United States

Samuel Ting

Discovery of the J particle at Brookhaven National Laboratory and the physics of electrons and positrons

Utilizing 4.5 $ \text{fb}^{-1} $ of $ e^+e^- $ annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider, we searched for singly Cabibbo-suppressed hadronic decays $ \Lambda_{c}^{+}\to\Sigma^{0} K^{+}\pi^{0} $ and $ \Lambda_{c}^{+}\to\Sigma^{0}K^{+} \pi^+ \pi^- $ with a single-tag method. No significant signals were observed for both decays. The upper limits on the branching fractions at the 90% confidence level were determined to be $ 5.0\times 10^{-4} $ for $ \Lambda_{c}^{+}\to\Sigma^{0} K^{+}\pi^{0} $ and $ 6.5\times 10^{-4} $ for $ \Lambda_c^{+}\to\Sigma^0K^{+}\pi^{+}\pi^{-} $ .

China

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

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

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

G. Chelkov

C. Chen

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

Y.B. Chen

Y.Q. Chen

Z.J. Chen

Z.K. Chen

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

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

Z.H. 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

Y.T. Feng

M. Fritsch

C.D. Fu

J.L. Fu

Search for Cabibbo-suppressed decays ${\boldsymbol\Lambda_{\boldsymbol c}^{\bf +} }$ → Σ$^{0}$ $\textit{K}$ $^{+}$ $\textit{π}$ $^{0}$ and $ {\boldsymbol\Lambda_{\boldsymbol c}^{\bf +} }$ → Σ$^{0}$ $\textit{K}$ $^{+}$ $\textit{π}$ $^{+}$ $\textit{π}$ $^{−}$ * This study has been supported in part by National Key R&D Program of China (2020YFA0406300, 2020YFA0406400, 2023YFA1606000); National Natural Science Foundation of China (NSFC) (12205141, 11635010, 11735014, 11935015, 11935016, 11935018, 12025502, 12035009, 12035013, 12061131003, 12192260, 12192261, 12192262, 12192263, 12192264, 12192265, 12221005, 12225509, 12235017, 12361141819); Natural Science Foundation of Hunan Province (2024JJ2044); the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; the CAS Center for Excellence in Particle Physics (CCEPP); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1832207); 100 Talents Program of CAS; The Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology; German Research Foundation DFG (FOR5327); Istituto Nazionale di Fisica Nucleare, Italy; Knut and Alice Wallenberg Foundation (2021.0174, 2021.0299); Ministry of Development of Turkey (DPT2006K-120470); National Research Foundation of Korea (NRF-2022R1A2C1092335); National Science and Technology fund of Mongolia; National Science Research and Innovation Fund (NSRF) via the Program Management Unit for Human Resources & Institutional Development, Research and Innovation of Thailand (B16F640076, B50G670107); Polish National Science Centre (2019/35/O/ST2/02907); Swedish Research Council (2019.04595); The Swedish Foundation for International Cooperation in Research and Higher Education (CH2018-7756); and U. S. Department of Energy (DE-FG02-05ER41374)

We analyze the recent data from the BESIII collaboration on the $ X(3872) $ state in the $ J/\psi\pi^+\pi^- $ and $ D^0\bar{D}^0\pi^0 $ decay channels. The quantum number and mass of the $ X(3872) $ state allow us to exploit the universal feature of the very near-threshold $ D\bar D^* $ scattering in the $\textit{S}$ wave. The analysis of $ J/\psi\pi^+\pi^- $ and $ D^0\bar{D}^0\pi^0 $ data separately, as well as the combined analysis of these data together, all support the conclusion that $ X(3872) $ is an extremely weakly bound charm meson molecule.

