In light of recent high-precision data taken by the BESIII Collaboration, we reconsider the dipion transition <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math>. The strong pion-pion final-state interactions are taken into account model independently by using dispersion theory. We find that we can reproduce the substructure near the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> threshold observed experimentally without introducing an extra resonance state. While a helicity-flip amplitude plays an important role for the formation of the dip in the invariant-mass distribution, the virtual exchange of the charmoniumlike exotic <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>3900</mn><mo stretchy="false">)</mo></math> state improves the fit quality only slightly.

China

Yun-Hua Chen

Germany

Xiang-Kun Dong

Feng-Kun Guo

Christoph Hanhart

Bastian Kubis

Decoding the structure near the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> mass threshold in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math> decays

Using a data sample of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>2.712</mn><mo>±</mo><mn>0.014</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mn>9</mn></msup><mtext> </mtext><mtext> </mtext><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo></math> events collected at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>3.686</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> by the BESIII detector, we search for the rare electromagnetic Dalitz decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mi>ϕ</mi><mo stretchy="false">(</mo><mi>J</mi><mo>=</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo stretchy="false">)</mo></math> via the radiative transitions <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><mi>γ</mi><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub></math>. No statistically significant <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mi>ϕ</mi></math> signals are observed. The upper limits on the branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>χ</mi></mrow><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>ϕ</mi><mtext> </mtext><mo stretchy="false">(</mo><mi>J</mi><mo>=</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo stretchy="false">)</mo></mrow></math>, excluding the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi></math> resonance to <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> final states, are set to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.4</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><mo>,</mo><mn>6.7</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4.1</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup></math> at the 90% confidence level, respectively. This is the first search for the electromagnetic Dalitz transition of P-wave charmonium <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub></math> states to a light vector meson.

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

JINR

O. Bakina

Y. Ban

H.R. Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

X.Y. Chai

J.F. Chang

G.R. Che

Y.Z. Che

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z. Chen

Z.J. Chen

Z.K. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Search for the electromagnetic Dalitz decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mo stretchy="false">→</mo><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mi>ϕ</mi></math>

In this work, we construct the <italic>D</italic>-wave isoscalar <math altimg='si1.svg'><mrow><mi>&#960;</mi><mi>&#960;</mi><mo linebreak='goodbreak'>/</mo><mi>K</mi><mover accent='true'><mi>K</mi><mo>&#175;</mo></mover></mrow></math> coupled-channel Omn&#232;s matrix, formulated to satisfy unitarity, analyticity, and the appropriate asymptotic behavior. We employ a two-channel <italic>K</italic>-matrix model containing poles associated with the <italic>f</italic> <inf>2</inf>(1270) and <math altimg='si7.svg'><mrow><msubsup><mi>f</mi><mrow><mn>2</mn></mrow><mo>&#8242;</mo></msubsup><mrow><mo>(</mo><mn>1525</mn><mo>)</mo></mrow></mrow></math> resonances. The resulting unitary scattering matrix, which reproduces the experimental <italic>&#960;&#960;</italic>&#8239;&#8594;&#8239; <italic>&#960;&#960;</italic> and <math altimg='si27.svg'><mrow><mi>&#960;</mi><mi>&#960;</mi><mo>&#8594;</mo><mi>K</mi><mover accent='true'><mi>K</mi><mo>&#175;</mo></mover></mrow></math> data and PDG information, serves as input to the homogeneous two-channel Muskhelishvili-Omn&#232;s equation. We compare our Omn&#232;s matrix with previous constructions based on <math altimg='si27.svg'><mrow><mi>&#960;</mi><mi>&#960;</mi><mo>&#8594;</mo><mi>K</mi><mover accent='true'><mi>K</mi><mo>&#175;</mo></mover></mrow></math> phases extracted from sums of Breit-Wigner amplitudes. The Omn&#232;s matrix developed here provides a reliable dispersive input for form-factor calculations and resonance studies in the tensor-meson sector. As an application, we show that it enables a simultaneous and accurate description of the BESIII <italic>J</italic>/ <italic>&#968;</italic>&#8239;&#8594;&#8239; <italic>&#960;</italic> 0 <italic>&#960;</italic> 0 <italic>&#947;</italic> and <italic>J</italic>/ <italic>&#968;</italic>&#8239;&#8594;&#8239; <italic>K<inf>S</inf>K<inf>S</inf>&#947;</italic> spectra in the <math altimg='si2.svg'><mrow><mi>J</mi><mo linebreak='goodbreak'>=</mo><mn>2</mn></mrow></math> electric-dipole (E1) partial wave.

