We investigate gluonic hidden-charm tetraquark states composed of two valence quarks, two valence antiquarks and an explicit valence gluon. In the color configuration $$[\bar{3}_c]_{c q}\otimes [8_c]_{G}\otimes [3_c]_{\bar{c}\bar{q}}$$ , a complete set of eight interpolating currents is constructed for states with quantum numbers $$^{PC}=0^{++}$$ , $$0^{-+},$$ $$0^{-}{-}$$ , and $$0^{+-}$$ . The corresponding mass spectra are systematically analysed within the QCD sum rule framework, including nonperturbative condensate contributions up to dimension eight. Our numerical analysis indicates the possible existence of six gluonic hidden-charm tetraquark states exhibiting stable behaviour in the adopted Borel windows. By replacing the charm quark with the bottom quark, masses for the corresponding hidden-bottom partners are also estimated. Possible production mechanisms and dominant decay channels are discussed, providing phenomenological guidance for experimental searches. These predicted states may be accessible at current and forthcoming facilities, including Belle II, PANDA, SuperB and LHCb, and thus offer an opportunity to probe explicit gluonic degrees of freedom in multiquark systems and deepen our understanding of nonperturbative QCD.

China

Bing-Dong Wan

Ming-Yang Yuan

Jun-Hao Zhang

Yan Zhang

Spectrum of $$J^{PC} = 0^{\pm \pm }$$ gluonic hidden-charm tetraquark states

The first observation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mrow><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></mrow></math> decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>9</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. The decay mode is observed for the first time, with a significance of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>6.5</mn><mi>σ</mi></math>. Its branching fraction is measured relative to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mrow><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></mrow></math> decay mode <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mfrac><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mrow><mrow><mi>J</mi><mo stretchy="false">/</mo><mi>ψ</mi></mrow><msup><mrow><mi>μ</mi></mrow><mrow><mo stretchy="false">+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo stretchy="false">−</mo></mrow></msup></mrow><mo stretchy="false">)</mo></mrow><mrow><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></mrow><mo stretchy="false">→</mo><mrow><mrow><mi>J</mi><mo stretchy="false">/</mo><mi>ψ</mi></mrow><msup><mrow><mi>π</mi></mrow><mrow><mo stretchy="false">+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo stretchy="false">−</mo></mrow></msup></mrow><mo stretchy="false">)</mo></mrow></mfrac><mo>=</mo><mrow><mo stretchy="false">(</mo><mn>1.68</mn><mo>±</mo><mn>0.32</mn><mo>±</mo><mn>0.05</mn><mo stretchy="false">)</mo></mrow><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math>, where the first uncertainty includes both statistical contributions and systematic contributions which are uncorrelated between data-taking periods, and the second represents the systematic contributions that are correlated between data-taking periods.

Netherlands

R. Aaij

United Kingdom

A.S.W. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

United States

A.A. Adefisoye

Spain

B. Adeva

M. Adinolfi

P. Adlarson

France

C. Agapopoulou

C.A. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

Poland

M. Akthar

Italy

P. Albicocco

Germany

J. Albrecht

R. Aleksiejunas

CERN

F. Alessio

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J.L. Amey

Y. Amhis

L. An

L. Anderlini

M. Andersson

P. Andreola

M. Andreotti

S. Andres Estrada

A. Anelli

D. Ao

C. Arata

F. Archilli

Z. Areg

M. Argenton

Costa Rica

S. Arguedas Cuendis

L. Arnone

Russia

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

J.A. Authier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J.J. Back

P. Baladron Rodriguez

V. Balagura

A. Balboni

W. Baldini

Z. Baldwin

L. Balzani

H. Bao

J. Baptista de Souza Leite

C. Barbero Pretel

M. Barbetti

I.R. Barbosa

R.J. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

S. Bashir

B. Batsukh

P.B. Battista

A. Bay

A. Beck

M. Becker

F. Bedeschi

I.B. Bediaga

N.A. Behling

S. Belin

A. Bellavista

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

S. Bernet Andres

A. Bertolin

F. Betti

J. Bex

O. Bezshyyko

S. Bhattacharya

J. Bhom

M.S. Bieker

N.V. Biesuz

A. Biolchini

M. Birch

F.C.R. Bishop

A. Bitadze

A. Bizzeti

T. Blake

Observation of the decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math>

Over the past two decades, numerous exotic hadron states have been discovered, yet their underlying nature remains unclear. It is widely acknowledged that understanding hadron-hadron interactions is essential to unraveling their properties. Hadron spectroscopy is a powerful tool for this endeavor, providing rich experimental data that can shed light on exotic systems. Recently, the LHCb experiment analyzed the process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>−</mo></msup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi mathvariant="normal">Λ</mi><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover></math> and observed a narrow peak in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi mathvariant="normal">Λ</mi></math> invariant mass spectrum, regarding it as a candidate for a pentaquark. In this work, we extract the coupled-channel <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi mathvariant="normal">Λ</mi><mo>−</mo><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub><mo>−</mo><msub><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mi>s</mi></msub><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub></math> potential based on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi mathvariant="normal">Λ</mi></math> invariant mass spectrum. Our results indicate the existence of a bound state below the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub></math> mass threshold, corresponding to the experimentally measured state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>P</mi><mrow><mi>c</mi><mi>s</mi></mrow></msub><mo stretchy="false">(</mo><mn>4338</mn><mo stretchy="false">)</mo></math>. Furthermore, we predict the scattering lengths and momentum correlation functions for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi mathvariant="normal">Λ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub></math> channels, which serve as theoretical references for future femtoscopy experiments.

