In the present work, the strong decays of the discovered $ P_c(4380) $ , $ P_c(4440) $ , $ P_c(4457) $ and their possible isospin cousins are systematically studied via the assignment that they are meson-baryon molecular states. In detail, the strong decay constants and partial decay widths of their decay channels are calculated under the framework of QCD sum rules. The decay widths of the discovered $ P_c(4380) $ , $ P_c(4440) $ , and $ P_c(4457) $ are in good agreement with the experiments. The predictions of the decays of these three related possible isospin cousins are presented, which would shed light on their findings in experiments. In return, this may testify to the assignments of the discovered $ P_c $ states.

China

Xiu-Wu Wang

Xin Li

Zhi-Gang Wang

Systematic study of the strong decays of the $\textit{P}$ $\textit{c}$ states and their possible isospin cousins via the QCD sum rules * Supported by the National Natural Science Foundation of China (12575083) and the Natural Science Foundation of Hebei Province (A2024502002)

We study the equation of state (EoS) of QCD matter in a bottom-up holographic setup that combines an Einstein-Maxwell-dilaton (EMD) sector with an improved Karch-Katz-Son-Stephanov (KKSS) flavor action. In the probe approximation, we perform an inverse reconstruction of the model functions by parameterizing them with neural networks and solving the EMD equations via a differentiable ODE solver (a neural ODE framework), calibrating the model to a reference thermodynamic table for $(2+1)$ -flavor QCD at finite temperature and finite baryon chemical potential. The reconstructed model functions are then parameterized and kept fixed across thermodynamic states. Next, viewing the EMD sector as an effective description of pure Yang-Mills theory, we fix its parameters by fitting the $\mu_B=0$ lattice pure-glue EoS using a hybrid optimization strategy. Finally, we go beyond the probe limit and solve the coupled EMD+KKSS equations with back-reaction, using the pure-glue-calibrated EMD sector as a fixed input and varying the KKSS couplings to compare with the $\mu_B=0$ two-flavor lattice EoS. We find a visible mismatch and a high-temperature behavior in which the back-reacted dimensionless ratios approach a nearly $\beta_1$ -insensitive plateau close to the pure-glue baseline, providing a simple structural diagnostic for the present flavor-sector truncation.

Yutian Deng

Mei Huang

Lin Zhang

Holographic QCD equation of state constrained by lattice QCD: neural-ODE for probe-limit and a back-reaction test * Start-up funding from Sun Yat-sen University (SYSU) (Y. Deng and L. Zhang); National Natural Science Foundation of China (NSFC) (12235016) (L. Zhang and M. Huang) and 12221005 (M. Huang)

<p>Using <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo stretchy="false">(</mo><mn>10</mn><mtext> </mtext><mn>087</mn><mo>±</mo><mn>44</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> events collected with the BESIII detector, a full angular analysis is carried out on the process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi mathvariant="normal">Λ</mi><mover accent="true"><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">→</mo><mi>n</mi><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><mover accent="true"><mrow><mi>p</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi></mrow></math>. The decay parameters <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mn>0</mn></msub></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi><mo stretchy="false">→</mo><mi>n</mi><msup><mi>π</mi><mn>0</mn></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>α</mi><mo stretchy="false">¯</mo></mover><mn>0</mn></msub></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mover accent="true"><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">→</mo><mover accent="true"><mrow><mi>n</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup></mrow></math> are measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>0.668</mn><mo>±</mo><mn>0.007</mn><mo>±</mo><mn>0.002</mn></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><mn>0.677</mn><mo>±</mo><mn>0.007</mn><mo>±</mo><mn>0.003</mn></math>, respectively, yielding the most precise test for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> symmetry of neutral decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>A</mi></mrow><mrow><mi>C</mi><mi>P</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo>=</mo><mo stretchy="false">(</mo><msub><mrow><mi>α</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>+</mo><msub><mrow><mover accent="true"><mrow><mi>α</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy="false">)</mo><mo>/</mo><mo stretchy="false">(</mo><msub><mrow><mi>α</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>−</mo><msub><mrow><mover accent="true"><mrow><mi>α</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mn>0</mn></mrow></msub><mo stretchy="false">)</mo></mrow></math>, to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>−</mo><mn>0.006</mn><mo>±</mo><mn>0.007</mn><mo>±</mo><mn>0.002</mn></math>. The ratios <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mn>0</mn></msub><mo>/</mo><msub><mi>α</mi><mo>−</mo></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mover accent="true"><mi>α</mi><mo stretchy="false">¯</mo></mover><mn>0</mn></msub><mo>/</mo><msub><mi>α</mi><mo>+</mo></msub></math> are determined to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>0.884</mn><mo>±</mo><mn>0.013</mn><mo>±</mo><mn>0.006</mn></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>0.885</mn><mo>±</mo><mn>0.013</mn><mo>±</mo><mn>0.004</mn></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mo>−</mo></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mo>+</mo></msub></math> are the decay parameters of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi><mo stretchy="false">→</mo><mi>p</mi><msup><mi>π</mi><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi mathvariant="normal">Λ</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">→</mo><mover accent="true"><mi>p</mi><mo stretchy="false">¯</mo></mover><msup><mi>π</mi><mo>+</mo></msup></math>, respectively. The ratios, found to be smaller than unity by more than <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5</mn><mi>σ</mi></math>, confirm the presence of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Δ</mi><mi>I</mi><mo>=</mo><mn>3</mn><mo>/</mo><mn>2</mn></math> transition in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi mathvariant="normal">Λ</mi><mo stretchy="false">¯</mo></mover></math> decays, which is expected to improve the theoretical calculations for isospin amplitudes, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>A</mi><mrow><mi>C</mi><mi>P</mi></mrow></msub></math>, in hyperon decays. In all results, the first and second uncertainties are statistical and systematic, respectively.</p>

