Anomalies in the non-leptonic $$\bar{B}^0\rightarrow D^{(*)+}K^{(*)-}$$ and $$\bar{B}^0_s\rightarrow D^{(*)+}_s\pi ^-$$ decays may be an indication of physics beyond the Standard Model, but the large deviations require strongly coupled new physics that should be visible at colliders. We explore three new directions that could lead to viable new physics models, performing a detailed collider study to examine the possible weakening of previously known constraints on additional $$SU(2)_L$$ doublets. Our results show that, despite the difficulty of probing $$t\bar{t}$$ final states, increasing the branching ratio to this decay mode does not significantly weaken the bounds on weak doublet scalars, as additionally existing charged Higgs searches are equally strong. Beyond this, we analyse a potentially large breakdown of QCD factorisation by including large-power corrections to $\textit{B}$ decays, and the effect of diluting collider searches with multi-scalar extensions. We find that these typical model-building routes for constructing a viable scenario remain constrained by collider measurements, indicating that these non-leptonic anomalies remain among the most puzzling discrepancies from the SM.

United Kingdom

Jack Araz

Christoph Englert

Matthew Kirk

Germany

Gilberto Tetlalmatzi-Xolocotzi

New insights into the $$b\rightarrow c \bar{u}q$$ puzzle through Top–Bottom synergies

$\textit{B}$ mesogenesis offers an interesting mechanism to generate the baryon asymmetry of the universe by converting the CP violation of the Standard Model into a net baryon number asymmetry. In this work we extend the $\textit{B}$ mesogenesis framework by incorporating all relevant $\textit{B}$ meson channels active after low-temperature reheating. We first revisit neutral $\textit{B}$ mesogenesis, providing the time-dependent decay rates including electron scattering. We then perform a systematic study of $\textit{B}$ decays, which are basically unexplored. We provide branching-ratio predictions using both leading-order factorization and a data-driven approach inspired by $\textit{D}$ → $\textit{M}$ $\textit{M}$ decays. These estimates allow us to quantify two $\textit{B}$ sources of mesogenesis: the previously discussed $${B}_{c}^{+}\to {B}^{+}{M}^{0}$$ channel and a new mechanism introduced in this work, $${B}_{c}^{+}\to {B}_{q}^{0}M$$ , in which the asymmetry is generated by combining direct CP violation with neutral-meson oscillations. Interestingly, in these channels the charm quark decays. Therefore, these decays give access to $\textit{charm CP violation}$ in modes with percent level branching ratios. With moderate assumptions, we find that $\textit{B}$ mesogenesis can match or exceed the neutral contribution depending on the semileptonic asymmetry and reheating temperature. Finally, we combine all three mechanisms and explore their viability in terms of the direct CP asymmetry, neutral-meson mixing parameters, early-universe fragmentation fractions and reheating temperature. We find that successful $\textit{B}$ mesogenesis requires an enhancement in the fragmentation fraction and semileptonic asymmetry of $${B}_{s}^{0}$$ at low reheating temperatures. For higher reheating temperatures, $\textit{B}$ mesogenesis dominates and can explain the baryon asymmetry with fragmentation fraction and direct CP asymmetry of $\textit{B}$ mesons at the percent level. Future measurements of $\textit{B}$ modes are thus highly anticipated to further probe the viability of unified $\textit{B}$ mesogenesis.

Netherlands

M. Burgos Marcos

A. Verheyden

K. Vos

From $\textit{B}$ $\textit{c}$ mesons to the baryon asymmetry: a unified $\textit{B}$ mesogenesis framework

