Based on <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 data collected with the BESIII detector at center-of-mass energies from 4.600 to 4.699 GeV, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>4.5</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>, we present the first measurement of the longitudinal polarization of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi></math> hyperon produced in the inclusive decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Λ</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><mi mathvariant="normal">Λ</mi><mi>X</mi></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi></math> denotes any allowed final states. The polarizations are determined to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">P</mi><mi mathvariant="normal">Λ</mi></msub><mo>=</mo><mo>−</mo><mn>0.393</mn><mo>±</mo><mn>0.05</mn><msub><mn>5</mn><mrow><mi>stat</mi></mrow></msub><mo>±</mo><mn>0.02</mn><msub><mn>0</mn><mrow><mi>syst</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="script">P</mi><mover accent="true"><mi mathvariant="normal">Λ</mi><mo stretchy="false">¯</mo></mover></msub><mo>=</mo><mn>0.288</mn><mo>±</mo><mn>0.05</mn><msub><mn>6</mn><mrow><mi>stat</mi></mrow></msub><mo>±</mo><mn>0.01</mn><msub><mn>7</mn><mrow><mi>syst</mi></mrow></msub></math>. A search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation is performed using an asymmetry constructed from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Λ</mi></math> polarization and the <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> decay asymmetry parameter, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="script">A</mi><mrow><mi>C</mi><mi>P</mi></mrow><mi>pol</mi></msubsup><mo>=</mo><mn>0.15</mn><mo>±</mo><mn>0.1</mn><msub><mn>2</mn><mrow><mi>stat</mi></mrow></msub><mo>±</mo><mn>0.0</mn><msub><mn>3</mn><mrow><mi>syst</mi></mrow></msub></math> was obtained. Furthermore, an updated measurement of the absolute branching fraction is reported as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msubsup><mi mathvariant="normal">Λ</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><mi mathvariant="normal">Λ</mi><mi>X</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>38.07</mn><mo>±</mo><mn>0.3</mn><msub><mn>8</mn><mrow><mi>stat</mi></mrow></msub><mo>±</mo><mn>0.4</mn><msub><mn>9</mn><mrow><mi>syst</mi></mrow></msub><mo stretchy="false">)</mo><mo>%</mo></math>, representing a fourfold precision improvement over the previous BESIII measurement. A search for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in the decay rate yields <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="script">A</mi><mrow><mi>C</mi><mi>P</mi></mrow><mi>dir</mi></msubsup><mo>=</mo><mo stretchy="false">(</mo><mn>1.5</mn><mo>±</mo><msub><mn>1.0</mn><mrow><mi>stat</mi></mrow></msub><mo>±</mo><msub><mn>1.0</mn><mrow><mi>syst</mi></mrow></msub><mo stretchy="false">)</mo><mo>%</mo></math>. No evidence for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation is observed in this inclusive charm baryon decay. The subscripts ‘stat’ and ‘syst’ denote statistical and systematic uncertainties, respectively.

China

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Italy

C.S. Akondi

Germany

R. Aliberti

A. Amoroso

Q. An

Y.H. An

Y. Bai

JINR

O. Bakina

Y. Ban

H.R. Bao

X.L. 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

W. Chen

X.R. Chen

X.T. Chen

X.Y. Chen

Y.B. Chen

Y.Q. Chen

Z.K. Chen

J. 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.Q. 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

Precision Studies and Searches for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> Asymmetries in the Inclusive Decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Λ</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><mi mathvariant="normal">Λ</mi><mi>X</mi></math>

We present a study of two-body decay widths of heavy baryons into another heavy baryon and a light pseudoscalar meson in the framework of the non-relativistic quark model in combination with the elementary emission model for the strong couplings. The present study includes the decays of 1$\textit{S}$- and 1$\textit{P}$-wave baryons with one or two heavy quarks, either charm ($\textit{c}$) or bottom ($\textit{b}$). The flavor, spin and orbital contributions are discussed explicitly as well as selection rules for forbidden decays. The relative partial widths are given by the appropriate flavor $\textit{SU}$(3) isoscalar factors. The total widths are compared with the available experimental data as well as with other theoretical studies. The calculated widths of singly-heavy baryons are found to be in reasonable agreement with the observed widths. The decay widths of doubly-heavy baryons are suppressed with respect to those of the singly-heavy baryons by the ratios of the quark masses appearing in the orbital contributions.