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

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.B. 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

T.T. 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.M. Chen

T. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z.K. Chen

J.C. Cheng

L.N. Cheng

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

United Kingdom

J. Cottee-Meldrum

H.L. Dai

J.P. Dai

X.C. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denisenko

M. Destefanis

F. De Mori

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

X.L. 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

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

L. Feng

Q.X. Feng

Y.T. Feng

M. Fritsch

Test of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> Symmetry in the Neutral Decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi></math> via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi mathvariant="normal">Λ</mi><mover accent="true"><mi mathvariant="normal">Λ</mi><mo stretchy="false">¯</mo></mover></math>

<p>Based on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>334</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>pb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> of photoproduction data collected with the GlueX detector at Jefferson Lab, we have measured for the first time the cross section of the exclusive reaction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>γ</mi><mo>+</mo><mi>p</mi><mo stretchy="false">→</mo><mi>ϕ</mi><mo stretchy="false">(</mo><mn>1020</mn><mo stretchy="false">)</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>p</mi></mrow></math> by reconstructing the final state <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mi>p</mi></math> produced with a photon beam of energies between 8.0 and 11.6 GeV. Based on the measured differential cross section, we have performed a search for the strangeoniumlike exotic candidate <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>2175</mn><mo stretchy="false">)</mo></math>, recently renamed to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><mo stretchy="false">(</mo><mn>2170</mn><mo stretchy="false">)</mo></math>. This state has been reported by different <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> annihilation experiments and it is addressed here for the first time in a photoproduction experiment. We do not find evidence for this state when using the resonance parameters quoted by the Particle Data Group and provide upper limits on the photoproduction cross section. Instead, we find a structure at a mass of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>m</mi><mo stretchy="false">(</mo><mi>ϕ</mi><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">)</mo><mo>=</mo><mn>2.24</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><msup><mrow><mi>c</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math> with a statistical significance of about <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>5</mn><mi>σ</mi></mrow></math>. The parameters of this structure differ from those quoted by the Particle Data Group for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ϕ</mi><mo stretchy="false">(</mo><mn>2170</mn><mo stretchy="false">)</mo></math> and are consistent with a previous observation 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></math> annihilation. In addition, there is evidence for a second structure at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.82</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo>/</mo><msup><mi>c</mi><mn>2</mn></msup></math>.</p>

F. Afzal

M. Albrecht

M. Amaryan

S. Arrigo

V. Arroyave

A. Asaturyan

A. Austregesilo

Z. Baldwin

F. Barbosa

J. Barlow

E. Barriga

R. Barsotti

D. Barton

V. Baturin

V.V. Berdnikov

A. Berger

W. Boeglin

M. Boer

W.J. Briscoe

T. Britton

R. Brunner

S. Cao

C. Chen

E. Chudakov

G. Chung

P.L. Cole

O. Cortes

V. Crede

M.M. Dalton

D. Darulis

A. Deur

S. Dobbs

A. Dolgolenko

M. Dugger

R. Dzhygadlo

D. Ebersole

M. Edo

H. Egiyan

P. Eugenio

A. Fabrizi

C. Fanelli

S. Fang

S. Furletov

L. Gan

H. Gao

A. Gardner

A. Gasparian

D.I. Glazier

C. Gleason

K. Goetzen

B. Grube

J. Guo

Canada

A. Hamdi

J. Hernandez

K. Hernandez

N.D. Hoffman

D. Hornidge

G.M. Huber

P. Hurck

W. Imoehl

D.G. Ireland

M.M. Ito

I. Jaegle

N.S. Jarvis

T. Jeske

M. Jing

R.T. Jones

Armenia

V. Kakoyan

G. Kalicy

X. Kang

V. Khachatryan

Greece

C. Kourkoumelis

A. LaDuke

I. Larin

D. Lawrence

Search for the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>Y</mi><mo stretchy="false">(</mo><mn>2175</mn><mo stretchy="false">)</mo></mrow></math> in the Photoproduction Cross Section Measurement of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>γ</mi><mi>p</mi><mo stretchy="false">→</mo><mi>ϕ</mi><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>p</mi></mrow></math> at GlueX