Igor Danilkin

Oleksandra Deineka

Spain

Emilie Passemar

Marc Vanderhaeghen

Coupled-channel Omnès matrix for the <italic>D</italic>-wave isoscalar <math altimg='si1.svg'><mrow><mi>&#960;</mi><mi>&#960;</mi><mo linebreak='goodbreak'>/</mo><mi>K</mi><mover accent='true'><mi>K</mi><mo>&#175;</mo></mover></mrow></math> system and its application to <italic>J</italic>/ <italic>&#968;</italic>&#8239;&#8594;&#8239; <italic>&#960;</italic> 0 <italic>&#960;</italic> 0 <italic>&#947;</italic>,&#8201; <italic>K<inf>S</inf>K<inf>S</inf>&#947;</italic>

We present theoretical predictions for the transverse-momentum distribution of $\textit{J/ψ}$ produced within jets at the upcoming Electron-Ion Collider (EIC). Utilizing the semi-inclusive fragmenting jet function (FJF) framework, our calculation achieves next-to-leading order (NLO) accuracy in the strong coupling and leading-logarithmic (LL) accuracy by resumming both collinear and threshold logarithms. In contrast to the gluon-dominated regime of the LHC, EIC photoproduction is characterized by an enhanced quark-initiated component, offering a complementary probe into the charmonium production mechanism governed by nonperturbative long-distance matrix elements (LDMEs). We examine the impact of representative LDME sets, demonstrating the EIC’s distinct discriminating power for the mechanisms. We find that quark contributions are particularly significant in the small momentum fraction region. This region is also shown to be sensitive to both the jet radius $\textit{R}$ and the experimental muon identification criteria for the $\textit{J/ψ}$ → $\textit{μ}$ $\textit{μ}$ decay channel. These findings establish quarkonium-in-jet observables at the EIC as a vital, independent probe for constraining the production mechanisms and advancing our understanding of heavy quarkonium formation.

Yunlu Wang

Hee Chung

Taewook Ha

Daekyoung Kang

U-Rae Kim

$\textit{J/ψ}$ production within jets at the EIC

In this work, we distinguish the isospin unambiguously to construct the diquark–diquark–antiquark type five-quark currents with the isospin $$I=1/2$$ , and study the $$uudc\bar{c}$$ pentaquark states with the QCD sum rules systematically for the first time. Then we obtain the mass spectrum of the diquark–diquark–antiquark type $$uudc\bar{c}$$ pentaquark states with the isospin-spin-parity $$IJ^P=\frac{1}{2}{\frac{1}{2}}^-$$ , $$\frac{1}{2}{\frac{3}{2}}^-$$ and $$\frac{1}{2}{\frac{5}{2}}^-$$ , and make possible assignments of the $$P_c(4312)$$ , $$P_c(4337)$$ , $$P_c(4380)$$ , $$P_c(4440)$$ and $$P_c(4457)$$ states. As a byproduct, we obtain the lowest hidden-charm pentaquark state which lies just above the $$\bar{D}\Lambda _c$$ threshold.