Xian-Wei Kang

Jin-Zhe Zhang

Xin-Heng Guo

Nature of $\textit{X}$(3872) from recent BESIII data: considering the universal feature of an $\textit{S}$-wave threshold resonance * Supported by the National Natural Science Foundation of China (12275023)

<p>The cross sections for the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi><mo>→</mo><mi>p</mi><mi>p</mi><mi>η</mi></mrow></math> reaction are evaluated at energies relevant for the HADES, PANDA, and SIS100 experiments at GSI-FAIR (Facility for Antiproton and Ion Research). Consideration includes the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>η</mi></math>-bremsstrahlung mechanism involving intermediate proton exchange via the <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>π</mi><mn>0</mn></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>η</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><msup><mi>ρ</mi><mn>0</mn></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>ω</mi></math> exchanges and the mechanism involving the nucleon resonances <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>N</mi><mo>(</mo><mn>1535</mn><mo>)</mo></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>N</mi><mo>(</mo><mn>1650</mn><mo>)</mo></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>N</mi><mo>(</mo><mn>1710</mn><mo>)</mo></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>N</mi><mo>(</mo><mn>1880</mn><mo>)</mo></mrow></math> excited via the pseudoscalar- and/or vector-meson exchanges, depending on the model. The role of the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>ω</mi><mi>ω</mi></mrow></math>- and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>ρ</mi><mn>0</mn></msup><msup><mi>ρ</mi><mn>0</mn></msup></mrow></math>-fusion processes with the Reggeized vector-meson exchanges is also discussed. The calculation is done in an effective Lagrangian approach. To determine the parameters of the model, the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>γ</mi><mi>p</mi><mo>→</mo><mi>η</mi><mi>p</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msup><mi>π</mi><mo>−</mo></msup><mi>p</mi><mo>→</mo><mi>η</mi><mi>n</mi></mrow></math> reactions are studied and the results are then compared with the Crystal Ball and CLAS data. For the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi><mo>→</mo><mi>p</mi><mi>p</mi><mi>η</mi></mrow></math> reaction, the model results are compared with the energy dependence of the cross section measured far from the threshold and with the differential distributions <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>d</mi><mi>σ</mi><mo>/</mo><mi>d</mi><mo form="prefix">cos</mo><msub><mi>θ</mi><mi>η</mi></msub></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>d</mi><mi>σ</mi><mo>/</mo><mi>d</mi><msub><mi>p</mi><mi>η</mi></msub></mrow></math> measured by the DISTO Collaboration. The comparison shows that the <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>N</mi><mo>(</mo><mn>1535</mn><mo>)</mo></mrow></math> resonance is the dominant contribution and that other contributions are also important due to interference effects. Assuming that the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>ρ</mi></math> exchange is the dominant resonant excitation process, the model is able to describe the available data, e.g., it reproduces the shape of the angular distributions measured by the DISTO Collaboration. Predictions are given for the HADES experiment at center-of-mass energy of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>3.46</mn></mrow></math> GeV, which can be verified in the near future, and for planned PANDA and SIS100 experiments at higher energies.</p>

Piotr Lebiedowicz

Exclusive <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>η</mi></math> production in proton-proton collisions at energies available at the GSI Facility for Antiproton and Ion Research

Correlation $ \chi^{BQ}_{11} $ and quadratic fluctuations $ \chi^B_2,\ \chi^Q_2,\ \chi^T_2 $ of baryon number $\textit{B}$, electric charge $\textit{Q,}$ and temperature $\textit{T}$ are investigated in a two-flavor Polyakov loop extended Nambu-Jona-Lasinio (PNJL) model at finite temperature and magnetic field. The inverse magnetic catalysis (IMC) effect is introduced through magnetic-field-dependent parameters $ G(eB) $ and $ T_0(eB) $ , and we compare the results in scenarios with and without the IMC effect. Under a nonvanishing magnetic field, correlation $ \chi^{BQ}_{11} $ and fluctuations $ \chi^B_2,\ \chi^Q_2,\ \chi^T_2 $ increase with temperature and then exhibit a peak around the pseudocritical temperatures of chiral restoration and deconfinement phase transitions in the cases with and without the IMC effect. The correlation and fluctuations along the phase transition line under an external magnetic field are characterized by scaled correlation ${\hat {\chi}}_{11}^{BQ}={\chi_{11}^{BQ}(eB,T_{pc}^c(eB))}/{\chi_{11}^{BQ}(eB=0,T_{pc}^c(eB=0))}$ and scaled fluctuations ${\hat {\chi}}_2^{B(Q,T)}={\chi_2^{B(Q,T)}(eB,T_{pc}^c(eB))}/{\chi_2^{B(Q,T)}(eB=0,T_{pc}^c(eB=0))}$ at pseudocritical temperature $ T_{pc}^c $ of chiral restoration phase transition. $ {\hat {\chi}}_{11}^{BQ},\ {\hat {\chi}}_2^{B} $ , and $ {\hat {\chi}}_2^{Q} $ increase with the magnetic field, and the inclusion of the IMC effect enhances their values somewhat. However, $ {\hat {\chi}}_2^{T} $ is altered by the IMC effect. Without the IMC effect, $ {\hat \chi}^T_2 $ increases slightly and then decreases with the magnetic field. Considering the IMC effect using $ G(eB) $ , $ {\hat \chi}^T_2 $ monotonically increases with the magnetic field, and that using $ T_0(eB) $ is a nonmonotonic function of the magnetic field.

