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 study cosmological gravitational particle production (CGPP) in Higgs inflation, wherein the inflaton is a scalar field with quartic self-coupling $\textit{λ}$ and a nonminimal coupling to gravity $\textit{ξ}$, and which may, but need not be, the Higgs boson of the Standard Model (SM). We find an explosive particle production peaked on a characteristic comoving wavenumber $\textit{k}$ ~ $\textit{ξ}$ $\textit{aH}$ with a peak occupation number that scales with $\textit{ξ}$. This new peak in production can easily dominate over the conventional (minimally coupled inflation) CGPP even for modest values of $\textit{ξ}$. The results apply for a wide range of $\textit{ξ}$, e.g., as low as $\textit{ξ}$ = 10, which can be realized for the Standard Model Higgs given suitable RG flow of the quartic coupling. We discuss implications for late time relics such as dark matter.

Canada

Tammi Chowdhury

United States

Leah Jenks

Edward Kolb

Evan McDonough

Higgs inflation: particle factory

We investigate the phenomenology of 2 Higgs doublet models (2HDMs) with a new U(1) gauge symmetry, U(1) , by which flavor changing neutral currents are forbidden at tree level. As an important consequence of the spontaneous breaking of both the U(1) and electroweak symmetries by electroweak vacuum expectation values, upper limits appear on masses of an additional gauge boson $\textit{Z′}$ and extra Higgs bosons which are less than the TeV scale. In addition, the standard model (SM) like Higgs boson $\textit{h}$ and a heavier Higgs boson $\textit{H}$ mainly decay into a pair of $\textit{Z′}$ which induces four lepton final states. These new decay modes cannot be suppressed by taking no $\textit{Z}$-$\textit{Z′}$ mixing and/or the Higgs alignment limit. We find that the minimum setup of these 2HDMs has been excluded by current data for four lepton searches at LHC. Such severe constraints can, however, be avoided by introducing a pair of vector-like fermions $\textit{χ}$ which are singlet under the SM symmetry but charged under U(1) , and can be a candidate of dark matter. Thanks to the existence of $\textit{χ}$, $\textit{Z′}$ can mainly decay into $$ \chi \overline{\chi} $$ instead of SM leptons. As benchmark models, we consider the U(1) and U(1) models realized by fixing specific U(1) charges, and find regions of parameter space allowed by theoretical and current experimental constraints. We clarify that $\textit{m}$ ∈ [160$\textit{,}$ 220] GeV and tan $\textit{β}$ ∈ [3$\textit{,}$ 4$\textit{.}$4] are allowed in the U(1) model, while $\textit{m}$ ∈ [160$\textit{,}$ 380] GeV and tan $\textit{β}$ ∈ [1$\textit{.}$6$\textit{,}$ 4$\textit{.}$4] are allowed in the U(1) model. In both the models, the $\textit{Z′}$ mass is constrained to be 100 GeV ≲ $$ {m}_{Z^{\prime }} $$ ≲ 110 GeV. Such a quite limited parameter space can further be explored at future collider experiments, e.g., High-Luminosity LHC and lepton colliders.

Yuanchao Lou

Takaaki Nomura

Hong Kong

Xinran Xu

Japan

Kei Yagyu

Are 2HDMs with a gauged U(1) symmetry alive?

We investigate a bosonic system within an effective quantum field theory defined on a non-trivial topology in the presence of an external magnetic field. Using the proper-time formalism in the one-loop approximation, we obtain thermal, density, and finite-volume corrections to the effective Lagrangian under spatial confinement. We also analyze the effects of topology and boundary conditions on the system magnetization. Periodic boundary conditions lead to diamagnetic behavior, while antiperiodic boundary conditions induce paramagnetism for the same fixed parameters. Twisted boundary conditions exhibit an intermediate behavior. The analysis is performed within an approximate implementation of the boundary condition in the $$x$$ -direction, where the explicit $$y$$ -dependence of the corresponding transition function is neglected. Consequently, the numerical investigation is not restricted to exactly flux-quantized torus configurations. In all cases considered, the external magnetic field induces a monotonic enhancement of the magnetization intensity. In the zero-temperature and infinite-volume limits, our results recover Schwinger’s expression for a spinless quantum field in an external magnetic field.