Hungary

Emmanuel Ortiz-Pacheco

Mexico

Roelof Bijker

Strong decay widths of $\textit{S}$- and $\textit{P}$-wave singly- and doubly-heavy charm and bottom baryons

The production of exotic hadrons <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mi>c</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></math> in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>7</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> is compared using the parton and hadron cascade model together with the dynamically constrained phase-space coalescence model. In the simulation, the compact tetraquark state and the loose molecular state are formed in the partonic and hadronic levels, respectively. Our analysis of the transverse momentum spectra reveals a significant discrepancy between the compact state and the molecular states. Furthermore, the production asymmetry between <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>T</mi><mrow><mi>c</mi><mi>c</mi></mrow><mo>+</mo></msubsup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>T</mi><mrow><mi>c</mi><mi>c</mi></mrow><mo>−</mo></msubsup></math> is investigated. Finally, the coalescence parameters are extracted from the calculated spectra to further characterize the emission source properties. These distributions are proposed as valuable criteria for distinguishing between these states and investigating their internal structures in experimental measurements.

Hongge Xu

Tianqi Luo

Yi-Long Xie

Zhi-Lei She

Ning Yu

Zuman Zhang

Comparative study of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>T</mi><mrow><mi>c</mi><mi>c</mi></mrow></msub></math> versus <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></math> production in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>7</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math>

<math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi>t</mi></msub></math>-differential quantity <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>v</mi><mn>2</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>t</mi></msub><mo>)</mo></mrow></mrow></math> is meant to measure elliptic flow manifested by a dense QCD medium formed in high-energy nucleus-nucleus collisions. Elliptic flow may be referred to more neutrally as a cylindrical quadrupole component of the transverse motion of particle sources within a collision. As defined, <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>v</mi><mn>2</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>t</mi></msub><mo>)</mo></mrow></mrow></math> relies on an implicit assumption that almost all produced particles emerge from a single source. This article describes a detailed study of the algebraic structure of <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>v</mi><mn>2</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>t</mi></msub><mo>)</mo></mrow></mrow></math>. A procedure is developed to derive a common monopole boost (“radial flow”) value and quadrupole <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mi>t</mi></msub></math> spectra for several hadron species. The method is applied to <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>v</mi><mn>2</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>t</mi></msub><mo>)</mo></mrow></mrow></math> data for four hadron species from 2.76-TeV Pb-Pb collisions. According to available <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>v</mi><mn>2</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>t</mi></msub><mo>)</mo></mrow></mrow></math> data the assumption of a single dominant particle source within <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>A</mi></mrow><mtext>−</mtext><mrow><mi>A</mi></mrow></math> collisions is unjustified. Combined with a previous study of quadrupole amplitude variation for 200-GeV <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mtext>−</mtext><mi>p</mi></mrow></math> collisions these results demonstrate that quadrupole structure is related to a novel QCD process separate from projectile-nucleon dissociation and jet production. Given quadrupole evolution it is unlikely that a hydrodynamic description is relevant to that process.

Thomas A. Trainor

Quadrupole spectra derived from 2.76-TeV Pb-Pb identified-hadron <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mi>v</mi><mn>2</mn></msub><mrow><mo>(</mo><msub><mi>p</mi><mi>t</mi></msub><mo>)</mo></mrow></mrow></math> data

We have achieved a unified description of 26P from nuclear structure to reaction dynamics by combining the self-consistent relativistic mean-field theory in the complex momentum representation (RMF-CMR) with the Glauber model. First, using the RMF-CMR theory, we calculated the structural properties of 26P and provided strong evidence for its proton halo structure dominated by the 2 <italic>s</italic> <inf>1/2</inf> orbital. Subsequently, the nucleon density distributions and valence-nucleon wave functions obtained from RMF-CMR calculations were used as input to the Glauber model to predict experimental observables. The results show that the narrow longitudinal momentum distribution of the fragment following one-proton removal from 26P corresponds to its diffuse density distribution and the configurational mixture distribution of the momentum distribution is also investigated. Furthermore, the calculated reaction and one-proton removal cross sections reveal a pronounced increase in 26P compared to the differences observed among 25Si, 24Al, and 23Mg. These findings validate the feasibility of the combined RMF-CMR and Glauber model approach for investigating proton-rich exotic nuclear properties.