Yi-Bo Shen

Zhi-Wei Liu

Ming-Zhu Liu

Rui-Xiang Shi

Chu-Wen Xiao

Wei-Hong Liang

Li-Sheng Geng

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mi mathvariant="normal">Λ</mi></math> femtoscopy and the nature of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>P</mi><mrow><mi>ψ</mi><mi>s</mi></mrow><mi mathvariant="normal">Λ</mi></msubsup><mo stretchy="false">(</mo><mn>4338</mn><mo stretchy="false">)</mo></math>

Motivated by the discrepancies noted recently between the theoretical predictions of the electromagnetic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mn>0</mn></msup><msup><mi>γ</mi><mo>*</mo></msup></math> transition form factor and the BESIII data, we reanalyze this transition form factor using the dispersive Khuri-Treiman equations, with final-state interactions in both the direct channel and the crossed channels properly considered. This improved framework incorporates <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi><mi>–</mi><mi>ω</mi></math> mixing effects. The effect of four-pion states is evaluated through a dispersively improved vector-meson-dominance model. From this information, we propose a two-parameter fit that provides an excellent description of the BESIII data over the broad energy range from 0 to 2.8 GeV. We demonstrate that the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi><msup><mi>π</mi><mn>0</mn></msup></math> decay mode of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> is dominated by strong interaction, while the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ω</mi><msup><mi>π</mi><mn>0</mn></msup></math> mode is dominated by one-photon exchange. From this, we extract the relative phase between the strong and the one-virtual-photon (electromagnetic) modes in hadronic decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>62</mn><mo>±</mo><mn>21</mn><mo stretchy="false">)</mo><mo>°</mo></math>. This could provide useful information in understanding the long-standing <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi><mi>π</mi></math> puzzle in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> decays.

Xiong-Hui Cao

Feng-Kun Guo

Christoph Hanhart

Bastian Kubis

Dispersive analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><msup><mi>π</mi><mn>0</mn></msup><msup><mi>γ</mi><mo>*</mo></msup></math> transition form factor with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ρ</mi><mo>–</mo><mi>ω</mi></math> mixing effects

The normalised decay rate of $\textit{B}$ → $\textit{J/ψ}$(→ $\textit{μ}$ $\textit{μ}$ )$\textit{K}$ is measured as a function of the lepton helicity angle using a data sample corresponding to an integrated luminosity of 1$\textit{.}$1 fb collected during October 2024 with the upgraded (Upgrade I) LHCb detector. This angular distribution can be parameterised by two coefficients, the forward-backward asymmetry, $\textit{A}$ , and the flatness parameter, $\textit{F}$ , whose values are constrained by conservation of angular momentum. These coefficients are measured both integrated and differentially across various kinematic and detector-response variables, and the results are found to be in good agreement with expectations. These measurements show that the detector response of the LHCb Upgrade I experiment is understood to the precision required to reliably extract the angular coefficients associated with rare $\textit{b}$ → $\textit{sμ}$ $\textit{μ}$ and $\textit{b}$ → $\textit{dμ}$ $\textit{μ}$ transitions, which are particularly sensitive to physics beyond the Standard Model.

A. Abdelmotteleb

A. Adefisoye

Sweden

C. Aidala

Lithuania

J. Amey

J. Authier

J. Back

I. Barbosa

R. Barlow

P. Battista

I. Bediaga

N. Behling

Ukraine

Hungary

M. Bieker

N. Biesuz

F. Bishop

Differential decay rate of $\textit{B}$ + $\textit{→ J/ψK}$ + with the LHCb Upgrade I experiment

We investigate the inclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> production in proton-proton <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mo>(</mo><mi>p</mi><mi>p</mi><mo>)</mo></mrow></math> collisions at center-of-mass energies <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>5.02</mn></mrow></math>, 7, and 13 TeV using the parton and hadron cascade model PACIAE 4.0. This model extends PYTHIA 8.3 by incorporating partonic and hadronic rescatterings before and after hadronization, respectively. Compared to our earlier study [K.-F. Ye et al., <a href="http://dx.doi.org/10.1103/PhysRevC.109.035201">Phys. Rev. C 109, 035201 (2024)</a>], which considered only the color-singlet processes, the present work includes both the color-singlet and color-octet contributions within the nonrelativistic QCD (NRQCD) framework. In addition to the NRQCD, we also consider the contributions from the cluster collapse and weak decays of <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi></math> hadrons. We find that the simulated inclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> transverse momentum differential cross sections agree well with the experimental data at both the middle and forward rapidities. We provide a quantitative analysis of the relative contributions for different production mechanisms and their energy and rapidity dependence in the inclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> production. Furthermore, we offer a quantification of the relative contributions of the various components and their energy and rapidity dependence in the NRQCD channels, including the direct production via the hard scattering and the feed-down from the decays of heavier charmonium states such as <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>ψ</mi><mo>(</mo><mn>2</mn><mi>S</mi><mo>)</mo></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>χ</mi><mrow><mi>c</mi><mn>0</mn></mrow></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>χ</mi><mrow><mi>c</mi><mn>1</mn></mrow></msub></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>χ</mi><mrow><mi>c</mi><mn>2</mn></mrow></msub></math>. Finally, we examine the effects of partonic and hadronic rescatterings and offer the quantitative estimate of their impact on the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> production. These results are entirely new and represent a significant step forward in understanding the mechanisms of the inclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> production in high-energy <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions.

