Hadron-hadron interactions, being nonperturbative in nature, play a significant role in addressing phenomenological questions in particle physics. Femtoscopy is a powerful tool in heavy-ion collision experiments, enabling the extraction of hadron-hadron interactions via momentum-correlation functions (CFs). These CFs are typically expressed as a convolution of source functions and hadron-hadron wave functions, with the latter encoding information about the interactions. However, source functions remain poorly constrained and are commonly approximated by a Gaussian form. Reconstructing source functions from experimental correlation data constitutes an 'inverse problem.' To address this, we propose a toy model based on Tikhonov regularization. Using a square-well potential with four distinct strengths, we calculate the CFs for inputs of single Gaussian source functions and mixed Gaussian source functions. The resulting CFs are then used to reconstruct the source functions via Tikhonov regularization. Our results show that the Gaussian source function can be successfully reconstructed, highlighting the potential of this approach for extracting realistic source functions from hadron pairs of interest.

China

Ao-Sheng Xiong

Qi-Wei Yuan

Ming-Zhu Liu

Fu-Sheng Yu

Zhi-Wei Liu

Li-Sheng Geng

Solving the inverse source problem in femtoscopy with a toy model * Supported in part by the Fundamental and Interdisciplinary Disciplines Breakthrough Plan of the Ministry of Education of China (JYB2025XDXM204) and the National Natural Science Foundation of China (W2543006, 12435007). Ming-Zhu Liu acknowledges support from the National Natural Science Foundation of China (12575086). Zhi-Wei Liu acknowledges support from the National Natural Science Foundation of China (12405133) and from the Shenzhen Science and Technology Program (ZDSYS20230626091501002). Fu-Sheng Yu and Ao-Sheng Xiong acknowledge support from the Scientific Research Innovation Capability Support Project for Young Faculty (ZYGXQNJSKYCXNLZCXM-P2) and from the Fundamental Research Funds for the Central Universities (lzujbky-2023-stlt01, lzujbky-2024-oy02, lzujbky-2025-eyt01)

Excesses in di-photon, $$Z\gamma $$ , and $\textit{WW}$ spectra indicate the existence of a new Higgs boson with mass $$152\pm 1$$ GeV. However, no excess is observed in the $\textit{ZZ}$ channel. This pattern aligns with a Real Higgs Triplet model with hypercharge $$Y = 0$$ ( $$\varDelta \hbox {SM}$$ ). A prediction of this model is the Drell–Yan production of scalars at the LHC, which dominantly decay to electroweak bosons, thus enhancing the cross sections of triboson channels such as $\textit{WWZ}$, $\textit{WZZ}$, and $\textit{WWW}$. Interestingly, both ATLAS and CMS have reported higher-than-expected significances for such processes: $$6.4\sigma $$ (observed) vs $$4.7\sigma $$ (expected) in the $\textit{VVZ}$ (where $$V = W$$ or $\textit{Z}$) channel and $$4.4\sigma $$ vs $$3.6\sigma $$ in $\textit{WWZ}$, suggesting the possibility that these signals may be the manifestations of an extended Higgs sector. We investigate whether the $$\varDelta $$ SM can account for these triboson excesses through electroweak production and decay of triplet scalars. We find that while current data prefers a non-zero new physics signal ( $$2.6\sigma $$ ), the $$\varDelta $$ SM predicts more events than observed, such that it is consistent with data but not preferred over the SM. However, this tension could be clarified with Run 3 and HL-LHC data.

South Africa

India

Siddharth Maharathy

Srimoy Bhattacharya

Spain

Andreas Crivellin

Mukesh Kumar

Rachid Mazini

Bruce Mellado

Multi-lepton probes of the Drell-Yan production of triplet higgses

The transverse-momentum spectrum of Drell–Yan lepton pairs at small $$p_\textrm{T}(\ell \ell )$$ probes non-perturbative QCD effects, including intrinsic partonic transverse momentum and initial-state soft-gluon radiation. The novel approach, which implements the Parton Branching (PB) framework in while employing the same evolution ingredients, is used to study this spectrum in the low- $$p_\textrm{T}(\ell \ell )$$ region. This framework is particularly well suited for such investigations, as it allows for a systematic treatment of the dominant non-perturbative effects and their interplay. We examine in detail the implementation of primordial transverse momentum in . With an improved recoil treatment, we determine the width of the intrinsic- $$k_\textrm{T}$$ distribution and find a $$\sqrt{s}$$ dependence that is steeper than in PB, but much flatter than in . We identify the origin of these differences. Furthermore, different treatments of the strong coupling at low scales are investigated and confronted with available experimental data. We find that, at the highest centre-of-mass energy considered, the low- $$p_\textrm{T}(\ell \ell )$$ Drell–Yan spectrum becomes sensitive to the transition between the perturbative and non-perturbative regimes.