Zhi-Gang Wang

Analysis of the hidden-charm pentaquark candidates in the $$J/\psi p$$ mass spectrum with QCD sum rules

The process of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mrow><mi>b</mi><mi>c</mi></mrow><mo>+</mo></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>+</mo></msubsup><mi>J</mi><mo>/</mo><mi>ψ</mi></math> is among the most favored modes for searching for bottom-charm baryons. However, its branching fraction has never been studied in theory. In this work, we investigate the branching fraction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mrow><mi>b</mi><mi>c</mi></mrow><mo>+</mo></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>+</mo></msubsup><mi>J</mi><mo>/</mo><mi>ψ</mi></math> in the final-state-interaction approach, as it is dominated by the color-suppressed nonfactorizable contributions. A similar process, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Λ</mi><mi>b</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><msup><mi mathvariant="normal">Λ</mi><mn>0</mn></msup><mi>J</mi><mo>/</mo><mi>ψ</mi></math>, is used as a control mode to fix the model parameter. Consequently, the branching fraction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mrow><mi>b</mi><mi>c</mi></mrow><mo>+</mo></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>+</mo></msubsup><mi>J</mi><mo>/</mo><mi>ψ</mi></math> is predicted to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>1.5</mn><msubsup><mn>5</mn><mrow><mo>−</mo><mn>0.42</mn></mrow><mrow><mo>+</mo><mn>0.50</mn></mrow></msubsup><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math>. With the production rate of bottom-charm baryons and the detection efficiencies of the final states, it is expected for considerable signal events to observe <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mrow><mi>b</mi><mi>c</mi></mrow><mo>+</mo></msubsup></math> in the near future.

Xiao-Hui Hu

Cai-Ping Jia

Ye Xing

Fu-Sheng Yu

Branching fraction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mrow><mi>b</mi><mi>c</mi></mrow><mo>+</mo></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>+</mo></msubsup><mi>J</mi><mo>/</mo><mi>ψ</mi></math> in the final-state-interaction approach

We systematically investigate the production of $$J/\psi + \gamma $$ in $$\gamma \gamma $$ collisions within nonrelativistic QCD (NRQCD) factorization, with the direct-photon channel calculated specifically up to the next-to-leading order in $$\alpha _s$$ . Calculations for CEPC energy region show the resolved photon contribution is negligible, while the direct photon process dominates, yielding substantial annual $$J/\psi $$ yields. Significant modifications to $$J/\psi $$ polarization parameters emerge from color-octet mechanisms, and different NRQCD long distance matrix elements (LDMEs) further yield distinct polarization patterns. Furthermore, the polarization predictions are highly sensitive to the $$P_J^{[8]}$$ LDME, while being insensitive to the $$S_0^{[8]}$$ and $$S_1^{[8]}$$ LDMEs. Leveraging the cleaner environment of $$e^+e^-$$ collisions versus hadronic processes, the production of $$J/\psi $$ associated with a photon in $$\gamma \gamma $$ collisions provides a high-precision platform to test LDMEs universality and resolve longstanding $$J/\psi $$ polarization puzzles.

Ying-Zhao Jiang

Zhan Sun

Next-to-leading order analysis of $$J/\psi + \gamma $$ production in photon–photon collisions at CEPC

