Motivated by the recently reported resonant structure <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>2300</mn><mo stretchy="false">)</mo></math>, a strong candidate for a fully strange tetraquark with positive parity, we perform a systematic study of fully strange tetra- and pentaquark systems within a chiral quark model. Low-lying <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math>-wave configurations of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi><mi>s</mi><mover accent="true"><mi>s</mi><mo stretchy="false">¯</mo></mover><mover accent="true"><mi>s</mi><mo stretchy="false">¯</mo></mover></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>s</mi><mi>s</mi><mi>s</mi><mi>s</mi><mover accent="true"><mi>s</mi><mo stretchy="false">¯</mo></mover></math> systems are investigated using the Gaussian expansion method combined with the complex scaling method, which allow for a unified treatment of bound, resonant, and scattering states. For tetraquarks, all possible configurations: meson-meson, diquark-antidiquark, and K-type structures, with complete color bases, are incorporated, while baryon-meson and diquark-diquark-antiquark configurations are considered for pentaquarks. Several weakly bound states and narrow resonances are identified in both sectors. In particular, a compact fully strange tetraquark with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>J</mi><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>=</mo><msup><mn>1</mn><mrow><mo>+</mo><mo>−</mo></mrow></msup></math> is found near 2.3 GeV, providing a natural interpretation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>2300</mn><mo stretchy="false">)</mo></math> resonance. Additional exotic states with dominant hidden-color and K-type components are predicted in the mass ranges 1.6–3.1 GeV for tetraquarks and 2.6–3.2 GeV for pentaquarks. The internal structure of these states is analyzed through their sizes, magnetic moments, and wave-function compositions, highlighting the essential role of channel coupling and exotic color configurations. Finally, promising two-body strong decay channels are proposed to facilitate future experimental searches.

China

Gang Yang

Jialun Ping

Spain

Jorge Segovia

Fully strange tetra- and pentaquarks in a chiral quark model

We present an interesting study of Feynman integral reduction that does not employ integration-by-parts identities. Our approach proceeds by studying the equivalence relations of integral contours in the Feynman parametrization. We find that the integration contour can take a more general form than that given by the Cheng-Wu theorem. We apply this idea to one-loop integrals and derive universal reduction formulas that can be used to efficiently reduce any one-loop integral. We expect that this approach can be useful in the reduction of multiloop integrals as well.

Ziwen Wang

Li Lin Yang

Feynman integral reduction without integration by parts

The azimuthal-correlation distributions between electrons from the decays of heavy-flavor hadrons and associated charged particles in Pb–Pb collisions at $$\sqrt{s_{\textrm{NN}}} = 5.02$$ TeV are reported for the 0–10% and 30–50% centrality classes. This measurement provides access to the jet-like correlation observables in the heavy-flavor sector in Pb–Pb collisions. The analysis is performed for trigger electrons from heavy-flavor hadron decays with transverse momentum $$4< p_\textrm{T}^\textrm{e} < 16~\textrm{GeV}/c$$ , considering associated particles within the transverse-momentum range $$1< p_\textrm{T}^\textrm{assoc} < 7$$ $$\textrm{GeV}/c$$ , and a pseudorapidity difference of $$|\Delta \eta |<1$$ between the trigger electron and associated particles. The per-trigger nuclear modification factor ( $$I_\textrm{AA}$$ ) is calculated to compare the near- and away-side peak yields to those in pp collisions at $$\sqrt{s} = 5.02$$ TeV. In 0–10% central collisions, the $$I_\textrm{AA}$$ indicates a hint of enhancement of associated-particle yields with $$p_\textrm{T}<3$$ GeV/$\textit{c}$ on the near side, and a suppression of yields with $$p_\textrm{T}>4$$ GeV/$\textit{c}$ on the away side. The $$I_\textrm{AA}$$ for electron triggers from heavy-flavor hadron decays is compared with that for light-flavor and strange-particle triggers to investigate the dependence on different fragmentation processes and parton-medium dynamics, and is found to be the same within uncertainties.