Montenegro

D. Subotić

Germany

Belgium

H. Jung

Russia

A. Kotikov

N. Raičević

Non-perturbative effects and soft-gluon dynamics in low- $$p_\textrm{T}$$ Drell–Yan production

Recent observations from the DESI Collaboration indicate a preference for quintom dark energy, i.e., its equation of state evolves across the cosmological constant boundary $$w=-1$$ . It is well known that models with single perfect fluid or single scalar field minimally coupled to Einstein gravity develop perturbative instabilities around the crossing, thereby cannot realize the quintom scenario. In this paper, we propose a method to circumvent the instability problem of these models by considering the coupling of dark energy to the Nieh–Yan density within the framework of teleparallel gravity. We show that with this coupling the background evolution is not affected, but the dark energy perturbation is removed from the menu of dynamical degrees of freedom, thus avoiding the inherent difficulties in the old models. Furthermore, the Nieh–Yan coupling causes parity violation in gravitational waves, and this can be considered as a clear prediction of this mechanism.

Yuxuan Kang

Mingzhe Li

Changzhi Yi

Realization of quintom dark energy after DESI DR2 in Nieh–Yan modified teleparallel gravity

This study investigates the ultraviolet realization of semileptonic four-fermion operator $ O_{ledq}^{\alpha \beta 11} $ that incorporates Majorana dark matter (DM) in both lepton-flavor-conserving (LFC) and lepton-flavor-violating (LFV) scenarios at the one-loop level via box diagram, thereby effectively alleviating the lower bounds on the new physics scale. In addition, we investigate the interplay between model-independent constraints on the Wilson coefficients and DM direct detection, relic density, and collider searches in the context of fermion portal DM model with two mediators. We found that both the projected future constraint on the LFC Wilson coefficient $ C_{ledq}^{2211}/\Lambda^2 \lt $ $ (12.3\; \text{TeV})^{-2} $ from the measurements of neutrino non-standard interaction in the next-generation neutrino oscillation experiments, and the LFV constraint $ C_{ledq}^{1211}/\Lambda^2 \lt \left(2.2\times 10^3\; \text{TeV} \right)^{-2} $ from ongoing charged-lepton-flavor-violation searches, provide a complementary exploration of the parameter space encompassing the DM and scalar masses. With a colored mediator mass of approximately $ 2\; \text{TeV} $ , the sensitivity of the indirect constraints on the four-fermion operator can surpass those of collider searches and DM direct detection, in scenarios where the masses of the DM and scalar are close. By ensuring the correct DM relic density, however, we find that the collider searches and DM direct detection are more sensitive to the electroweak-scale DM and scalar than indirect constraints.

Yuxuan He

Gang Li

Jia Liu

Xiao-Ping Wang

Xiang Zhao

Lepton flavor of four-fermion operator and fermion portal dark matter * Gang Li and Xiang Zhao are supported by the National Natural Science Foundation of China (12347105, 12505127), the Guangdong Basic and Applied Basic Research Foundation (2024A1515012668). The work of Jia Liu is supported by the National Science Foundation of China (12235001, 12475103) and State Key Laboratory of Nuclear Physics and Technology (NPT2025ZX11). The work of Xiao-Ping Wang is supported by National Science Foundation of China (12375095) and the Fundamental Research Funds for the Central Universities

We perform a complete calculation of the next-to-next-to-leading order (NNLO) electroweak fermionic corrections to fermion-pair production processes, where “fermionic” refers to contributions with closed fermion loops. We do this via a semi-numerical technique that uses dispersion relations for the fermion sub-loop in two-loop box and vertex diagrams and dispersion relations and Feynman parameters for vertex diagrams with fermionic triangle sub-loops. UV and IR divergences are treated with suitable subtraction terms. We present numerical results for the cross-sections of $$ {e}^{+}{e}^{-}\to {\mu}^{+}{\mu}^{-}/u\overline{u}/d\overline{d} $$ and differential distributions at representative center-of-mass energies. The NNLO corrections are found to modify the NLO cross-section on the order of 1%.

United States

Ayres Freitas

E. Wallace

Fermionic electroweak two-loop corrections to Drell-Yan and related processes

Positive and negative flows of the Chen-Lee-Liu model and its various reductions, including Burgers hierarchy, are formulated within the framework of Riemann-Hilbert-Birkhoff decomposition with the constant grade two generator. Two classes of vacua, namely zero vacuum and constant non-zero vacuum can be realized within a centerless Heisenberg algebra. The tau functions for soliton solutions are obtained by a dressing method and vertex operators are constructed for both types of vacua. We are able to select and classify the soliton solutions in terms of the type of vertices involved. A judicious choice of vertices yields in a closed form a particular set of multi soliton solutions for the Burgers hierarchy. We develop and analyze a class of gauge-Bäcklund transformations that generate further multi soliton solutions from those obtained by dressing method by letting them interact with various integrable defects.

