We combine existing perturbative results to show that a precise analytic determination of the charm-quark contribution to the hadronic light-by-light (HLbL) part of the muon anomalous magnetic moment is possible. Working in the <math altimg='si5.svg'><mover><mrow><mtext>MS</mtext></mrow><mo stretchy='true'>&#8254;</mo></mover></math> scheme, we include the NLO <math altimg='si6.svg'><mrow><mi mathvariant='script'>O</mi><mo>(</mo><msub><mi>&#945;</mi><mi>s</mi></msub><mo>)</mo></mrow></math> correction, which significantly reduces the residual renormalization-scale dependence and the perturbative uncertainty. Our final result is <math altimg='si7.svg'><mrow><msubsup><mi>a</mi><mrow><mi>&#956;</mi></mrow><mtext>HLbLc</mtext></msubsup><mo linebreak='goodbreak'>=</mo><mn>3.65</mn><mrow><mo>(</mo><mn>25</mn><mo>)</mo></mrow><mo linebreak='goodbreak'>&#215;</mo><msup><mn>10</mn><mrow><mo>&#8722;</mo><mn>11</mn></mrow></msup></mrow></math>, in good agreement with recent lattice determinations.

Sweden

Johan Bijnens

United Kingdom

Nils Hermansson-Truedsson

Spain

Antonio Rodríguez-Sánchez

On the charm contribution to the muon g - 2 light-by-light

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

H. Abreu

Y. Abulaiti

Italy

B. Acharya

A. Ackermann

C. Bourdarios

Poland

L. Adamczyk

S. Addepalli

M. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A. Affolder

Y. Afik

M. Agaras

J. Agarwala

A. Aggarwal

Romania

C. Agheorghiesei

Azerbaijan

F. Ahmadov

Canada

W. Ahmed

S. Ahuja

China

X. Ai

G. Aielli

A. Aikot

M. Tamlihat

B. Aitbenchikh

M. Akbiyik

T. Åkesson

A. Akimov

Japan

D. Akiyama

N. Akolkar

S. Aktas

K. Khoury

G. Alberghi

J. Albert

P. Albicocco

G. Albouy

S. Alderweireldt

Z. Alegria

Switzerland

M. Aleksa

I. Aleksandrov

C. Alexa

Greece

T. Alexopoulos

F. Alfonsi

M. Algren

M. Alhroob

Czechia

B. Ali

H. Ali

S. Ali

S. Alibocus

South Africa

M. Aliev

G. Alimonti

W. Alkakhi

C. Allaire

B. Allbrooke

J. Allen

Chile

C. Flores

P. Allport

A. Aloisio

Argentina

F. Alonso

C. Alpigiani

Z. Alsolami

M. Estevez

A. Fernandez

M. Cardoso

M. Alviggi

M. Aly

Brazil

Y. Coutinho

A. Ambler

C. Amelung

M. Amerl

C. Ames

D. Amidei

B. Amini

K. Amirie

Portugal

S. Santos

K. Amos

D. Amperiadou

S. An

V. Ananiev

C. Anastopoulos

T. Andeen

J. Anders

A. Anderson

S. Andrean

A. Andreazza

S. Angelidakis

A. Angerami

A. Anisenkov

A. Annovi

C. Antel

Erratum: Precision measurement of the $$B^0$$ meson lifetime using $$B^0 \rightarrow J/\psi K^{*0}$$ decays with the ATLAS detector

We formulate a general fusion procedure for open $$\mathfrak{g}\mathfrak{l}(N)$$ spin chains. We construct the fused boundary reflection matrices and the corresponding fused reflection equations. By using the intertwining relation between the fused reflection matrices and the fusion operator, we identify the invariant subspace of the fused reflection matrices carrying the irreducible representations of $$\mathfrak{g}\mathfrak{l}(N)$$ . We also construct the fused transfer matrix and evaluate it explicitly in the total tensor product space and the invariant subspaces. Finally, we demonstrate that the ABJM spin chain model originates from such fusion procedure and derive three classes of boundary reflection matrices solutions on the anti-fundamental representation space of $$\mathfrak{s}\mathfrak{u}(4)$$ .

Nan Bai

A general fusion procedure for open $$\mathfrak{g}\mathfrak{l}(N)$$ spin chains: application to the ABJM spin chain

In this work we focus on the evaluation of the leading-order hadronic vacuum polarization contribution from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>π</mi><mi>π</mi></math> channel to the muon anomalous magnetic moment <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mi>μ</mi></msub></math> by using the experimental <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi><msub><mi>ν</mi><mi>τ</mi></msub></math> data. The isospin breaking corrections play the decisive role in this approach of computing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mi>μ</mi></msub></math>. One of such important isospin breaking sources is the long-distance electromagnetic correction factor <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>G</mi><mrow><mi>EM</mi></mrow></msub></math> of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi><msub><mi>ν</mi><mi>τ</mi></msub></math> process from the real photon radiation. The latter effect can be calculated from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi><msub><mi>ν</mi><mi>τ</mi></msub><mi>γ</mi></math> amplitude, which is revised in this work within the resonance chiral theory by simultaneously including the even-intrinsic-parity and odd-intrinsic-parity resonance operators. We update the determination of the only unknown resonance coupling through the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ω</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mn>0</mn></msup><msup><mi>π</mi><mn>0</mn></msup><mi>γ</mi></math> decay by including contributions from both the vector and scalar resonances. By taking other remaining contributions from the muon <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mo>−</mo><mn>2</mn></math> White Paper 2025, we further revise the complete value of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mi>μ</mi></msub></math>, which turns out to deviate from the newest world average result after Fermilab’s measurement at the level of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2.7</mn><mi>σ</mi></mrow></math>.

