We investigate the discovery potential of the $T_{bc}$ state with $J^P = 0^+$ in proton-proton ( $pp$ ) collisions at LHCb at a center-of-mass energy of $\sqrt{s} = 13~{\rm{TeV}}$ . The study focuses on the decay channel $T_{bc} \to B^- D^+$ . A phenomenological approach is employed to construct the background model based on the associated production of $\textit{B}$ and $\textit{D}$ mesons, incorporating previously published LHCb results. Background processes are simulated using ${\mathtt{MadGraph5\_aMC@NLO}}$ and ${\mathtt{Pythia8.3}}$ . We explore the parameter space of the $T_{bc}$ mass, width, production cross section, and the effective double-parton scattering cross section ( $\sigma_{{\rm{eff}}}$ ) relevant for the $B D$ meson background. The integrated luminosity required for a $5\sigma$ discovery at LHCb is evaluated under various assumptions. In particular, we consider three representative $T_{bc}$ production cross section scenarios: an optimistic estimate of $103~{\rm{nb}}$ , an intermediate value of $18~{\rm{nb}}$ obtained by scaling from the $T_{cc}^+$ production cross section, and a conservative lower bound of $0.3~{\rm{nb}}$ . We find that a $5\sigma$ observation is achievable for a production cross section of $103~{\rm{nb}}$ , which is expected to be within reach during Run4. In contrast, the more realistic cross section estimate of $18~{\rm{nb}}$ requires the full Run5 dataset ( $300~{\rm{fb}}^{-1}$ ) under the most favorable parameter choices. For the conservative scenario, no significant signal would be observable even with $300~{\rm{fb}}^{-1}$ . In addition, we estimate the minimum observable $\sigma(T_{bc}) \times {\cal{B}}(T_{bc} \to $ $ B^- D^+)$ for a $5\sigma$ discovery under different luminosity scenarios, providing guidance for future experimental searches at LHCb.

China

Mingjie Feng

Yiming Li

France

Hua-Sheng Shao

Prospects for discovering strongly decaying doubly heavy T$_{bc}$ tetraquark states at LHCb * Mingjie Feng and Yiming Li is Supported by the National Natural Science Foundation of China (NSFC) (2175245, 12188102, W2443008). Hua-Sheng Shao is Supported by the European Research Council (101041109, 'BOSON') and the French National Research Agency (grant ANR-20-CE31-0015, 'PrecisOnium')

In this work, we investigate the production and decay of molecular states with quark content $cc\bar c\bar q$ and $J^P=1^+$ using a phenomenological analysis and an effective Lagrangian approach. Based on an $\textit{SU}$(3) flavor-symmetry analysis to identify golden channels, we further explore the dynamics of these processes under the molecular assumptions of ${\eta_c D^*}$ and ${J/\psi D^*}$ . Our results indicate that the production branching ratio in $B_c$ decays is sizable: it can be of order $10^{-4}$ for the molecular configuration ${{\eta}_cD^*}$ and $10^{-5}$ for the molecule ${J/\psi D^*}$ . In addition, we find that the decay widths of the two molecular configurations ${{\eta}_cD^*}$ and ${J/\psi D^*}$ are not significant, at the level of ${\cal{O}}$ ( $\text{MeV}$ ).

Na Li

Ye Xing

Jing-Rui Shi

Analysis of molecular state $\textit{η$_{c}$D}$ $^{*}$ and $\textit{J}$/$\textit{ψD}$ $^{*}$ in the effective Lagrangian approach * Supported by the National Natural Science Foundation of China (NSFC) (12005294)

We report stronger evidence for the $X(7200)$ state and markedly improved measurements of the $X(6900)$ resonance parameters based on a combined analysis of the di- $J/\psi$ mass spectrum using published data from LHCb, ATLAS, and CMS. Through simultaneous fits to the datasets from all three experiments, we observe the $X(6900)$ with overwhelming significance ( $ \gt 12\sigma$ ) and determine its mass and width with improved precision. For the $X(7200)$ , we find consistent signals across multiple interference models, with significances ranging from $3.7\sigma$ to $6.6\sigma$ ; in the best-fit model (the CMS three-resonance scheme), the significance reaches $6.6\sigma$ , providing substantially stronger evidence for this state. Our results underscore the essential role of interference effects in fully charmed tetraquark spectroscopy and offer new constraints on their production mechanisms at the LHC.

