math altimg='si3.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi mathvariant='script'>G</mi><mo>)</mo></mrow></math> gravity, a modified theory incorporating the Ricci scalar <italic>R</italic> and the Gauss-Bonnet scalar <math altimg='si4.svg'><mi mathvariant='script'>G</mi></math>. By extending the quasilocal energy definition to both static spherically symmetric spacetime and the dynamic Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime, we derive explicit expressions for the generalized Misner-Sharp energy using two complementary approaches: the integration method and the conserved charge method based on the Kodama vector. Our analysis shows that the Misner-Sharp energy expression in <math altimg='si3.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi mathvariant='script'>G</mi><mo>)</mo></mrow></math> gravity reduces to standard <italic>f</italic>( <italic>R</italic>) gravity results when the Gauss-Bonnet term is absent, revealing how curvature modifications influence the geometric structure and dynamics of cosmic evolution. Furthermore, we investigate the thermodynamic properties at the apparent horizon associated with the FLRW background, and we find a connection to non-equilibrium thermodynamics unique to <math altimg='si3.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi mathvariant='script'>G</mi><mo>)</mo></mrow></math> gravity. These findings underscore the subtle and fundamental role of curvature corrections in determining the energy distribution and thermodynamic behavior of gravitational systems.

Iran

Amin Rezaei Akbarieh

Navid Safarzadeh Ilkhchi

Yaghoub Heydarzade

Generalized Misner-Sharp energy in <math altimg='si3.svg'><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><mi mathvariant='script'>G</mi><mo>)</mo></mrow></math> gravity