From December 8 to 10, 2025, an international workshop on hadron physics at J-PARC (J-PARC Hadron 2025) was held at the Osaka University Convention Center. The third session of the J-PARC Hadron series focused on the theme “Femtoscopy and J-PARC Hadron Experiments.” Hadron interactions are, needless to say, fundamental and essential in hadron physics research. In recent years, a new experimental method called “Femtoscopy,” which utilizes nuclear collisions to study hadron interactions, has been gaining attention. Additionally, research on hyperon-nucleon interactions through scattering experiments was conducted successfully at the J-PARC Hadron Hall. Research on interactions using Lattice QCD and effective field theories has also advanced. Involving many theorists, lively discussions were held on the physics of both complementary approaches. Furthermore, heated discussions covered a wide range of related topics: the physics of hadron many-body systems studied at J-PARC (hypernuclei and kaonic nuclei, and the properties of hadrons in nuclear media), the physics of high-density nuclear matter and neutron stars, and exotic hadrons whose discoveries are continuing worldwide today, including those from the Belle experiment. 

Notably, Prof. Laura Fabbietti (Technical University of Munich), who leads the Femtoscopy experiments, participated in person and provided a detailed explanation of the analysis methods used in Femtoscopy. Thanks to her, many participants gained a deeper understanding of the Femtoscopy experiments. 

As a new initiative this year, we established the “Young Scientist Award” for students, postdocs, and others. We wish the three award recipients, all those who entered the award, and all the young participants every success in advancing their research. (See the workshop website for award results.) 

Additionally, at the post-workshop “Femtoscopy Physics” held at the Research Center for Nuclear Physics (RCNP) in Osaka University on December 11th, four speakers, including Prof. Fabbietti, gave in-depth presentations in a seminar format. The workshop was so exciting, and various ideas emerged there which included the potential for femtoscopy experiments at J-PARC. The future development of both femtoscopy and J-PARC hadron experiments is highly anticipated. 

Unfortunately, due to some circumstances, our Chinese participants were unable to attend in person just before the workshop. However, most switched to online participation and delivered their presentations. During breaks, participants enjoyed lively discussions regardless of nationality, with laughter heard throughout the venue as they deepened their exchanges. We hope this workshop contributes to further development in the research of all participants. 

・Workshop website:

　・Main workshop https://kds.kek.jp/event/54304/

　・Post workshop https://kds.kek.jp/event/57795/

・Participant Information:

・Total Participants: 100 (On-site: 65, Online: 35)

  ・Participating Countries: Asia (Japan, China, South Korea, Indonesia),

Europe (Germany, Spain, Czech Republic, Italy)