Zhi-Xin Li

Ao Li

Jin Hao

Chun-Gui Duan

Zhi-Hui Guo

Revisit of the electromagnetic correction to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>τ</mi><mo stretchy="false">→</mo><mi>π</mi><mi>π</mi><msub><mrow><mi>ν</mi></mrow><mrow><mi>τ</mi></mrow></msub></mrow></math> and its implication for muon <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mo>−</mo><mn>2</mn></math> based on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math> data

We consider mixed strong-electroweak corrections to Higgs production via gluon fusion, in which the Higgs boson couples to the top quark. Using the method of differential equations, we compute all of the master integrals that contribute to this process at two loops through <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mrow><mi>ϵ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo stretchy="false">)</mo></mrow></math> in the dimensional regularization parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>ϵ</mi><mo>=</mo><mo stretchy="false">(</mo><mi>d</mi><mo>−</mo><mn>4</mn><mo stretchy="false">)</mo><mo>/</mo><mn>2</mn></mrow></math>, keeping full analytic dependence on the top quark, Higgs, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson masses. We present the results for these master integrals in terms of iterated integrals whose kernels depend on elliptic curves.

Robin Marzucca

Andrew J. McLeod

Christoph Nega

Two-loop master integrals for mixed QCD-EW corrections to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>g</mi><mi>g</mi><mo stretchy="false">→</mo><mi>H</mi></mrow></math> through <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>O</mi><mo stretchy="false">(</mo><msup><mrow><mi mathvariant="normal">ϵ</mi></mrow><mrow><mn>2</mn></mrow></msup><mo stretchy="false">)</mo></mrow></math>

This paper presents a search for physics beyond the Standard Model targeting a heavy resonance visible in the invariant mass of the lepton-jet system. The analysis focuses on final states with a high-energy lepton and jet, and is optimised for the resonant production of leptoquarks — a novel production mode mediated by the lepton content of the proton originating from quantum fluctuations. Four distinct and orthogonal final states are considered: $\textit{e}$+light jet, $\textit{μ}$+light jet, $\textit{e}$+$\textit{b}$-jet, and $\textit{μ}$+$\textit{b}$-jet, constituting the first search at the Large Hadron Collider for resonantly produced leptoquarks with couplings to electrons and muons. Events with an additional same-flavour lepton, as expected from higher-order diagrams in the signal process, are also included in each channel. The search uses proton-proton collision data from the full Run 2, corresponding to an integrated luminosity of 140 fb at a centre-of-mass energy of $$ \sqrt{s}=13 $$ TeV, and from a part of Run 3 (2022–2023), corresponding to 55 fb at $$ \sqrt{s}=13.6 $$ TeV. No significant excess over Standard Model predictions is observed. The results are interpreted as exclusion limits on scalar leptoquark $$ \left({\overset{\sim }{S}}_1\right) $$ production, substantially improving upon previous ATLAS constraints from leptoquark pair production for large coupling values. The excluded $$ {\overset{\sim }{S}}_1 $$ mass ranges depend on the coupling strength, reaching up to 3.4 TeV for quark-lepton couplings $\textit{y}$ = 1$\textit{.}$0, and up to 4.3 TeV, 3.1 TeV, and 2.8 TeV for $\textit{y}$ , $\textit{y}$ , and $\textit{y}$ couplings set to 3.5, respectively.

C. Adam Bourdarios

M. Ait Tamlihat

U. Alberti

Saudi Arabia

A. Alvarez Fernandez

M. Alves Cardoso

Y. Amaral Coutinho

T. Amezza

A. Amirkhanov

S. Amor Dos Santos

E. Antipov

M. Antonelli

F. Anulli

M. Aoki

Search for resonant leptoquark production via lepton-jet signatures in $\textit{pp}$ collisions at $$ \sqrt{s}=13 $$ TeV and $$ \sqrt{s}=13.6 $$ TeV with the ATLAS detector