Shijun Mao

Correlations and fluctuations in a magnetized PNJL model with and without the inverse magnetic catalysis effect * Supported by the National Natural Science Foundation of China (12275204)

We search for the leptonic decay $ D^+\to e^+\nu_{e} $ using an $ e^+e^- $ collision data sample with an integrated luminosity of 20.3 fb $ ^{-1} $ collected with the BESIII detector at a center-of-mass energy of 3.773 GeV. Significant signal is not observed, and an upper limit on the branching fraction of $ D^+\to e^+\nu_{e} $ is set as $ 9.7 \times 10^{-7} $ , at a confidence level of 90%. Our upper limit is an order of magnitude smaller than the previous limit for this decay mode.

O. Afedulidis

I. Balossino

Z.Y. Chen

Y. Fang

Y.W. Fu

H. Gao

Search for the leptonic decay ${\boldsymbol D^{\bf +}{\bf\to}{\boldsymbol e}^{\bf +}\boldsymbol\nu_{\boldsymbol e}}$ * Supported in part by the National Key R&D Program of China (2023YFA1606000, 2020YFA0406400, 2020YFA0406300), the National Natural Science Foundation of China(NSFC) (11635010, 11735014, 11935015, 11935016, 11875054, 11935018, 12025502, 12035009, 12035013, 12061131003, 12192260, 12192261, 12192262, 12192263, 12192264, 12192265, 12221005, 12225509, 12235017, 12361141819), the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program, the CAS Center for Excellence in Particle Physics (CCEPP), the Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U2032104, U1832207), the 100 Talents Program of CAS, the Excellent Youth Foundation of Henan Scientific Commitee (242300421044), the Institute of Nuclear and Particle Physics (INPAC) and Shanghai Key Laboratory for Particle Physics and Cosmology, the German Research Foundation DFG (FOR5327), the Istituto Nazionale di Fisica Nucleare, Italy, the Knut and Alice Wallenberg Foundation (2021.0174, 2021.0299), the Ministry of Development of Turkey (DPT2006K-120470), the National Research Foundation of Korea (NRF-2022R1A2C1092335), the National Science and Technology Fund of Mongolia, the National Science Research and Innovation Fund (NSRF) via the Program Management Unit for Human Resources & Institutional Development, Research, and Innovation of Thailand (B16F640076, B50G670107), the Polish National Science Center (2019/35/O/ST2/02907), the Swedish Research Council (2019.04595), the Swedish Foundation for International Cooperation in Research and Higher Education (CH2018-7756), and the US Department of Energy (DE-FG02-05ER41374).

We present the first lattice result of the near threshold $ \Lambda_c\Lambda_c $ scattering with $ I(J^P) = 0(0^+) $ . The calculation is performed on two $ N_f = 2+1 $ Wilson-Clover ensembles with pion mass $ m_\pi \sim 303 $ MeV and lattice spacing $ a = 0.07746 $ fm. Lüscher's finite volume method is utilized to extract the scattering parameters from the finite-volume spectrum. The coupled channel $ \Xi_{cc}N $ is ignored in the scattering analysis based on the observation that the energy levels computed from the $ \Lambda_c\Lambda_c $ and $ \Xi_{cc}N $ operators do not mix. The $ \Sigma_c\Sigma_c $ channel is not included either since the energy range explored in this study is well below its threshold. Our results indicate that the interaction in the $ \Lambda_c\Lambda_c $ single channel is repulsive, and the scattering length is determined to be $ a_0 = -0.21(4)(8) $ fm, where the first error is statistical and the second is systematic.

