We investigate baryogenesis in Standard Model (SM) extensions with new SU(2) multiplet fields. We focus on sphalerogenesis, in which the baryon asymmetry of the Universe (BAU) is generated through the gradual decoupling of CP-violating electroweak sphaleron-like processes. We show that the observed BAU can be reproduced when the new fields possess CP-violating Yukawa interactions, which leave a CP-violating dimension-six operator involving the SU(2) gauge fields at low energies. As representative examples, we study models with fermionic SU(2) quintuplets and septuplets, and find that these field masses should be $$ \mathcal{O}(1) $$ TeV to explain the BAU. We also show that viable parameter regions for the BAU are consistent with current bounds on the electron electric dipole moment and thoroughly probed by future measurements such as ACME III and by mono-lepton searches at the HL-LHC. Our results provide a concrete and phenomenologically testable ultraviolet completion of sphalerogenesis.

Japan

Kiyoto Ogawa

China

Masanori Tanaka

Baryogenesis in SU(2) $\textit{L}$ multiplet models

<p>We have investigated the prospects of probing the five-dimensional <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>τ</mi></msub></mrow></msub></math> interactions in present and future muon dump experiments, namely, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>NA</mi><mn>6</mn><msub><mn>4</mn><mi>μ</mi></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi mathvariant="normal">M</mi></mrow><mrow><mn>3</mn></mrow></msup></mrow></math>, MuSIC, and a future muon beam dump experiment. These experiments are classified into two categories: the first two can probe processes where feebly interacting massive particles go into invisible channels, while the latter two can probe processes where these states decay into muon pairs. These two types of experiments are complementary in that they allow exploration of different parameter regions of a model. In our scenario, the presence of multiple massive gauge bosons as Kaluza-Klein (KK) particles leads to an enhancement in the signal events compared to the corresponding four-dimensional scenario. In particular, the decay process into muon pairs enables mass reconstruction of the parent particle, making it possible to directly demonstrate the existence of multiple KK particles in at least some parameter regions. This can provide clear evidence that the origin of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>τ</mi></msub></mrow></msub></math> interaction lies in five dimensions. Furthermore, the muon (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>g</mi><mo>−</mo><mn>2</mn></mrow></math>) value, which is now consistent with the Standard Model, can be used to exclude specific parameter regions for new particles interacting with muons. We also carefully discuss the nontrivial effects arising from nonzero kinetic mixing.</p>

India

Dibyendu Chakraborty

Arindam Chatterjee

Ayushi Kaushik

Kenji Nishiwaki

Muon beam dump experiments probe five-dimensional nature of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mrow><msub><mi>L</mi><mi>μ</mi></msub><mo>−</mo><msub><mi>L</mi><mi>τ</mi></msub></mrow></msub></math>

We consider realizations of a gauged B-L symmetry in the context of the Dark Dimension scenario, where the SM lives on a codimension one brane in 5d spacetime. The B-L can naturally be a bulk gauge symmetery leading to a global symmetry on the SM brane, and have its gauge anomaly canceled by charged bulk modes. This naturally leads to the existence of 3 right-handed neutrinos propagating in the dark dimension. Allowing for Higgsing of B-L by a bulk scalar at the Higgs scale, results in a massive gauge field with $\textit{m}$ ~ 100 GeV and weak coupling $\textit{g}$ ~ 10 which is allowed by current bounds. The model also predicts a natural matching $\textit{m}$ ~ $\textit{m}$ ~ Λ , thereby providing a theoretical explanation for the observed coincidence between neutrino masses and the Dark Energy scale. It also predicts a tower of sterile right-handed neutrinos in the $\textit{keV}$ mass range.

Spain

Miguel Montero

United States

Cumrun Vafa

Switzerland

Irene Valenzuela

Neutrinos, B-L symmetry and the dark dimension

A modified gravitational model whose action is given by an arbitrary function of the Ricci scalar, the matter Lagrangian density, a scalar field, and its kinetic term is investigated as an extension of the gravitational sector including an additional dynamical degree of freedom. Within this framework, the causal structure of rotating cosmological solutions is analyzed by considering Gödel and Gödel-type spacetimes as background geometries used as theoretical probes of the model consistency. Different matter sources are examined, including a perfect fluid and scalar-field configurations. It is found that the standard Gödel metric is not compatible with the scalar sector of the theory unless the model reduces to the General Relativity limit. In contrast, Gödel-type geometries admit a wider class of solutions whose causal properties depend on the model parameters and on the matter content. In particular, perfect-fluid sources may lead to either causal or noncausal configurations, whereas scalar-field configurations constrain the geometry to the causal limit, preventing the formation of closed timelike curves, highlighting that the scalar field plays a nontrivial dynamical role distinct from that of a cosmological constant.