We present updated predictions for the lifetimes of all weakly decaying doubly heavy baryons, including $\textit{bb}$, $\textit{cc}$, and $\textit{bc}$ baryons, as well as for the $\textit{B}$ meson. The analysis includes NNLO corrections to the leading dimension-three contribution, NLO corrections to the chromomagnetic term, and the complete set of currently known NLO corrections to the dimension-six heavy-light quark spectator contributions, including penguin terms. We also compare the results in the $$\overline{\text{M}\text{S} }$$ , kinetic, and, where applicable, Υ mass schemes. For the $\textit{bc}$ baryons, we present predictions for both possible ground-state diquark-spin assignments, $\textit{S}$ = 0 and $\textit{S}$ = 1. In the kinetic scheme we obtain the lifetime hierarchies $$\tau \left({\Xi}_{bb}^{0}\right)&lt;\tau \left({\Xi}_{bb}^{-}\right)\simeq \tau \left({\Omega}_{bb}^{-}\right),\tau \left({\Xi}_{cc}^{+}\right)&lt;\tau \left({\Omega}_{cc}^{+}\right)&lt;\tau \left({\Xi}_{cc}^{++}\right),\tau \left({\Xi}_{bc}^{0}\right)\lesssim \tau \left({\Omega}_{bc}^{0}\right)&lt;\tau \left({\Xi}_{bc}^{+}\right)$$ for $\textit{S}$ = 0, and $$\tau \left({\Xi}_{bc}^{{\prime}0}\right)&lt;\tau \left({\Omega}_{bc}^{{\prime}0}\right)&lt;\tau \left({\Xi}_{bc}^{{\prime}+}\right)$$ for $\textit{S}$ = 1. We also revisit the $\textit{B}$ lifetime and discuss the impact of the newly included Darwin term.

Croatia

Lovro Dulibić

Blaženka Melić

Ivan Nišandžić

New predictions for the lifetimes of doubly heavy baryons and the $\textit{B}$ $\textit{c}$ meson

A search for the decay $ B^+\to D_s^+ K^+K^- $ has been reported by the LHCb Collaboration using $ pp $ collision data corresponding to an integrated luminosity of $4.8\;{\rm{fb}}^{-1}$ , collected at center-of-mass energies of 7, 8, and 13 TeV, in which no amplitude analysis of the $ K^+K^- $ subsystem was performed. In this work, we study the resonant contributions to the decay $ B^+\to D_s^+ K^+K^- $ within the perturbative QCD (PQCD) factorization framework. Contributions from the $\textit{S}$-wave resonances $ f_0(980) $ , $ f_0(1370) $ , and $ f_0(1500) $ , the $\textit{P}$-wave resonance $ \phi(1020) $ , and the $\textit{D}$-wave resonances $ f_2(1270) $ and $ f_2(1525) $ are taken into account. By introducing the corresponding two-meson distribution amplitudes for the $ K^+K^- $ system, we perform a complete perturbative analysis of the quasi-two-body decays $ B^+\to D_s^+(R\to)K^+K^- $ , where $\textit{R}$ denotes an intermediate resonance, and present the first PQCD predictions for the associated branching fractions. Using the narrow-width approximation, we further extract the branching fractions of the corresponding two-body decays $ B^+\to D_s^+R $ . Our results are consistent with the available experimental measurements and previous theoretical studies. Finally, we find that direct CP asymmetries vanish for these quasi-two-body decays within the Standard Model, so that any experimentally observed nonzero CP asymmetry would constitute a clear signal of physics beyond the Standard Model.

China

Zhi-Tian Zou

Jun-Peng Wang

Rui Zhou

Ying Li

Quasi-two-body decays $ {B^+\to D_s^+ (R\to) K^+K^-} $ in the perturbative QCD approach * Supported in part by the National Science Foundation of China (12375089, 12435004, 12075086), and the Natural Science Foundation of Shandong province (ZR2022ZD26, ZR2022MA035)