Hanyang Xing

Yiqi Geng

Chuan Liu

Liuming Liu

Peng Sun

Jiajun Wu

Zhicheng Yan

Ruilin Zhu

Lattice QCD study of Λ $\textit{c}$ Λ $\textit{c}$ scattering * Supported by NSFC (12293060, 12293061, 12293063, 12175279, 12435002, 12322503, 12175239). L. Liu also acknowledges the Strategic Priority Research Program of the Chinese Academy of Sciences with (XDB34030301) and Guangdong Major Project of Basic and Applied Basic Research (2020B0301030008). We also acknowledge the Science and Education Integration Young Faculty Project of University of Chinese Academy of Sciences (YSBR-101)

We introduce a relative $\textit{P}$-wave to construct the doubly charmed diquark $ (\widetilde{V}) $ vector. Therefore, scalar and tensor four-quark currents were constructed to investigate the decay widths of the fully charmed tetraquark states with $ J^{PC}=0^{++} $ , $ 1^{+-} $ and $ 2^{++} $ via quantum chromodynamics (QCD) sum rules. We observed that the total width of the ground state $ \widetilde{V}\overline{\widetilde{V}} $ -type scalar tetraquark state is compatible with that of the $ X(6552) $ within uncertainties, and the branching ratios are quite different from that of the first radial excitation of the $ A\bar{A} $ -type scalar tetraquark state. Other predictions can be verified in future experiments to shed light on the nature of the fully charmed tetraquark states.

Xiao-Song Yang

Zhi-Gang Wang

Strong decays of the fully charmed tetraquark states with explicit $\textit{P}$-waves via QCD sum rules * Supported by the National Natural Science Foundation (12175068), and the Fundamental Research Funds for the Central Universities

A traversable wormhole generally violates the averaged null energy condition, typically requiring exotic matter. Recently, it was discovered that a traversable wormhole can be realized with non-exotic matter in Einstein-Dirac-Maxwell theories in flat space. This study extends the discussion to AdS spacetime and finds traversable wormholes with spherical and planar topologies. Furthermore, based on the AdS/CFT correspondence, we compute the entanglement entropy of strips and disks on the two AdS boundaries of the wormhole. We find that the entanglement entropy undergoes a phase transition as the subsystem size increases.

Hua-Chao Liu

Rong-Xin Miao

Traversable wormholes in AdS and entanglement * Supported by the National Natural Science Foundation of China (12275366)

The roles of the $ \Delta (1232) $ , $ {N}^{*}(1520) $ , and $ {N}^{*}(1650) $ resonances in the $ \gamma p\to{\pi }^{0}{\pi }^{0}p $ reaction near threshold is investigated within an effective Lagrangian approach. The differential cross sections of the $ \gamma p\to{\pi }^{0}{\pi }^{0}p $ reaction was calculated including contributions from the $ \Delta (1232) $ , $ {N}^{*}(1520) $ , and $ {N}^{*}(1650) $ intermediate states decaying into $ \pi^0 p $ via the $\textit{s}$-channel nucleon pole and $\textit{t}$-channel $\textit{ρ}$ exchange. Current experimental measurements were well reproduced. The production of $ \Delta(1232) $ was mainly from the mechanism of the $\textit{s}$-channel nucleon pole, while the $ {N}^{*}(1520) $ and $ {N}^{*}(1650) $ were produced from the mechanism of the $\textit{t}$-channel $\textit{ρ}$ exchange. More experimental data on the $ \gamma p \to \pi^0 \pi^0 p $ reaction could be used to explore the properties of the low-lying excited baryon state.

Meng-Yuan Dai

Si-Wei Liu

Cheng Chen

De-Min Li

En Wang

Ju-Jun Xie

Roles of ${\boldsymbol\Delta(\bf 1232)}$ , ${\boldsymbol N^*(\bf 1520)}$ , and ${\boldsymbol N^*(\bf 1650)}$ resonances in ${\boldsymbol\gamma \boldsymbol p\to \boldsymbol\pi^{\bf 0} \boldsymbol\pi^{\bf 0}\boldsymbol p}$ reaction within an effective Lagrangian approach * Supported by the National Key R&D Program of China (2023YFA1606703, 2024YFE0105200), the Natural Science Foundation of Henan Province, China (232300421140, 222300420554), and the National Natural Science Foundation of China (12435007, 12361141819, 12475086, 12192263)