Jin-Peng Zhang

Guan-Yu Wang

Wen-Chao Zhang

Bo Feng

An-Ke Lei

Zhi-Lei She

Hua Zheng

Dai-Mei Zhou

Yu-Liang Yan

Ben-Hao Sa

Inclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> productions in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>5.02</mn><mo>,</mo><mo> </mo><mn>7</mn><mo>,</mo><mo> </mo><mtext>and</mtext><mo> </mo><mn>13</mn><mo> </mo><mi>TeV</mi></mrow></math> with the parton and hadron cascade model PACIAE

In double charmonium production, a long-standing challenge is that the theoretical predictions are not consistent with the measurements at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> factories. Within the Non-Relativistic Quantum Chromodynamics (NRQCD) framework, the next-to-leading order calculation has proved its power to cut down the discrepancy between theory and experiments. To further clarify this puzzle, we have performed the next-to-next-to-leading order calculation. The amplitude is obtained as an analytical asymptotic expansion in the ratio of the squared charm-quark mass over the squared center-of-mass energy, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>m</mi><mi>c</mi><mn>2</mn></msubsup><mo>/</mo><mi>s</mi></math>. We investigate the origin of the leading logarithms by performing a region analysis, revealing the intricate factorization structure in this process. We provide numerical predictions on the total cross sections of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><msub><mi>η</mi><mi>c</mi></msub></math> production, which agree with the experimental results. Extension of our computation to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo>+</mo><msub><mi>η</mi><mi>b</mi></msub></math> production is also discussed.

Xiang Chen

Xin Guan

Chuan-Qi He

Yan-Qing Ma

Jian Wang

Da-Jiang Zhang

Analytical two-loop amplitudes of <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>J</mi><mo>/</mo><mi>ψ</mi><mo>+</mo><msub><mi>η</mi><mi>c</mi></msub></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> factories

The next-to-leading order hard function for quarkonium electroproduction is calculated within the framework of transverse-momentum-dependent (TMD) factorization in the low-transverse-momentum regime. The structure of the TMD shape function in quarkonium leptoproduction is analyzed through its operator-level definition. Particular attention is given to the convolution of the unpolarized TMD gluon distribution with the TMD shape function, thereby illustrating the latter’s phenomenological role. Building on this framework, we provide predictions for the unpolarized differential cross-section of $\textit{J/ψ}$ electroproduction at the future Electron-Ion Collider in the region of small transverse momentum.

Miguel Echevarria

Raj Kishore

Samuel Romera

Modeling the TMD shape function in $\textit{J}$/$\textit{ψ}$ electroproduction

The top-quark mass is measured using top-quark decays producing an isolated lepton and $\textit{J}$/$\textit{ψ}$ meson reconstructed in its $\textit{μ}$ $\textit{μ}$ decay mode. The data sample was recorded with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of $$ \sqrt{s}=13 $$ TeV during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb . The measurement is based on the invariant mass $\textit{m}$($\textit{ℓμ}$ $\textit{μ}$ ) of the system made of the isolated lepton $\textit{ℓ}$ from the $\textit{W}$ boson decay and the non-isolated $\textit{μ}$ $\textit{μ}$ pair from a $\textit{J}$/$\textit{ψ}$ decay of a $\textit{b}$-hadron, exploiting its sensitivity to the top-quark mass. An unbinned maximum-likelihood fit to the $\textit{m}$($\textit{ℓμ}$ $\textit{μ}$ ) distribution is performed to extract the top-quark mass. The top-quark mass is measured to be $\textit{m}$ = 172.17 ± 0.80 (stat) ± 0.81 (syst) ± 1.07 (recoil) GeV, with a total uncertainty of 1.56 GeV. The third uncertainty arises from changing the dipole parton shower gluon-recoil scheme used in top-quark decays.

G. Aad

Norway

E. Aakvaag

B. Abbott

United Arab Emirates

S. Abdelhameed

K. Abeling

N. Abicht

S. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Y. Abulaiti

B. Acharya

A. Ackermann

C. Adam Bourdarios

Measurement of the top-quark mass using decays with a $\textit{J/ψ}$ meson at $$ \sqrt{s}=13 $$ TeV with the ATLAS detector