Yuan Wang

Ran Li

Bin Zhong

Ya-Qian Wang

Enhanced evidence of $\textit{X}$(7200) and improved measurements of $\textit{X}$(6900) parameters from a combined LHCb-ATLAS-CMS analysis * Supported by the National Natural Science Foundation of China (NSFC) (12475077)

The Kerr/CFT correspondence establishes a correspondence between extremal black holes in higher dimensions and a chiral conformal field theory (CFT) in their near-horizon limit. A generalization of this framework, known as the EVH/CFT correspondence, has been developed for four- and five-dimensional AdS black holes. It was further proposed in [ ${\rm{AdS}}_{D=6,7}$ black holes, a generalized duality between $(D-2)$ -dimensional geometry and $(D-3)$ -dimensional field theory may emerge in a suitably defined extremal vanishing horizon (EVH) limit. In this work, we show that, in the EVH limit, the near-EVH geometries of these ${\rm{AdS}}_{D=6,7}$ black holes reduce to lower-dimensional black holes whose metrics are conformally related to solutions of Einstein-Maxwell-Maxwell-dilaton (EMMD) gravity. This structural resemblance suggests a potential route toward the microscopic counting of non-AdS black hole entropy via higher-dimensional AdS/CFT techniques.

Weichao Bu

Yang Lei

Probing decoupled throats of AdS $\textit{D}$ black holes in $\textit{D}$ = 6, 7 * Supported by National Natural Science Foundation of China (NSFC) (2305081), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the NSFC-Royal Society International Collaboration (W2421035)

We explain that the logic behind the derivation of the Noumi-Shiraishi function can be applied directly to the Baker-Akhiezer function (BAF). This amounts to changing an ansatz for BAF to a nested one, where the BAF of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi><mo>+</mo><mn>1</mn></math> variables is recursively expressed as a sum over BAFs of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>N</mi></math> variables. This may be seen as a generalization of symmetrization trick from [A. Mironov, A. Morozov, and A. Popolitov, <a href="http://arXiv.org/abs/2601.10500">arXiv:2601.10500</a>] but for the generally nonsymmetric BAF. We demonstrate that, for usual nontwisted (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>a</mi><mo>=</mo><mn>1</mn></math>) BAFs, this method correctly reproduces the Noumi-Shiraishi formula directly from linear equations, resolving the ambiguity related to nonsimple roots. For the first nontrivial twisted case (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>N</mi><mo>=</mo><mn>3</mn></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>a</mi><mo>=</mo><mn>2</mn></mrow></math>) this method also fixes this ambiguity, moreover, answers for the first few layers of coefficients are in the form of direct quantization of the above article.

Russia

A. Mironov

A. Morozov

A. Popolitov

Nested ansatz method for Baker-Akhiezer functions

In this paper, we give a detailed account of the algorithm outlined in [I. Bree et al. (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϵ</mi></math> Collaboration), companion Letter, <a href="http://dx.doi.org/10.1103/pyt8-d7rt">Phys. Rev. Lett. 136, 241602 (2026)</a>.] for Feynman integral reduction and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϵ</mi></math>-factorized differential equations. The algorithm consists of two steps. In the first step, we use a new geometric order relation in the integration-by-parts reduction to obtain a basis of master integrals, whose differential equations on the maximal cut are of a Laurent polynomial form in the regularization parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϵ</mi></math> and compatible with a filtration. This step works entirely with rational functions. In a second step, we provide a method to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϵ</mi></math>-factorize the aforementioned Laurent differential equations. The second step may introduce algebraic and transcendental functions. We illustrate the versatility of the algorithm by applying it to different examples with a wide range of complexity.

