Connecting the QCD vacuum with experimental observables through realistic proton-nucleus reaction simulations

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K03940
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Gubler Philipp 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 先端基礎研究センター, 研究職 (00632390)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 強い相互作用 / ベクトル・メソン / phi中間子 / 核物質 / カイラル対称性

Outline of Final Research Achievements

The purpose of this project was to perform numerical simulations of proton-nucleus (pA) reactions, making use of a state-of-the-art transport framework, that can particularly treat the off-shell dynamics of vector mesons, with the goal of studying the mass modification of the phi meson in nuclear matter. The result of this analysis can be used to constrain the order parameter of chiral symmetry of the strong interaction at finite density.
During the research period, we succeeded in conducting realistic transport simulations of the pA reactions probed at KEK and J-PARC, but found that for clearly determining the mass shift of the phi meson in nuclear matter, more work will be needed in the future, including the measurement of more precise dilepton data from pA reactions and the further development of pA reaction simulations.

Free Research Field

ハドロン物理学

Academic Significance and Societal Importance of the Research Achievements

The research of this project will help to clarify the the origin of the visible (hadronic) mass in our universe. This mass is thought to be generated by the spontaneous breaking of the chiral symmetry of the strong interaction, but this assumption has so far never been experimentally confirmed.