Brazil

L. Evangelista

M. Silva

J. Moretti

A. Santos

Causality and its violation in $$f(R,\mathcal {L}_m,\phi ,g^{\mu \nu }\nabla _\mu \phi \nabla _\nu \phi )$$ gravity

The production of single top quarks and top antiquarks via the $\textit{t}$-channel exchange of a virtual $\textit{W}$ boson is measured in proton-proton collisions at a centre-of-mass energy of 13 TeV at the Large Hadron Collider. The full Run 2 data sample recorded with the ATLAS detector in the years 2015–2018 is used, corresponding to an integrated luminosity of 140 fb . The absolute and normalised production cross-sections are measured differentially as a function of the transverse momentum and absolute rapidity of the top quark and top antiquark. In addition, the ratio of top quark to top antiquark production cross-sections is measured. The measured distributions are compared with next-to-leading-order quantum chromodynamics predictions obtained with different combinations of matrix-element generators, parton-shower programs and proton parton distribution functions, as well as to next-to-next-to-leading-order calculations. Overall, good agreement is observed between the measurements and the theoretical predictions. For most measured distributions, the sensitivity to differences between the predictions is limited by the systematic uncertainties in the measurement. The measured differential distributions are also interpreted in an effective field theory approach to constrain the Wilson-Coefficient $$ {C}_{Qq}^{3,1} $$ associated with a four-quark operator. The interpretation accounts for the effect of the selection efficiency, which is altered significantly by non-zero contributions from $$ {C}_{Qq}^{3,1} $$ .

France

G. Aad

Norway

E. Aakvaag

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

M. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

Azerbaijan

F. Ahmadov

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Ait Tamlihat

B. Aitbenchikh

Sweden

T. Åkesson

A. Akimov

D. Akiyama

N. Akolkar

S. Aktas

G. Alberghi

Canada

J. Albert

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

M. Aoki

Measurement of differential $\textit{t}$-channel single top (anti)quark production cross-sections at 13 TeV with the ATLAS detector

A measurement of the associated production of a top-quark pair with the Higgs boson ( $$ t\overline{t}H $$ ) in multilepton final states is presented. The analysis is based on a data sample of proton-proton collisions at $$ \sqrt{s}=13 $$ TeV recorded with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 140 fb . Six final states defined by the number and flavour of reconstructed charged leptons are combined in a simultaneous likelihood fit to extract the $$ t\overline{t}H $$ signal and constrain the most relevant backgrounds. The measured $$ t\overline{t}H $$ cross-section normalised to Standard Model (SM) prediction is $$ {\sigma}_{t\overline{t}H}/{\sigma}^{\mathrm{SM}}=0.{63}_{-0.19}^{+0.20} $$ . This result corresponds to an observed (expected) significance of 3.3$\textit{σ}$ (5.3$\textit{σ}$). Additionally, two other fits are used to measure the $$ t\overline{t}H $$ cross-section differentially in bins of the Higgs boson transverse momentum in the simplified template cross-section framework, and to extract the associated production cross-section of a single top-quark with the Higgs boson ($\textit{tH}$) together with the $$ t\overline{t}H $$ one. The $\textit{CP}$ structure of the top quark-Higgs boson Yukawa coupling is probed through an analysis of $$ t\overline{t}H $$ and $\textit{tH}$ events. The results are compatible with the SM hypothesis, and values of the mixing angle between $\textit{CP}$-even and $\textit{CP}$-odd top-Higgs Yukawa couplings of |$\textit{α}$| $\textit{>}$ 62 are excluded at 68% confidence level.

T. Aoki

M. Aparo

L. Aperio Bella

M. Apicella

C. Appelt

Measurement of the Higgs boson production in association with top quarks in multilepton final states in $\textit{pp}$ collisions at $$ \sqrt{s}=13 $$ TeV with the ATLAS detector

A search is presented for massive long-lived particles in events featuring at least one displaced vertex and at least one displaced muon, using proton–proton collision data collected by the ATLAS detector at the Large Hadron Collider from 2022 to 2024 at a centre-of-mass energy of 13.6 TeV. The data sample corresponds to an integrated luminosity of 164 fb <math altimg='si22.svg'><msup><mrow /><mrow><mo>&#8722;</mo><mn>1</mn></mrow></msup></math>. The analysis targets scenarios in which long-lived particles decay inside the ATLAS inner detector, resulting in a topology of at least one massive, displaced vertex (DV) with multiple associated tracks, and at least one muon with a large transverse impact parameter relative to the primary interaction point. The muon is not required to be associated with the DV. Two signal regions are defined by the transverse distance of the reconstructed DV from the interaction point. Background contributions are estimated by using fully data-driven techniques. No significant excess above the expected background is observed. Upper limits at 95% confidence level are set on the visible cross-section and on the production cross-sections of several benchmark models of <italic>R</italic>-parity-violating supersymmetry.

