In this work, we investigate the production and decay of molecular states with quark content $cc\bar c\bar q$ and $J^P=1^+$ using a phenomenological analysis and an effective Lagrangian approach. Based on an $\textit{SU}$(3) flavor-symmetry analysis to identify golden channels, we further explore the dynamics of these processes under the molecular assumptions of ${\eta_c D^*}$ and ${J/\psi D^*}$ . Our results indicate that the production branching ratio in $B_c$ decays is sizable: it can be of order $10^{-4}$ for the molecular configuration ${{\eta}_cD^*}$ and $10^{-5}$ for the molecule ${J/\psi D^*}$ . In addition, we find that the decay widths of the two molecular configurations ${{\eta}_cD^*}$ and ${J/\psi D^*}$ are not significant, at the level of ${\cal{O}}$ ( $\text{MeV}$ ).

China

Na Li

Ye Xing

Jing-Rui Shi

Analysis of molecular state $\textit{η$_{c}$D}$ $^{*}$ and $\textit{J}$/$\textit{ψD}$ $^{*}$ in the effective Lagrangian approach * Supported by the National Natural Science Foundation of China (NSFC) (12005294)

The collinear and transverse-momentum-dependent jet fragmentation function and the radial profile for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup></math> mesons in jets are measured. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup></math> mesons are reconstructed through the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow><mo stretchy="false">(</mo><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup><mo stretchy="false">)</mo><msup><mi>K</mi><mo>±</mo></msup></math> decay channel using proton-proton collision data collected during 2016–2018 with the LHCb detector at a center-of-mass (c.m.) energy of <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>, corresponding to an integrated luminosity of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>5.4</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math>. The results complement recent measurements of jet fragmentation functions for heavy-flavor hadrons and suggest a growing contribution of gluon fragmentation to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup></math> mesons as the jet transverse momentum increases.

Netherlands

R. Aaij

United Kingdom

A.S.W. Abdelmotteleb

Switzerland

C. Abellan Beteta

F. Abudinén

T. Ackernley

United States

A.A. Adefisoye

Spain

B. Adeva

M. Adinolfi

P. Adlarson

France

C. Agapopoulou

C.A. Aidala

Z. Ajaltouni

S. Akar

K. Akiba

Italy

P. Albicocco

Germany

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

M. Arias

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

Z.B. Bai

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

I.R. Barbosa

R.J. Barlow

M. Barnyakov

S. Barsuk

W. Barter

J. Bartz

Poland

S. Bashir

B. Batsukh

P.B. Battista

A. Bavarchee

A. Bay

A. Beck

M. Becker

F. Bedeschi

I.B. Bediaga

N.A. Behling

S. Belin

A. Bellavista

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

A. Bertolin

F. Betti

J. Bex

O. Bezshyyko

S. Bhattacharya

M.S. Bieker

N.V. Biesuz

A. Biolchini

M. Birch

F.C.R. Bishop

A. Bitadze

A. Bizzeti

T. Blake

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math>-jet fragmentation with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>B</mi><mo>±</mo></msup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><msup><mi>K</mi><mo>±</mo></msup></math> decays in <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> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>p</mi><mi>p</mi></math> collisions at LHCb