The recent measurement of the branching ratio of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mo>+</mo><mi>inv</mi></math> (where “inv” denotes invisible states) by the Belle II Collaboration is enhanced relative to the standard model expectation by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2.7</mn><mi>σ</mi></mrow></math>. An older puzzle persists in measurements of the branching ratios and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> asymmetries of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><mi>π</mi><mi>K</mi></math> decays. We address these two anomalies in flavor-changing neutral current <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> decays, with a short-lived axionlike particle (ALP) with mass close to that of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mn>0</mn></msup></math>. In the model with the minimum number of new couplings, the ALP has couplings to the photon, top quark and a heavy sterile neutrino. The ALP contributes to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mn>0</mn></msup><mi>K</mi></math> decays by mixing with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mn>0</mn></msup></math>. It contributes to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mo>+</mo></msup><mo>+</mo><mi>inv</mi></math> by its off-shell coupling to sterile neutrino pairs. The model can explain the excess in the total rate, but not the observed distribution of signal events. We make predictions for all <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msup><mi>K</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msup><mo>+</mo><mi>inv</mi></math> modes and for the rare kaon decays, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><mo>+</mo><mi>inv</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi>L</mi></msub><mo stretchy="false">→</mo><msup><mi>π</mi><mn>0</mn></msup><mo>+</mo><mi>inv</mi></math>. We find an appreciable contribution to the magnetic moment of the muon, and negligible contributions to the magnetic moment of the electron and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mo stretchy="false">→</mo><mi>s</mi><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math>.

United States

Bhubanjyoti Bhattacharya

Alakabha Datta

Girish Kumar

Danny Marfatia

Axionlike particles and sterile neutrinos solve the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>B</mi><mo stretchy="false">→</mo><mi>K</mi><mi>ν</mi><mover accent="true"><mrow><mi>ν</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>B</mi><mo stretchy="false">→</mo><mi>π</mi><mi>K</mi></mrow></math> puzzles

The B <inf>4/2</inf> anomaly is defined in the literature for even-even nuclei as the ratio of the 4 <math altimg='si27.svg'><mrow><msup><mrow /><mo>+</mo></msup><mo>&#8594;</mo><msup><mn>2</mn><mo>+</mo></msup></mrow></math>/2 <math altimg='si28.svg'><mrow><msup><mrow /><mo>+</mo></msup><mo>&#8594;</mo><msup><mn>0</mn><mo>+</mo></msup></mrow></math> transition strengths with values smaller than unity. This is a peculiar behavior that cannot be explained by standard collective models, including the three paradigms of nuclear structure: vibrational, rotational, or <italic>&#947;</italic>-soft, all of which predict B <inf>4/2</inf>&#8239;&gt;&#8239; 1. As new experimental data have emerged in recent years, we re-examine this pattern in even-even nuclei by summarizing all the experimental information available in the 28&#8239;&#8804;&#8239;Z&#8239;&#8804;&#8239;92 region. We find 17 isotopes for which the data indicate a clear B <inf>4/2</inf>&#8239;&lt;&#8239; 1 case. In addition, we compare these nuclei with the predictions of the proxy-SU(3) model, and show for the first time that enhanced triaxiality alone does not suffice to guarantee the presence of the B <inf>4/2</inf> anomaly, with the proximity to the border of some region of shape coexistence appearing to also be a necessary condition.

Romania

S. Pascu

Greece

Dennis Bonatsos

Correlations of the B <inf>4/2</inf> anomaly with increased triaxiality and the borders of shape coexistence

We report a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>3.3</mn><mi>σ</mi></mrow></math> measurement of coherent elastic neutrino-nucleus scattering from solar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">B</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>8</mn></mrow></mmultiscripts></mrow></math> neutrinos using a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>6.77</mn><mtext> </mtext><mtext> </mtext><mi mathvariant="normal">t</mi><mo>×</mo><mi>yr</mi></mrow></math> exposure from the XENONnT experiment, inferring a solar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">B</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>8</mn></mrow></mmultiscripts></mrow></math> neutrino flux of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">(</mo><msubsup><mrow><mn>5</mn></mrow><mrow><mo>−</mo><mn>2</mn></mrow><mrow><mo>+</mo><mn>3</mn></mrow></msubsup><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>cm</mi></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mtext> </mtext><msup><mrow><mi mathvariant="normal">s</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>, consistent with previous measurements. In the presence of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">B</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>8</mn></mrow></mmultiscripts></mrow></math> “neutrino fog,” we find no evidence for light dark matter, and observe diminishing returns in sensitivity with increasing exposure. A 93% increase in exposure from the previous search improves the median sensitivity to the nucleon scattering cross section for a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><msup><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math> spin-independent weakly interacting massive particle by 10%. The dataset was also used to measure the weak mixing angle at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><mn>0.02</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><mi>c</mi></math> momentum transfer and constrain physics beyond the Standard Model.