Zhe Wang

Jian-You Guo

A unified description of proton-halo nucleus 26P from structure to reactions

We present hydrodynamic predictions for the new observable <italic>v</italic> <inf>02</inf>( <italic>p<inf>T</inf></italic>), which measures the correlation of particle spectra with elliptic flow. We implement a data-driven correction so as to match hydrodynamic calculations to elliptic flow ( <italic>v</italic> <inf>2</inf>( <italic>p<inf>T</inf></italic>)) data. The corrected results are in fair agreement with <italic>v</italic> <inf>0</inf>( <italic>p<inf>T</inf></italic>) data up to high <italic>p<inf>T</inf></italic>. We make predictions for <italic>v</italic> <inf>02</inf>( <italic>p<inf>T</inf></italic>) of unidentified charged hadrons up to <math altimg='si2.svg'><mrow><msub><mi>p</mi><mi>T</mi></msub><mo linebreak='goodbreak'>=</mo><mn>10</mn></mrow></math> GeV/ <italic>c</italic>, and of pions, kaons and protons up to <math altimg='si3.svg'><mrow><msub><mi>p</mi><mi>T</mi></msub><mo linebreak='goodbreak'>=</mo><mn>5</mn><mo linebreak='goodbreak'>&#8722;</mo><mn>6</mn></mrow></math> GeV/ <italic>c</italic>, in several centrality windows, for Pb+Pb collisions at <math altimg='si4.svg'><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo linebreak='goodbreak'>=</mo><mn>5.02</mn></mrow></math> TeV. We predict a decrease of <italic>v</italic> <inf>02</inf>( <italic>p<inf>T</inf></italic>) of charged hadrons for <italic>p<inf>T</inf></italic>&#8239;&gt;&#8239;4 GeV/ <italic>c</italic> and meson-baryon splitting for <italic>p<inf>T</inf></italic>&#8239;&gt;&#8239;3 GeV/ <italic>c</italic> in mid-central collisions. We also predict a non-monotonic variation of <italic>v</italic> <inf>02</inf>( <italic>p<inf>T</inf></italic>) for protons at low <italic>p<inf>T</inf></italic> above 30% centrality. This is a specific feature of this new observable, which is not observed for the usual flow observables <italic>v</italic> <inf>2</inf>( <italic>p<inf>T</inf></italic>) and <italic>v</italic> <inf>0</inf>( <italic>p<inf>T</inf></italic>).

Rupam Samanta

Tribhuban Parida

France

Jean-Yves Ollitrault

Enhanced hydrodynamic predictions for <italic>v</italic> <inf>02</inf>( <italic>p<inf>T</inf></italic>)

We calculate the fragmentation functions for a gluon into $\textit{P}$-wave $\textit{B}$ mesons within the nonrelativistic QCD factorization framework, incorporating color-singlet and color-octet contributions. Ultraviolet divergences arising from phase-space integrals are removed via operator renormalization in the modified minimal subtraction scheme. The resulting fragmentation functions are presented in both graphical form and as fitted analytic expressions.

Xu-Chang Zheng

Xing-Gang Wu

Fragmentation functions for gluon into $\textit{P}$-wave $\textit{B}$ $\textit{c}$ mesons

A precision measurement of the muon charge asymmetry from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-boson decays in proton-proton collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></math> is presented. The analysis utilizes data corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>5.1</mn><mtext> </mtext><mtext> </mtext><msup><mrow><mi>fb</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math>, recorded by the LHCb detector during 2016, 2017, and 2018. The asymmetry is measured for muons with transverse momentum between 25 and 55 GeV and pseudorapidity between 2.0 and 4.5. This result represents the most precise determination of the muon charge asymmetry in the forward region to date, exhibiting excellent agreement with next-to-next-to-leading-order predictions in perturbative quantum chromodynamics. The measured asymmetries are corrected for experimental efficiencies, resolution, and final-state photon radiation.

Netherlands

R. Aaij

M. Abdelfatah

A.S.W. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

A.A. Adefisoye

Spain

B. Adeva

M. Adinolfi

C. Agapopoulou

C.A. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

P. Albicocco

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

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

Z.B. Bai

P. Baladron Rodriguez

V. Balagura

Precision Measurement of the Muon Charge Asymmetry from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math>-Boson Decays in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> Collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>13</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math> in the Forward Region