In neutrino physics, a class of models with local or global family symmetries may be invoked, and then a flavon field is needed to realize full neutrino mixing. This flavon may leave hints in lepton <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mo>−</mo><mn>2</mn></math> and address their possible anomalies. In this work, we explore this idea in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mrow><mi>B</mi><mo>−</mo><mi>L</mi></mrow><msub><mo stretchy="false">)</mo><mrow><mi>i</mi><mi>j</mi></mrow></msub></math> gauge extension to the standard model (SM), in which realistic neutrino mixing requires both a SM singlet flavon <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi></math> and a vectorlike lepton (VLL) doublet. The dominant coupling between the flavon and leptons is in the manner of lepton-flavor-violation (LFV). Through an analytical analysis of the SM lepton-VLL mixing matrix, we find that the parameter space of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi><mover accent="true"><mi>μ</mi><mo stretchy="false">¯</mo></mover><mi>e</mi></math>-type flavon to explain <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>g</mi><mo>−</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>μ</mi></msub></math> has been completely excluded by the specific LFV process, muonium-antimuonium oscillation. But the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi><mover accent="true"><mi>μ</mi><mo stretchy="false">¯</mo></mover><mi>τ</mi></math>-type flavon still has the opportunity to account for the excess in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>g</mi><mo>−</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>μ</mi></msub></math> or the deficit in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>g</mi><mo>−</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>e</mi></msub></math>; however, it faces the strong constraint from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi><mo stretchy="false">→</mo><mi>μ</mi></math> conservation and, in particular, the lepton flavor universality (LFU) test of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> boson decay, which arises due to our way to realize the LFV flavon. The surviving flavon is highly predictable, with mass in the narrow window <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>τ</mi></msub><mo>≲</mo><msub><mi>m</mi><mi>s</mi></msub><mo>≲</mo><mn>2</mn><msub><mi>m</mi><mi>τ</mi></msub></math> and LFV coupling strength <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>2</mn></mrow></msup></math>. Besides, it leaves a TeV scale VLL with a multilepton signature at the LHC.

Shuyang Han

Zhaofeng Kang

Light lepton-flavor-violating flavon: The messenger of neutrino mixing and lepton <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mo>−</mo><mn>2</mn></math>

Processes with $$\tau $$ -leptons in the final state are important for Standard Model measurements and searches for physics beyond the Standard Model. The ATLAS experiment at the Large Hadron Collider observes $$\tau $$ -leptons produced in proton–proton collisions only through their decay products. Data analyses involving hadronically decaying $$\tau $$ -leptons face challenges due to backgrounds from jets misidentified as $$\tau $$ -leptons that are not modelled reliably by Monte Carlo simulations. Data-driven methods such as the fake-factor method allow such misidentified backgrounds to be predicted by measuring transfer factors, known as fake factors, in data from dedicated regions. This paper describes a refined technique for determining the fake factors, the Universal Fake Factor method. It evaluates the fake factors for a signal region by using fake factors from samples enriched in different sources of jets misidentified as $$\tau $$ -leptons (light-quark, gluon, $\textit{b}$-quark, and pile-up jets). Each fake factor is calculated as a linear combination of fake factors measured in these different enriched samples. For the full Run 2 data set, the systematic uncertainty of the calculated fake factors, evaluated using $$W(\mu \nu )$$ enriched event sample, ranges from 15 to 35% depending on the $$\tau $$ -lepton’s transverse momentum and charged-particle decay multiplicity.

T. Aoki

Estimation of backgrounds from jets misidentified as $$\tau $$ -leptons using the Universal Fake Factor method with the ATLAS detector

D. Abbott

A. Abusleme Hoffman

B. Achkar

L. Adam

L. Adamek

S. Adorni

J. Aguilar-Saavedra

A. Ahmad

I. Aizenberg

M. Alconada Verzini

Netherlands

A. Alfonsi

Taiwan

E. Alunno Camelia

M. Alvarez Estevez

S. Amoroso

C. Amrouche

N. Andari

M. Anthony

D. Antrim

J. Aparisi Pozo

M. Aparo

L. Aperio Bella

C. Appelt

N. Aranzabal

V. Araujo Ferraz

C. Arcangeletti

A. Arce

E. Arena

Erratum: Search for boosted diphoton resonances in the 10 to 70 GeV mass range using 138 fb

A search for R-parity-conserving supersymmetry in events with large missing transverse momentum, jets and at least one hadronically decaying $$\tau $$ -lepton is presented. Both gluino and squark pair production are considered, with the cascade decay of each gluino or squark producing either a $$\tau $$ -slepton or a $$\tau $$ -sneutrino. Three channels are examined, requiring either exactly one hadronically decaying $$\tau $$ -lepton and no other leptons, exactly one hadronically decaying $$\tau $$ -lepton and at least one other lepton, or two or more hadronically decaying $$\tau $$ -leptons. Analyses in the three channels are optimised independently and combined statistically. Two separate analysis strategies, either a cut-and-count or machine-learning approach, are used. The search uses 140 $$\textrm{fb}^{-1}$$ and 51.8 $$\textrm{fb}^{-1}$$ of $\textit{pp}$ collision data recorded by the ATLAS detector at the Large Hadron Collider during 2015–2018 at $$\sqrt{s} = 13$$ TeV and 2022–2023 at $$\sqrt{s} = 13.6$$ TeV, respectively. Gluino masses below 2.25 TeV and squark masses up to 1.7 TeV are excluded

Search for squarks and gluinos in $\textit{pp}$ collisions at $$\sqrt{s} = 13$$ TeV and 13.6 TeV in events with $$\tau $$ -leptons, jets and missing transverse momentum using the ATLAS detector