E. Aprile

J. Aalbers

Japan

K. Abe

Israel

M.M. Abu Rmeileh

Switzerland

M. Adrover

France

S. Ahmed Maouloud

L. Althueser

B. Andrieu

Italy

E. Angelino

D. Antón Martin

S.R. Armbruster

United Arab Emirates

F. Arneodo

L. Baudis

M. Bazyk

V. Beligotti

L. Bellagamba

R. Biondi

A. Bismark

K. Boese

R.M. Braun

G. Bruni

R. Budnik

C. Cai

C. Capelli

Portugal

J.M.R. Cardoso

A.P. Cimental Chávez

A.P. Colijn

Sweden

J. Conrad

J.J. Cuenca-García

V. D’Andrea

L.C. Daniel Garcia

M.P. Decowski

A. Deisting

C. Di Donato

P. Di Gangi

S. Diglio

K. Eitel

S. el Morabit

R. Elleboro

A. Elykov

A.D. Ferella

C. Ferrari

H. Fischer

T. Flehmke

M. Flierman

R. Frankel

D. Fuchs

W. Fulgione

C. Fuselli

F. Gao

R. Giacomobono

F. Girard

R. Glade-Beucke

L. Grandi

J. Grigat

H. Guan

M. Guida

P. Gyorgy

R. Hammann

C. Hils

L. Hoetzsch

N.F. Hood

M. Iacovacci

Y. Itow

J. Jakob

F. Joerg

Y. Kaminaga

M. Kara

S. Kazama

P. Kharbanda

M. Kobayashi

D. Koke

K. Kooshkjalali

A. Kopec

E. Kozlova

H. Landsman

R.F. Lang

L. Levinson

A. Li

H. Li

I. Li

S. Li

S. Liang

Z. Liang

Y.T. Lin

S. Lindemann

M. Lindner

K. Liu

M. Liu

F. Lombardi

J.A.M. Lopes

G.M. Lucchetti

T. Luce

Y. Ma

C. Macolino

G.C. Madduri

J. Mahlstedt

F. Marignetti

T. Marrodán Undagoitia

K. Martens

Probing the Solar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">B</mi></mrow><mprescripts></mprescripts><none></none><mrow><mn>8</mn></mrow></mmultiscripts></mrow></math> Neutrino Fog with XENONnT

We study and explore the low scale implications of Yukawa unification (YU) in the minimal gauge mediated supersymmetry breaking models. We also assume nonzero nonholomorphic terms, with which the YU solutions can be accommodated in the cases with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi><mo>&gt;</mo><mn>0</mn></math>. These results can be considered a direct effect from the nonholomorphic terms, but they also lead to testable low scale implications compatible with YU. We observe abundant solutions consistent with the Higgs boson mass. This constraint leads to heavy strongly interacting supersymmetric particles, while the electroweak sector can be relatively light and can be probed by several experiments. We find that the chargino can be lighter than 1 TeV and it is degenerate with the lightest neutralino in most of these solutions. Consistent solutions in this region can accommodate charginos as light as about 120 GeV, and they will likely be tested soon by the analyses over the compressed spectra. These solutions are also subjected in the lifetime analyses. Our analyses identify such light charginos as decaying in about <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>2</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>ns</mi></math>. Probing such points may need a slight improvement in the sensitivity of current analyses, and one can expect them to be tested very soon. In the same region, the stau is found to be another light supersymmetric particle, and some of the solutions can be inconsistently lighter. We find that it can weigh as light as about 600 GeV consistently, and it can be tested over its lifetime. We summarize and also exemplify our findings with five benchmark scenarios. Furthermore, the benchmark solutions also reveal that the solutions can be tested in heavy Higgs boson searches, which shape the whole Higgs boson spectrum in models.

