Workshop on Origin of Hadron Mass - Experimental Opportunities and Theoretical Challenges

27 Sept 2026, 09:30 → 30 Sept 2026, 15:30 Asia/Tokyo

Science Knot 2F Conference Room (Hiroshima University)

Abhay Deshpande (Stony Brook University & BNL), Kenta Shigaki (Hiroshima University), Taku Gunji (Center for Nuclear Study, the University of Tokyo)

The timetable is posted.  Please see the "Timetable" tab on the menu.

The excellent list of invited speakers is posted.  Please see the "Invited Speakers" tab on the menu.

Understanding the origin of mass in QCD is one of the central goals of modern nuclear physics. Importantly, most of the mass of visible matter does not come from the Higgs mechanism or from the small masses of the up and down quarks. Instead, it emerges dynamically from QCD through quark-gluon interactions, confinement, and spontaneous chiral symmetry breaking.

There is no single experimental technique that directly "measures the origin of mass." Rather, several complementary approaches probe different aspects of the problem. The goal of this workshop is to bring people involved in different approaches together and try to understand the complementarity of different techniques.

Today, the most promising experimental routes to understanding the origin of QCD mass include, though not limited to:

1. Threshold J/ψJ/ψ production → direct probe of gluonic mass generation and the trace anomaly.

2. Exclusive electron scattering (DVCS, vector mesons) → access to energy-momentum tensor form factors, pressure, and mass distributions.

3. Precision DIS at the EIC → determine how quarks and gluons generate the proton's mass, momentum, and structure.

4. Hadron spectroscopy → reveal how confinement generates hadron masses.

5. Heavy-ion collisions → study what happens when the mechanisms responsible for mass generation are switched off.

 

Together, these approaches attack the same fundamental question from different angles: how mass emerges from nearly massless quarks and massless gluons through the dynamics of QCD.

Based on this big picture, we host a 4 day workshop. There should be time for discussion after each talk and then a recap or a broader discussion at end of the day.

The registration deadline is Friday, September 18, 2026.

This workshop is supported by WPI-SKCM², Hiroshima University,  Quark-Nuclear Science Institute (QNSI), the University of Tokyo, and by KAKENHI International Leading Research "Origins of Matter Explored through Femtoscale Quantum Many-Body Systems - Nurturing Talent in the Quantum Era".

Sunday 27 September

13:00 → 13:30 welcome: Welcome

13:00 Welcome and Opening Address

Speaker: Takahiro Iwata (Hiroshima University)

13:15 Welcome and Logistics

Speaker: Kenta Shigaki (Hiroshima University)

13:30 → 15:45 scientific: Session 1 - Introductory Overview / Lattice-QCD Calculations Constrained by Experiments

13:30 (Introductory Overview)

Speaker: Xiangdong Ji (Shanghai Jiao Tong University)

14:45 (Lattice-QCD Calculations Constrained by Experiments)

Speaker: Sungwoo Park (Sejong University)

15:45 → 16:15 coffee break

16:15 → 18:15 scientific: Session 2 - Deep Inelastic Scattering and Electron-Ion Collisions

16:15 Gravitational Form Factors in NNLO QCD Constrained by the DIS Data and Hadron Mass Decompositions

Speaker: Kazuhiro Tanaka (Juntendo University)

17:15 (Deep Inelastic Scattering and Electron-Ion Collisions)

Speaker: Ralf Seidl (University of Tokyo QNSI)

18:30 → 20:30 welcome reception

Monday 28 September

09:30 → 11:30 scientific: Session 3 - Gravitational Form Factors and Mechanical Structure Measurements / Ultra Peripheral Collisions

09:30 Gravitational Form Factors of the Nucleons and Nuclei (remote)

Speaker: Yoshitaka Hatta (Brookhaven National Laboratory)

10:30 (Ultra Peripheral Collisions)

Speaker: Zhangbu Xu (Kent State University)

11:30 → 13:00 lunch break

13:00 → 15:00 scientific: Session 4 - Heavy-Ion Collisions

13:00 (Heavy-Ion Collisions)

Speaker: Swagato Mukherjee (Brookhaven National Laboratory)

14:00 Overview of STAR Dilepton Measurements

Speaker: Lijuan Ruan (Brookhaven National Laboratory)

15:00 → 15:30 coffee break

15:30 → 17:30 scientific: Session 5 - Heavy-Ion Collisions

15:30 Correlations of Energy Flow in Jets and the Hadronization Process

Speaker: Barbara Jacak (Lawrence Berkeley National Laboratory)

16:30 (Heavy-Ion Collisions)

Speaker: Gianluca Usai (INFN Cagliari)

Tuesday 29 September

09:30 → 11:30 scientific: Session 6 - Origin of QCD Mass

09:30 (Origin of QCD Mass) (remote)

Speaker: Dmitri Kharzeev (University of Connecticut)

10:30 (Origin of QCD Mass)

Speaker: Zein-Eddine Meziani (Argonne National Laboratory)

11:30 → 13:00 lunch break

13:00 → 15:30 scientific: Session 7 - Short Talk / Meson Structure Measurements

13:00 (Short Talk)

Speaker: Chen Yang (University of Maryland, College Park)

13:30 (Meson Structure Measurements)

Speaker: Parada Hutauruk (Hiroshima University)

14:30 (Meson Structure Measurements)

Speaker: Tanja Horn (The Catholic University of America)

15:30 → 16:00 coffee break

16:00 → 18:00 scientific: Session 8 - Quarkonium Production Near Threshold

16:00 (Quarkonium Production Near Threshold)

Speaker: Feng Yuan (Lawrence Berkeley National Laboratory)

17:00 (Quarkonium Production Near Threshold)

Speaker: Keigo Mizutani (RCNP, Osaka University)

19:00 → 21:30 workshop dinner

Wednesday 30 September

09:30 → 11:30 scientific: Session 9 - Hadron Spectroscopy

09:30 Chiral Symmetry and U(1)_A Anomaly in QCD and Some Related Topics in Hadron Spectroscopy

Speaker: Teiji Kunihiro (Yukawa Institute for Theoretical Physics, Kyoto University)

10:30 Experimental Highlights of Hadron Spectroscopy

Speaker: Yunxuan Song (University of Chinese Academy of Science)

11:30 → 13:00 lunch break

13:00 → 15:00 scientific: Session 10 - Non-Trivial Structure of QCD Vacuum and Nuclear Medium Effects

13:00 Two-Color QCD as a Laboratory to Explore Cold and Dense Matter

Speaker: Daiki Suenaga (KMI/Nagoya U.)

14:00 (Non-Trivial Structure of QCD Vacuum and Nuclear Medium Effects)

Speaker: Yoshiki Tanaka (RIKEN)

15:00 → 15:30 scientific: Closing

15:00 (Closing)

Speaker: Kenji Fukushima