Germany

Iris Bree

Federico Gasparotto

Antonela Matijašić

Pouria Mazloumi

Dmytro Melnichenko

Switzerland

Sebastian Pögel

Toni Teschke

Xing Wang

Stefan Weinzierl

Konglong Wu

Xiaofeng Xu

New algorithms for Feynman integral reduction and epsilon-factorized differential equations

The determination of the Higgs boson trilinear self-coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>λ</mi><mrow><mn>3</mn><mi>H</mi></mrow></msub></math> is a key goal of the LHC physics program. Its precise measurement will provide unique insight into the scalar potential and the mechanism of electroweak symmetry breaking. Higgs boson pair production in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mi>g</mi><mo stretchy="false">→</mo><mi>H</mi><mi>H</mi></math> process, and particularly in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>H</mi><mi>H</mi><mo stretchy="false">→</mo><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mi>γ</mi><mi>γ</mi></math> final state, offers direct sensitivity to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>λ</mi><mrow><mn>3</mn><mi>H</mi></mrow></msub></math>. We present the first implementation of the matrix element method (MEM) at next-to-leading order (NLO) for this process, which is publicly available. The MEM is a statistically optimal approach that maximizes information extraction from collision events. Extending it to NLO represents a major methodological challenge, which we address with a new formalism integrated into the momemta framework. Results with simulated pseudoexperiments demonstrate, in a proof-of-principle study, the strong discriminating power of the method and its ability to extract the coupling modifier <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>κ</mi><mi>λ</mi></msub><mo>=</mo><msub><mi>λ</mi><mrow><mn>3</mn><mi>H</mi></mrow></msub><mo>/</mo><msubsup><mi>λ</mi><mrow><mn>3</mn><mi>H</mi></mrow><mi>SM</mi></msubsup></math> with high precision.

Matthias Tartarin

Jan Stark

Novel implementation of the matrix element method at next-to-leading order for the measurement of the Higgs self-coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>λ</mi><mrow><mn>3</mn><mi>H</mi></mrow></msub></math>

In view of the recent theoretical developments in the fixed center approximation for the scattering of a particle with a a two-body cluster, implementing elastic unitarity on the standard fixed center formalism, and the imminent availability of ALICE data on the correlation function of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mtext> </mtext><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></math> system, we update the results of a previous work for this correlation function and the low-energy scattering observables. The new results show appreciable changes in some observables and should provide valuable input for comparison with the forthcoming experimental data. Such a comparison is expected to yield relevant information on the nature of the axial-vector meson states.

Spain

P. Encarnación

A. Feijoo

E. Oset

Scattering observables and correlation function for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>1</mn></msub><mo stretchy="false">(</mo><mn>1285</mn><mo stretchy="false">)</mo></math> revisited

The determination of the weak mixing angle, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>sin</mi><mn>2</mn></msup><msub><mi>θ</mi><mi>W</mi></msub></math>, at low momentum transfers remains a powerful test of the Standard Model and its potential new physics extensions. In this paper, we explore some physics opportunities at present and future reactor neutrino experiments through elastic neutrino-electron scattering (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">E</mi><mi>ν</mi><mi>ES</mi></mrow></math>). We assess the expected sensitivity to the weak mixing angle considering the CLOUD, TAO, and DANSS experimental configurations. We find that both CLOUD and TAO may achieve a precision that surpasses the current global fit from reactor experiments, while DANSS alone is expected to surpass the benchmark precision set by TEXONO measurement of the weak mixing angle. Additionally, we derive projected upper limits for the nonstandard neutrino interactions, effective neutrino magnetic moment (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>μ</mi><mi>ν</mi></msub></math>) and translate these into constraints on the neutrino transition magnetic moments (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Λ</mi><mi>i</mi></msub></math>). Our results demonstrate the physics potential of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">E</mi><mi>ν</mi><mi>ES</mi></mrow></math> channel at current and upcoming reactor-based neutrino experiments.

Luis A. Delgadillo

Qishan Liu

Randhir Singh

Elastic neutrino-electron scattering perspectives at nuclear reactors

In this work, we employ both theoretical and data-driven methods to derive the QCD vacuum energy, utilizing the GMOR relation, the low-energy theorem, and the equation of state from lattice QCD. The QCD vacuum energy is determined to be between around <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>163</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi><msup><mo stretchy="false">)</mo><mn>4</mn></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>190</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi><msup><mo stretchy="false">)</mo><mn>4</mn></msup></math>. With the assumptions of complete deconfinement, vanishing gluon condensate, full chiral-symmetry restoration, and the validity of perturbative QCD at baryon chemical potentials of order of the proton mass, a very specific kind of quark nugget is found to be less stable than ordinary nuclei.

United States

Yang Bai

Ting-Kuo Chen

QCD vacuum energy and its implication for quark nugget stability