The upcoming electron-positron collider provides an ideal place to probe deviation from the Standard Model predictions with its clean environment, beam polarization, and significant luminosity. We studied anomalous quartic gauge boson couplings (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>V</mi><mi>V</mi><msup><mi>W</mi><mo>−</mo></msup><msup><mi>W</mi><mo>+</mo></msup><mo>,</mo><mi>V</mi><mo>∈</mo><mo stretchy="false">{</mo><mi>γ</mi><mo>,</mo><mi>Z</mi><mo stretchy="false">}</mo></math>), triple gauge couplings (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>W</mi><mo>−</mo></msup><msup><mi>W</mi><mo>+</mo></msup><mi>γ</mi><mo>/</mo><mi>Z</mi></math>), and Higgs-gauge couplings <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">(</mo><mi>H</mi><mi>V</mi><mi>V</mi><mo>,</mo><mi>V</mi><mo>∈</mo><mo stretchy="false">{</mo><msup><mrow><mi>W</mi></mrow><mrow><mo>±</mo></mrow></msup><mo>,</mo><mi>Z</mi><mo>,</mo><mi>γ</mi><mo stretchy="false">}</mo><mo stretchy="false">)</mo></mrow></math> induced by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>2</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub><mo>×</mo><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mi>Y</mi></msub></math> gauge-invariant dimension-6 operators in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2</mn><mi>j</mi><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>μ</mi><menclose notation="updiagonalstrike" other="updiag1"><mrow><mi>E</mi></mrow></menclose></mrow></math> final events with initial beam polarization. The phase space of two prominent amplitudes—i.e., triple gauge boson production (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>W</mi><mi>Z</mi></math>) and vector boson scattering subprocesses—are selected with kinematic cuts on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mrow><msup><mi>e</mi><mo>−</mo></msup><msup><mi>e</mi><mo>+</mo></msup></mrow></msub></math>. The full quantum states of the diboson system in vector boson scattering (VBS) and the triboson system in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>W</mi><mi>Z</mi></math> are given by 80 and 728 independent parameters (polarizations and spin correlations), respectively, which are obtained in the form of angular asymmetries. Further, the reconstruction of vector polarization asymmetries associated with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> boson and their correlations requires flavor tagging of light jets and is thus neglected. We provide one-parameter limits at a 95% confidence level, combining cross section and spin-related observables. The projected one-parameter constraints on Wilson coefficients (WCs) are found to be more stringent than the current limits reported by the LHC experiments. A channel study highlights that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi><mi>W</mi><mi>Z</mi></math> puts stringent bounds on two <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>C</mi><mi>P</mi></mrow></math>-even WCs, viz. <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>c</mi><mi>W</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>c</mi><mrow><mi>W</mi><mi>W</mi><mi>W</mi></mrow></msub></math>, while VBS topology puts stringent bounds on the remaining seven WCs. Finally, marginalized limits on all nine anomalous couplings are obtained with Markov chain Monte Carlo analysis. The limits are found to be insensitive to systematic errors and dominated by statistics.

India

Amir Subba

Ritesh K. Singh

Bounds on SMEFT affecting multigauge and Higgs-gauge couplings using two and three body spin correlations in <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><mn>2</mn><mi>j</mi><msup><mi>e</mi><mo>−</mo></msup><msup><mi>e</mi><mo>+</mo></msup><mi>μ</mi><menclose notation="updiagonalstrike" other="updiag1"><mrow><mi>E</mi></mrow></menclose></math> process

We investigate 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 collisions at tens of GeV <math xmlns="http://www.w3.org/1998/Math/MathML"><msqrt><mi>s</mi></msqrt></math> energy, relevant for forthcoming measurements with the Spin Physics Detector (SPD) at NICA. Simulations are performed using the PEGASUS event generator with transverse-momentum-dependent (TMD) gluon densities, comparing the recent KMR-based <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mrow><mi>KL</mi></mrow><mo>′</mo></msup><mn>2025</mn></mrow></math> and CCFM-based <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mrow><mi>LLM</mi></mrow><mo>′</mo></msup><mn>2024</mn></mrow></math> parametrizations. Differential cross sections in rapidity and transverse momentum exhibit smooth, stable behavior under renormalization-scale variation. Normalized <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi>T</mi></msub></math> spectra reveal distinct hardening patterns linked to the underlying gluon <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>k</mi><mi>T</mi></msub></math> broadening in each model. The relative contributions of color-singlet and color-octet channels are also quantified, demonstrating the dominance of color-octet mechanisms in the SPD energy regime. These results provide the first detailed assessment of quarkonium production sensitivity to gluon TMDs near threshold, offering timely theoretical guidance for upcoming <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> measurements at SPD/NICA.

Shubham Sharma

Kazakhstan

Alexey Aparin

<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> production in proton-proton collisions at Spin Physics Detector energies of the JINR Nuclotron-based Ion Collider fAcility