Brazil

Emerson Corrêa

Michelli Sarges

Airton Rodrigues

Carlos Bahia

Effective Lagrangian of a bosonic system in a non-trivial topology under magnetic effects

The internal structure of hadrons is characterized by form factors which correspond to matrix elements of currents. Among those, the stress-energy-momentum tensor is a universally conserved quantity providing the gravitational form factors, from which mechanical properties may be derived via the response to the space-time fluctuations. They have received much attention due to their role as moments of the Generalized Parton Distributions, where the stress-energy-momentum tensor couples to two photons, and more recently, due to the explicit lattice QCD determination for the pion and nucleon. In these lectures, we attempt a pedagogical review of the topic from a purely hadronic point of view, based on the notion of dispersion relations, meson dominance, and parton–hadron duality. We show that despite the overwhelming simplicity of the approach, a rather successful description of the lattice QCD data is achieved. Abstract Published by the Jagiellonian University 2026 authors

Spain

E. Ruiz Arriola

Poland

W. Broniowski

Particle Seismology: Mechanical and Gravitational Properties from Parton–Hadron Duality

<p>We report the first observation of the radiative decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi><mn>0</mn></mrow><mrow><mo>*</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>2317</mn><msup><mrow><mo stretchy="false">)</mo></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>*</mo><mo>+</mo></mrow></msubsup><mi>γ</mi></mrow></math> with a statistical significance exceeding 10 standard deviations. The signal is observed in the continuum <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> process, using combined data samples of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>980.4</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> from Belle and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>427.9</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> from Belle II, collected at the KEKB and SuperKEKB asymmetric-energy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></math> colliders, respectively. The branching fraction ratio <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="script">B</mi><mo stretchy="false">[</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi><mn>0</mn></mrow><mrow><mo>*</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>2317</mn><msup><mrow><mo stretchy="false">)</mo></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>*</mo><mo>+</mo></mrow></msubsup><mi>γ</mi><mo stretchy="false">]</mo><mo>/</mo><mi mathvariant="script">B</mi><mo stretchy="false">[</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi><mn>0</mn></mrow><mrow><mo>*</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>2317</mn><msup><mrow><mo stretchy="false">)</mo></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>+</mo></mrow></msubsup><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><mo stretchy="false">]</mo></mrow></math> is measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">[</mo><mn>7.13</mn><mo>±</mo><mn>0.70</mn><mo stretchy="false">(</mo><mrow><mi>stat</mi></mrow><mo stretchy="false">)</mo><mo>±</mo><mspace linebreak="goodbreak"></mspace><mn>0.26</mn><mo stretchy="false">(</mo><mrow><mi>syst</mi></mrow><mo stretchy="false">)</mo><mo stretchy="false">]</mo><mo>%</mo></mrow></math>. This result provides crucial discrimination between theoretical models of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mrow><mi>s</mi><mn>0</mn></mrow><mo>*</mo></msubsup><mo stretchy="false">(</mo><mn>2317</mn><msup><mo stretchy="false">)</mo><mo>+</mo></msup></math> structure.</p>