Türkiye

Ali Çiçi

Büşra Niş

Cem Salih Ün

Nonholomorphic impact on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>t</mi><mo>−</mo><mi>b</mi><mo>−</mo><mi>τ</mi></mrow></math> Yukawa unification in minimal gauge mediated supersymmetry breaking

We explore the sensitivity of a future FCC-ee to multi-TeV new physics (NP) that can generate vector, scalar and tensor flavor-changing (FC) <italic>eetu<inf>k</inf></italic> contact interactions ( <math altimg='si58.svg'><mrow><msub><mi>u</mi><mi>k</mi></msub><mo linebreak='goodbreak'>=</mo><mi>u</mi><mo>,</mo><mi>c</mi></mrow></math> for <math altimg='si10.svg'><mrow><mi>k</mi><mo linebreak='goodbreak'>=</mo><mn>1</mn><mo>,</mo><mn>2</mn></mrow></math>), probed via single top-quark production, <math altimg='si59.svg'><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>&#8722;</mo></msup><mo>&#8594;</mo><mi>t</mi><msub><mover accent='true'><mi>u</mi><mo>&#175;</mo></mover><mi>k</mi></msub><mo>,</mo><mi>t</mi><msub><mover accent='true'><mi>u</mi><mo>&#175;</mo></mover><mi>k</mi></msub><mi>&#947;</mi></mrow></math> (+ c.c.) and leading (following the top-quark decay) to two- and four-jet signals, <math altimg='si60.svg'><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>&#8722;</mo></msup><mo>&#8594;</mo><mn>2</mn><mi>j</mi><mo linebreak='goodbreak'>+</mo><mi>X</mi><mo>,</mo><mn>4</mn><mi>j</mi><mo linebreak='goodbreak'>+</mo><mi>X</mi></mrow></math>, where <italic>X</italic> denotes any non-jet final-state particles. Our analysis exploits an approximately conserved Standard Model (SM) quantum number introduced in [1] and termed &#8220; <italic>b</italic>-Parity&#8221; ( <italic>b<inf>P</inf></italic>), which is applicable to scattering processes of the type <math altimg='si61.svg'><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>&#8722;</mo></msup><mo>&#8594;</mo><mi>n</mi><mo>&#183;</mo><msub><mi>j</mi><mi>b</mi></msub><mo linebreak='goodbreak'>+</mo><mi>m</mi><mo>&#183;</mo><msub><mi>j</mi><mi>&#8467;</mi></msub><mo linebreak='goodbreak'>+</mo><mi>X</mi></mrow></math>, where <italic>n</italic> and <italic>m</italic> are the number of produced <italic>b</italic>-jets and light-jets ( <italic>u, d, c, s</italic>, and/or gluons) and <math altimg='si62.svg'><mrow><msub><mi>b</mi><mi>P</mi></msub><mo linebreak='goodbreak'>=</mo><msup><mrow><mo>(</mo><mo>&#8722;</mo><mn>1</mn><mo>)</mo></mrow><mi>n</mi></msup></mrow></math>. The FC <italic>eetu<inf>k</inf></italic> four-fermion interactions can generate distinct <italic>b<inf>P</inf></italic>-odd ( <math altimg='si63.svg'><mrow><msub><mi>b</mi><mi>P</mi></msub><mo linebreak='goodbreak'>=</mo><mo>&#8722;</mo><mn>1</mn></mrow></math>) signals in these multi-jet events, for which the only significant SM background stems from <italic>b</italic>-jet misidentification. We demonstrate that the FCC-ee, operating at <math altimg='si64.svg'><mrow><msqrt><mi>s</mi></msqrt><mo linebreak='goodbreak'>=</mo><mn>240</mn></mrow></math> GeV (the <italic>ZH</italic> run phase) with high luminosity and excellent flavor-tagging performance, is an ideal platform to search for these <italic>b<inf>P</inf></italic>-odd signatures. Indeed, by simply counting the number of final-state <italic>b</italic>-jets, the FCC-ee can probe NP scales of &#923;&#8239;&#8764;&#8239;10 TeV for the new heavy states that generate the vector, scalar and tensor <italic>eetu</italic> and/or <italic>eetc</italic> interactions. This reach, remarkably about 40 times the assumed FCC-ee center-of-mass energy, improves upon current bounds on some of these four-fermion operators by an order of magnitude and it critically relies on high-purity b-jet tagging.