United States

I. Abualrob

Italy

S. Acharya

G. Aglieri Rinella

L. Aglietta

M. Agnello

N. Agrawal

India

Z. Ahammed

S. Ahmad

Slovakia

I. Ahuja

Indonesia

Z. Akbar

A. Akindinov

Germany

V. Akishina

M. Al-Turany

D. Aleksandrov

B. Alessandro

H. Alfanda

Mexico

R. Alfaro Molina

B. Ali

A. Alici

South Korea

A. Alkin

Norway

J. Alme

G. Alocco

T. Alt

A. Altamura

I. Altsybeev

Romania

C. Andrei

United Kingdom

N. Andreou

A. Andronic

E. Andronov

V. Anguelov

F. Antinori

P. Antonioli

N. Apadula

H. Appelshäuser

France

C. Arata

S. Arcelli

R. Arnaldi

Brazil

J. Arneiro

I. Arsene

M. Arslandok

A. Augustinus

R. Averbeck

M. Azmi

Japan

H. Baba

A. Babu

A. Badalà

J. Bae

Y. Bae

Y. Baek

X. Bai

R. Bailhache

Y. Bailung

R. Bala

A. Baldisseri

Poland

B. Balis

S. Bangalia

Z. Banoo

V. Barbasova

F. Barile

L. Barioglio

Greece

M. Barlou

B. Barman

Hungary

G. Barnaföldi

L. Barnby

E. Barreau

V. Barret

L. Barreto

K. Barth

E. Bartsch

N. Bastid

G. Batigne

D. Battistini

B. Batyunya

D. Bauri

Peru

J. Alba

Denmark

I. Bearden

P. Becht

D. Behera

S. Behera

I. Belikov

V. Bella

F. Bellini

R. Bellwied

L. Beltran

Y. Beltran

G. Bencedi

A. Bensaoula

S. Beole

Y. Berdnikov

A. Berdnikova

L. Bergmann

L. Bernardinis

L. Betev

P. Bhaduri

T. Bhalla

A. Bhasin

B. Bhattacharjee

S. Bhattarai

L. Bianchi

Czechia

J. Bielčík

Medium-induced modification of azimuthal correlations of electrons from heavy-flavor hadron decays with charged particles in Pb–Pb collisions at $$\mathbf {\sqrt{s_{\textrm{NN}}} = 5.02}$$ TeV

Observable signatures of black hole thermodynamics remain far from fully explored. Previous works have suggested that thermodynamic phase transitions of black holes could leave imprints on their images. In this work, we demonstrate that richer black hole thermodynamic information can also leave imprints on the resulting images. Using the charged anti-de Sitter black hole as an example, we study the evolution of its images (shadow and accretion-disk images) along isobaric and isothermal processes. We find that the image size evolves monotonically along isobars but becomes nonmonotonic along isotherms. After further considering phase transitions, the image size exhibits a sudden increase in both thermodynamic processes. More importantly, in the isothermal process, the phase transition further results in the emergence of a critical reduced temperature that separates two qualitatively distinct image evolutions. These results show that black hole images can probe not only phase transitions, but also thermodynamic process and temperature.

Lei You

Jinsong Yang

Black hole images as probes of thermodynamic evolution

The first measurements of the top- and antitop-quark differential production cross sections and the top-quark charge asymmetry in the forward region are presented, using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>5.4</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>. The total production cross sections of top and antitop quarks are also determined. Measurements are performed using the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>μ</mi><mo>+</mo><mrow><mi>b</mi><mtext>-jet</mtext></mrow></mrow></math> final state within a fiducial region defined by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>b</mi></mrow></math>-jet <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant="normal">T</mi><mo>,</mo><mtext>jet</mtext></mrow></msub><mo>&gt;</mo><mn>50</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> and pseudorapidity <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>2.2</mn><mo>&lt;</mo><msub><mrow><mi>η</mi></mrow><mrow><mtext>jet</mtext></mrow></msub><mo>&lt;</mo><mn>4.0</mn></mrow></math>, with the muon from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-boson decay required to have <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant="normal">T</mi><mo>,</mo><mi>μ</mi></mrow></msub><mo>&gt;</mo><mn>25</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.0</mn><mo>&lt;</mo><msub><mi>η</mi><mi>μ</mi></msub><mo>&lt;</mo><mn>4.5</mn></math>. The muon and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>b</mi></mrow></math>-jet system must satisfy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi mathvariant="normal">T</mi></mrow></msub><mo stretchy="false">(</mo><mi>μ</mi><mo>+</mo><mtext>jet</mtext><mo stretchy="false">)</mo><mo>&gt;</mo><mn>20</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math>. The measured integrated production cross sections for the top and antitop quarks are <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mi>t</mi></mrow></msub><mo>=</mo><mn>0.95</mn><mo>±</mo><mn>0.04</mn><mo>±</mo><mn>0.08</mn><mo>±</mo><mn>0.02</mn><mtext> </mtext><mtext> </mtext><mi>pb</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>σ</mi></mrow><mrow><mover accent="true"><mrow><mi>t</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></msub><mo>=</mo><mn>0.81</mn><mo>±</mo><mn>0.03</mn><mo>±</mo><mn>0.07</mn><mo>±</mo><mn>0.02</mn><mtext> </mtext><mtext> </mtext><mi>pb</mi></mrow></math>, where the first uncertainty is statistical, the second systematic, and the third accounts for the luminosity uncertainty. The top-quark charge asymmetry is measured to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi>A</mi></mrow><mrow><mi>C</mi></mrow><mrow><mi>t</mi></mrow></msubsup><mo>=</mo><mn>0.08</mn><mo>±</mo><mn>0.03</mn><mo>±</mo><mn>0.01</mn></mrow></math>, where the first uncertainty is statistical and the second is systematic. These results are consistent with next-to-leading order Standard Model predictions.

Netherlands

R. Aaij

A.S.W. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

A.A. Adefisoye

B. Adeva

M. Adinolfi

P. Adlarson

C. Agapopoulou

C.A. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

M. Akthar

P. Albicocco

J. Albrecht

R. Aleksiejunas

CERN

F. Alessio

P. Alvarez Cartelle

R. Amalric

S. Amato

J.L. Amey

Y. Amhis

L. An

L. Anderlini

M. Andersson

P. Andreola

M. Andreotti

S. Andres Estrada

A. Anelli

D. Ao

F. Archilli

Z. Areg

M. Argenton

Costa Rica

S. Arguedas Cuendis

L. Arnone

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

Measurement of the Top-Quark Production Cross Section and Charge Asymmetry at LHCb