M. Abumusabh

I. Adachi

L. Aggarwal

H. Ahmed

Y. Ahn

H. Aihara

N. Akopov

S. Alghamdi

M. Alhakami

A. Aloisio

N. Althubiti

K. Amos

N. Anh Ky

C. Antonioli

D.M. Asner

H. Atmacan

T. Aushev

R. Ayad

V. Babu

N.K. Baghel

S. Bahinipati

P. Bambade

Sw. Banerjee

M. Barrett

M. Bartl

J. Baudot

A. Beaubien

J. Becker

J.V. Bennett

F.U. Bernlochner

V. Bertacchi

M. Bertemes

E. Bertholet

M. Bessner

S. Bettarini

F. Bianchi

T. Bilka

D. Biswas

A. Bobrov

D. Bodrov

A. Bondar

G. Bonvicini

J. Borah

A. Boschetti

A. Bozek

M. Bračko

P. Branchini

R.A. Briere

T.E. Browder

A. Budano

S. Bussino

Q. Campagna

M. Campajola

G. Casarosa

C. Cecchi

P. Chang

P. Cheema

L. Chen

B.G. Cheon

C. Cheshta

H. Chetri

K. Chilikin

K. Chirapatpimol

H.E. Cho

K. Cho

S.J. Cho

S.K. Choi

S. Choudhury

S. Chutia

J.A. Colorado-Caicedo

I. Consigny

L. Corona

J.X. Cui

E. De La Cruz-Burelo

S.A. De La Motte

G. De Nardo

G. De Pietro

R. de Sangro

M. Destefanis

S. Dey

A. Di Canto

Z. Doležal

I. Domínguez Jiménez

T.V. Dong

X. Dong

M. Dorigo

G. Dujany

P. Ecker

J. Eppelt

R. Farkas

P. Feichtinger

T. Ferber

T. Fillinger

C. Finck

G. Finocchiaro

F. Forti

B.G. Fulsom

A. Gabrielli

E. Ganiev

M. Garcia-Hernandez

Observation of the Radiative Decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi><mn>0</mn></mrow><mrow><mo>*</mo></mrow></msubsup><mo stretchy="false">(</mo><mn>2317</mn><msup><mrow><mo stretchy="false">)</mo></mrow><mrow><mo>+</mo></mrow></msup><mo stretchy="false">→</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>*</mo><mo>+</mo></mrow></msubsup><mi>γ</mi></mrow></math>

<p>The microphysics underlying nonbaryonic dark matter remains unknown. I derive the two-species Schrödinger-Poisson-Yukawa system for spin-<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mfrac><mn>1</mn><mn>2</mn></mfrac></math> dark-sector fermion fields, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> (mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>1</mn></msub></math>) and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>χ</mi></math> (mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>2</mn></msub></math>), coupled through a scalar mediator of mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>ϕ</mi></msub></math> via a universal Yukawa coupling, within an orbital-free density-functional framework with the Kirzhnits gradient coefficient <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>λ</mi><mi mathvariant="normal">B</mi></msub><mo>=</mo><mn>1</mn><mo>/</mo><mn>9</mn></math>. A central result is that the Bohm potential, far from being negligible in the Thomas-Fermi regime, contributes a species-dependent surface-energy correction analogous to the nuclear liquid-drop model; the heavier fermion species generates an outward quantum-pressure wall whilst the lighter species provides an inward surface tension, with degeneracy pressure furnishing the bulk confinement. In the single-species Schrödinger-Poisson limit the ground state recovers the benchmarked invariants <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>M</mi><mi>dim</mi></msub><mo>≃</mo><mn>3.883</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>x</mi><mi>T</mi></msub><mo>≃</mo><mn>2.562</mn></math>, yielding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>M</mi><msub><mi>R</mi><mi>T</mi></msub><mo>≃</mo><mn>9.95</mn><msub><mi>λ</mi><mi mathvariant="normal">B</mi></msub><msup><mi>ℏ</mi><mn>2</mn></msup><mo>/</mo><mo stretchy="false">(</mo><mi>G</mi><msubsup><mi>m</mi><mn>1</mn><mn>2</mn></msubsup><mo stretchy="false">)</mo></math>. For polytropic index <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mo>=</mo><mn>5</mn><mo>/</mo><mn>3</mn></math> the mass-radius relation satisfies <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>R</mi><mo>∝</mo><msup><mi>M</mi><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>3</mn></mrow></msup></math>; for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mo>=</mo><mn>4</mn><mo>/</mo><mn>3</mn></math> a limiting mass emerges above which no stable equilibrium exists. Illustrative configurations span <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>M</mi><mo>=</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>8</mn></mrow></msup><mi>–</mi><mn>5</mn><msub><mi>M</mi><mo stretchy="false">⊙</mo></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>1</mn></msub><mo>∼</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup><mo>−</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></math>, and radii from a few km to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><msup><mn>10</mn><mn>3</mn></msup><msub><mi>R</mi><mo stretchy="false">⊙</mo></msub></math>, with gravitational-wave contact frequencies in the Einstein Telescope and LISA bands and microlensing signatures accessible to current surveys. The predictive rigidity of the resulting mass-radius relation, in which the single microphysical parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mn>1</mn></msub></math> determines the equilibrium radius once the total mass is specified, furnishes a reproducible, first-principles reference for constraining the dark-fermion mass in multicomponent dark sectors.</p>

Portugal

Ilídio Lopes

Self-gravitating quantum stars with a globally relevant Bohm potential