Shaouly Bar-Shalom

Jose Wudka

Counting b-jets at the FCC-ee as a probe of top-quark flavor physics

This Letter presents the first evidence of the simultaneous production of two <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi></math> bosons and one photon with the ATLAS detector at the Large Hadron Collider. The measurement is performed using the full Run-2 dataset, recorded from 2015 to 2018, of proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>140</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. The fully leptonic final state with four leptons and one photon is analyzed, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>p</mi><mi>p</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>Z</mi><mi>γ</mi><mo stretchy="false">→</mo><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>′</mo><mo>+</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>′</mo><mo>−</mo></mrow></msup><mi>γ</mi></mrow></math> with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>ℓ</mo><mo>,</mo><msup><mo>ℓ</mo><mo>′</mo></msup><mo>=</mo><mi>e</mi></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>μ</mi></math>. This final state is measured in a fiducial region where photon final-state radiation is minimized, and the photon has a transverse momentum of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>p</mi></mrow><mrow><mi mathvariant="normal">T</mi></mrow><mrow><mi>γ</mi></mrow></msubsup><mo>&gt;</mo><mn>20</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math>. Eight events are selected, with a background estimate of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>0.92</mn><mo>±</mo><mn>0.15</mn></math>. This results in an observed (expected) significance of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Z</mi><mi>Z</mi><mi>γ</mi></math> final state of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4.4</mn><mi>σ</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4.0</mn><mi>σ</mi></math>). The measured cross section for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>p</mi><mi>p</mi><mo stretchy="false">→</mo><mi>Z</mi><mi>Z</mi><mi>γ</mi><mo stretchy="false">→</mo><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>′</mo><mo>+</mo></mrow></msup><msup><mrow><mo>ℓ</mo></mrow><mrow><mo>′</mo><mo>−</mo></mrow></msup><mi>γ</mi></mrow></math> in the fiducial region is <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mi>Z</mi><mi>Z</mi><mi>γ</mi></mrow></msub><mo>=</mo><mn>0.14</mn><msubsup><mrow><mn>4</mn></mrow><mrow><mo>−</mo><mn>0.051</mn></mrow><mrow><mo>+</mo><mn>0.065</mn></mrow></msubsup><msubsup><mrow><mo stretchy="false">(</mo><mi>stat</mi><mo stretchy="false">)</mo></mrow><mrow><mo>−</mo><mn>0.004</mn></mrow><mrow><mo>+</mo><mn>0.008</mn></mrow></msubsup><mrow><mo stretchy="false">(</mo><mi>syst</mi><mo stretchy="false">)</mo></mrow><mtext> </mtext><mtext> </mtext><mi>fb</mi></mrow></math>, in agreement with the standard model prediction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>σ</mi></mrow><mrow><mi>fid</mi></mrow><mrow><mi>SM</mi></mrow></msubsup><mo>=</mo><mn>0.130</mn><mo>±</mo><mn>0.006</mn><mtext> </mtext><mtext> </mtext><mi>fb</mi></mrow></math>.

G. Aad

Norway

E. Aakvaag

B. Abbott

S. Abdelhameed

K. Abeling

N.J. Abicht

S.H. Abidi

M. Aboelela

Morocco

A. Aboulhorma

H. Abramowicz

B.S. Acharya

A. Ackermann

C. Adam Bourdarios

Poland

L. Adamczyk

S.V. Addepalli

M.J. Addison

J. Adelman

A. Adiguzel

T. Adye

A.A. Affolder

Y. Afik

Spain

M.N. Agaras

A. Aggarwal

C. Agheorghiesei

A. Ahmad

F. Ahmadov

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

T.P.A. Åkesson

D. Akiyama

N.N. Akolkar

S. Aktas

G.L. Alberghi

Evidence of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>Z</mi><mi>Z</mi><mi>γ</mi></mrow></math> Production with the ATLAS Detector