N.J. Abicht

S.H. Abidi

B.S. Acharya

S.V. Addepalli

M.J. Addison

A.A. Affolder

M.N. Agaras

A. Ahmad

T.P.A. Åkesson

N.N. Akolkar

G.L. Alberghi

Z.L. Alegria

I.N. Aleksandrov

H.M.J. Ali

S.W. Alibocus

B.M.M. Allbrooke

D.R. Allen

J.S. Allen

J.F. Allen

Australia

C.S. Alley

E.R. Almazan

M.G. Alviggi

Y. Amaral Coutinho

J.K. Anders

A.C. Anderson

A.V. Anisenkov

M.A. Aparo

A. Apyan

M. Arampatzi

Search for massive, long-lived particles in events with displaced vertices and displaced muons in <italic>pp</italic> collisions at <math altimg='si21.svg'><mrow><msqrt><mi>s</mi></msqrt><mo linebreak='goodbreak'>=</mo><mn>13.6</mn></mrow></math> TeV with the ATLAS experiment

We consider type IIB string theory on AdS × $\textit{S}$ /ℤ orbifold spaces with generic $\textit{L}$. Recent localisation results in the dual 4d $$ \mathcal{N}=2 $$ circular quiver gauge theories provide us with strong coupling expansions of certain correlators involving twisted half-BPS operators. To leading order, these results have been matched to an effective theory for massless twisted string states, which can be constructed by resolving the orbifold singularity and considering localised supergravity modes on the resolution cycles. Applying this reasoning to subleading order in strong coupling, we observe that for $\textit{L}$ ≠ 2, 3, 4, 6, a naive reduction of the 10d ($\textit{α′}$) -correction does not result in the correct coefficients to match the localisation result. We explain this mismatch by the appearance of twisted sector resonances in string amplitudes involving external twisted sector states. We perform the low-energy expansion of a “twisted” Virasoro-Shapiro amplitude and recover the expected coefficients, suggesting that the orbifold resolution and the low-energy expansion can not be interchanged directly. Finally, we comment on the long-quiver limit, $\textit{L}$ → ∞, in the context of the low-energy effective action.

Carlos Barredo Martínez

Torben Skrzypek

Exploring the twisted sector of ℤ $\textit{L}$ orbifolds: matching $\textit{α′}$-corrections to localisation

<p>We report a search for an invisible particle <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math> in the decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>K</mi></mrow><mrow><mi>L</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">→</mo><mi>γ</mi><mi>X</mi></mrow></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">→</mo><mtext>invisible</mtext></math>), where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math> can be interpreted as a massless or massive dark photon. No evidence for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math> was found, based on 13 candidate events consistent with a predicted background of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>12.66</mn><mo>±</mo><mn>4.4</mn><msub><mrow><mn>2</mn></mrow><mrow><mi>stat</mi></mrow></msub><mo>±</mo><mn>2.1</mn><msub><mrow><mn>3</mn></mrow><mrow><mi>syst</mi></mrow></msub></mrow></math> events. Upper limits on the branching ratio of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>K</mi><mi>L</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><mi>γ</mi><mi>X</mi></math> were set for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math> mass range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0</mn><mo>≤</mo><msub><mrow><mi>m</mi></mrow><mrow><mi>X</mi></mrow></msub><mo>≤</mo><mn>425</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi><mo>/</mo><msup><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math>. For massless <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math>, the upper limit was <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math> at the 90% confidence level, improving the previous indirect bound by over three orders of magnitude. This result yielded a new lower bound of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4.1</mn><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> on the probed effective mass scale governing flavor-changing dark-photon couplings, representing approximately two orders of magnitude improvement on existing constraints. For massive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math>, the upper limits in the searched mass region ranged from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><mo stretchy="false">)</mo></math> to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">O</mi><mo stretchy="false">(</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup><mo stretchy="false">)</mo></math>.</p>

T. Wu

Taiwan

Y.C. Tung

Y.B. Hsiung

South Korea

J.K. Ahn

M. Gonzalez

E.J. Kim

T.K. Komatsubara

Search for Dark Particles in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>K</mi></mrow><mrow><mi>L</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">→</mo><mi>γ</mi><mi>X</mi></mrow></math> at the KOTO Experiment