Brazil

Ireland

Y.F. Adans

H. Aratyn

C.P. Constantinidis

J.F. Gomes

G.V. Lobo

T.C. Santiago

New soliton solutions for Chen-Lee-Liu and Burgers hierarchies and its Bäcklund transformations

<p>The Fermilab E906/SeaQuest collaboration performed measurements of the Drell-Yan process using 120 GeV proton beams bombarding liquid hydrogen and liquid deuterium targets. A combined analysis of all collected data was performed to obtain the final results for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>σ</mi><mrow><mi>p</mi><mi>d</mi></mrow></msub><mo>/</mo><mn>2</mn><msub><mi>σ</mi><mrow><mi>p</mi><mi>p</mi></mrow></msub></math> Drell-Yan cross section ratio covering the kinematic region of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>0.13</mn><mo>&lt;</mo><mi>x</mi><mo>&lt;</mo><mn>0.45</mn></math>. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> dependencies of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mover accent="true"><mrow><mi>d</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow><mo>/</mo><mover accent="true"><mrow><mi>u</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>d</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow><mo>−</mo><mover accent="true"><mi>u</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></math> are extracted from these cross section ratios. It is found that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>d</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></math> is greater than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>u</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></math> over the entire measured <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> range, with improved statistical accuracy compared to previous measurements. The new results on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>d</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow><mo>/</mo><mover accent="true"><mi>u</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>d</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow><mo>−</mo><mover accent="true"><mi>u</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></mrow></math> are compared to various parton distribution functions and theoretical calculations.</p>

C.H. Leung

J. Dove

Taiwan

Japan

K. Nagai

K. Nakano

S. Prasad

A.S. Tadepalli

C.A. Aidala

J. Arrington

C. Ayuso

C.L. Barker

W.C. Chang

A. Chen

D.C. Christian

B.P. Dannowitz

L. El Fassi

D.F. Geesaman

R. Gilman

Y. Goto

R.S. Guo

L. Guo

T.J. Hague

R.J. Holt

M.F. Hossain

L.D. Isenhower

E.R. Kinney

A. Klein

D. Kleinjan

P.J. Lin

K. Liu

M.X. Liu

W. Lorenzon

R.E. McClellan

P.L. McGaughey

M.M. Medeiros

Y. Miyachi

S. Miyasaka

D.H. Morton

K. Nakahara

J.C. Peng

A.J.R. Puckett

A. Pun

B.J. Ramson

P.E. Reimer

J.G. Rubin

F. Sanftl

S. Sawada

T. Sawada

M.B.C. Scott

T.A. Shibata

D.S. Su

M. Teo

R. Towell

S. Uemura

S.G. Wang

J. Wu

N. Wuerfel

Z.H. Ye

Final SeaQuest Results on the Flavor Asymmetry of the Proton Light-Quark Sea with Proton-Induced Drell-Yan Process

<p>We propose the “naive” <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-odd Collins-Soper moments in the Drell-Yan process as probes of previously unexplored directions in the Standard Model effective field theory (SMEFT) parameter space. We show that the moments <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>A</mi><mn>6</mn></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>A</mi><mn>7</mn></msub></math> in the high invariant mass and transverse momentum region are sensitive to dimension-8 <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>C</mi><mi>P</mi></mrow></math>-odd semileptonic four-fermion operators with an additional gluon field strength tensor. Using the projected integrated luminosity of a future high-luminosity LHC, we show that effective ultraviolet scales in the few-TeV range can be probed with this process.</p>

Frank Petriello

Kaan Şimşek

Naive <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-odd Drell-Yan angular coefficients as a probe of the dimension-8 SMEFT

We present an analytical study of the interior structure of hairy rotating black holes in three-dimensional Einstein gravity, minimally coupled to a complex scalar field with a super-exponential potential. The interior dynamics of these black holes are characterized by an infinite sequence of Kasner epochs, separated by inversion and transitions, each of which admits an analytical description. We derive an explicit analytical expression for this infinite sequence of epochs. At late interior times, the geometry evolves into a curvature singularity, despite the local resemblance of each Kasner epoch to a regular Milne universe on a circle. These results reveal an interior structure richer and more complex than that of its 4D static black hole counterparts.

Ling-Long Gao

Yan Liu

Rui-Long Zhao

Analytical studies on 3D hairy rotating black hole interiors