New threshold measurements for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>γ</mi><mi>p</mi><mo stretchy="false">→</mo><mi>p</mi><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>p</mi><mo stretchy="false">(</mo><msup><mrow><mi>μ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>μ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">)</mo></mrow></math> by 007 and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>γ</mi></mrow><mrow><mo>*</mo></mrow></msup><mi>p</mi><mo stretchy="false">→</mo><mi>p</mi><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>p</mi><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><mo stretchy="false">)</mo></mrow></math> by CLAS12 allow us to extend the previous phenomenological determination of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">J</mi><mo>/</mo><mi>ψ</mi></math>-proton scattering length, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>α</mi><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>p</mi></mrow></msub></math>, using GlueX threshold data for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>γ</mi><mi>p</mi><mo stretchy="false">→</mo><mi>p</mi><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>p</mi><mo stretchy="false">(</mo><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">)</mo></math>. The agreement between all three <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">J</mi><mo>/</mo><mi>ψ</mi></math> datasets shows no indication of systematic differences between methodologies. Furthermore, perturbative QCD predictions support the phenomenological determination of heavy vector meson-nucleon scattering lengths. The role of the nucleon form factor, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>F</mi><mi>N</mi></msub></math>, is discussed, and a possible correction to the phenomenological scattering length for heavy vector meson photoproduction is calculated using the pole form of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>F</mi><mi>N</mi></msub></math>. Upcoming J-PARC threshold measurements of the reaction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mtext> </mtext><mi>p</mi><mo stretchy="false">→</mo><mi>n</mi><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>n</mi><mo stretchy="false">(</mo><msup><mrow><mi>l</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>l</mi></mrow><mrow><mo>−</mo></mrow></msup><mo stretchy="false">)</mo></mrow></math> will help to evaluate the possible role of heavy pentaquark, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>P</mi><mi>c</mi></msub></math>, states in low-energy <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> production and the effects caused by the nucleon form factors.

Igor I. Strakovsky

William J. Briscoe

South Korea

Jung Keun Ahn

Russia

Misha G. Ryskin

Axel Schmidt

JLab and J-PARC measurements for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> production at threshold

We present measurements of the total and differential cross sections for near-threshold <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> photoproduction obtained with the CLAS12 detector at the Thomas Jefferson National Accelerator Facility. The results are based on data collected during the fall 2018 and spring 2019 running periods, using electron beams with energies of 10.6 and 10.2 GeV, respectively, scattered off a liquid-hydrogen target. Near-threshold <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> photoproduction offers a unique sensitivity to the strong interaction in the nonperturbative regime of quantum chromodynamics (QCD). The energy dependence of the cross section constrains the underlying <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> production mechanisms, including multigluon exchange and potential baryonic excitations. Additionally, the <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>t</mi></math> dependence of the differential cross section can be related to the transverse spatial distribution of gluons in the proton, providing critical input for theoretical descriptions of the gluonic structure of the proton. An interpretation of the results in terms of the gluon content of the proton is presented, providing new experimental constraints on QCD-inspired models of the proton structure and the role of gluonic degrees of freedom in hadronic mass generation.

P. Chatagnon

V. Kubarovsky

R. Paremuzyan

S. Stepanyan

M. Tenorio

R. Tyson

A.G. Acar

P. Achenbach

J.S. Alvarado

M.J. Amaryan

W.R. Armstrong

H. Avakian

N.A. Baltzell

L. Barion

M. Bashkanov

M. Battaglieri

F. Benmokhtar

A. Bianconi

A.S. Biselli

S. Boiarinov

M. Bondi

F. Bossù

K.-Th. Brinkmann

W.J. Briscoe

S. Bueltmann

V.D. Burkert

T. Cao

D.S. Carman

A. Celentano

H. Chinchay

G. Ciullo

P.L. Cole

A. D'Angelo

Armenia

N. Dashyan

M. Defurne

R. De Vita

A. Deur

S. Diehl

C. Dilks

C. Djalali

M. Dugger

R. Dupré

H. Egiyan

M. Ehrhart

Chile

A. El Alaoui

L. El Fassi

L. Elouadrhiri

M. Farooq

S. Fegan

R.F. Ferguson

I.P. Fernando

E. Ferrand

A. Filippi

C. Fogler

K. Gates

G.P. Gilfoyle

D.I. Glazier

R.W. Gothe

Y. Gotra

B. Gualtieri

K. Hafidi

H. Hakobyan

F. Hauenstein

T.B. Hayward

D. Heddle

M. Hoballah

D. Holmberg

M. Holtrop

C.E. Hyde

Measurement of the near-threshold <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>J</mi><mo>/</mo><mi>ψ</mi></mrow></math> photoproduction cross section with the CLAS12 experiment